Orthopedics

Which type of fracture is characterized by sharp fragments?

• Acute fractures

Which type of fracture is characterized by rounded fragments with callous formation?

• Chronic fractures; callous indicates an attempt at healing.

What are "greenstick" fractures?

• Incomplete disruptions of all aspects of the bony cortex in children; bone can be bent but not displaced with greenstick fractures.

Which type of fracture occurs through diseased bone (eg, a tumor or osteopenic bone)?

• Pathologic fractures

What are fractures called that have a communication to the skin?

• Open fractures (sometimes called "compound fractures")

What type of fracture is caused by rotational forces?

• A spiral fracture

What term is given to a fracture that breaks in multiple places?

• A comminuted fracture

What is a "butterfly fragment?"

• A smaller portion of bone that is separated from the larger portions by comminution; implies greater force and a bending mechanism; must be at least 3 fragments

Define a Monteggia fracture:

• Fracture of the proximal one-third of the ulna with associated dislocation of the radial head

Define a Galeazzi fracture:

• Fracture of the mid radius with associated dislocation of the distal radial-ulnar joint

Define a Lisfranc injury:

• A disruption of the Lisfranc ligament—the ligament binding the first metatarsal to the second

Scaphoid fractures most commonly occur as a result of:

• Fall on an outstretched hand

Where does a scaphoid (navicular) fracture of the wrist classically produce tenderness?

• Pain on the radial aspect of the wrist with tenderness over the anatomic snuffbox

Define a Chance fracture:

• A distraction-type injury of the spine where the anterior ligament fails under tension; often caused by a seatbelt injury. There is a high likelihood of associated abdominal injury (~60%).

Define a Jefferson fracture:

• Burst fracture of C1, the atlas—actually widens the spinal canal; therefore, spinal cord injury is uncommon.

Define a Hangman fracture:

• Fracture of the pars interarticularis of C2, the axis, with dissociation of the C2-C3 articulation—has a high incidence of neurologic injury.

Define a clay shoveller fracture:

• Avulsion of the lower cervical spinous process—no association with the spinal canal, therefore has no association with neurologic injury

What is the "Salter Harris" classification?

• It is a classification of physeal fractures in children

  • Grade 1: Transphyseal parallel to the joint

  • Grade 2: Fracture extends away from the joint

  • Grade 3: Fracture extends toward the joint

  • Grade 4: Fracture crosses the physis from joint to metaphysis

  • Grade 5: Crush injury to the physis

What is a Holstein-Lewis fracture?

• Fracture of the distal third of the humerus resulting in radial nerve entrapment

What associated injury must be ruled out in posterior knee dislocations?

• Popliteal artery injury

What test is indicated in posterior knee dislocations in order to rule out intimal injury?

• Arteriography

What injuries can be associated with supracondylar humerus fractures?

• Brachial artery, radial nerve, and/or median nerve (most common nerve is the anterior interosseus nerve, which is a branch of the median nerve)

What injury must you worry about with a midshaft humerus fracture?

• Radial nerve injury

What injury must you worry about with an elbow dislocation?

• Brachial artery injury

What injury must you worry about with a distal radius fracture?

• Median nerve injury

What injury must you worry about with a anterior shoulder dislocation?

• Axillary nerve injury

What injury must you worry about with a posterior shoulder dislocation?

• Axillary artery injury

What injury must you worry about with a posterior hip dislocation?

• Sciatic nerve injury (peroneal division)

What injury must you worry about with a fibula neck fracture?

• Common peroneal nerve injury

What is the typical mechanism of action of a calcaneal fracture?

• Fall from a height unto outstretched legs

What injuries are associated with calcaneal fractures?

• Contralateral foot fractures, pelvic fractures (vertical shear), spinal compression fractures

Name the 3 broad types of pelvic fracture mechanisms:

• Anterior-posterior compression, lateral compression, vertical shear

Which is the most common mechanism of pelvic fracture?

• Lateral compression

What is the Gustilo-Anderson classification of open fractures?

What is the usual surgical treatment for type I, II, and IIIA open fractures of the tibia?

• Intramedullary nailing

What is the usual surgical treatment for type IIIB and IIIC open fractures of the tibia?

• Some form of external fixation with conversion to a reamed, locked nail within 2 weeks of injury

What mangled extremity severity score (MESS) consistently predicts the need for amputation?

• MESS >7

How many points do you get on the MESS with low-energy (stab, simple fracture, "civilian" gunshot wound) skeletal and soft tissue injury?

• 1

How many points do you get on the MESS with medium-energy (open or multiplex fractures, dislocation) skeletal and soft tissue injury?

• 2

How many points do you get on the MESS with high-energy (close-range shotgun or "military" gunshot wound; crush injury) skeletal and soft tissue injury?

• 3

How many points do you get on the MESS with very high-energy (same as above plus gross contamination, soft tissue avulsion) skeletal and soft tissue injury?

• 4

How many points do you get on the MESS with a reduced or absent pulse with normal perfusion?

• 1 (doubled if limb ischemia >6 hours)

How many points do you get on the MESS with pulselessness, paresthesias, and diminished capillary refill?

• 2 (doubled if limb ischemia >6 hours)

How many points do you get on the MESS with a cool, paralyzed, insensate, numb limb?

• 3 (doubled if limb ischemia >6 hours)

How many points do you get on the MESS with a systolic blood pressure always >90 mm Hg?

• 0

How many points do you get on the MESS with transient hypotension?

• 1

How many points do you get on the MESS with persistent hypotension?

• 2

How many points do you get on the MESS with age <30 years?

• 0

How many points do you get on the MESS with age 30 to 50 years?

• 1

How many points do you get on the MESS with age >50 years?

• 2

What are the 6 "P's" of an acute compartment syndrome?

1. Pain out of proportion to exam or on passive stretch (most important)

2. Pallor

3. Pulselessness

4. Paraesthesia

5. Paralysis

6. Poikiliothermia

Which is the last of the "P's" to occur?

• Pulselessness—usually does not occur unless there is concomitant vascular injury

What diagnostic test can be helpful in the diagnosis of compartment syndrome of the extremities?

• Measurement of compartment pressures—requires a special device and in general, should not be used to rule out compartment syndrome, only to rule in

What 5 methods have been described for evaluation of compartment pressure?

• Stic (Stryker) catheter, wick catheter, slit catheter, Whitesides' infusion technique; near-infrared spectroscopy

What intracompartmental pressure is generally regarded as indicative of compartment syndrome in the extremities?

• 30 mm Hg. A better measurement is the compartment perfusion pressure, measured by CPP = diastolic pressure − intracompartmental pressure. If the CPP <30, then this indicates poor perfusion.

What is the order in which compartment syndrome causes vascular compromise?

1. Capillary perfusion

2. Venous outflow

3. Arterial inflow (pressure must be extremely elevated)

What are the compartments of the leg?

• Anterior, lateral, deep posterior, and superficial posterior

To perform an adequate fasciotomy of the leg, which compartments must be opened?

• All of them

What test is indicated in posterior knee dislocations in order to rule out intimal injury?

• Arteriography

What must be documented before and after all attempts at reduction?

• A neurovascular examination

What is the most common cause of compartment syndrome in an orthopedic patient?

• Muscle edema from direct trauma to the extremity or reperfusion after vascular injury

What level of compartment pressure is needed before surgical intervention is required?

• Controversial; compartment pressure approaching 20 mm Hg below diastolic pressure in the presence of worsening general condition, documented rising tissue pressure, significant tissue injury, or a history of 6 hours of total ischemia time of an extremity versus absolute tissue pressure of 30 mm Hg versus critical compartment pressure = 45 mm Hg

How long can peripheral nerves and muscles survive under ischemic conditions without irreversible damage?

• Up to 4 hours

Place the following in order of decreasing frequency of compartment syndrome in the lower extremity: anterior compartment; deep posterior compartment; lateral compartment; superficial posterior compartment?

• Anterior compartment; lateral compartment; deep posterior compartment; superficial posterior compartment

Most frequent compartment in the thigh to develop compartment syndrome:

• Anterior quadriceps compartment

What might the first neurologic finding be in a patient with compartment syndrome of the calf?

• Numbness of the great toe web space (anterior compartment most commonly affected (pressure on deep peroneal nerve)

Describe how to do a 2-incision, 4-compartment fasciotomy?

• Make a longitudinal incision just posterior to the tibia; carry incision through the fascia into the superficial posterior space; incise the soleus muscle longitudinally near its tibial insertion; incise the deep fascia longitudinally to decompress the deep posterior compartment; make a second longitudinal anterolateral calf incision; carry incision down through the fascia into the anterior compartment; make another longitudinal fascial incision over the lateral compartment to decompress the peroneus muscles

What is the most common iatrogenic injury during an anterior fasciotomy?

• Injury to the superficial peroneal nerve in the superior aspect of the incision

What muscles are contained in the anterior compartment of the leg?

• Tibialis anterior; extensor hallucis longus; extensor digitorum communis

What vessels are contained in the anterior compartment of the leg?

• Anterior tibial vessels

What nerve is contained in the anterior compartment of the leg?

• Deep peroneal nerve

What muscles are contained in the deep posterior compartment of the leg?

• Tibialis posterior; flexor hallucis longus; flexor digitorum longus

What vessels are contained in the deep posterior compartment of the leg?

• Posterior tibial and peroneal vessels

What nerve is contained in the deep posterior compartment of the leg?

• Tibial nerve

What muscles are contained in the superficial posterior compartment of the leg?

• Gastrocnemius, soleus, plantaris

What muscles are contained in the lateral compartment of the leg?

• Peroneals

What nerve is contained in the lateral compartment of the leg?

• Superficial peroneal

What is the technical term for the growth plate?

• Physis

What is the term for the part of the bone that is between the physis and the articular surface?

• Epiphysis

What is the term for the section of bone between the epiphysis and the bony shaft (the diaphysis)?

• The metaphysis (This includes the physis.)

What term is given to a ligamentous injury in which the ligament remains in continuity?

• Sprain

What term describes a tendinous or muscular injury?

• Strain

Early reduction should be performed in hip dislocations and femoral neck fractures in order to prevent what complication?

• Avascular necrosis of the femoral head—the blood vessels travel in the femoral neck

What is the recommended time period that all open fractures should be treated?

• Within the first 8 hours after injury

What is external fixation?

• Stabilization of an injured limb segment with pins or wires connected to the rods of a rigid construct external to the body via clamps or rings

In what situations is external fixation used?

• Complex fractures where open reduction plus internal fixation (ORIF) is not indicated; fractures with associated vascular injuries requiring stabilization and urgent vascular repair; fractures in unstable patients unable to tolerate significant blood loss or anesthesia time; treatment of open fractures; specialized limb reconstruction surgery

What is open reduction and internal fixation?

• An incision is made at or near the site of injury and the fracture is reduced under direct vision (open reduction) and subsequently rigidly stabilized with plates, screws, wires, or a combination (internal fixation).

What is the incidence of fat emboli syndrome?

• 1% to 17%

Fat emboli syndrome is characterized by:

• Respiratory distress, altered mental status, skin petechiae