Chapter 15 Extensor Tendon Repairs
Rehabilitation Overview
• Historically, extensor tendon repairs have been immobilized in a splint, whether conservatively or surgically managed, for a minimum of 3 weeks. Studies over the last 20 years indicate that immobilization of tendons following surgical repair leads to a high percentage of fair to poor results because of adhesion formation that limits tendon excursion and joint motion.
• In the past several years, early mobilization, supported by evidence related to flexor tendon management, has been advocated in the care extensor tendon injuries. Studies on postoperative flexor and extensor management demonstrate that repaired tendons tolerate early active motion and have better outcomes.
• Evans has described the following principles for the therapeutic management of extensor tendons.
1 Extensor tendons in all zones (with the exception of zones I and II) tolerate early controlled active motion.
2 Wrist position affects tendon excursion by decreasing the resistive forces from the flexor system.
• The decision to use an immobilization or early mobilization protocol depends on several factors.
1 To withstand the force of early mobilization, a strong surgical repair and good tendon quality are required.
2 Conservatively managed tendons, not surgically managed, require a period of immobilization to allow the gap between the interrupted tendons to heal sufficiently.
3 In addition, the physiology of the tendons over the distal phalanges of the fingers and thumb prevents these tendons from being able to tolerate the stress of early mobilization.
4 Therefore, tendons in zones I, II, and T-I, whether treated conservatively or surgically, benefit from an immobilization period.
• At the Hospital for Special Surgery (HSS), the authors use an early mobilization program for postoperative care of extensor tendons in all zones, except zones I, II, and T-I, where active force is not tolerated by the flat, thin, and broad extensor tendon.
2 Early mobilization programs require a strong surgical repair, good tendon integrity, patient compliance, and referral to therapy within 24 hours to 3 days after surgery.
3 The early active motion program is based on the scientific studies describing an immediate active short arc motion protocol by Evans and studies regarding positive effects of active mobilization for flexor tendons.
4 The early mobilization guidelines for thumb zones T-II and T-IV are also based on Evans’ suggestions.
5 Early active motion requires a strong repair to withstand active tension of the involved extensor tendon.
6 In addition, early active motion must begin when the repaired tendon quality is at its best 24 hours to 3 days after surgery.
7 Studies indicate that the projected tensile strength of an unstressed tendon repair may decrease as much as 25% to 50% at 5 to 51 days after surgery because of softening of the tendon ends.
• Early active motion for zones III through VIII and zones T-IV and T-V in the thumb begins with passive wrist tenodesis exercises, followed by active placehold extension, and protected active extension.
• A safe arc of motion is described for each zone to protect the repair site and promote healing. The arc of motion has been determined by calculations of tendon excursion measured in radians.
• Protected joint motion allowing for 3 to 5 mm of tendon excursion has been defined as safe and effective in preventing rupture or gapping while promoting functional glide and cellular healing.
Calculating Extensor Tendon Excursion
• To theoretically determine how much joint motion provides 3 to 5 mm of tendon excursion, Evans synthesized information from excursion studies in the literature, mathematical calculations by radians, and intraoperative measurements.
• In zones III and IV, 30 degrees of proximal interphalangeal (PIP) flexion creates 4mm of extensor digitorum communis (EDC) excursion.
• In zones V through VIII, 30 to 40 degrees of metacarpophalangeal (MP) flexion offers 4 to 5 mm of EDC excursion.
Splinting
• The basic splints included in this guideline are static finger or forearm-based splints that include only the joints crossed by the affected tendon.
Edema Control
• Postoperative edema relates directly to the fibroblastic response and collagen production at the injury site. Edema control is mandatory in treating the postoperative extensor tendon.
• Digital edema is minimized with a single layer of Coban (3M Health Care, St. Paul, MN) for as long as any excessive volume is present around the PIP joint (up to 8 to 12 weeks postoperatively).
• Dorsal hand edema is controlled with bulky, compressive dressing between exercises and therapy sessions.
Scar Management
• Dorsal hand and forearm scars often require custom silicone scar pads for improved fit and effectiveness.
Home Exercise Program
• The patient is instructed in a specific home exercise program (HEP) that is appropriate for the repaired zone.
Criteria For Advancement
• Extensor lag is defined as passive extension that exceeds active extension. When full active extension is present, there is no lag, and treatment is progressed according to the phases in the guideline.
• When an extension lag of 10 degrees or more is present, active flexion is curtailed and the focus is aimed at obtaining full active extension before advancement to the next phase.
• It is important to concentrate on the extension exercises and avoid emphasizing flexion at the expense of extension.
• Increases in passive and active flexion are avoided unless full active extension has been achieved.
Zones I and II: Immobilization
GOALS
• 0 to 6 weeks
1 Splint to prevent DIP extensor lag and educate patient for proper donning/doffing of splint to protect healing extensor tendon
PRECAUTIONS
• Do not splint DIP joint in so much hyperextension that beginning signs of ischemia develop (volar distal phalange blanches)
TREATMENT STRATEGIES
Splints
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