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Until recently, extensor tendon injuries were often discounted as an important hand problem. However, studies have shown that not all extensor lacerations fare well and that loss of flexion can be problematic. Newer postoperative protocols emphasizing tendon gliding have improved results, and better repair techniques and postoperative rehabilitation regimens are under investigation. This article reviews the evaluation of acute open and closed extensor tendon injuries, their conservative and surgical treatment, and postoperative rehabilitation options. J Am Acad Orthop Surg 1997;5:59-66

The use of dynamic extension splinting in the rehabilitation of extensor tendon injuries is gaining interest because of its apparent ability to improve clinical results. With such splinting, the extensor musculature is theoretically quiescent during both active flexion and rubber band-mediated extension; the gliding produced thereby decreases adhesion formation. Our initial intent was to perform electromyographic studies on volunteers in dynamic extension splinting to test this electrophysiologic principle. It was found, however, that only 16% of normal volunteers have quiescent extensor digitorum communis muscle activity within the dynamic extension splint typically used in this type of rehabilitation. A second splint was developed with a dorsal hood to keep the metacarpophalangeal joints in approximately 15 degrees of flexion. In this splint, 18 of 19 volunteers (95%) showed no extensor activity. The explanation for this phenomenon is not yet clear, but it shows that splint design plays a more significant role than previously expected. The expected electrophysiologic principle of dynamic extension splinting for extensor tendon injuries has been validated, but only in a splint design that is not commonly used.

A retrospective analysis was done in 62 patients with 101 digits having extensor tendon injury. Quality of outcome and parameters that might influence outcome were evaluated. The majority of patients were treated with conventional static splinting. Sixty percent of all fingers sustained an associated injury (fracture, dislocation, joint capsule or flexor tendon damage). Patients without associated injuries achieved 64% good/excellent results, and total active motion of 212 degrees. This difference was statistically significant (p less than 0.05). Distal zones (1 to 4) had a significantly poorer result than more proximal zones (5 to 8). The percentage of fingers losing flexion was greater than the percentage of fingers losing extension. In addition, the average degree loss of flexion was greater than the average degree loss of extension. This would seem to indicate that loss of flexion may be a more significant complication from extensor tendon injury than previously thought.

Carpal tunnel syndrome, Colles' fracture, and osteoarthritis of the basilar joint of the thumb are only three of the many upper extremity conditions that preferentially affect women. With more and more women entering the workplace, these conditions become more disruptive of patients' lifestyles and even may be increasing in incidence. Orthopaedic surgeons traditionally have focused on the surgical treatment of patients with these conditions, but it is becoming increasingly clear that surgeons also must focus on delineating pathophysiology to better identify those individuals at risk and help prevent these potentially disabling disorders.

This study was designed to investigate several biomechanical parameters involved in repair of extensor tendons in Zone IV (over the proximal phalanx). Typical suture techniques over the proximal phalanx did not shorten the tendon significantly nor was there significant loss of flexion at the metacarpophalangeal or proximal interphalangeal joints. The Kleinert modification of the Bunnell technique and modified Kessler technique seemed to be the strongest and provided evidence that dynamic or active range of motion, under controlled conditions and in short arcs, might be physiologically tolerated by repaired tendons.

John Gray Seiler III, editor. Philadelphia: Lippincott Williams and Wilkins; 2001. 304 pages. $49.95. This book, a collaborative effort of eleven experienced hand surgeons, is a compact and portable overview of hand surgery that seeks to provide easy access to basic information concerning the diagnosis and treatment of hand problems. The text is neatly laid …

Despite their ease of exposure, extensor tendons can be difficult to handle and suture well. Compared with flexor repair, little is known about the various factors that affect the suturing of extensor tendons. The present study was designed to investigate several biomechanical parameters involved in extensor repair. All techniques studied shortened the tendon considerably and produced significant losses of flexion at the metacarpophalangeal and proximal interpha-langeal joints. In addition, repairs achieved with all suture techniques were considerably weaker than those achieved when comparable techniques were used on flexor tendons. However, the Kleinert modification of the Bunnell technique provided the strongest sutures in extensor tendons, produced no gapping, caused the least worrisome loss of metacarpophalangeal and proximal interphalangeal flexion, and best approximated the results found in an idealized tendon-shortening model.

A retrospective study of 235 patients with 338 primary trigger fingers determined the efficacy and safety of steroid injection. Initial treatment consisted of one to three injections of corticosteroid mixed with local anesthetic. Those fingers that failed injection therapy had conventional release of the first annular pulley. Seventy-seven percent of all fingers showed resolution or improvement; 49% after a single injection, 23% after two injections, and 5% after three injections.