Repair of the lacerated flexor tendon should only be performed under ideal conditions, because the best (and sometimes only) opportunity for a good functional result is the first attempt at repair. Presence of severe contamination, infection, or massive tissue destruction should be a contraindication for immediate repair. Debridement and wound preparation should be performed first with delayed repair performed at a later time.
There are five zones of injury for flexor tendons (figure 1). Each zone has its own method of repair. Traditionally, zone II injuries (within the flexor tendon sheath) were known as “no man’s land” because of the poor results of repairs in this zone. Today, with proper surgical repair and aggressive and comprehensive rehabilitation by a specialized hand therapy service, even these patients can have satisfactory return of function.
General or axillary block anesthesia may be used. Regional blocks of the wrist or elbow of the median, ulnar, and radial nerves can also be performed. These blocks can be of benefit in the emergency room while the patient is awaiting surgery. Digital blocks are generally of little use in this setting.
Prior to surgery, the wound should be cleansed thoroughly (as tolerated) in the emergency room and a sterile dressing applied. Once adequate anesthesia is obtained, exsanguination of the arm is performed with gravity or an elastic bandage and a tourniquet should be placed on the upper arm. In the normal adult, a blood pressure cuff is inflated to 250 mm Hg, or at least 80 mm Hg above systolic blood pressure. This tourniquet may be left inflated for 2 hours. It may be reinflated again after a 20-minute period of normal circulation. The wound is then uncovered and thoroughly irrigated with several liters of warm saline.
Exposure must be adequate. It is usually necessary to extend the original limits of the wound (figure 2). However, care must be taken that the extending incisions do not injure neurovascular structures and will not cause scar contracture across the joints. Incisions in the digits should be based on the laceration pattern. For oblique lacerations on the digit, Brunner-style diagonal extensions between interphalangeal joints should be utilized, creating a zig-zag pattern along the volar surface. For transverse lacerations, midaxial incisions should be performed to prevent narrow skin flaps. It is imperative to keep the digital skin flaps widely based to prevent ischemia. The neurovascular bundles of the digits lie along the lateral volar surface of the digit and should be protected at all costs. Poorly made incisions may result in skin compromise and deformity.
Debridement and exploration of the involved area are carried out. Adjacent nerves and vessels are identified and retracted. Frequently nerve and vascular injury can ...