All lacerations to the hands or feet must be carefully examined for underlying tendon injury. To find such injuries, examine the patient for a functional deficit of the anatomic part. Flexor tendon injuries of the hand require complex specialized repairs and should be promptly referred to a surgical hand specialist. Although many extensor tendon injuries may also require specialized repair, extensor injuries to the dorsum of the hand (Verdan classification zone VI) may often be treated in the office or emergency department.
Even with normal function on finger examination, a tendon may be partially lacerated. Unrepaired partial tendon lacerations can result in delayed rupture 1 to 2 days after the initial injury. Repair any tendon that is more than 50% transected. If only a minimal laceration is discovered, apply a splint for 3 weeks, followed by passive motion exercises for 2 to 3 weeks.
A tendon that angles around curves, pulleys, or joints is surrounded by a thin tendon sheath. A lacerated tendon within an intact sheath often will not heal. If the sheath is absent or severed, the proximal part of the tendon will grow in an attempt to reattach to the distal portion, often resulting in adherence to surrounding structures. Adhesions are part of the repair process, and they occasionally may interfere with function. Patients who are compliant with instructions and motivated toward rehabilitation usually have a greater chance of a good outcome after tendon repair.
When the tendon is cut completely through, the ends may retract a significant distance from the site of trauma. Careful examination and extension of the incision may be necessary to identify both ends. However, extensor tendons on the dorsum of the hand are cross-linked and usually do not retract to the same degree as flexor tendons. During the first 2 weeks of healing, a repaired tendon develops a fibroblastic bulbous connection. Organized tendon collagen usually does not begin to form until the third week. By the end of the fourth week, swelling and vascularity markedly decrease. After the swelling has abated and the junction becomes strong, the tendon can fully perform its gliding motion.
For tendon repairs to be successful, the tendons must be covered with healthy skin. Skin grafting should be performed when there is a significant area of skin avulsion or necrosis. Tendon injuries that are complicated by tissue maceration, contamination, or passage of more than 8 hours should be treated in the operating room.
Uncontrolled motion of the hand during the first 3 weeks after repair often results in rupture or attenuation of the repair. Classically, the repaired tendons are immobilized for 1 week to prevent rupture and to promote healing. Place a plaster splint on the palmar surface from the forearm to the fingertips. Place the wrist in 30 degrees of extension, the metacarpophalangeal joints in 20 degrees of flexion, and the fingers in slight flexion. Keep the fingers from flexing during splint changes. Active motion is started after 5 to 14 days to improve the final strength of the repair. Physical and occupational therapy consultation is usually helpful. Strong healing can be observed as early as 6 weeks after the tendon repair. Some centers have shown that early, limited, controlled motion using specialized orthotics may improve outcomes (see Chow et al., 1989).
Extensor tendon injuries over fingers (Verdan classification zones I through IV) involve complex structures and often result in poor healing with office repair. Because these tendons lie close to the joint capsule, any complete tendon laceration over a joint should raise the suspicion of joint capsule injury and should be treated in the operating room. Lacerations directly over the metacarpophalangeal joints (zone V) may be successfully repaired in the office by skilled surgeons. Zone VI repairs are the most commonly performed repairs by primary care physicians.
Possible complications of tendon repair include local infection, finger contracture, delayed tendon rupture, or local adhesions. Patients with associated digital fractures or with ragged lacerations tend to have poorer results.
Examine the hand laceration, and identify the ends of the tendon. If the ends of the tendon have retracted from the skin incision, extend the fingers to push the tendon ends back to the incision site.
(1) Examine the laceration, and identify the ends of the tendon.
Perform a direct end-to-end repair of extensor tendon. The Kessler technique involves passing a 4-0 nylon, stainless steel, or Dacron suture into the cut end and exiting on the proximal side (Figure 2A). An externalized loop is then made; the suture traverses the tendon (Figure 2B), makes another external loop, and finally exits the proximal cut end (Figure 2C). The opposite (distal) end of the cut tendon is sutured in a like manner (Figure 2D, exploded view). Place the knot inside the repaired tendon. Finish the repair with a running 6-0 nylon suture to provide additional stability (Figure 2E). The approximated tendon ends should not be buckled or excessively compressed. A flat end-to-end repair promotes proper healing and a return of the proper gliding action of the tendon.
(2) The Kessler technique.
PITFALL: Do not use this technique to repair extensor tendons injuries of the fingers.
The modified Bunnell technique uses 5-0 nonabsorbable suture that enters the cut portion of the tendon. It exits the opposite side of the tendon (Figure 3A), transverses to the near side (Figure 3B), and exits the proximal cut side (Figure 3C). The other (distal) side of the tendon is sutured in a like manner (Figure 3D, exploded view). Finish the repair with a running 6-0 nylon suture (Figure 3E).
(3) The modified Bunnell technique.
Partial or complete lacerations may also be repaired with interrupted horizontal mattress sutures using 5-0 nylon.
(4) Interrupted mattress sutures with 5-0 nylon can be used to repair partial or complete lacerations.
Repair the skin in a normal fashion.
(5) Repair the skin.
Chapter 14 contains the Current Procedural Terminology (CPT®) codes (12001–12020) for simple repair closures of the skin.
INSTRUMENT AND MATERIALS ORDERING
Appendix A lists the suggested instruments and materials in an office surgery tray. A suggested anesthesia tray that can be used for this procedure is listed in Appendix G. Skin preparation recommendations appear in Appendix H.
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