A splint for controlled active motion after flexor tendon repair. Design, mechanical testing, and preliminary clinical results

A systematic review of rehabilitation protocols following surgical repair of the extensor pollicis longus

Introduction

The goal of this systematic review was to determine which rehabilitation protocol (static, dynamic or early active) yields the best outcomes following repair of the extensor pollicis longus (EPL) tendon in the following domains: total active motion (TAM), grip strength and range of motion.

Methods

A comprehensive and systematic literature search was run. The retrieved abstracts and titles were screened by two independent reviewers. Rehabilitation protocols were classified as static, dynamic or early active. Methodological quality of included randomized controlled trials and cohort studies were assessed using the SIGN50 scale.

Results

Fifteen articles were included in the final analysis ( κ = 0.8). From this total, five studies employed static splinting, 12 dynamic splinting and two early active splinting. Static splinting yielded ‘excellent’/‘good’ results ranging from 50% (minimum) to 60% (maximum) on the TAM classification system and a weighted mean TAM of 73.0 ± 24.0° (range 58.75–85°). Dynamic splinting studies demonstrated ‘excellent’/‘good’ results ranging from 64.4% (minimum) to 98% (maximum) and a weighted mean TAM of 111.2 ± 11.7° (range 89–134°) ( P < 0.001 and mean difference of 38.2 (95% confidence interval: 32.2–44.2). In one study, early active motion resulted in 83% of patients having ‘excellent’/‘good’ ratings.

Discussion

The available level II–IV evidence suggests better outcomes when using dynamic splinting over static splinting for rehabilitation of the EPL tendon repair. Further evidence is required to clinically confirm the differences between early active and dynamic rehabilitation protocols.

Systematic review of flexor tendon rehabilitation protocols in zone II of the hand

BACKGROUND

Restoration of function following flexor tendon repair in zone II represents a difficult clinical problem. Despite many publications on rehabilitation methods, there exists no consensus as to which method is superior. This study was undertaken to determine which flexor tendon rehabilitation protocol provides the best outcome after surgical repair in zone II.

METHODS

Electronic databases were searched for articles published between 1970 and 2009. The population included patients aged 5 years and older who sustained a flexor tendon laceration in zone II. The primary outcome was rupture rate. Secondary outcomes were range of motion and quality of life. The following protocols and their variations were considered: passive flexion and active extension protocols (Kleinert type protocols), controlled passive motion protocols (Duran type protocols), combination of the Kleinert and Duran protocols, and early active motion protocols.

RESULTS

Seventy-nine articles were identified. Fifteen studies met the inclusion criteria. The mean rate of rupture was lowest in the combined Kleinert and Duran protocols (2.3 percent) and highest in the Kleinert protocols (7.1 percent). No statistically significant differences were found. The combined Kleinert and Duran protocols and the early active motion protocols exhibited the highest proportion of digits with excellent or good results using the Strickland and Buck-Gramcko systems. One study included a quality-of-life assessment-meaningful comparison was not possible.

CONCLUSIONS

Both early active motion protocols and combined Kleinert and Duran protocols result in low rates of tendon rupture and acceptable range of motion following flexor tendon repair in zone II. Future studies should include quality-of-life measurements using validated scales.

Outcome of early active mobilization after flexor tendons repair in zones II-V in hand

BACKGROUND

The functional outcome of a flexor tendon injury after repair depends on multiple factors. The postoperative management of tendon injuries has paved a sea through many mobilization protocols. The improved understanding of splinting techniques has promoted the understanding and implication of these mobilization protocols. We conducted a study to observe and record the results of early active mobilization of repaired flexor tendons in zones II-V.

MATERIALS AND METHODS

25 cases with 75 digits involving 129 flexor tendons including 8 flexor pollicis longus (FPL) tendons in zones II-V of thumb were subjected to the early active mobilization protocol. Eighteen (72%) patients were below 30 years of age. Twenty-four cases (96%) sustained injury by sharp instrument either accidentally or by assault. Ring and little finger were involved in 50% instances. In all digits, either a primary repair (n=26) or a delayed primary repair (n=49) was done. The repair was done with the modified Kessler core suture technique with locking epitendinous sutures with a knot inside the repair site, using polypropylene 3-0/4-0 sutures. An end-to-end repair of the cut nerves was done under loupe magnification using a 6-0/8-0 polyamide suture. The rehabilitation program adopted was a modification of Kleinert's regimen, and Silfverskiold regimen. The final assessment was done at 14 weeks post repair using the Louisville system of Lister et al.

RESULTS

Eighteen of excellent results were attributed to ring and little fingers where there was a flexion lag of < 1 cm and an extension lag of < 15 degrees . FPL showed 75% (n=6) excellent flexion. 63% (n=47) digits showed excellent results whereas good results were seen in 19% (n=14) digits. Nine percent (n=7) digits showed fair and the same number showed poor results. The cases where the median (n=4) or ulnar nerve (n=6) or both (n=3) were involved led to some deformity (clawing/ape thumb) at 6 months postoperatively. The cases with digital or common digital nerve involvement (n=7 with 17 digits) showed five excellent, two good, four fair, and six poor results. Complications included tendon ruptures in 2 (3%) cases (one thumb and one ring finger) and contracture in 2 (3%) cases whereas superficial infection and flap necrosis was seen in 1 case each.

CONCLUSION

The early active mobilization of cut flexor tendons in zones II-V using the modified mobilization protocol has given good results, with minimal complications.

Chemoprotection of flexor tendon repairs using botulinum toxin

BACKGROUND

After flexor tendon repair, tendon gapping or rupture may be replaced by joint stiffness and poor function. After surgical repair of injured flexor tendons, botulinum toxin type A was injected into the forearm flexor muscles. This selectively decreased the force of muscle contraction. During this period of partial muscle denervation, patients could generate enough force to allow for early active mobilization (with its attendant benefits) but insufficient force to induce gapping or rupture of the repaired tendon.

METHODS

Eighteen adult patients with zone 2 flexor tendon injuries (34 digits) were studied prospectively for up to 3 years. Tendons were repaired using the modified Kessler technique and marked with stainless steel wire. Botulinum toxin was injected into the appropriate proximal flexor muscle belly under localizing electromyographic control. A matched cohort consisted of 53 patients (104 digits).

RESULTS

Results were assessed according to range of joint motion (Kleinert and Verdan criteria) and electromyographic and radiologic studies. Ninety-four percent had excellent results and 6 percent of digits had good results. There were no patients with fair or poor results. Average active range of motion was 244 degrees at 18 months. No gapping or ruptures occurred and no tenolyses were required. The control group of matched controls (modified Kessler repair; no botulinum injection) showed that 81 percent of digits had excellent results, 6 percent had good results, 8 percent had fair results, and 6 percent had poor results.

CONCLUSIONS

Botulinum toxin injection statistically significantly improves the results of flexor tendon repair. The authors have termed this technique "chemoprotection" of flexor tendon repairs.

The scientific basis for advances in flexor tendon surgery

During the last 40 years, there has been an enormous amount of basic scientific research designed to improve our knowledge of the structure of tendons, the biomechanics of their action, their biologic response to injury and repair, the mechanical characteristics of various tendon suture methods, and the effect of postrepair motion stress on tendon strength and healing. These investigative efforts have given rise to improved methods of tendon repair and protocols for the early application of passive and active wrist and digital motion as a means to more rapidly increase the strength and gliding of repaired tendons. The surgical techniques of hand surgeons and the rehabilitation protocols of hand therapists have improved enormously from these scientific efforts and the results of flexor tendon repair have become much more reliable. This article attempts to review many of the important scientific reports dealing with flexor tendons that have been published during the last three-plus decades and indicate how those works have improved our management of these difficult injuries.

The evolution of early mobilization of the repaired flexor tendon

The most important difference between the various approaches to postoperative digital flexor tendon rehabilitation is how the repaired tendon is treated during the first three to six weeks, in the earliest stages of healing. Early mobilization is the most commonly reported method of managing the healing flexor tendon. There are many different protocols and abundant research to support published approaches to tendon management. With so many choices, today's hand therapist must understand not only what those choices are, but also why and when to use them. There is no one correct way to manage a repaired flexor tendon; the specialist who does not understand how current techniques evolved is ill-equipped to design the appropriate treatment for a given patient. This article presents an overview of management options and how they have been developed over time, with special attention to changes in splint and exercise design in the crucial first few weeks after repair.

Dynamic splinting after extensor tendon repair in zones V to VII

This retrospective study evaluates a dynamic active motion protocol for extensor tendon repairs in zones V to VII. Fifty-eight patients with 87 extensor tendon injuries were examined. Using Geldmacher's and Kleinert and Verdan's evaluation systems, the results were graded as "excellent" and "good" in more than 94%, and as "satisfactory" in the remainder. The need for secondary tenolysis was low (6%), and no other surgical complication occurred.

Splinting programmes for tendon injuries

It is beyond doubt that splinting programmes have often been an integral and important part of the rehabilitation process in tendon injuries. Over the past three decades, hand splints for tendon injuries of various designs and different mobilisation programmes have been developed in the hope of pursuing better clinical and functional outcome for patients. In this paper, the development of different splinting programmes in flexor and extensor tendon injuries and the current practice in some acute hospitals in Hong Kong were discussed.

Evidence-based practice in splinting the injured hand

Evidence-based medicine has been practised in the early 1990s in the Western countries and its model has aroused interests in the Asian countries including Hong Kong in the late 1990s. The need for evidence-based practice was called upon by Sackett and his colleagues 14-16 mainly because of the exponential growth of new evidence of treatment effectiveness. There is a great demand for clinicians to search for the best evidence and to incorporate into the daily practice so as to ensure the best quality and standard of treatment. This paper is to review the development and process of evidence-based practice in the area of hand splinting for our local clinicians. Some major problems were identified in the delivery of clinical evidence-based practice, and suggestions have been made to overcome these problems with a view in supporting its model in the local clinical field.

Adhesion formation after nerve repair: an experimental study of early protected mobilization in the rabbit

The common peroneal nerve and its surrounding muscles were cut and repaired in 14 rabbits. The injured limb was then either immobilized for 3 weeks or passively mobilized within a "safety range" every day. At 3 weeks after operation, the "stretch test" and "peel test" showed no difference in the biomechanical features of the adhesions between the nerve repair and the surrounding soft tissues.

Results of dynamic splintage following extensor tendon repair

We report a prospective study of dynamic splintage following extensor tendon repair. Eighty-four patients with 101 extensor tendon injuries were studied. Using Dargan's evaluation system, there were 97% excellent results for the thumb and 93% excellent and good results for the fingers. The average total active motions were 107 degrees for thumbs and 245 degrees for fingers. Over 80% of patients regained good power grip. Patients with associated digital fractures or with ragged lacerations had poorer results. Overall, we found that dynamic splintage was a satisfactory method after extensor repair.

The application of force to the healing tendon

This paper redefines the term "active motion" in postoperative tendon management programs as "minimal active muscle-tendon tension" (MAMTT), and reports a study of internal forces applied to a repaired tendon with MAMTT, with specific guidelines for joint angle and external load application, that allows a repeatable and reliable technique for the application of active stress to a healing tendon repaired with some currently available popular suture techniques. A comparative analysis of the reported tensile strengths of 28 different repair techniques comparing methods of study with conversion of newtons to grams provides the therapist easy access to a workable equation for force application being less than the tensile strength of any specific repair. The "active" hold position or MAMTT for the digital flexor system is calculated mathematically, with drag eliminated, and joint angle position of 45 degrees wrist extension, metacarpophalangeal joint flexion of 83 degrees, proximal interphalangeal joint flexion of 75 degrees, and distal interphalangeal joint flexion of 40 degrees, and an external load applied at the fingertip of 50 grams. In this position, the internal force on the flexor digitorum profundus is 41 grams, and that on the flexor digitorum superficialis is 605 grams. These forces dramatically increase as joint angles become greater, creating forces that exceed the tensile strengths of most repairs. Internal forces along the extensor system are calculated mathematically at approximately 300 grams when the wrist is positioned at 20 degrees of flexion, and the digital joints at a position of 0 degrees of extension in an active hold position. Postoperative management of the repaired flexor or extensor tendon with immediate active motion described as MAMTT is supported by a clinical review of 165 tendons treated with this technique.