Chapter 44: Surgery of the Hand and Wrist

1. Surgery of the hand is a regional specialty, integrating components of neurologic, orthopedic, plastic, and vascular surgery.

2. Understanding hand anatomy is the key to proper diagnosis of injury, infection, and degenerative disease of the hand.

3. After evaluation and/or treatment, patients should be splinted to protect the injured digits and keep the collateral ligaments of the injured joints on tension (metacarpophalangeal joints flexed, interphalangeal joints extended).

4. Healing of an injured or diseased structure in the hand is not the endpoint of treatment; the goal of any intervention must be to obtain structure healing, relief of pain, and maximization of function.

5. If a patient managed conservatively for cellulitis does not improve within 24 to 48 hours of appropriate intravenous antibiotics, abscess must be suspected.

6. Clinical examination, particularly noting the area of greatest tenderness and/or inflammation, is the most useful diagnostic tool for hand infections.

The highly mobile, functional, and strong hand is a major distinguishing point between humans and the nonhuman primates. The hand is an essential participant for activities of daily living, vocation, and recreational activities. The hand is even adaptable enough to read for the blind and speak for the mute. The underlying goal of all aspects of hand surgery is to maximize mobility, sensibility, stability, and strength while minimizing pain. These goals are then maximized to the extent possible given the patient’s particular pathology. Hand surgery is a regional specialty. Hand surgeons integrate components of neurologic, orthopedic, plastic, and vascular surgery in the care of patients with disorders of the upper extremities.

In order to understand any disorder of the hand, one must understand the anatomy of the underlying structures. Examination of the hand is based on demonstrating the function or lack thereof of each of these structures.

Bones

The hand is highly mobile in space to allow maximum flexibility in function. As such, a number of directions particular to the hand are necessary in order to properly describe position, motion, and so on.¹ Palmar (or volar) refers to the anterior surface of the hand in the anatomic position; dorsal refers to the posterior surface in the anatomic position. The hand can rotate at the wrist level; rotation to bring the palm down is called pronation, rotation to bring the palm up is called supination. Because the hand can rotate in space, the terms medial and lateral are avoided. Radial and ulnar are used instead as these terms do not vary with respect to the rotational position of the hand. Abduction and adduction, when used on the hand, refer to movement of the digits away from and toward the middle finger, respectively (Fig. 44-1).

The hand is comprised of 19 bones arranged in five rays.² A ray is defined as a digit (finger or thumb) from the metacarpal base to the tip of the digit (Fig. 44-2A). The rays are numbered 1 to 5, beginning with the thumb. By convention, however, they are referred to by name: thumb, index, middle, ring, and small. There are five metacarpals, comprising the ­visible palm of the hand. Each digit has a proximal and a distal phalanx, but only the fingers have a middle phalanx as well. The metacarpophalangeal (MP) joint typically allows 90° of flexion with a small amount of hyperextension. In addition, the fingers can actively abduct (move away from the middle finger) and adduct (move toward the middle finger). The thumb, in contrast, moves principally in the flexion-extension arc at the MP joint. Although there can be laxity in the radial and ulnar direction, the thumb cannot actively move in these directions at the MP level. The proximal interphalangeal joint (PIP) is the critical joint for ­finger mobility. Normal motion is 0 to 95° (full extension to flexion). The distal interphalangeal joint (DIP) also moves only in a flexion-extension plane from 0 to 90° on average. The thumb interphalangeal joint (IP) also moves only in a flexion-extension plane. Its normal motion is highly variable between individuals, but averages 0 to 80°.

Each of the MP and IP joints has a radial and ulnar collateral ligament to support it. The IP joint collateral ligaments are on tension with the joint fully extended. For the fingers, the MP joint collateral ligaments are on tension with the joint bent 90°. Collateral ligaments have a tendency to contract when not placed on tension; this becomes relevant when splinting the hand (see later Trauma section on splinting).

The wrist consists of eight carpal bones divided into two rows (Fig. 44-2B).² The proximal row consists of the scaphoid, lunate, and triquetrum. The lunate is the principle axis of motion of the hand onto the forearm. It bears approximately 35% of the load of the wrist onto the forearm. The scaphoid is shaped like the keel of a boat and bears 55% of the load of the hand onto the forearm, but also serves as the principle link between the proximal and distal rows, allowing for motion while ­maintaining stability. Both the scaphoid and the lunate articulate with the radius. The triquetrum resides ulnar to the lunate. It does not interact with the ulna proximally; rather, it interacts with a cartilage suspended between the ulnar styloid and the distal radius called with triangular fibrocartilage complex (TFCC) (Fig. 44-2B). The remaining 10% of load of the hand onto the forearm is transmitted through the TFCC.³

The distal row consists of four bones. The trapezium resides between the scaphoid and the thumb metacarpal. Distally, it has a saddle-shaped surface, which interacts with a reciprocally saddle-shaped base of the thumb metacarpal to allow for high mobility of the thumb carpometacarpal (CMC) joint in radial-ulnar and palmar-dorsal directions and opposition (Fig. 44-1B). The trapezoid rests between the scaphoid and the index finger metacarpal. The capitate, the largest carpal bone and first to ossify in a child, lies between the lunate and the middle finger metacarpal, but also interacts with the scaphoid on its proximal radial surface. The index and middle finger CMC joints are highly stable and have minimal mobility. The hamate is the ulnar-most bone in the distal row, sitting between the triquetrum proximally and the ring and small finger metacarpals distally. The ring and small finger CMC joints are mobile, principally in the flexion-extension direction.

The pisiform is a carpal bone only by geography. It is a sesamoid bone within the FCU tendon (see below). It does not bear load and can be excised, when necessary, without consequence.

Muscles Affecting the Hand and Wrist

The wrist is moved by multiple tendons that originate from the forearm and elbow. The digits of the hand are moved by both intrinsic (originating within the hand) and extrinsic (originating in the forearm) muscles. All of these muscles are innervated by the median, radial, or ulnar nerves (or their branches) (Fig. 44-3).

Three muscles flex the wrist, all of which originate from the medial epicondyle of the humerus. The flexor carpi radialis (FCR, median nerve) inserts on the volar base of the index finger metacarpal. The flexor carpi ulnaris (FCU, ulnar nerve) also originates from the proximal ulna and inserts on the volar base of the small finger metacarpal. The palmaris longus (PL) tendon does not insert on a bone; it inserts on the palmar fascia, located deep to the skin in the central proximal palm, and is absent in up to 15% of patients. The FCR also deviates the wrist radially, whereas the FCU deviates the wrist ulnarly.

All three wrist extensors are innervated by the radial nerve or its branches. The extensor carpi radialis longus (ECRL) originates from the distal shaft of the humerus and inserts on the dorsal base of the index finger metacarpal. The extensor carpi radialis brevis (ECRB) originates from the lateral epicondyle of the humerus and inserts on the dorsal base of the middle finger metacarpal. The extensor carpi ulnaris (ECU) also originates from the lateral epicondyle of the humerus and inserts on the dorsal base of the small finger metacarpal. The ECRL deviates the wrist radially, whereas the ECU deviates the wrist ulnarly.

The long flexors of the fingers all originate from the medial epicondyle of the humerus. The flexor digitorum superficialis (FDS) inserts on the base of the middle phalanx of each finger and primarily flexes the PIP joint. The flexor digitorum profundus (FDP) inserts on the base of the distal phalanx and primarily flexes the DIP joint. The flexor pollicis longus (FPL) originates more distally, from the ulna, radius, and interosseous membrane between them in the forearm. It inserts on the base of the distal phalanx of the thumb and primarily flexes the IP joint. All of these tendons can also flex the more proximal joint(s) in their respective rays. All of these muscles are innervated by the median nerve (or its branches) except the FDP to the ring and small fingers, which are innervated by the ulnar nerve.

The extrinsic extensors of the fingers and thumb are all innervated by the posterior interosseous nerve (PIN, branch of the radial nerve). The extensor digitorum communis (EDC) originates from the lateral epicondyle of the humerus and extends the MP joints of the fingers. Unlike most tendons that attach directly into a bone, the EDC tendons do not insert on the dorsal base of the proximal phalanx, but rather into a soft tissue sling called the sagittal hood, which surrounds the proximal phalanx base and pulls up on the volar surface in a hammock-like ­manner. More distally in the dorsal forearm, the extensor indices proprius (EIP) and extensor digiti quinti (EDQ) originate from the ulna, radius, and posterior interosseous membrane and insert on the sagittal hood of the index and small fingers, respectively.

The thumb has three separate extrinsic extensors. All of these originate from the dorsal ulna in the mid-forearm and are innervated by the PIN. The abductor pollicis longus (APL) inserts on the radial base of the thumb metacarpal to produce some extension, but mostly abduction. The extensor pollicis brevis (EPB) inserts on the base of the thumb proximal ­phalanx. The extensor pollicis longus (EPL) inserts on the base of the thumb distal phalanx.

The intrinsic muscles of the hand are what allow humans fine, subtle movements of the hand. Microsurgery, typing, and even video gaming would be difficult, if not impossible, without them.

The thenar muscles originate from the volar radial surface of the scaphoid and trapezium and the flexor retinaculum. The abductor pollicis brevis (APB) inserts on the radial base of the thumb proximal phalanx and abducts the thumb in a radial and volar direction. The opponens pollicis (OP) inserts on the radial distal aspect of the thumb metacarpal and draws the thumb across the palm toward the small finger. The flexor pollicis ­brevis (FPB) inserts on the base of the thumb proximal phalanx and flexes the thumb MP joint. The APB, OP, and superficial head of the FPB are all innervated by the thenar motor branch of the median nerve.

The lumbrical muscles are unique in the body in that they originate from a tendon. Each finger’s lumbrical originates from the FDP tendon in the palm. The lumbrical tendon passes along the radial aspect of the digit to flex the MP and extend the IP joints. The index and middle lumbricals are median nerve innervated, and the ring and small finger lumbricals are ulnar nerve innervated.

The hypothenar muscles originate from the pisiform, hamate, and flexor retinaculum and insert on the ulnar base of the small finger proximal phalanx. The abductor digiti quinti (ADQ) abducts the small finger. The opponens digiti quinti (ODQ) brings the small finger across the palm in reciprocal motion to the OP. The flexor digiti quinti (FDQ) flexes the small finger metacarpal. All of these muscles are innervated by the ulnar nerve.

The interosseous muscles occupy the space between the metacarpal bones. Their tendons insert on the bases of the proximal phalanges. All act to flex the MP joints and extend the IP joints. The three palmar interosseous muscles adduct the fingers. The four dorsal interosseous muscles abduct the fingers. The adductor pollicis originates from the middle finger metacarpal and inserts on the ulnar base of the thumb proximal phalanx. It acts to adduct the thumb. All of these muscles, as well as the deep head of the FPB, are innervated by the ulnar nerve.

Tendons and Pulleys

Multiple pulleys pass over or surround the extrinsic tendons en route to or within the hand. There purpose is to maintain tendon position near the bone, allowing maximal translation of tendon excursion into joint motion.

The most well known of the wrist-level pulleys is the flexor retinaculum, also known as the transverse carpal ­ligament. It attaches to the scaphoid tubercle and trapezium radially and the hook of the hamate bone and pisiform ulnarly. Deep to this ligament, between the scaphoid (radially) and the hamate (ulnarly), pass the FDS, FDP, and FPL tendons as well as the median nerve. This area is also known as the carpal tunnel (see Fig. 44-3).

On the dorsum of the wrist, the extensor retinaculum is divided into six compartments. Beginning on the radial aspect of the radius, the first compartment contains the APL and EPB tendons. The second holds the ECRL and ECRB tendons. The EPL passes through the third compartment. The fourth compartment contains the EIP and EDC tendons, the fifth the EDQ, and the sixth the ECU. The sixth compartment is located on the ulnar aspect of the distal ulna. Although the compartments end at the radiocarpal/ulnocarpal joints, the relative geography of the tendons is preserved over the carpal bones (see Fig. 44-3).

In the hand, the pulleys maintain the long flexor tendons in close apposition to the fingers and thumb. There are no extensor pulleys within the hand. Each finger has five annular and three cruciate pulleys (Fig. 44-4). The second and fourth (A2 and A4) pulleys are the critical structures to prevent bowstringing of the finger.⁴ The remaining pulleys can be divided as needed for ­surgical exposure or to relieve a stricture area.

Vascular

Two major arteries serve the hand. The radial artery travels under the brachioradialis muscle in the forearm. At the junction of the middle and distal thirds of the forearm, the artery becomes superficial and palpable, passing just radial to the FCR tendon. At the wrist level, the artery splits into two branches. The smaller, superficial branch passes volarly into the palm to contribute to the superficial palmar arch. The larger branch passes dorsally over the scaphoid bone, under the EPL and EPB tendons (known as the anatomic snuffbox) and back volarly between the proximal thumb and index finger metacarpals to form the superficial palmar arch.

The ulnar artery travels deep to the FCU muscle in the forearm. When the FCU becomes tendinous, the ulnar artery resides deep and slightly radial to it. At the wrist, the artery travels between the hamate and pisiform bones superficial to the transverse carpal ligament (known as Guyon’s canal) into the palm. The larger, superficial branch forms the superficial palmar arch. The deeper branch contributes to the deep palmar arch (Fig. 44-5A). In 97% of patients, at least one of the deep or superficial palmar arches is intact, allowing for the entire hand to survive on the radial or ulnar artery.⁵

Each digit receives a radial and ulnar digital artery. For the thumb, the radial digital artery may come from the deep palmar arch or the main body of the radial artery. The larger ulnar digital artery comes off the deep arch as either a discrete unit, the princeps pollicis artery, or less frequently as the first common digital artery, which then splits into the radial digital artery to the index finger and the ulnar digital artery to the thumb. The second, third, and fourth digital arteries typically branch off the superficial palmar arch and pass over the similarly named interosseous spaces respectively, ultimately dividing into two proper digital arteries each. The ulnar digital artery of the small finger comes off as a separate branch from the superficial arch. Within the finger, the proper digital arteries travel lateral to the bones and tendons, just palmar to the midaxis of the digit, but dorsal to the proper digital nerves (Fig. 44-5B).

Nerve

Three principal nerves serve the forearm, wrist, and hand: the median, radial, and ulnar nerves. The most critical of these from a sensory standpoint is the median nerve. The median nerve begins as a terminal branch of the medial and lateral cords of the brachial plexus. It receives fibers from C5–T1. The palmar cutaneous branch of the median nerve separates from the main body of the nerve 6 cm proximal to the volar wrist crease and serves the proximal, radial-sided palm. The main body of the median nerve splits into several branches after the carpal tunnel: a radial digital branch to the thumb, an ulnar digital nerve to the thumb, and a radial digital nerve to the index finger (sometimes beginning as a single first common digital nerve); the second common digital nerve that branches into the ulnar digital nerve to the index finger and the radial digital nerve to the middle finger; and a third common digital nerve that branches into the ulnar digital nerve to the middle finger and a radial digital nerve to the ring finger. The digital nerves provide volar-sided sensation from the metacarpal head level to the tip of the digit. They also, through their dorsal branches, provide dorsal-sided sensation to the ­digits from the midportion of the middle phalanx distally via dorsal branches. The thenar motor branch of the median nerve most commonly passes through the carpal tunnel and then travels in a recurrent fashion back to the thenar muscles. Less commonly, the nerve passes through or proximal to the transverse carpal ligament en route to its muscles.

In the forearm, the median nerve gives motor branches to all of the flexor muscles except the FCU, and the ring and small finger portions of the FDP. Distal median motor fibers (with the exception of those to the thenar muscles) are carried through a large branch called the anterior interosseous nerve.

The ulnar nerve is a terminal branch of the medial cord of the brachial plexus. It receives innervation from C8 and T1 roots. The FCU and FDP (ring/small) receive motor fibers from the ulnar nerve. In the distal forearm, 5 cm above the head of the ulna, the nerve gives off a dorsal sensory branch. Once in the hand, the nerve splits into the motor branch and sensory branches. The motor branch curves radially at the hook of the hamate bone to innervate the intrinsic muscles, as described ­earlier. The sensory branches become the ulnar digital nerve to the small finger and the fourth common digital nerve, which splits into the ulnar digital nerve to the ring finger and the radial digital nerve to the small finger. The sensory nerves provide distal dorsal sensation similar to the median nerve branches.

The radial nerve is the larger of two terminal branches of the posterior cord of the brachial plexus. It receives fibers from C5–T1 nerve roots. It innervates all of the extensor muscles of the forearm and wrist through the PIN branch except for the ECRL, which is innervated by the main body of the radial nerve in the distal upper arm. There is no ulnar nerve contribution to extension of the wrist, thumb, or finger MP joints. As noted earlier, the ulnar innervated intrinsic hand muscles are the principle extensors of the finger IP joints, although the long finger extensors (EDC, EIP, EDQ) make a secondary contribution to this function.

In the proximal dorsal forearm, the superficial radial nerve (SRN) is the other terminal branch of the radial nerve. It travels deep to the brachioradialis muscle until 6 cm proximal to the radial styloid, where it becomes superficial. The SRN provides sensation to the dorsal hand and the radial three and a half digits up to the level of the mid-middle phalanx (where the dorsal branches of the proper digital nerves take over, as described earlier). The dorsal branch of the ulnar nerve provides sensation to the ulnar one and a half digits and dorsal hand in complement to the SRN.

Emergency Room/Inpatient Consultation

A common scenario in which the hand surgeon will be introduced to the patient is in trauma or other acute situations. The patient is evaluated by inspection, palpation, and provocative testing.

On inspection, one should first note the position of the hand. The resting hand has a normal cascade of the fingers, with the small finger flexed most and the index finger least (Fig. 44-6). Disturbance of this suggests a tendon or skeletal problem. Also note any gross deformities or wounds and what deeper structures, if any, are visible in such wounds. Observe for abnormal coloration of a portion or all of the hand (this can be confounded by ambient temperature or other injuries), edema, and/or clubbing of the fingertips.

Palpation typically begins with the radial and ulnar artery pulses at the wrist level. Pencil Doppler examination can supplement this and evaluate distal vessels. A pulsatile signal is normally detectable by pencil Doppler in the pad of the finger at the center of the whorl of creases. Discrepancies between digits should be noted. If all other tests are inconclusive, pricking the involved digit with a 25-gauge needle should produce bright red capillary bleeding. If an attached digit demonstrates inadequate or absent blood flow (warm ischemia), the urgency of completing the evaluation and initiating treatment markedly increases.

Sensation must be evaluated prior to any administration of local anesthetic. At a minimum, light and sharp touch sensation should be documented for the radial and ulnar aspects of the tip of each digit. Beware of writing “sensation intact” at the conclusion of this evaluation. Rather, one should document what was tested (e.g., “light and sharp touch sensation present and symmetric to the tips of all digits of the injured hand”). In the setting of a sharp injury, sensory deficit implies a lacerated structure until proven otherwise. Once sensation has been evaluated and documented, the injured hand can be anesthetized for patient comfort during the remainder of the examination (see below).

Ability to flex and extend the wrist and digital joints is typically examined next. At the wrist level, the FCR and FCU tendons should be palpable during flexion. The wrist extensors are not as readily palpated due to the extensor retinaculum. Ability to flex the DIP joint (FDP) is tested by blocking the finger at the middle phalanx level. To test the FDS to each finger, hold the remaining three fingers in slight hyperextension and ask the patient to flex the involved digit (Fig. 44-7). This maneuver makes use of the fact that the FDP tendons share a common muscle belly. Placing the remaining fingers in extension prevents the FDP from firing, and allows the FDS, which has a separate muscle belly for each tendon, to fire. Strength in grip, finger abduction, and thumb opposition is tested and compared to the uninjured side. Range of motion for the wrist, MP, and IP joints should be noted and compared to the opposite side.

If there is suspicion for closed space infection, the hand should be evaluated for erythema, swelling, fluctuance, and localized tenderness. The dorsum of the hand does not have fascial septae; thus dorsal infections can spread more widely than palmar ones. The epitrochlear and axillary nodes should be palpated for enlargement and tenderness. Findings for specific infectious processes will be discussed in the Infections section.

Additional exam maneuvers and findings, such as those for office consultations, will be discussed with each disease process covered later in this chapter.

Plain X-Rays

Almost every hand evaluation should include plain X-rays of the injured or affected part. A standard, anteroposterior, lateral, and oblique view of the hand or wrist (as appropriate) is rapid, inexpensive, and usually provides sufficient information about the bony structures to achieve a diagnosis in conjunction with the symptoms and findings.⁶

Lucencies within the bone should be noted. Most commonly, these represent fractures, but they can on occasion represent neoplastic or degenerative processes. Great care should be taken to evaluate the entire X-ray, typically beginning away from the area of the patient’s complaint. Additional injuries can be missed, which might affect the treatment plan selected and eventual outcome.

Congruency of adjacent joints should also be noted. The MP and IP joints of the fingers should all be in the same plain on any given view. Incongruency of the joint(s) of one finger implies fracture with rotation. At the wrist level, the proximal and distal edge of the proximal row and proximal edge of the distal row should be smooth arcs,⁷ known as Gilula’s arcs (Fig. 44-8A). Disruption of these implies ligamentous injury or possibly dislocation (Fig. 44-8B).

Computed Tomography

Computed tomography (CT) scanning of the hand and wrist can provide additional bony information when plain X-rays are insufficient. Comminuted fractures of the distal radius can be better visualized for number and orientation of fragments. Scaphoid fractures can be evaluated for displacement and comminution preoperatively as well as for the presence of bony bridging postoperatively (Fig. 44-9). CT scans are also useful for CMC fractures of the hand where overlap on a plain X-ray lateral view may make diagnosis difficult.

Unlike the trunk and more proximal extremities, CT scans with contrast are less useful to demonstrate abscess cavities due to the small area of these spaces.

Ultrasonography

Ultrasonography has the advantages of being able to demonstrate soft tissue structures and being available on nights and weekends. Unfortunately, it is also highly operator dependent. In the middle of the night when magnetic resonance imaging (MRI) is not available, ultrasound may be able to demonstrate a large deep infection in the hand but is rarely more useful than a thorough clinical examination.

Magnetic Resonance Imaging

MRI provides the best noninvasive visualization of the soft tissue structures. With contrast, MRI can demonstrate an occult abscess. Unfortunately, it is often not available on an urgent basis for hand issues when this information is often needed. MRI can also demonstrate soft tissue injuries such as cartilage or ligament tears or tendonitis (usually by demonstrating edema in the area in question). It can demonstrate occult fractures that are not sufficiently displaced to be seen on X-ray or CT (again, by demonstrating edema). MRI can also demonstrate vascular disturbance of a bone, as in a patient with avascular necrosis of the scaphoid (Fig. 44-10).

Angiography

Angiography of the upper extremity is rarely used. In many centers, MRI and CT angiography provide sufficient resolution of the vascular structures to make traditional angiography unnecessary. Also, primary ­vascular disease of the upper extremity is relatively uncommon. In the trauma setting, vascular disturbance usually mandates exploration and direct visualization of the structures in ­question, and angiography is thus obviated.

For a patient with vascular disease of the upper extremity, angiography of the upper extremity is usually performed through a femoral access much like with the leg. An arterial catheter can be used to deliver thrombolytic drugs to treat a thrombotic process.

The upper extremity–injured patient may have additional injuries to other parts of the body. All injured patients should receive an appropriate trauma survey to look for additional injuries.

The patient with upper extremity trauma is evaluated as described in the Hand Examination section. Sensory examination should be performed early. Once sensory status has been documented, administration of local anesthesia can provide comfort to the patient during the remainder of the evaluation and subsequent treatment. Patients should receive tetanus toxoid for penetrating injuries if more than 5 years have passed since the last vaccination.

Local Anesthesia

Anesthetic blockade can be administered at the wrist level, digital level, or with local infiltration as needed. Keep in mind that all local anesthetics are less effective in areas of inflammation.

The agents most commonly used are lidocaine and ­bupivacaine. Lidocaine has the advantage of rapid onset, whereas bupivacaine has the advantage of long duration (average 6– 8 hours).⁸ Although bupivacaine can produce irreversible heart block in high doses, this is rarely an issue with the amounts typically used in the hand. For pediatric patients, the tolerated dose is 2.5 mg/kg. This can be easily remembered by noting that when using 0.25% bupivacaine, 1 mL/kg is acceptable dosing.

A commonly held axiom is that epinephrine is unacceptable to be used in the hand. Several recent large series have dispelled this myth.⁹ Epinephrine should not be used in the fingertip and not in concentrations higher than 1:100,000 (i.e., what is present in commercially available local anesthetic with epinephrine). Beyond that, its use is acceptable and may be ­useful in an emergency room (ER) where tourniquet control may not be available. Also, because most ER procedures are done under pure local anesthesia, many patients will not tolerate the discomfort of the tourniquet beyond 30 minutes.¹⁰ Epinephrine will provide hemostasis and also prolong the effect of the local anesthetic.

Simple lacerations, particularly on the dorsum of the hand, can be anesthetized with local infiltration. This is performed in the standard fashion.

Blocking of the digital nerves at the metacarpal head level is useful for volar injuries distal to this point and for dorsal injuries beyond the midpoint of the middle phalanx (via dorsal branches of the proper digital nerves). Fingertip injuries are particularly well anesthetized by this technique. A digit can be anesthetized via a flexor sheath approach or via the dorsal web space (Fig. 44-11A,B).

Blocking one or more nerves as they cross the wrist can provide several advantages: anesthesia for multiple injured digits, avoiding areas of inflammation where the local anesthetic agent may be less effective, and avoiding injection where the volume of fluid injected may make treatment harder (such as fracture reduction). Four major nerves cross the wrist: the median nerve, SRN, ulnar nerve, and dorsal sensory branch of the ulnar nerve (Fig. 44-11C–E). When blocking the median and ulnar nerves, beware of intraneural injection, which can cause irreversible neural scarring. If the patient complains of severe paresthesias with injection or high resistance is encountered, the needle should be repositioned.

Fractures and Dislocations

For dislocations and displaced fractures, a visible deformity is often present. Nondisplaced fractures may not show a gross deformity but will have edema and tenderness to palpation at the fracture site. A fracture is described by its displacement, rotation, and angulation. A fracture is also described in terms of comminution and the number and complexity of fracture fragments. Displacement is described as a percentage of the diameter of the bone; rotation is described in degrees of supination or pronation with respect to the rest of the hand; angulation is described in degrees. To avoid confusion, it is useful to describe which direction the angle of the fracture points. All injuries should be evaluated for nearby wounds (open) that may introduce bacteria into the fracture site or joint space.

Once the initial force on the fracture ceases, the tendons passing beyond the fracture site provide the principal deforming force. Their force is directed proximally and, to a lesser extent, volarly. Based on this, the stability of a ­fracture can be determined by the orientation of the fracture with respect to the shaft of the bone. Transverse fractures are typically stable. Oblique fractures typically shorten. ­Spiral fractures typically rotate as they shorten and thus require surgical treatment.

Fractures of the tuft of the distal phalanx are common. Catching of a finger in a closing door is a common causative mechanism. These fractures are often nondisplaced and do not require treatment beyond protection of the distal phalanx from additional trauma while the fracture heals.

Displaced transverse fractures of the phalanges can usually be reduced with distraction. The distal part is pulled away from the main body of the hand and then pushed in the direction of the proximal shaft of the finger, and then distraction is released. Postreduction X-rays should routinely be performed to document satisfactory reduction. Oblique and spiral fractures usually are unstable after reduction. The involved digit(s) should be splinted until appropriate surgical intervention can be performed.

Articular fractures of the IP and MP joints are worrisome because they may compromise motion. Chip fractures must be evaluated for instability of the collateral ligaments. If the joint is stable, the patient should initially be splinted for comfort. Motion therapy should be instituted early (ideally within the first week) to prevent stiffness. For larger fractures, the patient should be splinted until surgical treatment can be performed. In surgery, the fracture is typically internally fixated to allow for early motion, again with the goal of preventing stiffness.¹¹

Dislocations of the PIP joints produce traction on the neurovascular structures but usually do not lacerate them. In general, the patient should not be sent home with a joint that remains dislocated. Most commonly, the distal part is dorsal to the proximal shaft and sits in a hyperextended position. For this patient, the examiner gently applies pressure to the base of the distal part until it passes beyond the head of the proximal phalanx. Once there, the relocated PIP joint is gently flexed, confirming the joint is in fact reduced. The joint is splinted in slight flexion to prevent redislocation. On occasion, the head of the proximal phalanx may pass between the two slips of the FDS tendon. For these patients, the joint may not be reducible in a closed fashion.

Angulated fractures of the small finger metacarpal neck (“boxer’s fracture”) are another common injury seen in the ER. Typical history is that the patient struck another individual or rigid object with a hook punch. These are often stable after reduction using the Jahss maneuver (Fig. 44-12).

Fractures of the thumb metacarpal base are often unstable. The Bennett fracture displaces the volar-ulnar base of the bone. The remainder of the articular surface and the shaft typically dislocate dorsoradially and shorten. The thumb often appears grossly shortened, and the proximal shaft of the metacarpal may reside at the level of the trapezium or even the scaphoid on X-ray. In a Rolando fracture, a second fracture line occurs between the remaining articular surface and the shaft. These fractures nearly always require open reduction and internal fixation.

Most nondisplaced fractures do not require surgical treatment. The scaphoid bone of the wrist is a notable exception to this rule. Due to peculiarities in its vascular supply, particularly vulnerable at its proximal end, nondisplaced scaphoid fractures can fail to unite in up to 20% of patients even with appropriate immobilization. Recent developments in hardware and surgical technique have allowed stabilization of the fracture with minimal surgical exposure. One prospective randomized series of scaphoid wrist fractures demonstrated shortening of time to union by up to 6 weeks in the surgically treated group, but no difference in rate of union.¹² Surgery may be useful in the younger, more active patient who would benefit from an earlier return to full activity.

Ligament injuries of the wrist can be difficult to recognize. Patients often present late and may not be able to localize their pain. In severe cases, the ligaments of the wrist can rupture to the point of dislocation of the capitate off the lunate or even the lunate off the radius. Mayfield and colleagues classified the progression of this injury into four groups.¹³ In the most severe group, the lunate dislocates off the radius into the carpal tunnel. In some circumstances, the scaphoid bone may break rather than the scapholunate ligament rupturing. Attention to the congruency or disruption of Gilula’s arcs will help the examiner to recognize this injury. For patients with type 4 (most severe) and some with type 3 injury, the examiner should also evaluate for sensory disturbance in the median nerve distribution because this may indicate acute carpal tunnel syndrome and necessitate more urgent intervention. Although the Mayfield pattern of injury is most common, force can also transmit along alternate paths through the carpus.¹⁴

After reduction of fractures and dislocations (as well as after surgical repair of these and many other injuries), the hand must be splinted in a protected position. For the fingers, MP joints should be splinted 90°, and the IP joints at 0° (called the intrinsic plus position). The wrist is generally splinted at 20° extension because this puts the hand in a more functional ­position. This keeps the collateral ligaments on tension and helps prevent secondary contracture. In general, one of three splints should be used for the ER patient (Fig. 44-13). The ulnar gutter splint uses places plaster around the ulnar ­border of the hand. It is generally appropriate for small finger injuries only. Dorsal plaster splints can be used for injuries of any of the ­fingers. Plaster is more readily contoured to the dorsal surface of the hand than the volar surface, particularly in the setting of trauma-associated edema. For thumb injuries, the thumb spica splint is used to keep the thumb radially and palmarly abducted from the hand.

Tendons

Injuries to the flexor and extensor tendons compromise the mobility and strength of the digits. On inspection, injury is normally suspected by loss of the normal cascade of the fingers. The patient should be examined as described earlier to evaluate for which tendon motion is deficient. If the patient is unable to cooperate, extension of the wrist will produce passive flexion of the fingers and also demonstrate a deficit. This is referred to at the tenodesis maneuver.

Flexor tendon injuries are described based on zones (Fig. 44-14). Up until 40 years ago, zone 2 injuries were always reconstructed and never repaired primarily due to concern that the bulk of repair within the flexor sheath would prevent tendon glide. The work of Dr. Kleinert and colleagues at the University of Louisville changed this “axiom” and established the principle of primary repair and early controlled mobilization postoperatively.¹⁵ Flexor tendon injuries should always be repaired in the operating room. Although they do not need to be repaired on the day of injury, the closer to the day of injury they are repaired, the easier it will be to retrieve the retracted proximal end in surgery. The laceration should be washed out and closed at the skin level only using permanent sutures. The hand should be splinted as described earlier; one notable difference is that the wrist should be splinted at slight flexion (about 20°) to help decrease the retracting force on the proximal cut tendon end.

Extensor tendons do not pass through a sheath in the ­fingers. As such, bulkiness of repair is less of a concern. With proper supervision/experience and equipment, primary extensor tendon repair can be performed in the ER.

Very distal extensor injuries near the insertion on the dorsal base of the distal phalanx may not have sufficient distal tendon to hold a suture. Closed injuries, called mallet fingers, can be treated with extension splinting of the DIP joint for 6 continuous weeks. For patients with open injuries, a dermatotenodesis suture is performed. A 2-0 or 3-0 suture is passed through the distal skin, tendon remnant, and proximal tendon as a mattress suture. Using a suture of a different color than the skin closing sutures will help prevent removing the dermatotenodesis suture(s) too soon. The DIP joint is splinted in extension.

More proximal injuries are typically repaired with a 3-0 braided permanent suture. Horizontal mattress or figure-of-eight sutures should be used, two per tendon if possible. Great care should be used to ensure matching the appropriate proximal and distal tendon ends. The patient is splinted with IP joints in extension and the wrist in extension per usual. MP joints should be splinted in 45° flexion, sometimes less. Although this position is not ideal for MP collateral ligaments, it is important for taking tension off of the tendon repairs.

Nerve Injuries

In the setting of a sharp injury, a sensory deficit implies a nerve laceration until proven otherwise. For blunt injuries, even displaced fractures and dislocations, nerves are often contused but not lacerated and are managed expectantly. Nerve repairs require appropriate microsurgical equipment and suture; they should not be performed in the ER. As with tendons, nerve injuries do not require immediate exploration. However, earlier exploration will allow for easier identification of structures and less scar tissue to be present. The nerve must be resected back to healthy nerve fascicle prior to repair. Delay between injury and repair can thus make a difference between the ability to repair a nerve primarily or the need to use a graft. The injured hand should be splinted with MPs at 90° and IPs at 0°, as described earlier.

Vascular Injuries

Vascular injuries have the potential to be limb or digit threatening. A partial laceration of an artery at the wrist level can potentially cause exsanguinating hemorrhage. Consultations for these injuries must be evaluated urgently.

Initial treatment for an actively bleeding wound should be direct local pressure for no less than 10 continuous minutes. If this is unsuccessful, an upper extremity tourniquet inflated to 100 mmHg above the systolic pressure should be used. One should keep this tourniquet time to less than 2 hours to avoid tissue necrosis. Once bleeding is controlled well enough to evaluate the wound, it may be cautiously explored to evaluate for bleeding points. One must be very cautious if attempting to ligate these to ensure that adjacent structures such as nerves are not included in the ligature.

The hand must be evaluated for adequacy of perfusion to the hand as a whole as well as the individual digits. Capillary refill, turgor, Doppler signal, and bleeding to pinprick all provide useful information regarding vascular status. The finger or hand with vascular compromise requires urgent operative exploration. Unlike the complete amputation, in which the amputated part can be cold preserved (see below), devascularization without amputation produces warm ischemia, which is tolerated only for a matter of hours.

For the noncritical vascular injury, two treatment options exist. Simple ligation will control hemorrhage. At least one of the palmar arterial arches is intact in 97% of patients,⁵ so this will usually not compromise hand perfusion. Each digit also has two arterial inflows and can survive on one (see Amputations and Replantation section below). In the academic hospital setting, however, consideration should be given to repairing all vascular injuries. Instructing a resident in vascular repair in the noncritical setting will produce a more skilled and prepared resident for when a critical vascular injury does arise.

Amputations and Replantation

After replantation was first reported,¹⁶ replantation was attempted for nearly all amputations. Over the ensuing decades, more stringent guidelines have been established regarding what should be replanted. Indications for replantation include amputations of the thumb, multiple digit amputations, and amputations in children. Relative contraindications to replantation include crush injuries, injuries to a single digit distal to the PIP joint, and patients who are unable to tolerate a long surgical procedure. As with all guidelines, one should evaluate the particular needs of the injured patient.

In preparation for replantation, the amputated part and proximal stump should be appropriately treated. The amputated part should be wrapped in moistened gauze and placed in a sealed plastic bag. This bag should then be placed in an ice water bath. Do not use dry ice, and do not allow the part to contact ice directly; frostbite can occur in the amputated part, which will decrease its chance of survival after replantation. Bleeding should be controlled in the proximal stump by as minimal a means necessary, and the stump should be dressed with a nonadherent gauze and bulky dressing.

For digital amputations deemed unsalvageable, revision amputation can be performed in the ER if appropriate equipment is available. Bony prominences should be smoothed off with a rongeur and/or rasp. Great care must be taken to identify the digital nerves and resect them back as far proximally in the wound as possible; this helps decrease the chance of painful neuroma in the skin closure. Skin may be closed with permanent or absorbable sutures; absorbable sutures will spare the patient the discomfort of suture removal several weeks later. For more proximal unsalvageable amputations, revision should be performed in the operating room to maximize vascular and neural control.

Prostheses can be made for amputated parts. The more proximal the amputation, the more important to function the prosthesis is likely to be. Although finger-level prostheses are generally considered cosmetic, patients with multiple finger amputations proximal to the DIP have demonstrable functional benefit from their prosthesis as well.¹⁷

Fingertip Injuries

Fingertip injuries are among the most common pathologies seen in an ER. The usual history is that a door closed on the finger (commonly the middle, due to its increased length) or something heavy fell on the finger.

Initial evaluation should include: wound(s) including the nail bed, perfusion, sensation, and presence and severity of fractures. For the common scenario, complex lacerations with minimally displaced fracture(s) and no loss of perfusion, the wound is cleansed, sutured, and splinted in the ER. To properly assess the nail bed, the nail plate (hard part of the nail) should be removed. A Freer periosteal elevator is well suited for this purpose. Lacerations are repaired with 6-0 fast gut suture. Great care must be taken when suturing because excessive traction with the needle can further lacerate the tissue. After repair, the nail folds are splinted with the patient’s own nail plate (if available) or with aluminum foil from the suture pack. This is done to prevent scarring from the nail folds down to the nail bed that would further compromise healing of the nail.

In some situations, tissue may have been avulsed in the injury and be unavailable for repair. Choice of treatment options depends on the amount and location of tissue loss (Fig. 44-15). For wounds less than 1 cm² with no exposed bone, secondary intention will produce excellent functional and aesthetic results. For larger wounds or wounds or with bone exposed, one must decide if the finger is worth preserving at the current length or if shortening to allow for primary closure is a better solution. A useful guideline is the amount of fingernail still present; if greater than 50% is present, local or regional flap coverage may be a good solution.

If sufficient local tissue is present, homodigital flaps can be considered. A wide range of antegrade and retrograde homodigital flaps can be mobilized to cover the defect. Some carry ­sensation or can receive nerve coaptation to recover sensation over time.¹⁸ For the thumb only, the entire volar skin including both neurovascular bundles can be raised and advanced distally up to 1.5 cm.¹⁹ The thumb receives separate vascularity to its dorsal skin from the radial artery. This flap is not appropriate for the fingers. Patients retain full sensibility in the advanced skin and can be mobilized within days of surgery (Fig. 44-16A–C).

For wounds too large to cover with homodigital tissue, regional flaps can be considered. The skin from the distal radial thenar eminence can be raised as a random pattern flap (Fig. 44-16D–F). The finger is maintained in flexion for 14 to 21 days until division of the flap pedicle and inset of the flap. Some authors have reported prolonged stiffness in patients over 30 years old, but careful flap design helps minimize this complication.²⁰ Alternatively, the skin from the dorsum of the middle phalanx of an adjacent digit can be raised as a flap to cover the volar P3 (Fig. 44-16G–I). The flap is inset at 14 to 21 days. Long-term studies have shown this flap develops sensation over time.²¹

Patients with fingertip injures must be assessed for the possibility of salvage of the injured digit(s) taken within the context of the patient’s recovery needs and goals. The surgeon then matches the available options to the particular patient needs.

High-Pressure Injection Injuries

High-pressure devices are commonly used for cleaning and applications of liquids such as lubricants and paint. Most commonly, the inexperienced worker accidentally discharges the device into his nondominant hand at the base of the digit. Severity of injury depends on the amount and type of liquid injected; hydrophobic compounds cause greater damage.

These injuries are typically quite innocuous to inspection. They are, however, digit-threatening emergencies. The patient should be informed of the severity of the injury, and exploration is ideally performed within 6 hours of injury. Up to 50% of such injuries result in loss of the digit, but early recognition and treatment are associated with increased chance of digit ­survival.²² Early frank discussion with the patient and initiation of appropriate treatment produce the best results and medicolegal protection.

Compartment Syndromes

Compartment syndromes can occur in the forearm and/or the hand. As in other locations, these are potentially limb-­threatening issues. Principle symptoms are pain in the affected compartments, tense swelling, tenderness to palpation over the compartment, and pain with passive stretch of the muscles of the compartment.²³ Pulse changes are a late finding; normal pulses do not rule out compartment syndrome.

There are three compartments in the forearm and four groups of compartments in the hand. The volar forearm is one compartment. On the dorsum of the forearm, there is the dorsal compartment as well as the mobile wad compartment, beginning proximally over the lateral epicondyle. In the hand, the thenar and hypothenar eminences each represent a compartment. The seven interosseous muscles each behave as a separate ­compartment.

Compartment syndrome can be caused by intrinsic and extrinsic causes. Intrinsic causes include edema and hematoma due to fracture. Extrinsic causes include splints and dressings that are circumferentially too tight and intravenous infiltrations. Infiltrations with hyperosmolar fluids such as x-ray contrast are particularly dangerous, because additional water will be drawn in to neutralize the hyperosmolarity.

Measurement of compartment pressures can be a useful adjunct to assessment of the patient. The Stryker pressure measurement device or similar device is kept in many operating rooms for this purpose. The needle is inserted into the compartment in question, a gentle flush with 0.1 to 0.2 cc of saline clears the measurement chamber, and a reading is obtained. Studies have disagreed about whether the criterion is a measured pressure (30–45 mmHg, depending on the series) or within a certain amount of the diastolic blood pressure.²⁴

Compartment releases are performed in the operating room under tourniquet control. Release of the volar forearm compartment includes release of the carpal tunnel. As the incision travels distally, it should pass ulnar and then curve back radially just before the carpal tunnel. This avoids a linear incision across a flexion crease and also decreases the chance of injury to the palmar cutaneous branch of the median nerve. One dorsal forearm incision can release the dorsal compartment and the mobile wad. In the hand, the thenar and hypothenar compartments are released each with a single incision. The interosseous compartments are released with incisions over the index and ring metacarpal shafts. Dissection then continues radial and ulnar to each of these bones and provides release of all the muscle compartments. Any dead muscle is débrided. Incisions are left open and covered with a nonadherent dressing. The wounds are reexplored in 2 to 3 days to assess for muscle viability. Often the incisions can be closed primarily, but a skin graft may be needed for the forearm.

If the examiner feels the patient does not have a compartment syndrome, elevation and serial examination are mandatory. When in doubt, it is safer to release an early compartment syndrome than wait to release and risk muscle necrosis. Progression of compartment syndrome can lead to Volkmann’s ischemic contracture with muscle loss and scarring that may compress nerves and other critical structures. Medicolegally, it is far easier to defend releasing an early compartment syndrome than delaying treatment until the process has progressed to necrosis and/or deeper scarring.

Nonunion

Any fractured bone has the risk of failing to heal. Fortunately, in the fingers and hand, this is a rare problem. Tuft injuries, where soft tissue interposes between the fracture fragments, have relatively higher risk of this problem. The nonunited tuft can be treated with débridement and bone grafting or revision amputation depending on the needs and goals of the patient. Phalangeal and metacarpal nonunions are also quite rare. They can similarly be treated with débridement of the nonunion, grafting, and rigid fixation.²⁵ More proximally, the scaphoid bone of the wrist has a significant risk of nonunion even if nondisplaced (see Fig. 44-9A). Any patient suspected of a scaphoid injury, namely those with tenderness at the anatomic snuffbox, should be placed in a thumb spica splint and reevaluated within 2 weeks even if initial X-rays show no fracture. Scaphoid nonunions can be quite challenging to repair,²⁶ and immobilization at the time of injury in a thumb spica splint is essentially always warranted.

Stiffness

The desired outcome of any hand injury is a painless, mobile, functional hand. Multiple factors can contribute to decreased mobility, including complex injuries of soft tissue and bone, noncompliance of the patient with postoperative therapy, and inappropriate splinting. The surgeon performing the initial evaluation can greatly impact this last factor. The goal of splinting is to keep the collateral ligaments on tension (MPs at 90°, IP joints straight). For severe cases of stiffness, mobilization surgeries such as tenolysis and capsulotomies²⁷ can be performed, but these rarely produce normal range of motion. Prevention of joint contractures with appropriate splinting and early, protected mobilization is the best option to maximize mobility at the end of healing. Healing of an injured or diseased structure in the hand is not the endpoint of treatment; the goal of any intervention must be to obtain structure healing, relief of pain, and maximization of function.

Neuroma

Any lacerated nerve will form a neuroma. A neuroma consists of a ball of scar and axon sprouts at the end of the injured nerve.²⁸ In unfavorable circumstances, this neuroma can become painful. The SRN is particularly notorious for this problem. By providing proximal axon sprouts a target, nerve repair is an excellent preventive technique. In some circumstances, such as injuries requiring amputation, this is not possible. As mentioned earlier, the surgeon should resect the nerve stump as far proximally in the wound as possible to avoid the nerve stump healing in the cutaneous scar to minimize this risk.

For the patient who develops a painful neuroma, nonsurgical treatments are initiated first. The neuroma can be identified by the presence of a Tinel’s sign. Therapy techniques of desensitization, ultrasound, and electrical stimulation have all proven useful. Corticosteroid injection to the neuroma has also proven useful in some hands.

When these techniques fail, surgery is contemplated. The neuroma can be resected, but a new one will form to replace it. The nerve ending can be buried in muscle or even bone to prevent the neuroma from residing in a superficial location where it may be impacted frequently.

Regional Pain Syndromes

Injuries to the upper extremity can occasionally result in the patient experiencing pain beyond the area of initial injury. Reflex sympathetic dystrophy and sympathetic mediated pain are two terms that have been used in the past to describe this phenomenon. Both are inaccurate, as the sympathetic nervous system is not always involved. Current terminology for this condition is complex regional pain syndrome (CRPS). Type I occurs in the absence of a documented nerve injury; type II occurs in the presence of one.²⁹

CRPSs manifest as pain beyond the area of initial ­injuries. There is often associated edema and changes in hair and/or sweat distribution. Comparison to the unaffected side is useful to better appreciate these findings. There are currently no imaging studies that can be considered diagnostic for CRPS.³⁰

For the patient in whom the diagnosis of CRPS is not clear, no definitive diagnostic study exists. Patients suspected of CRPS should be referred for aggressive hand therapy. Brief trials of oral corticosteroids have been successful in some series. Referral to a pain management specialist including a trial of stellate ganglion blocks is also frequently employed.

Nerves conduct signals along their axonal membranes toward their end organs. Sensory axons carry signals from distal to proximal; motor axons from proximal to distal. Myelin from Schwann cells allows faster conduction of signals. Signals jump from the start of one Schwann cell to the end of the cell (a location called a gap junction) and only require the slower membrane depolarization in these locations.

Nerve compression creates a mechanical disturbance of the nerve.³¹ In early disease, the conduction signal is slowed across the area of compression. When compression occurs to a sufficient degree for a sufficient time, individual axons may die. On a nerve conduction study, this manifests as a decrease in amplitude. Muscles receiving motor axons may show electrical disturbance on electromyogram (EMG) when sufficiently deprived of their axonal input.

Compression of sensory nerves typically produces a combination of numbness, paresthesias (pins and needles), and pain. Knowledge of the anatomic distribution of the peripheral nerves can aid in diagnosis. Sensory disturbance outside an area of distribution of a particular nerve (e.g., volar and dorsal radial-sided hand numbness for median nerve) makes compression of that nerve less likely. Diseases that cause systemic neuropathy (e.g., diabetes) can make diagnosis more difficult.

Nerve compression can theoretically occur anywhere along a peripheral nerve’s course. The most common sites of nerve compression in the upper extremity are the median nerve at the carpal tunnel, ulnar nerve at the cubital tunnel, and ulnar nerve at Guyon’s canal. Other, less common locations of nerve compression are described as well. In addition, a nerve can become compressed in scar due to a previous trauma.

Carpal Tunnel Syndrome

The most common location of upper extremity nerve compression is the median nerve at the carpal tunnel, called carpal tunnel syndrome (CTS). The carpal tunnel is bordered by the scaphoid bone radially, the lunate and capitate bones dorsally, and the hook of the hamate bone ulnarly (see Fig. 44-3). The transverse carpal ligament, also called the flexor retinaculum, is its superficial border. The FPL, four FDS, and four FDP tendons pass through the carpal tunnel along with the median nerve. Of these 10 structures, the median nerve is relatively superficial and radial to the other nine.

An estimated 53 per 10,000 working adults have evidence of CTS. The National Institute for Occupational Safety and Health website asserts, “There is strong evidence of a positive association between exposure to a combination of risk factors (e.g., force and repetition, force and posture) and CTS.”³² There is disagreement among hand surgeons regarding whether occurrence of CTS in a patient who does repetitive activities at work represents a work-related injury.

Initial evaluation of the patient consists of symptom inventory: location and character of the symptoms, sleep disturbance due to symptoms, history of dropping objects, and difficulty manipulating small objects such as buttons, coins, or jewelry clasps.

Physical examination should begin with inspection. Look for evidence of wasting of the thenar muscles. Tinel’s sign should be tested over the median nerve from the volar wrist flexion crease to the proximal palm, although this test has significant interexaminer variability.³³ Applying pressure over the carpal tunnel while flexing the wrist has been shown in one series to have the highest sensitivity when compared to Phalen’s and Tinel’s signs.³⁴ Strength of the thumb in opposition should also be tested.

Early treatment of CTS consists of conservative management. The patient is given a splint to keep the wrist at 20° extension worn at nighttime. Many patients can have years of symptom relief with this management. As a treatment and diagnostic modality, corticosteroid injection of the carpal tunnel is often employed. Mixing local anesthetic into the solution provides the benefit of early symptom relief (corticosteroids often take 3–7 days to provide noticeable benefit), and report of postinjection anesthesia in the median nerve distribution confirms the injection went into the correct location. Multiple authors have shown a strong correlation to relief of symptoms with corticosteroid injection and good response to carpal tunnel release.³⁵

When lesser measures fail or are no longer effective, carpal tunnel release is indicated. Open carpal tunnel release is a time-tested procedure with documented long-term relief of symptoms. A direct incision is made over the carpal tunnel, typically in line with where the ring finger pad touches the proximal palm in flexion. Skin is divided followed by palmar fascia. The carpal tunnel contents are visualized as they exit the carpal tunnel. The transverse carpal ligament is divided with the median nerve visualized and protected at all times. Improvement in symptoms is typically noted by the first postoperative visit, although symptom relief may be incomplete for patients with long-standing disease or systemic nerve-affecting diseases such as diabetes.

Endoscopic techniques have been devised to address CTS. All involve avoidance of incising the skin directly over the carpal tunnel. In experienced hands, endoscopic carpal tunnel release provides the same relief of CTS with less intense and shorter lasting postoperative pain. After 3 months, however, the results are equivalent to open release.³⁶ In inexperienced hands, there may be a higher risk of injury to the median nerve with the endoscopic techniques; this procedure is not for the occasional carpal tunnel surgeon.

Cubital Tunnel Syndrome

The second most common location of upper extremity nerve compression is the ulnar nerve where it passes behind the elbow at the cubital tunnel. The cubital tunnel retinaculum passes between the medial epicondyle of the humerus and the olecranon process of the ulna. It stabilizes the ulnar nerve in this location during elbow motion. Over time, or sometimes after trauma, the ulnar nerve can become less stabilized in this area. Motion of the elbow then produces trauma to the nerve as it impacts the retinaculum and medial epicondyle.

Cubital tunnel syndrome may produce sensory and motor symptoms.³⁷ The small finger and ulnar half of the ring fingers may have numbness, paresthesias, and/or pain. The ulnar nerve also innervates the dorsal surface of the small finger and ulnar side of the ring finger, so numbness in these areas can be explained by cubital tunnel syndrome. The patient may also report weakness in grip due to effects on the FDP tendons to the ring and small fingers and the intrinsic hand muscles. Patients with advanced disease may complain of inability to fully extend the ring and small finger IP joints.

Physical examination for cubital tunnel syndrome begins with inspection. Look for wasting in the hypothenar eminence and the interdigital web spaces. When the hand rests flat on the table, the small finger may rest in abduction with respect to the other fingers; this is called Wartenberg’s sign. Tinel’s sign is often present at the cubital tunnel. Elbow flexion test will often be positive. Grip strength and finger abduction strength should be compared to the unaffected side. Froment’s sign can be tested by placing a sheet of paper between the thumb and index finger and instructing the patient to hold on to the paper while the examiner pulls it away without flexing the finger or thumb (this tests the strength of the adductor pollicis and first dorsal interosseous muscles). If the patient must flex the index finger and/or thumb (FDP-index and FPL, both median nerve supplied) to maintain traction on the paper, this is a positive response.

Early treatment of cubital tunnel syndrome begins with avoiding maximal flexion of the elbow. Splints are often used for this purpose. Corticosteroid injection is rarely done for this condition; unlike in the carpal tunnel, there is very little space within the tunnel outside of the nerve. Injection in this area runs a risk of intraneural injection, which can cause permanent scarring of the nerve and dysfunction.

When conservative management fails, surgery has been contemplated. Treatment options include releasing the cubital tunnel retinaculum with or without transposing the nerve anterior to the elbow. While some authors advocate anterior transposition into the flexor-pronator muscle group with the goal of maximizing nerve recovery,³⁷ recent studies have demonstrated equivalent results between transposition and in situ release of the nerve even in advanced cases.³⁸ For this reason, the simpler in situ release, either open or endoscopic, is preferred by many surgeons.

Other Sites of Nerve Compression

All nerves crossing the forearm have areas described where compression can occur.³⁷ The median nerve can be compressed as it passes under the pronator teres. The ulnar nerve can be compressed as it passes through Guyon’s canal. The radial nerve, or its posterior interosseous branch, can be compressed as it passes through the radial tunnel (distal to the elbow where the nerve divides and passes under the arch of the supinator muscle). The SRN can be compressed distally in the forearm as it emerges from under the brachioradialis tendon, called ­Wartenberg’s syndrome. As mentioned previously, any nerve can become compressed in scar at the site of a previous trauma.

As with other joints in the body, the joints of the hand and wrist can develop degenerative changes. Symptoms typically begin in the fifth decade of life. Symptoms consist of joint pain and stiffness and often are exacerbated with changes in the weather. Any of the joints can become involved. As the articular cartilage wears out, pain typically increases and range of motion decreases. The patient should always be asked to what degree symptoms are impeding activities.

Physical findings are documented in serial fashion from the initial visit and subsequent visits. Pain with axial loading of the joint may be present. Decreased range of motion may be a late finding. Instability of the collateral ligaments of the joint is uncommon in the absence of inflammatory arthritis.

Plain X-rays are typically sufficient to demonstrate arthritis. Initially, the affected joint has a narrower radiolucent space between the bones. As joint degeneration progresses, the joint space further collapses. Bone spurs, loose bodies, and cystic changes in the bone adjacent to the joint all may become ­apparent. X-ray findings do not always correlate with patient symptoms. Patients with advanced x-ray findings may have minimal symptoms, and vice versa. Treatment is initiated and progressed based on the patient’s symptoms regardless of imaging findings.

Initial management begins with rest of the painful joint. Splints are often useful, but may significantly impair the patient in activities and thus are frequently used at nighttime only. Oral nonsteroidal anti-inflammatory medications such as ibuprofen and naproxen are also useful. Patients on anticoagulants and antiplatelet medications may not be able to take these, and some patients simply do not tolerate the gastric irritation side effect even if they take the medication with food.

For patients with localized disease affecting only one or a few joints, corticosteroid injection may be contemplated. ­Needle insertion can be difficult since these joint spaces are quite ­narrow even before degenerative disease sets in. Also, many corticosteroid injections are suspensions, not solutions; injected corticosteroid will remain in the joint space and can be seen as a white paste if surgery is performed on a joint that has been previously injected.

Small Joints (Metacarpophalangeal and Interphalangeal)

When conservative measures fail, two principal surgical options exist: arthrodesis and arthroplasty. The surgeon and patient must decide together as to whether conservative measures have failed. Surgery for arthritis, whether arthrodesis or arthroplasty, is performed for the purpose of relieving pain. Arthrodesis, fusion of a joint, provides excellent relief of pain and is durable over time. However, it comes at the price of total loss of motion.

Silicone implant arthroplasty has been available for over 40 years.³⁹ Rather than a true replacement of the joint, the silicone implant acts as a spacer between the two bones adjacent to the joint. This allows for motion without bony contact that would produce pain. Long-term studies have shown that all implants fracture over time, but usually continue to preserve motion and pain relief.⁴⁰

In the past 15 years, resurfacing implant arthroplasties have become available for the small joints of the hand. Multiple different materials have been used to fabricate such implants. These are designed to behave as a true joint resurfacing (as knee and hip arthroplasty implants are) and have shown promising outcomes in short- and intermediate-term studies.⁴⁰ Neither the silicone nor the resurfacing arthroplasties preserve (or restore) full motion of the MP or PIP joints.

Wrist

The CMC joint of the thumb, also called the basilar joint, is another common location of arthritis pain. Pain in this joint particularly disturbs function because the CMC joint is essential for opposition and cylindrical grasp. Patients will typically complain of pain with opening a tight jar or doorknob and strong pinch activities such as knitting. Conservative management is used first, as described earlier. Prefabricated, removable thumb spica splinting can provide excellent relief of symptoms for many patients.

Multiple surgical options exist for thumb CMC arthritis. Many resurfacing implants have been used in the past; often they have shown good short- and intermediate-term results and poor long-term results. Resection of the arthritic trapezium provides excellent relief of pain; however, most authors feel that stabilization of the thumb metacarpal base is necessary to prevent shortening and instability.⁴¹ Recently, one author demonstrated excellent long-term results from resection of the trapezium without permanent stabilization of the metacarpal base.⁴² For both of these operations, the thumb base may not be sufficiently stable to withstand heavy labor. For these patients, fusion of the thumb CMC in mild opposition provides excellent pain relief and durability. The patient must be warned preoperatively that he will not be able to lay his hand flat after the surgery. This loss of motion can be problematic when the patient attempts to tuck in clothing or reach into a narrow space.

Degenerative change of the radiocarpal and midcarpal joints is often a consequence of scapholunate ligament injury. Often the initial injury goes untreated, with the patient believing it is merely a “sprain”; the patient is first diagnosed with the initial injury when he presents years later with degenerative changes.

Degenerative wrist changes associated with the scapholunate ligament follow a predictable pattern over many years, called scapholunate advanced collapse or SLAC wrist.⁴³ Because of this slow progression (Fig. 44-17A), patients can usually be treated with a motion-sparing procedure. If there is truly no arthritic change present, the scapholunate ligament can be reconstructed.

If arthritis is limited to the radiocarpal joint, two motion-sparing options are available. The proximal carpal row (scaphoid, lunate, and triquetrum) can be removed (proximal row carpectomy [PRC]). The lunate facet of the radius then articulates with the base of the capitate, whose articular surface is similar in shape to that of the base of the lunate. Most series show maintenance of about 66% of wrist motion and 66% of hand strength or more, as compared to the opposite side.⁴⁴ Alternatively, the scaphoid can be excised, and four-bone fusion (lunate, capitate, hamate, and triquetrum) can be performed. This maintains the full length of the wrist and the lunate in the lunate facet of the radius. Some series have shown better strength but less mobility with this technique, others have shown equivalent results to the PRC.⁴⁵ The four-bone fusion does appear to be more durable for younger patients and/or those who perform heavy labor.

If the patient presents with pancarpal arthritis or motion-sparing measures have failed to alleviate pain, total wrist fusion is the final surgical option. The distal radius is fused, through the proximal and distal carpal rows to the third metacarpal, typically with a dorsal plate and screws. Multiple long-term studies have shown excellent pain relief and durability; this comes at the cost of total loss of wrist motion. This is surprisingly well tolerated in most patients, especially if the other hand/wrist is unaffected. The only activity of daily living that cannot be done with a fused wrist is personal toileting.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) is an inflammatory arthritis that can affect any joint in the body. Inflamed synovium causes articular cartilage breakdown with pain and decreased range of motion. The goals of hand surgery for the RA patient are relief of pain, improvement of function, slowing progression of disease, and improvement in appearance.⁴⁶ In addition, swelling of the joint due to the inflammation can cause laxity and even failure of the collateral ligaments supporting the joints. Recent advances in the medical care of RA have made the need for surgical care of these patients far less common than in previous decades.

MP joints of the fingers are commonly affected. The base of the proximal phalanx progressively subluxates and eventually dislocates volarly with respect to the metacarpal head. The collateral ligaments, particularly on the radial side, stretch out and cause the ulnar deviation of the fingers characteristic of the rheumatoid hand. In more advanced cases, the joint may not be salvageable (Fig. 44-17B). For these patients, implant arthroplasty is the mainstay of surgical treatment. Silicone implants have been used for over 40 years with good results.⁴⁷ The silicone implant acts as a spacer between proximal and distal bone, rather than as a true resurfacing arthroplasty. The radial collateral ligament must be repaired to appropriate length to correct the preoperative ulnar deviation of the MP joint. Extensor tendon centralization is then performed, as needed, at the end of the procedure.

For MP joint and PIP joint disease, fusion is an option. However, since RA usually affects multiple joints, fusion is typically avoided due to impaired function of adjacent joints, which would leave a severe motion deficit to the finger.

Failure of the support ligaments of the distal radioulnar joint (DRUJ) leads to the caput ulnae posture of the wrist with the ulnar head prominent dorsally. As this dorsal prominence becomes more advanced, the ulna head, denuded of its cartilage to act as a buffer, erodes into the overlying extensor tendons. Extensor tenosynovitis, followed ultimately by tendon rupture, begins ulnarly and proceeds radially. Rupture of the ECU tendon may go unnoticed due to the intact ECRL and ECRB tendons to extend the wrist. EDQ rupture may go unnoticed if a sufficiently robust EDC tendon to the small finger exists. Once the fourth compartment (EDC) tendons begin to fail, the motion deficit is unable to be ignored by the patient.

Surgical solutions must address the tendon ruptures as well as the DRUJ synovitis and instability and ulna head breakdown that led to them.⁴⁶ Excision of the ulna head removes the bony prominence. The DRUJ synovitis must also be resected. Alternatively, the DRUJ can be fused and the ulna neck resected to create a pseudoarthrosis to allow for rotation. For both procedures, the remaining distal ulna must be stabilized. Multiple techniques have been described using portions of FCU, ECU, wrist capsule, and combinations thereof.

The ruptured extensor tendons are typically degenerated over a significant length. Primary repair is almost never possible, and the frequent occurrence of multiple tendon ruptures makes repair with graft less desirable due to the need for multiple graft donors.

Strict compliance with postoperative therapy is essential to maximizing the surgical result. Due to the chronic inflammation associated with RA, tendon and ligament repairs will be slower to achieve maximal tensile strength. Prolonged nighttime splinting, usually for months, helps prevent recurrence of extensor lag. Finally, the disease may progress over time. Reconstructions that were initially adequate may stretch out or fail over time. Medical management is the key to slowing disease progression and maximizing the durability of any surgical reconstruction.

In 1614, a Swiss surgeon named Felix Plater first described contracture of multiple fingers due to palpable, cord-like structures on the volar surface of the hand and fingers. The disease state he described would ultimately come to be known as Dupuytren’s contracture. Dupuytren’s name came to be associated with the disease after he performed an open fasciotomy of a contracted cord before a class of medical students in 1831.⁴⁸

The palmar fascia consists of collagen bundles in the palm and fingers. These are primarily longitudinally oriented and reside as a layer between the overlying skin and the underlying tendons and neurovascular structures. There are also connections from this layer to the deep structures below and the skin above. Much is known about the progression of these structures from their normal state (called bands) to their contracted state (called cords), but little is known on how or why this process begins.

Increased collagen deposition leads to a palpable nodule in the palm. Over time, there is increased deposition distally into the fingers. This collagen becomes organized and linearly ­oriented. These collagen bundles, with the aid of myofibroblasts, contract down to form the cords, which are the hallmark of the symptomatic patient. Detail of the molecular and cell biology of Dupuytren’s disease is beyond the scope of this chapter but is available in multiple hand surgery texts.⁴⁹

Most nonoperative management techniques will not delay the progression of disease. Corticosteroid injections may soften nodules and decrease the discomfort associated with them but are ineffective against cords. Splinting has similarly been shown not to retard disease progression.

Disruption of the cord with a needle is an effective means of releasing contractures, particularly at the MP joint level. Long-term studies have demonstrated more rapid recovery from needle fasciotomy, as the procedure is called, but more durable results with fasciectomy.⁵⁰ Injectable clostridial collagenase was approved by the U.S. Food and Drug Administration in 2009 and shows good early results.⁵¹

For patients with advanced disease including contractures of the digits that limit function, surgery is the mainstay of therapy. Although rate of progression should weigh heavily in the ­decision of whether or not to perform surgery, general guidelines are MP contractures ≥30° and/or PIP contractures ≥20°.⁵²

Surgery consists of an open approach through the skin down to the involved cords. Skin is elevated off of the underlying cords. Great care must be taken to preserve as much of the subdermal vascular plexus with the elevated skin flaps to minimize postoperative skin necrosis. All nerves, tendons, and blood vessels in the operative field should be identified. Once this is done, the involved cord is resected while keeping the critical deeper structures under direct vision. Skin is then closed, with local flap transpositions as needed, to allow for full extension of the fingers that have been released (Fig. 44-18).

Alternative cord resection techniques include removal of the skin over the contracture (dermatofasciectomy). This requires a skin graft to the wound and should only be done if skin cannot be separated from the cords and local tissue cannot be rearranged with local flaps to provide closure of the wound.

Complications of surgical treatment of Dupuytren’s disease occur in as many as 24% of cases.⁵³ Problems include digital nerve laceration, digital artery laceration, buttonholing of the skin, hematoma, swelling, and pain, including some patients with CRPS (see earlier section on CRPS). Digital nerve injury can be quite devastating, producing annoying numbness at best or a painful neuroma in worse situations.

Hand therapy is typically instituted within a week of surgery to begin mobilization of the fingers and edema control. The therapist can also identify any early wound problems because he or she will see the patient more frequently than the surgeon. Extension hand splinting is maintained for 4 to 6 weeks, with nighttime splinting continued for an additional 6 to 8 weeks. After this point, the patient is serially followed for evidence of recurrence or extension of disease.

Trauma is the most common cause of hand infections. Other predisposing factors include diabetes, neuropathies, and immunocompromised patients. Proper treatment consists of incision and drainage of any collections followed by débridement, ­obtaining wound cultures, antibiotic therapy, elevation, and immobilization. Staphylococcus and Streptococcus are the offending pathogens in about 90% of hand infections. Infections caused by intravenous drug use or human bites and those associated with diabetes will often be polymicrobial, including gram-positive and gram-negative species. Heavily contaminated injuries require anaerobic coverage. Although α-hemolytic Streptococcus and Staphylococcus aureus are the most commonly encountered pathogens in human bites, Eikenella corrodens is isolated in up to one-third of cases and should be considered when choosing antimicrobial ­therapy. Ziehl-Neelsen staining and cultures at 28°C to 32°C in ­Lowenstein-Jensen medium must be performed if there is a suspicion for atypical ­mycobacteria.⁵⁴

Cellulitis

Cellulitis is characterized by a nonpurulent diffuse spreading of inflammation characterized by erythema, warmth, pain, swelling, and induration. Skin breakdown is a frequent cause, but often no inciting factor is identified. Group A β-hemolytic Streptococcus is the most common offending pathogen and causes a more diffuse spread of infection. S. aureus is the second most common offending pathogen and will cause a more localized cellulitis. The diagnosis of cellulitis is clinical. ­Septic arthritis, osteomyelitis, an abscess, a deep-space infection, and necrotizing fasciitis are severe infectious processes that may initially mimic cellulitis. These must be ruled out appropriately before initiating treatment, and serial exams should be ­conducted to ensure proper diagnosis. Treatment of ­cellulitis consists of elevation, splint immobilization, and antibiotics that cover both Streptococcus and Staphylococcus. ­Intravenous antibiotics are usually initiated for patients with severe comorbidities and those who fail to improve on oral antibiotics after 24 to 48 hours. Failure to improve after 24 hours indicates a need to search for an underlying abscess or other infectious cause.⁵⁴

Abscess

An abscess will present much like cellulitis, but they are two clinically separate entities. The defining difference is an area of fluctuance. Skin-puncturing trauma is the most common cause. S. aureus is the most common pathogen, followed by Streptococcus. Treatment consists of incision and drainage with appropriate débridement, wound cultures, wound packing, elevation, immobilization, and antibiotics. The packing should be removed in 12 to 24 hours or sooner if there is clinical concern, and warm soapy water soaks with fresh packing should be initiated. Most should be allowed to heal secondarily. Delayed primary closure should only be performed after repeat washouts for larger wounds where complete infection has been achieved.

Collar-Button Abscess

This is a subfascial infection of a web space and is usually caused by skin trauma that becomes infected; it often occurs in laborers. The adherence of the palmar web space skin to the ­palmar fascia prevents lateral spread, so the infection courses dorsally, resulting in both palmar web space tenderness and dorsal web space swelling and tenderness. The adjacent fingers will be held in abduction with pain on adduction (Fig. 44-19). Incision and drainage, often using separate volar and dorsal incisions, is mandatory, and follows the same treatment as for any abscess or deep-space infection.

Osteomyelitis

Osteomyelitis in the hand usually occurs due to an open fracture with significant soft tissue injury. The presence of infected hardware, peripheral vascular disease, diabetes, and alcohol or drug abuse are also predisposing factors. Presentation includes persistent or recurrent swelling with pain, erythema, and possible drainage. It will take 2 to 3 weeks for periosteal reaction and osteopenia to be detected on radiographs. Bone scans and MRI are useful modalities to aid in diagnosis. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) have low specificity but are useful for monitoring the progress of treatment, with CRP being more reliable. Treatment consists of antibiotics alone in the early stage as long as there is favorable response. All necrotic bone and soft tissue, if present, must be débrided. Initial intravenous antibiotic therapy should cover S. aureus, the most common pathogen, and should then be adjusted according to bone cultures. Antibiotic therapy is continued for 4 to 6 weeks once the patient clinically improves and there is no further need for débridement. For osteomyelitis in the setting of an acute fracture with internal fixation in place, the hardware should be left in place as long as it is stable and the fracture has not yet healed. If the hardware is unstable, it must be replaced. An external fixation device may be useful in this setting. If osteomyelitis occurs in a healed fracture, all hardware and necrotic bone and soft tissue must be removed.⁵⁵

Pyogenic Arthritis

Infection of a joint will progress quickly to severe cartilage and bony destruction if not addressed quickly. Direct trauma and local spread of an infection are the most common causes. Hematogenous spread occurs most commonly in patients who are immunocompromised. S. aureus is the most common pathogen, followed by Streptococcus species. Neisseria gonorrhoeae is the most common cause of atraumatic septic arthritis in an adult less than 30 years of age. Presentation includes exacerbation of pain with any joint movement, severe pain on axial load, ­swelling, erythema, and tenderness. Radiographs may show a foreign body or fracture, with widened joint space early in the process and decreased joint space late in the process due to destruction. Joint aspiration with cell count, Gram stain, and culture is used to secure the diagnosis. Treatment of nongonococcal septic arthritis includes open arthrotomy, irrigation, débridement, and packing the joint or leaving a drain in place. Intravenous antibiotics are continued until there is clinical improvement, followed by 2 to 4 weeks of additional oral or intravenous antibiotics. Gonococcal septic arthritis is usually treated nonoperatively. Intravenous ceftriaxone is first-line therapy. Joint aspiration may be used to obtain cultures and decrease joint pressure.⁵⁶

Necrotizing Infections

Necrotizing soft tissue infections occur when the immune system is unable to contain an infection, leading to extensive spread with death of all involved tissues. This is different from an abscess, which forms when a functioning immune system is able to “wall off” the infectious focus. Necrotizing infections can result in loss of limb or life, even with prompt medical care.

Bacteria spread along the fascial layer, resulting in the death of soft tissues, which is in part due to the extensive blood vessel thrombosis that occurs. An inciting event is not always identified. Immunocompromised patients and those who abuse drugs or alcohol are at greater risk, with intravenous drug users having the highest increased risk. The infection can by mono- or polymicrobial, with group A β-hemolytic Streptococcus being the most common pathogen, followed by α-hemolytic Streptococcus, S. aureus, and anaerobes. Prompt clinical diagnosis and treatment are the most important factors for salvaging limbs and saving life. Patients will present with pain out of proportion with findings. Appearance of skin may range from normal to erythematous or maroon with edema, induration, and blistering. Crepitus may occur if a gas-forming organism is involved. “Dirty dishwater fluid” may be encountered as a scant grayish fluid, but often there is little to no discharge. There may be no appreciable leukocytosis. The infection can progress rapidly and can lead to septic shock and disseminated intravascular ­coagulation. Radiographs may reveal gas formation, but they must not delay emergent débridement once the diagnosis is suspected. ­Intravenous antibiotics should be started immediately to cover gram-positive, gram-negative, and anaerobic bacteria. Patients will require multiple débridements, and the spread of infection is normally wider than expected based on initial assessment.⁵⁴

Necrotizing myositis, or myonecrosis, is usually caused by Clostridium perfringens due to heavily contaminated wounds. Unlike necrotizing fasciitis, muscle is universally involved and found to be necrotic. Treatment includes emergent débridement of all necrotic tissue along with empirical intravenous antibiotics.

Wet gangrene is most common in diabetics with renal failure and an arteriovenous shunt. It is usually polymicrobial. Patients will present with a necrotic digit that is purulent and very malodorous, with rapidly evolving pain, swelling, skin discoloration, and systemic collapse. Emergent treatment is the same as for other necrotizing infections, and amputation of the involved digit or extremity must often be performed.

Infectious Flexor Tenosynovitis

Flexor tenosynovitis (FTS) is a severe pathophysiologic state causing disruption of normal flexor tendon function in the hand. A variety of etiologies are responsible for this process. Most acute cases of FTS are due to purulent infection. FTS also can occur secondary to chronic inflammation as a result of diabetes, RA, crystalline deposition, overuse syndromes, amyloidosis, psoriatic arthritis, systemic lupus erythematosus, and sarcoidosis.

The primary mechanism of infectious FTS usually is penetrating trauma. Most infections are caused by skin flora, including both Staphylococcus and Streptococcus species. Bacteria involved vary by etiology of the infection: bite wounds (Pasteurella multocida—cat, E. corrodens—human); diabetic patients (Bacteroides, Fusobacterium, Haemophilus species, gram-negative organisms); hematogenous spread (Mycobacterium tuberculosis, N. gonorrhoeae); or water-related punctures (Vibrio vulnificus, Mycobacterium marinum). Infection in anyof the fingers may spread proximally into the wrist, carpal tunnel, and forearm, also known as Parona’s space.⁵⁷

Suppurative FTS has the ability to rapidly destroy a finger’s functional capacity and is considered a surgical emergency. Suppurative FTS results from bacteria multiplying in the closed space of the flexor tendon sheath and culture-rich synovial fluid medium causing migration of inflammatory cells and subsequent swelling. The inflammatory reaction within the closed tendon sheath quickly erodes the paratenon, leading to adhesions and scarring, as well as increase in pressures within the tendon sheath that may lead to ischemia. The ultimate consequences are tendon necrosis, disruption of the tendon sheath, and digital contracture.

Patients with infectious FTS present with pain, redness, and fever (Fig. 44-20). Physical examination reveals Kanavel’s “cardinal” signs of flexor tendon sheath infection: finger held in slight flexion, fusiform swelling, tenderness along the flexor tendon sheath, and pain over the flexor sheath with passive extension of the digit.⁵⁸ Kanavel’s signs may be absent in patients who are immunocompromised, have early manifestations of infection, have recently received antibiotics, or have a chronic, indolent infection.

If a patient presents with suspected infectious FTS, empiric intravenous antibiotics should be initiated. Prompt medical therapy in early cases may prevent the need for surgical drainage. For healthy individuals, empiric antibiotic therapy should cover Staphylococcus and Streptococcus. For immunocompromised patients (including diabetics) or infections associated with bite wounds, empiric treatment should include coverage of gram-negative organisms as well.

Adjuncts to antibiotics include splint immobilization (intrinsic plus position preferred) and elevation until infection is under control. Hand rehabilitation (i.e., range-of-motion exercises and edema control) should be initiated once pain and inflammation are under control.

If medical treatment alone is attempted, then initial inpatient observation is indicated. Surgical intervention is necessary if no obvious improvement has occurred within 12 to 24 hours.

Several surgical approaches can be used to drain infectious FTS. The method used is based on the extent of the infection. Michon developed a classification scheme that can be useful in guiding surgical treatment (Table 44-1).⁵⁹ Figure 44-20B & C demonstrates drainage of a stage II FTS. A Brunner incision allows better initial exposure but may yield difficulties with tendon coverage if skin necrosis occurs. A 16-gauge catheter or 5-French pediatric feeding tube then is inserted into the tendon sheath through the proximal incision. The sheath is copiously irrigated with normal saline. Avoid excessive fluid extravasation into the soft tissue, because the resulting increase in tissue pressure can lead to necrosis of the digit. The catheter is removed after irrigation. The incisions are left open. Some ­surgeons prefer a continuous irrigation technique for a period of 24 to 48 hours. The catheter is sewn in place, and a small drain is placed at the distal incision site. Continuous or intermittent irrigation every 2 to 4 hours with sterile saline can then be performed through the indwelling catheter.

After surgery, an intrinsic plus splint is applied, the hand is elevated, and the appropriate empiric antibiotic coverage is instituted while awaiting culture results. The hand is reexamined the following day. Whirlpool therapy and range of motion are begun. Drains are removed before discharge from the hospital. The wounds are left open to heal by secondary intention. In severe cases, repeat irrigation and operative débridement may be required.

Antibiotic therapy is guided by culture results as well as clinical improvement. Once there is no further need for debridement, a 7- to 14-day course of oral antibiotics is generally prescribed. Consultation with an infectious disease specialist should be considered early in order to maximize efficiency and efficacy of therapy.

Felon

A felon is a subcutaneous abscess of the fingertip and is most commonly caused by penetrating trauma. S. aureus is the most common pathogen. The fingertip contains multiple septa connecting the distal phalanx to the skin. These septa are poorly compliant, and presence of an abscess will increase pressure and lead to severe pain and tissue death. Patients will experience erythema, swelling, and tenderness of the volar digital pad. Oral antibiotics may resolve the infection if diagnosed very early, but incision and drainage is indicated when fluctuance is identified. A digital block should be performed, followed by a longitudinal incision over the point of maximal fluctuance (Fig. 44-21). Transverse and lateral incisions should be avoided, and the incision should never extend across the distal phalangeal joint crease. Deep incision should not be performed as this may cause seeding of bacteria into the flexor tendon sheath. The wound is irrigated and packed, with warm soapy water soaks and packing changes initiated within 24 hours and performed two to three times daily until secondarily healed. Antibiotic coverage should cover for Staphylococcus and Streptococcus species.⁶⁰

Paronychia

Paronychia is an infection beneath the nail fold. The nail plate can be viewed as an invagination into the dorsal skin ­extending down to the distal phalanx periosteum. Predisposing factors include anything that causes nail trauma, such as manicures, artificial nails, or nail biting. The infection may spread around the nail plate from one side to the other, or it may extend into the pulp and result in a felon. An acute paronychia is usually caused by S. aureus or Streptococcal species. Patients report pain, erythema, swelling, and possibly purulent drainage involving the periungual tissue. Treatment consists of warm water soaks and oral antibiotics if diagnosed early. If purulence or fluctuance is present, then a freer elevator or 18-gauge needle can be passed along the involved nail fold to decompress the collection (Fig. 44-22). If the infection involves the eponychial fold, a small proximally based flap of eponychium is created by using a scalpel, followed by irrigation and packing. The nail plate must be removed if the infection extends beneath the nail plate. Packing is kept in place for 24 to 48 hours, followed by warm water soaks and local wound care. Usually, the wound cannot be repacked once the dressing is removed.⁶⁰

A chronic paronychia is most commonly caused by ­Candida species and is most often found in patients who ­perform jobs involving the submersion of their hands in water or other moist environments. These develop into thickened nails with callus-like formation along the nail folds and may ­occasionally become red and inflamed. They do not respond to antibiotic treatment, and nail plate removal with marsupialization of the skin proximal to the eponychial fold will allow the wound to heal secondarily. The environmental factors leading to the chronic paronychia must also be corrected in order for treatment to be successful.

All hand infections other than cellulitis will require surgical management. Clinical examination, particularly noting the area of greatest tenderness and/or inflammation, is the single most useful diagnostic tool to localize any purulence requiring drainage. Specific recommendations for differentiating among the possible locations of hand infection are included in the diagnostic algorithm shown in Fig. 44-23.

Tumors of the hand and upper extremity can be classified as benign soft tissue tumors; malignant soft tissue tumors (subclassified into cutaneous and noncutaneous malignancies); benign bony tumors; malignant bony tumors; and secondary metastatic tumors. Initial investigation for any mass starts with a complete history and physical exam. Hand and/or wrist X-rays should be obtained in every patient presenting with a mass unless clearly not indicated (e.g., a superficial skin lesion with no aggressive/malignant features). The workup proceeds in an orderly fashion until a diagnosis is obtained. Once a benign diagnosis is secured (by strong clinical suspicion in an experienced hand surgeon, radiographic evidence, or tissue biopsy), further workup is not needed; this may occur at any point in the workup of a mass.

Most hand masses are benign and can be readily diagnosed without advanced imaging or tissue biopsy. When necessary, additional workup may include baseline laboratory studies, CT and/or MRI of the involved region, and a bone scan or positron emission tomography (PET) scan. Staging of a malignant tumor may occur before biopsy if a malignancy is strongly suspected, or it may occur after formal biopsy. Staging includes a chest X-ray and CT with intravenous contrast of the chest, abdomen, and pelvis to detect possible metastasis. Biopsy of the mass is always the last step of a workup and should occur only after all other available information has been gathered. Any mass that is over 5 cm in size, is rapidly increasing in size (as judged by an experienced surgeon or oncologist), is symptomatic or painful, or has an aggressive clinical or radiographic appearance warrants workup and biopsy to rule out malignancy.

CT scans are useful for detecting bony tumor extension across planes and identifying tumors of small bones, such as the carpal bones. MRI is useful for evaluating soft tissue tumor involvement (e.g., which muscle compartments are involved) as well as intramedullary lesions. Most soft tissue tumors will appear dark on T1-weighted images and bright on T2-weighted images. Hematomas, hemangiomas, lipomas, liposarcomas, and adipose tissue will appear bright on T1-weighted images and dark on T2-weighted images. Scintigraphy uses methylene diphosphonate attached to technetium-99m. This complex will attach to hydroxyapatite. Immediate uptake is seen in areas of increased vascularity, such as infection, trauma, and neoplasia. Increased uptake 2 to 3 hours later is seen in “pooled” areas where new bone formation has occurred. This modality is useful for detecting areas of tumor invasion or metastases not otherwise seen on prior CT, MRI, or radiographs.

Biopsy is reserved for masses that cannot be diagnosed as benign based on prior clinical and radiographic exams. Needle biopsy is not reliable for primary diagnosis, but it can be useful for recurrent or metastatic disease. Open excisional (if mass is <5 cm in size) or incisional (if mass is >5 cm in size) biopsy is the most common biopsy method. Proper surgical oncologic technique is strictly adhered to in order to prevent tumor spread into uninvolved tissues or compartments. This includes making all incisions longitudinally using sharp dissection and meticulous hemostasis; carrying the incision directly down to the tumor with no development of tissue planes (i.e., making a straight-line path from skin to tumor); incising through the fewest number of muscle compartments; and avoiding critical neurovascular structures. The CT or MRI images will help determine the best surgical approach for biopsy or resection in order to avoid uninvolved compartments and critical structures.⁶¹

Benign Soft Tissue Tumors

Ganglion Cyst

This is the most common soft tissue tumor of the hand and wrist, comprising 50% to 70% of all soft tissue tumors in this region. They can occur at any age but are most common in the second to fourth decades with a slight predilection toward females. Patients may report a slow-growing soft mass that may fluctuate in size and can sometimes be associated with mild pain. Compressive neuropathies may be seen if they occur in Guyon’s canal or the carpal tunnel, but are uncommon. There are no reports of malignant degeneration.⁶² History and physical exam are usually sufficient to establish a diagnosis. Occurrence by location is as follows: 60% to 70% occur on the dorsal wrist between the third and fourth extensor compartments and are connected by a stalk to the scapholunate ligament (Fig. 44-24); 18% to 20% occur on the volar wrist; and 10% to 12% occur in the digits as volar retinacular or flexor tendon sheath cysts. The cyst transilluminates. There is always a stalk that communicates with the underlying joint or tendon sheath. The cyst wall is composed of compressed collagen fibers with no epithelial or synovial cells present. Clear viscous mucin fills the cyst and is composed of glucosamine, albumin, globulin, and hyaluronic acid. The etiology is unclear. The most accepted theory currently is Angelides’ who proposed that repeated stress of a joint, ligament, or tendon sheath causes an increase of mucin-producing cells and subsequent mucin production. The increased mucin production dissects superficially and coalesces into a cyst. The successful treatment of dorsal ganglion cysts by excising only the stalk supports this theory.⁶³

Treatment consists of observation if asymptomatic. If symptoms exist or the patient desires removal for cosmetic appearance, aspiration of the cyst may be performed with a successful cure rate ranging from 15% to 89%. The benefit of injected steroids is inconclusive. Aspiration of a volar wrist ganglion cyst can be dangerous due to the potential of injuring neurovascular structures. Open excision and arthroscopic excision of the cyst stalk are surgical options for cysts that are not amendable to aspiration. Recurrence rate after surgical excision ranges from 4% to 40%.⁶²

Mucous Cyst

A mucous cyst is a ganglion cyst of the DIP joint. They occur most commonly in the fifth to seventh decades, and the underlying cause is associated osteoarthritis of the DIP joint. They are slow growing and usually occur on one side of the terminal extensor tendon between the DIP joint and the ­eponychium. The earliest clinical sign is often longitudinal grooving of the involved nail plate followed by a small enlarging mass and then attenuation of overlying skin. X-rays will show signs of osteoarthritis within the DIP joint. Heberden nodes (osteophytes within the DIP joint) are often seen on X-ray.

Possible treatment includes observation, aspiration, or excision. If the cyst is not draining and the overlying skin is intact, the patient may be offered reassurance. A draining cyst poses risk of DIP joint infection due to the tract communicating with the DIP joint and should be excised. If the cyst is symptomatic, painful, or the patient desires removal for cosmetic purposes, excision should be performed. Any osteophytes in the DIP joint must be removed to reduce recurrence. Aspiration is an option for treatment, but this poses the risk of DIP joint infection through seeding of bacteria into the joint or by the development of a draining sinus tract. It is generally not performed.

Giant Cell Tumor of the Tendon Sheath

Also known as a fibrohistocytoma, fibrous xanthoma, localized nodular ­synovitis, or pigmented villonodular synovitis, this is the second most common soft tissue mass of the hand and wrist. It is a benign lesion with no clear pathogenesis. The tumor is a growth of polyclonal cells with no risk of metastases. Despite the similarity in name, it is not histopathologically related to giant cell tumor of the bone.⁶⁴

Giant cell tumor of the tendon sheath occurs as a firm slow-growing painless mass over months to years and will often feel bumpy or nodular, which is a distinguishing characteristic helpful for diagnosis. It has a predilection for occurring in close proximity to joints along flexor surfaces of the wrist, hands, and digits (especially the PIP joints of the radial digits) and occurs most commonly between the second and fifth decades (Fig. 44-25A). These tumors do not transilluminate. Direct extension into joints and ligaments can make complete excision difficult. Gross appearance of the tumor will show a well-­circumscribed nodular firm mass with a deep brown color due to the large amount of hemosiderin content, which is easily detected on histologic staining (Fig. 44-25B). Multinucleated giant cells and hemosiderin-laden macrophages are characteristic.⁶⁴

This tumor is not visible on radiographs. Approximately 20% will show extrinsic cortical erosion on X-ray. This is a risk factor for recurrence, and removal of the cortical shell should be considered. MRI is useful for delineating involvement with tendons, ligaments, and joints.

The standard treatment is marginal excision. These tumors will often grow next to or around neurovascular bundles, and an Allen’s test should always be performed preoperatively to ­confirm adequate blood supply by both ulnar and radial arteries as well as dual blood supply to an involved digit via the ulnar and radial proper digital arteries. It is important to completely excise the stalk because this will greatly reduce tumor recurrence even in the setting of residual tumor. If tumor is suspected to have extended into the joint, the joint must be opened and all tumor removed. Despite this being a benign lesion, local recurrence is approximately 30% (range, 5%–50%). Some variants can mimic more aggressive processes, and malignancy must be considered if aggressive features are identified, such as direct bony invasion.⁶⁴

Lipoma

Lipomas of the hand and wrist may occur in multiple anatomic locations, including subcutaneous tissues; intramuscularly (especially thenar or hypothenar muscles); deep spaces; carpal tunnel or Guyon’s canal; and rarely bone or nerve. They typically present as a painless, slow-growing, soft, and mobile mass over a period of months to years. Painful findings suggest close approximation to a neurovascular structure or, less commonly, a malignant lesion such as liposarcoma. Lipomas do not transilluminate. They resemble mature fat histologically. X-rays typically reveal no abnormality. MRI is the most helpful imaging modality to evaluate a lipoma and will show a bright T1 lesion and dark T2 lesion.⁶⁵

Asymptomatic lesions with no aggressive findings may be observed. Marginal excision is recommended for symptomatic, painful, or enlarging lipomas or those that cause dysfunction. MRI is recommended for deep lipomas to evaluate proximity or involvement of critical structures, followed by marginal excision if MRI findings are consistent with a lipoma. If MRI findings are not consistent with a lipoma, incisional biopsy is warranted. Recurrence after marginal excision is rare. ­Malignant degeneration to liposarcoma is exceedingly rare but has been reported.

Schwannoma

A schwannoma, also known as a neurilemmoma, is a type of benign peripheral nerve sheath tumor. It is the most common benign peripheral nerve sheath tumor of the upper extremity.⁶⁶ The majority occur as single solitary masses. Patients with neurofibromatosis type 1 (NF1) or 2 (NF2) may develop multiple schwannomas involving large peripheral nerve trunks or bilateral acoustic schwannomas, respectively. These tumors arise from the Schwann cell and occur most often in the middle decades of life. They grow as painless, slow-growing, firm, round, well-encapsulated masses with a predilection toward flexor surfaces of the forearm and palm (given their presence of large nerves). Schwannomas grow from the peripheral nerve sheath and are usually connected by a pedicled stalk. The tumor is well demarcated and can be readily separated from the nerve fascicles (Fig. 44-26). Unlike neurofibromas, they do not grow within the nerve. Paresthesias or other neurologic findings may occur, but they are usually absent, as is the Tinel’s sign. Findings such as pain, paresthesias, or numbness should raise concern for a tumor causing a compressive neuropathy or a tumor that is malignant.⁶⁶

Histologic exam reveals Antoni type A palisades of spindle cells with large oval nuclei with interlacing fascicles. Less cellular regions appear as Antoni type B areas. Mutations of the schwanomin gene on chromosome 22 are found in 50% of sporadic cases and 100% of acoustic schwannomas in patients with NF2.⁶⁷

Surgical treatment is reserved for symptomatic tumors and those that require biopsy to rule out a malignant process. An MRI should be obtained prior to surgery to confirm that the tumor is not located within the nerve (i.e., a neurofibroma) and that it is consistent with a schwannoma. Operative treatment involves excisional biopsy. If the tumor is adherent to adjacent soft tissue or not encapsulated, incisional biopsy is performed and excision is delayed pending pathology results. Malignant degeneration is exceedingly rare.⁶⁶

Malignant Soft Tissue Tumors—Cutaneous

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is the most common primary malignant tumor of the hand, accounting for 75% to 90% of all malignancies of the hand. Eleven percent of all cutaneous SCC occurs in the hand.⁶⁸ It is the most common malignancy of the nail bed. Risk factors include sun exposure, radiation exposure, chronic ulcers, immunosuppression, xeroderma pigmentosa, and actinic keratosis. Marjolin’s ulcers represent malignant degeneration of old burn or traumatic wounds into an SCC and are a more aggressive type. Transplant patients on immunosuppression have a four-fold increased risk and patients with xeroderma pigmentosa have a 1000-fold increased risk of developing an SCC. They often develop as small, firm nodules or plaques with indistinct margins and surface irregularities ranging from smooth to verruciform or ulcerated (Fig. 44-27). They are locally invasive, with 2% to 5% lymph node involvement. Metastasis rates of up to 20% have been reported in radiation or burn wounds. Standard treatment is excision with 0.5- to 1.0-cm margins. Other treatment options include curettage and electrodessication, cryotherapy, and radiotherapy.⁶⁸

Basal Cell Carcinoma

Basal cell carcinoma (BCC) is the second most common primary malignancy of the hand, accounting for 3% to 12%; 2% to 3% of all BCCs occur on the hand. Risk factors are similar for SCC and include chronic sun exposure, light complexion, immunosuppression, inorganic arsenic exposure, and Gorlin’s syndrome. Presentation includes a small, well-defined nodule with a translucent, pearly border and overlying telangiectasias (Fig. 44-28). Metastasis is very rare. Standard treatment is excision with 5-mm margins. Other treatment options include curettage and electrodessication, cryotherapy, and radiotherapy.⁶⁸

Melanoma

Melanoma accounts for approximately 3% of all primary malignant hand tumors.⁶⁹ Risk factors include sun exposure (especially blistering sunburns as a child), dysplastic nevi, light complexion, family history of melanoma, and congenital nevi. Pigmented lesions with irregular borders, color changes, increase in growth, or change in shape are suggestive of melanoma. Breslow thickness is the most important factor in predicting survival for a primary melanoma. Surgical treatment includes excision with 1-cm margins for lesions up to 1 mm in thickness and 2-cm margins for lesions over 1 mm in thickness. Sentinel lymph node biopsy is done for lesions over 1 mm in thickness or for any lesion that is ulcerated and over 0.76 mm in thickness.⁷⁰ Any clinically palpable lymph node requires a formal lymph node dissection of the involved basin, as do sentinel lymph nodes positive for melanoma. Lymph node dissection has not been shown to offer any survival benefit, but the information gained from sentinel lymph node biopsy (or lymph node dissection) does offer valuable staging information that is important for prognosis. Subungual melanomas are treated with DIP amputation, with 5-year survival reported at 66%.⁷¹

Malignant Soft Tissue Tumors—Noncutaneous

Primary soft tissue sarcomas of the upper extremity are very rare, and most hand surgeons will only see several throughout their entire career. Only 14% of all soft tissue sarcomas occur in the entire upper extremity. Statistical inference is limited due to the rare occurrence of these tumors, but mortality rate is very high despite the aggressive treatments. Fewer than 5% of soft tissue sarcomas of the upper extremity will develop lymph node metastasis. Cutaneous malignancies must be considered in the differential diagnosis for any patient with palpable lymph nodes in the setting of any upper extremity mass. Any lesion of the upper extremity that is over 5 cm in diameter, rapidly enlarges, or is painful should be considered malignant until proven ­otherwise.⁷²

Treatment for soft tissue sarcomas can range from palliative debulking to attempted curative resection. Many muscles of the upper extremity and their compartments cross joints (e.g., forearm flexors). Any malignancy within a compartment mandates complete resection of that compartment, and therefore, amputations must often be performed at levels much more proximal than the level of the actual tumor. Many soft tissue sarcomas are not responsive to radiation or chemotherapy, and use of these adjuvant treatments must be decided upon after discussion with medical and radiation oncologists in a multidisciplinary team. Several studies have shown higher mortality rates in patients who undergo initial tumor biopsy of sarcomas at institutions from which they do not ultimately receive treatment. These studies recommend biopsy be performed at the institution at which definitive treatment will be provided.⁷³ Institutions best suited for such treatment should have pathologists familiar with soft tissue sarcomas, medical and radiation oncologists, surgical oncologists, and a multidisciplinary tumor board.

An in-depth review of each type of soft tissue sarcoma is beyond the scope of this chapter. Epithelioid sarcoma is the most common primary soft tissue sarcoma of the upper extremity and usually presents as a benign-like slow-growing mass during the third or fourth decades. It has a propensity for the forearm, palm, and digits. Spread to lymph nodes has been reported. It typically spreads along fascial planes.⁷⁴ Synovial sarcoma is argued by some to be the most common primary soft tissue sarcoma of the hand and wrist, but the paucity of case reports is inconclusive. It is a high-grade malignancy that is painless and slow-growing and usually occurs adjacent to, but not involving, joints. It is most common in the second to fifth decades of life. Tumor size (>5 cm) is positively correlated with mortality. Other sarcomas include malignant fibrous histiocytoma, liposarcoma, fibrosarcoma, dermatofibrosarcoma protuberans, and malignant peripheral nerve sheath tumors, and more information can be found in further selected reading.⁷⁵ The majority of metastases to the hand involve secondary bone tumors and are discussed later in the section Secondary Metastatic Tumors.

Benign Bone Tumors

Primary benign bone tumors of the hand and wrist make up a total of 7% of all primary benign bone tumors in the body. Benign tumors of cartilage origin comprise 79% of all primary benign bone tumors of the hand and wrist.⁷⁶

Enchondroma

This is the most common primary benign bone tumor of the hand and wrist and is of cartilage origin. Up to 90% of all bone tumors in the hand and wrist are enchondromas, with 35% to 54% of all enchondromas occurring in the hand and wrist. They are often found incidentally on X-rays taken for other reasons (e.g., hand trauma). They are usually solitary and favor the diaphysis of small tubular bones and are most common in the second and third decades of life. The most common location is in the proximal phalanges, followed by the metacarpals and then middle phalanges. Enchondroma has never been reported in the trapezoid. Presentation is usually asymptomatic, but pain may occur if there is a pathologic fracture or impending fracture. The etiology is believed to be from a fragment of cartilage from the central physis. Histology shows well-differentiated hyaline cartilage with lamellar bone and calcification.⁷⁶

Two variants of enchondroma include Ollier’s ­disease (multiple enchondromatosis) and Maffucci’s syndrome ­(multiple enchondromatosis associated with multiple soft ­tissue hemangiomas). Malignant transformation is very rare in the solitary form, but there is a 25% incidence by age 40 in Ollier’s patients and a 100% life-time incidence in Maffucci’s patients. When malignant transformation does occur, it is almost uniformly a chondrosarcoma with pain and rapid growth.⁷⁷

Diagnosis is usually made based on history, physical exam, and X-rays. There is a well-defined, multilobulated central lucency in the metaphysis or diaphysis that can expand causing cortical thinning or, sometimes, thickening (Fig. 44-29A). Further imaging is seldom needed, but a CT would be the study of choice.

Observation is indicated for asymptomatic enchondromas with no risk of impending fracture, followed by annual X-rays for 2 years. If a pathologic fracture is found, it is treated with immobilization until fracture union and then surgically treated. If there is any uncertainty as to whether it is an enchondroma, incisional biopsy is indicated and definitive treatment is postponed pending final pathology. Symptomatic lesions and those with impending fracture are treated surgically. Surgical treatment consists of an open incisional biopsy and confirmation by frozen section that it is well-differentiated hyaline cartilage. Curettage and high-speed burring are used to ablate the tumor. Intraoperative fluoroscopy is used to confirm complete ablation (Fig. 44-29B). The defect is then packed with bone graft or bone substitute. Recurrence ranges from 2% to 15%. X-rays should be obtained serially after surgery.⁷⁶

Periosteal Chondroma

Periosteal chondromas are benign bone tumors of cartilage origin that arise most commonly within or adjacent to periosteum at the metaphyseal-diaphyseal junction in phalanges. They occur usually in the second or third decade as solitary lesions with pain, swelling, deformity, and possible pathologic fracture. X-rays reveal a subperiosteal lytic, unilobular lesion with erosion into adjacent cortex. There is often a rim of sclerosis. Histologically, they appear as aggressive cartilage with atypia, and it can be difficult to differentiate these from chondrosarcomas.⁷⁶

Diagnosis involves X-rays with incisional biopsy to confirm the benign diagnosis and avoid unnecessary amputation. Treatment includes en-bloc resection of periosteum and corticocancellous bone. Recurrence is less than 4%.

Osteoid Osteoma

This is a tumor of bone origin. Approximately 5% to 15% of all osteoid osteomas occur in the hand and wrist and are most often found in the proximal phalanx or ­carpus. They usually occur in the second or third decade and present with a deep, dull ache that is classically worse at night and relieved by nonsteroidal anti-inflammatory drugs (NSAIDs). X-rays reveal a central lucency that is usually less than 1 cm in diameter surrounded by reactive sclerosis. Bone scan or CT is helpful to secure the diagnosis.⁷⁸

Treatment consists of NSAID therapy only, and resolution occurs at an average of 33 months. If the patient does not wish to undergo prolonged discomfort with conservative therapy, curettage or percutaneous ablation of the nucleus may be ­performed.⁷⁸

Giant Cell Tumor of Bone

Giant cell tumors of bone make up only 5% of all benign bone tumors in the body, and only 12% of these occur in the hand or wrist. Although its name is similar to that of “giant cell tumor of tendon sheath,” they are two separate tumors and do not share the same clinical or histopathologic characteristics. Approximately 2% occur in the hand and 10% occur in the distal radius; those within the distal radius are more aggressive. They usually occur in the fourth decade with pain and swelling and possibly pathologic fracture.⁷⁹

Giant cell tumor of the bone is unique in that it is benign on histology but does have metastatic potential and can cause death. It should be considered a low-grade ­malignancy.⁷⁹ Workup includes a CT of the chest and total-body scintigraphy to evaluate for metastases and multifocal lesions and MRI to evaluate the extent of local tissue involvement. Treatment consists of amputation of involved phalanges or metacarpals and wide excision of entire carpal rows. Local and systemic surveillance must be done for at least 10 years because metastasis has been reported to occur as late as 10 years postoperatively.⁷⁹

Malignant Bone Tumors

Malignant primary and secondary bone tumors of the hand, like soft tissue malignancies, are exceedingly rare. An in-depth review is beyond the scope of this chapter. The same principles for soft tissue sarcomas of the upper extremity apply here with regard to evaluation, biopsy, and treatment.

Chondrosarcoma comprises 41% of all primary malignant bone tumors of the hand and wrist but only 1.5% of all chondrosarcomas overall. It is most likely to occur from malignant degeneration from a preexisting lesion, with enchondromatosis and osteochondromatosis being the most common. It usually presents as a slow-growing, painless mass in the fourth to sixth decades and can be difficult to differentiate from its benign counterparts. X-ray reveals endosteal erosion, cortical expansion, cortical destruction, and calcification. Metastasis has never been reported for chondrosarcomas of the hand. Chondrosarcomas are not responsive to chemotherapy or radiation.⁸⁰

Osteosarcoma of the hand is exceedingly rare; only 0.18% of osteosarcomas occur in the hand. It usually presents as a painful swelling with pathologic fracture in the fifth to eighth decades of life. Radiation exposure is believed to be a possible risk factor. X-ray findings vary widely, with 90% of tumors occurring at a metaphyseal location. Findings include an osteoblastic or osteolytic lesion, cortical breakthrough with soft tissue extension, a “sunburst” pattern radially, or periosteal elevation (Codman’s triangle). The presence or absence of metastasis is the most important prognostic factor, with a 5-year survival of 70% in the absence of metastases and a 5-year survival of 10% if present. Preoperative chemotherapy is usually given, but radiation therapy plays no role.⁸¹

Secondary Metastatic Tumors

Metastases to the hand or wrist are rare, with only 0.1% of skeletal metastases occurring in the hand. The majority of metastases to the hand are bone lesions, but soft tissue metastases have been reported. The most common primary site is the lung (40%), followed by the kidney (13%) and the breast (11%). Approximately 16% will have no known diagnosis of cancer.⁸² The most common sites are the distal phalanges, followed by the proximal and middle phalanges, metacarpals, and carpus. Patients will present with pain, swelling, and erythema. Differential diagnosis includes felon, gout, osteomyelitis, trauma, RA, or skin cancer. Treatment of a hand or wrist metastatic lesion must not interfere with treatment of the primary cancer. Treatment is usually palliative (simple excision or amputation). The average life expectancy for these patients is less than 6 months.⁸²

The palm of the hand makes up only 1% of total body surface area. A burn involving the entire hand and digits is unlikely to cause life-threatening injury or shock, but seemingly small burns to the hand may cause severe permanent loss of function if not treated appropriately. Burns to the hand can cause serious short- and long-term disability. All burns to the hand are considered severe injuries that warrant transfer to a dedicated burn center for specialized treatment. This management will include a multidisciplinary team consisting of hand surgeons, burn surgeons, burn-specialized nurses, occupational therapists, case managers, and social workers.

First-degree burns involve damage to the epidermis only and present with erythema, no blistering, and full sensation with blanching of skin. These will heal without scarring. Second-degree burns are classified as superficial or deep. Superficial second-degree burns involve damage to the papillary dermis; all skin appendages are preserved, and therefore, these readily reepithelialize with minimal to no scarring. Superficial second-degree burns are sensate and present with pain, erythema, blistering, and blanching of skin. Topical dressings are the mainstay of treatment. Deep second-degree burns involve damage to the reticular dermis with damage to skin appendages, as well as the dermal plexus blood vessels and nerves. These have decreased sensation and no cap refill and appear pale or white. Blistering may be present. Damage to the skin appendages and blood supply in the dermal plexus precludes spontaneous healing without scar. Excision with skin grafting is needed. Third-degree burns involve full-thickness damage through the dermis and are insensate with no blistering. They appear dry, leathery, and even charred.

Acute Management

Advanced Trauma Life Support guidelines should be followed. After primary survey, circulation to the hand should be assessed. Palpation and Doppler ultrasound should be used to evaluate blood flow within the radial and ulnar arteries, the palmar arches, and digital blood flow at the radial and ulnar aspect of each volar digital pad. A sensorimotor exam should be performed. Objective evidence of inadequate perfusion (i.e., deteriorating clinical exam with changes in or loss of pulse or Doppler signal) indicates the need for escharotomy, especially in the setting of circumferential burns. Escharotomy may be performed at bedside with scalpel or electrocautery under local anesthesia or intravenous sedation. The depth of the escharotomy incision should extend into the dermis but not into subcutaneous tissues. In the forearm, axially oriented midradial and midulnar incisions are made for the entire extent of the burn. Escharotomy should proceed as distally as necessary into the wrist and hand to restore perfusion. Digital escharotomies are made via a midaxial (the middle of the longitudinal axis on sagittal view) incision over the radial aspects of the thumb and small finger and the ulnar aspects of the index, middle, and ring fingers.⁸³ These locations for digital escharotomies avoid painful scars on the heavy-contact surfaces of each respective digit. After primary survey, vascular, and sensorimotor exams are complete, careful documentation should be made of all burns. This is best done with a Lund and Browder chart and includes location, surface area, and initial depth of burn.

The burns should be dressed as soon as examination is complete. Gauze moistened with normal saline is a good initial dressing because it is easy, readily available, and will not leave ointment or cream on the wounds, which can hinder frequent examinations in the initial period. It is critical that no dressing is wrapped in a circumferential manner around any body part. Edema and swelling can lead to extremity ischemia if a circumferential dressing is in place. It is important to maintain body temperature above 37°C, especially in burn patients who have lost thermoregulatory function of the skin and now have moist dressings in place. The hands should be elevated above heart level to decrease edema formation, which can hinder motion and lead to late scar contracture. The hand should be splinted in the intrinsic plus position with the MPs flexed to 90° (placing MP collateral ligaments under tension), the IPs in straight extension (prevents volar plate adhesion), and the wrist in approximately 15° of extension.⁸⁴ If the burn involves the thenar eminence, thumb, or first web space, the thumb should be splinted in full abduction (to open up the first web space). Any other web space that is burned should have the adjacent fingers splinted in abduction. This will help prevent web space contracture. In rare cases, Kirschner wires or heavy steel wires/pins are needed to keep a joint in proper position. These are placed percutaneously through the involved joint and serve as a temporary joint stabilizer.

After the primary and secondary surveys are complete, the wound should be evaluated again. Devitalized tissue should be débrided. Wounds should be cleansed twice daily, typically with normal saline. Second-degree superficial burns may be dressed with Xeroform gauze and Bacitracin. Silver sulfadiazine cream is another option for any second- or third-degree wound. It covers gram-positive and gram-negative microbes, but it does not penetrate eschar. It should be applied at least one-sixteenth of an inch thick. Sulfamylon can be used in conjunction with silver sulfadiazine or alone. It deeply penetrates eschar and tissues and has good gram-positive coverage.

After débridement of necrotic skin, grafting will eventually be necessary. Allograft (human cadaver skin) is an expensive but useful temporary dressing for second- and third-degree burns. It can remain in place for up to 14 days before the body will reject it. It typically is left in place for 7 days. Allograft stimulates a wound to begin healing and can also serve as a way of “testing” a wound that needs skin grafting. If the allograft is adherent and there is evidence of temporary ingrowth, this suggests that the wound is ready to receive a skin graft.

Occupational hand therapy has played a major role in preserving hand function following burn injuries. Reestablishment of hand function is pivotal for burn patients and is directly dependent on their ability or effort to participate with an occupational therapist. Early work with an occupational therapist can minimize the need for later reconstruction.⁸⁴ Hand therapy should be initiated as soon as possible. Hand therapists are also able to make customized molded splints that facilitate frequent dressing changes.

Surgical Management

Any burn wound will eventually heal with proper wound care. However, this may involve unacceptable scarring, deformity, contractures, pain, and unstable wounds that are prone to breakdown. The goal is to restore preinjury function as much as possible with a wound that is durable, supple, nonpainful, and allows the patient to return to society as an active member. Local wound care is the ideal treatment for wounds that can heal completely within 14 days while not sacrificing function. Purely cosmetic concerns are addressed after complete scar maturation (∼12 months). In other cases, surgical excision and skin grafting are necessary. Skin grafting should be done as soon as it becomes obvious that a wound will not be healed completely by postburn day 14. It should also be considered for wounds that are likely to cause contractures, especially along the joints and web spaces.⁸⁴

Considerable controversy surrounds the need, timing, and method of grafting burns. Careful consideration must be given to the patient’s overall status, their preinjury state, and the type of work and recreational activities they enjoyed in order to have a better understanding of which issues should to be addressed.⁸⁵ Tangential excision of the wounds should be performed under tourniquet to minimize blood loss and is carried down to viable tissue. Avoid excising through fascia (epimysium) overlying muscles or exposing tendons, bone, joint capsules, or neurovascular structures. Tissues capable of receiving a skin graft include well-vascularized fat, muscle, perineurium, paratenon, perichondrium, and periosteum. Exposure of deep structures without an adequately graftable bed mandates further coverage before skin grafting can occur (discussed later in Reconstruction section).

Once there is an adequate bed, grafting is the next step. If there is any doubt as to whether the wound bed can support a skin graft, a temporary dressing should be placed and the patient reexamined frequently for signs of granulation tissue and wound bed viability. Skin grafts to the dorsum of the hand are typically split-thickness sheet grafts (not meshed). There are no functional differences between a sheet graft and a meshed graft, but sheet grafts have a much better final appearance. Skin grafts to the palmar aspects of the hand should be full-thickness in order to provide the dermal durability needed for daily functions.⁸⁴ Skin grafts are secured with staples, sutures, fibrin glue, or even skin glue. It is important to bolster every skin graft. This prevents shearing loss and also keeps the skin graft in contact with the wound bed, preventing fluid collections that can lead to graft loss. A bolster may consist of a tie-over bolster and a splint or a negative-pressure dressing. The hand should be splinted in intrinsic plus for 7 days after skin grafting. Once the graft is adherent, hand therapy should begin, consisting of active and passive range-of-motion exercises and modalities.

Reconstruction

Reconstruction of burn wounds can begin as early as the acute setting and continue into the subacute and late stages. Burns may initially be superficial but later convert to deep burns (especially with grease, oil, and alkali burns) due to infection, tissue desiccation, or continued trauma, or they may be deep from the outset of injury. Débridement or excision of burns may result in exposure of viable muscle, bone, tendon, cartilage, joints, and neurovascular structures, as well as loss of fascial layers that are required for overlying soft tissue to glide during movement. Simply skin grafting these exposed structures will result in unstable wounds that are prone to chronic breakdown. Soft tissue contractures will develop as the skin grafts adhere to the structures, effectively anchoring them in static position. This is especially true for tendons, where gliding capability is paramount for function. Flap coverage is required in these situations. The reversed radial forearm flap is a local flap and is often the first choice for flap coverage of the hand. If the zone of injury or size of defect precludes its use, other skin and fat flaps, including the free lateral arm, free anterolateral thigh, or even free parascapular flaps, may be useful, provided the patient can tolerate a free tissue transfer (see Chapter 45) operation (Fig. 44-30). The digits may also be buried subcutaneously in the lower abdominal skin or groin crease. Vascular ingrowth from the digits into the abdominal or groin skin occurs over 2 to 3 weeks, allowing division of the flap(s) and achieving full-thickness coverage of the wounds.^84,85

An acellular dermal regenerative substitute (e.g., Integra) may be used for wounds that have exposed structures and require more durability than is offered by a skin graft⁸⁶ such as full-thickness loss overlying the extensor tendons of the wrist and hand. Dermal substitute is a good option for wounds that are not extensive enough to warrant a flap and for patients who are poor candidates for an extensive surgery. Integra is composed of acellular cross-linked bovine tendon collagen and glycosaminoglycan with an overlying silicone sheet. It is applied much like a skin graft. After incorporation in 14 to 21 days, it is capable of accepting a skin graft (after removing the silicone sheet). Conceptually, it works by replacing the lost dermis and adds durability to a wound bed. It may be reapplied multiple times to the same area if thicker neodermis is desired. Although cultured autologous keratinocytes have been used, they are expensive, time-consuming, and do not provide prompt or durable coverage. They are not widely used.

Web space contractures are the most common deformity resulting after hand burns. They may occur late despite the best efforts. In the normal web space, the leading edge of the volar aspect of the web is distal to the dorsal aspect. This is reversed in web space contractures and limits digit abduction. Local modified Z-plasty (double-opposing Z-plasty) is the preferred treatment (Fig. 44-31).

Special Considerations

Chemical burns pose a risk to healthcare providers and should be considered hazardous material. They must also be removed from the patient or continued burn injury will occur. A complete discussion of all chemicals causing burns is beyond the scope of this chapter. Hydrofluoric acid produces a slow onset of severe pain and continues to penetrate deeper structures. It avidly binds tissue and circulating calcium and can lead to hypocalcemia and cardiac arrest. The wound should be irrigated copiously with water followed by topical application of an aqueous mixture of calcium gluconate. Calcium gluconate may also be infiltrated intradermally throughout the wound. Effectiveness of treatment is assessed by relief of pain. Intra-arterial injection of calcium gluconate into the artery supplying blood flow is another alternative if the other measures fail.⁸⁷ Alkaline and acid burns require copious irrigation with water, with alkali burns often requiring hours of irrigation. Phenol burns should be irrigated with water and treated topically with polyethylene glycol. Phosphorus burns leave phosphorus particles within the wound. A 0.5% copper sulfate solution is applied to stain the particles black, followed by débridement.^84,85

Vascular disease encompasses a broad spectrum of disorders leading to compromised perfusion to the hand and digits and may potentially cause ischemia and necrosis. Chronic vascular disorders tend to develop slowly and are typically seen in older patients. This includes progressive thrombosis, aneurysms, systemic vasculopathy, and vasospastic disorders. Disorders unique or common to the hand are discussed in the following sections.

Progressive Thrombotic Disease

Hypothenar hammer syndrome involves occlusion of the ulnar artery at the wrist and is the most common occlusive vascular disorder of the upper extremity. The etiology is believed to be chronic trauma to the ulnar artery as it exits Guyon’s canal. The classic example is a construction worker who frequently uses heavy equipment, such as jackhammers, that cause prolonged vibration and repetitive impact on the ulnar aspect of the palm. This causes periadventitial arterial damage that results in scarring and eventual compression, as well as medial and intimal damage.⁸⁸ The artery then becomes weakened and prone to aneurysm and/or thrombosis. If a thrombus forms, it may embolize, producing digital ischemia. Symptoms may be chronic or acute and include pain, numbness and tingling, weakness of grip, discoloration of the fingers, and even gangrene or ulcers of the fingertips.

If acute in onset, proximal occlusions may be extracted with a balloon catheter or, sometimes, under direct vision via an arteriotomy. Very distal embolism may require infusion of thrombolytics to dissolve clots and allow reperfusion. Large-vessel acute embolism and reperfusion may result in edema and compartment syndrome, requiring fasciotomy. A high index of suspicion must be maintained.

For the more common scenario of chronic, progressive occlusion, the involved segment of ulnar artery should be resected. There is disagreement in the literature regarding whether simple ligation and excision is sufficient for patients with sufficient distal flow or if all patients should undergo vascular reconstruction.⁸⁹ The authors’ personal preference is to reconstruct all patients.

Systemic Vasculopathy

Buerger’s disease (thromboangiitis obliterans) is an inflammatory occlusive disease affecting small and medium-sized arteries and veins. It is strongly influenced by smoking and will often resolve upon smoking cessation. Typical onset is before 50 years of age. Migratory phlebitis occurs distal to the elbow, resulting in ischemia, ulceration, and necrosis of the digits. It can continue to cause more proximal ischemia and ultimately lead to loss of the hands. Treatment must start with ­smoking cessation. Failure to stop smoking will make any surgical intervention unsuccessful. Arteriography is useful to determine arterial flow and whether bypass is possible. If direct bypass is not possible, alternatives include arterialization of the venous system by connecting the dorsal venous network to the brachial artery or possible free microvascular omental transfer beneath the dorsal forearm or hand for indirect revascularization.⁹⁰

Vasospastic Disorders

Raynaud’s syndrome results from excessive sympathetic nervous system stimulation. Perfusion is diminished and fingers often become cyanotic. Although the onset of the symptoms is benign, chronic episodes can result in atrophic changes and painful ulceration or gangrene of the digits. Raynaud’s disease occurs without another associated disease. This disease predominately affects young women and is often bilateral. The vascular system is structurally intact without any obstructions. There is no ulceration, gangrene, or digit loss. In contrast, Raynaud’s phenomenon is associated with an underlying connective tissue disorder, such as scleroderma. Arterial stenosis is present due to disease changes in blood vessels as a result of the specific medical disorder.⁹⁰

Scleroderma is an autoimmune connective tissue disorder resulting in fibrosis and abnormal collagen deposition in tissue. Many organs can be affected, with the skin most commonly and noticeably involved. In this disease, blood vessels are injured by intimal fibrosis leading to microvascular disease. The vessels become subject to Raynaud’s phenomenon, and patients develop painful, ulcerated, and sometimes necrotic digits.^91,92

Sympathectomy can provide pain relief and healing of ulcers for patients with scleroderma and Raynaud’s phenomenon. In this procedure, adventitia is stripped from the radial artery, ulnar artery, superficial palmar arch, and digital arteries in various combinations based on the affected digits being treated. The decrease in sympathetic tone allows for vasodilation and increased blood flow. If the patient notes significant distal pain relief and/or previously ischemic tissue improves in color after a test administration of local anesthetic, sympathectomy may provide the same results in a long-term fashion.^91,92

Congenital differences in a newborn can be particularly disabling as the child learns to interact with the environment by using the hands. The degree of anomaly can range from minor, such as a digital disproportion, to severe, such as total absence of a forearm bone. In recent years, increasing knowledge of the molecular basis of embryonic limb development has significantly enhanced the understanding of congenital differences. Congenital hand differences have an incidence of 1:1500 births. The two most common differences encountered are syndactyly and polydactyly.⁹³

There are numerous classification systems for hand ­differences. The Swanson classification, adopted by the ­American Society for Surgery of the Hand, delineates seven groups organized based on anatomic parts affected by types of embryonic failures.⁹⁴

Failure of Formation

The failure of the formation of parts is a group of congenital differences that forms as a result of a transverse or longitudinal arrest of development. Conditions in this group include radial club hand, a deformity that involves some or all of the tissues on the radial side of the forearm and hand, and ulnar club hand, which involves underdevelopment or absence of the ulnar-sided bones.

Failure of Differentiation

The failure of the differentiation of parts comprises conditions where the tissues of the hand fail to separate during embryogenesis. Syndactyly, in which two or more fingers are fused together, is the most common congenital hand deformity and occurs in seven out of every 10,000 live births. There is a familial tendency to develop this deformity. This deformity often involves both hands, and males are more often affected than females. Syndactyly is classified as either simple (soft tissue only) or complex (bone and/or cartilage also involved), and complete (full length of the digits) or incomplete (less than the full length).

Surgical release of syndactyly requires the use of local flaps to create a floor for the interdigital web space and to partially surface the adjacent sides of the separated digits (Fig. 44-32). Residual defects along the sides of the separated fingers are covered with full-thickness skin grafts. Surgery usually is performed at 6 to 12 months of age.

Duplication

Duplication of digits is also known as polydactyly. Radial polydactyly is usually manifests as thumb duplication. Wassel described a classification system for thumb duplications based on the level of bifurcation.⁹⁵ When two thumbs are present in the same hand, they are rarely both normal in size, alignment, and mobility. In the most common form of thumb duplication, a single broad metacarpal supports two proximal phalanges, each of which supports a distal phalanx. Optimal reconstruction requires merging of elements of both component digits. Usually the ulnar thumb is maintained. If the duplication occurs at the MP joint, the radial collateral ligament is preserved with the metacarpal and attached to the proximal phalanx of the retained ulnar thumb. Surgery is usually performed at 6 to 12 months of age. Ulnar-sided polydactyly may often be treated by simple excision of the extra digit.

Overgrowth

Overgrowth of digits also is known a macrodactyly, which causes an abnormally large digit. In this situation, the hand and the forearm also may be involved. In this rare condition, all parts of a digit are affected; however, in most cases, only one digit is involved, and it is usually the index finger. This condition is more commonly seen in males. Surgical treatment of this condition is complex, and the outcomes may be less than desirable. Sometimes, amputation of the enlarged digit provides the best functional result.

Undergrowth

Underdeveloped fingers or thumbs are associated with many congenital hand deformities. Surgical treatment is not always required to correct these deformities. Underdeveloped fingers may include the following: small digits (brachydactyly), missing muscles, underdeveloped or missing bones, or absence of a digit.

Constriction Band Syndrome

Constriction band syndrome is a set of congenital differences that occurs when a tissue band forms around the digit(s) or arm in utero, impairing blood flow and growth. This condition may be associated with other problems such as clubfoot, cleft lip, cleft palate, or other craniofacial anomalies. The cause of the ring constrictions is unknown. Some theories suggest that folds or bands in the amniotic membrane may be responsible for this condition.

Generalized Skeletal Anomalies and Syndromes

This is a rare and complex group of unclassified problems.

Hand transplantation was first performed in humans in the late 1990s both in Louisville, Kentucky, and Lyon, France.⁹⁶ The treating surgeons were able to successfully remove an upper extremity from a brain-dead donor, attach it to an upper extremity amputee, and have the tissue survive. In the subsequent 15 years, many additional centers have achieved technical success with upper extremity transplantation as well.

The technical considerations of hand transplantation have proven to be only the beginning of challenges in bringing this treatment option to the general public. Replantation of an amputated limb was first reported by Malt in 1962.⁹⁷ In a limb replantation, there is a zone of injury, and cold preservation of the amputated part does not begin immediately. In a limb transplant, the harvest can be done as proximally as necessary to ensure that only healthy tissue is present on both sides of the repair and to obviate the need for limb shortening, and cold preservation of the amputated part can begin immediately after harvest.

A major concern regarding the use of limb transplantation is the immunosuppression medications required to prevent rejection of the transplanted limb. Unlike organ transplantation, which provides a critical organ without which the recipient could not survive or would require chronic mechanical support (e.g., hemodialysis), the absence of one or even multiple limbs does not represent an immediate threat to a patient’s survival. Multiple studies have documented the nephrotoxic and other side effects of tacrolimus (FK 506), the principle antirejection agent used in transplant immunomodulation protocols.^98,99

Due to these concerns, much research has been directed at minimizing the amount of antirejection medication as well as promoting tolerance or even chimerism. Donor bone marrow transplantation to the limb transplant recipient has been shown to be beneficial toward this purpose and is part of the limb transplant protocol in some centers.¹⁰⁰ Recent research with donor bone marrow infusions has shown that lower levels of immunosuppressive drugs may be possible, as well as fewer immunosuppressive agents.¹⁰⁰ Further research is needed in order to determine the efficacy and utility of donor bone marrow transfusions and how they impact transplant recipients in the short and long term.

The final challenge in consideration of a patient for limb transplantation is selection of an appropriate candidate. There are multiple patient factors that need to be considered to determine if a patient is an appropriate candidate for hand transplantation. These include medical concerns, such as immunologic issues (both antibodies and the presence of occult neoplasms or indolent viruses such as cytomegalovirus), hematologic issues including coagulopathies, and anatomic issues such as quality of skin envelope and amputation level of the bone and neuromuscular structures. Psychological and social factors must also be considered related to the recipient’s ability to comply with postoperative medication and therapy protocols as well as to cope with a continuous visible presence of a limb originating from another person.¹⁰¹

The promise of upper limb transplantation as a reconstructive technique remains high. Both civilian and military amputees stand to receive a marked functional benefit from this treatment. With the number of transplants performed worldwide approaching 100 as well as decades of animal research, understanding of how best to use this technique from functional, patient safety, and cost-effectiveness standpoints continues to grow.