The Washington Regimen: rehabilitation of the hand following flexor tendon injuries.

This article describes the use of the "Washington Regimen" of early controlled motion in the rehabilitation of flexor tendon injuries of the band. This regimen is derived from a combination of Kleinert's controlled active extension with rubber band passive flexion, Duran',s controlled passive techniques, and the modification of the Kleinert orthosis that uses a palmar pulley system. Based on results of clincal investigations, this regimen of early controlled motion appears effective in inhibiting peritendinous scaning, joint contractures, and other complications that commonly occur secondary to flexor tendon repairs. A six-week staged regimen of postoperative rehabilitation is presented Splint design, exercise regimen, and rationale for treatment are reviewed [Dovelle S, Heeter PK The Washington Regimen: Rehabilitation of the band following flexor tendon injuries. Phy Ther 69:10-34-1040, 1989] Key Words: Exercise, strengthening; Hand injuries; Rehabilitation; Tendon injuries. Proper postoperative management following the surgical repair of flexor tendon injuries of the hand is of paramount importance. Because of the rapid formation of peritendinous scarring, achieving maximum functional return of the hand and preventing costly secondAry surgeries are therapeutic challenges.1,2 This article provides a brief overview of the history of flexor tendon rehabilitation, highlighting the milestones that have contributed to the current state of the art in flexor tendon rehabilitation. The "Washington Regimen" for flexor tendon rehabilitation is presented in detail. This regimen is a result of numerous clinical investigative studies for tendon injuries in zone 11 ("no man's land") (Fig. 1) of the hand and appears to be an effective method for the management of flexor tendon repairs. Historically, most surgeons have favored a long period of postoperative immobilization following flexor tendon surgical repair. Because the long-term functional results of these tendon repairs were poor, surgeons began implementing programs of early controlled motion. The concept of early controlled motion was designed to minimize the formation of peritendinous scarring and to maximize tendon gliding. This concept was based on studies of tensile strength by Mason and Allen, Gelberman et al, and Woo et al," in which the authors noted that early controlled motion reduced adhesion formation and stimulated the healing process and scar remodeling at the tenorrhaphy site. In 1975, Duran and Houser reported normal functional return in 80% of the cases studied.6 Based on these results, they concluded that controlled passive motion was sufficient to maintain movement and prevent tendon adhesions, This technique of controlled passive motion was later popularized by Strickland and Glogovac following their comparative study of the functional outcome of flexor tendon repairs using early postoperative motion and immobilization. Of those cases immobilized for 3.5 weeks, there were no excellent final results and 60% of the repairs resulted in a poor functional recovery. In contrast, 56% of the repairs managed using early controlled passive motion achieved excellent or good functional results. Various splinting techniques have been used to control motion of the involved digit following tendon repair. In 1973, Kleinert et al introduced a program of early controlled motion following flexor tendon repair using a plaster dorsal splint with a rubber-band traction device and early active extension of the digit against the tension of the passive rubber-band flexion. Slattery and McGrouther, however, noted theoretical disadvantages of the Kleinert splint. They suggested a splint modification to maximize distal interphalangeal (DIP) joint motion and to minimize metacarpophalangeal (MCP) joint contractures. These research studies and reports of splinting methods alluded to the clinical advantages of early controlled motion following flexor tendon repair. The percentage of poor functional results, however, indicated a need for further clinical investigative studies. In 1981, Chow et al developed the Washington Regimen of early controlled motion for rehabilitation following hand flexor tendon repairs.1 Their clinical investigations focused on flexor tendon injuries in zone 11 of the hand. The Washington Regimen of controlled motion is a six-week staged regimen derived from the combination of Duran and Houser's controlled passive motion techniques, Kleinert and associates' controlled active extension and rubber-band passive flexion, and a modification of the Kleinert splint that incorporates a palmar pulley system. Using the Strickland formula of percentage of total active motion (% TAM) of the IP joints and the Louisville classification system of flexion and extension deficits,8 Chow and colleagues reported that 98% of the participants in their study of zone 11 flexor tendon injuries achieved good to excellent functional results.3 The functional results of tendons repaired in zone II were also analyzed in a comparative prospective study of the surgical management of the tendon sheath. In this study, there were no statistical differences in functional results in hands where the tendon sheath was left open or was closed primarily. Management of Flexor Tendon injuries of the Hand Rehabilitation for flexor tendon injuries ideally begins prior to surgery with preoperative evaluation and counseling. During the preoperative counseling, time is taken to describe the six-week rehabilitation regimen. The therapist emphasizes that patient compliance is of utmost importance in achieving maximum function of the injured hand. A simplistic overview of flexor tendon anatomy and tendon healing is explained to enhance the patient's understanding of the rehabilitation demands. The function of the dynamic orthosis and the principles of controlled motion then are explained in relationship to the flexor tendon anatomy and the principles of tendon healing. Following the preoperative evaluation and counseling session, the patient is afforded the opportunity to simulatively demonstrate and express understanding of the rehabilitation procedures. If, at this time, there is evidence of probable noncompliance with the rehabilitation demands, alternate management programs are considered and discussed with the referring surgeon. If preoperative counseling is impossible, patient education should be provided as soon as possible following the surgical repair. Postoperative Managenlient of Flexor Tendon Repairs of the Hand The Washington Regimen of controlled motion for flexor tendon rehabilitation is divided into three stages, each of two weeks' duration (Fig. 2). The first stage consists of 1) therapist-assisted controlled passive flexion and extension exercises and 2) active extension exercises against passive flexion provided by a dynamic splint. The second stage consists only of active extension exercises against the passive flexion of the dynamic splint. Active flexion and active extension exercises without the use of the rubber-band passive flexion constitute the third stage of the rehabilitation regimen.3-', Stage I (Weeks 1 and 2) Following the surgical repair, the hand is immobilized for two to three days. This procedure ensures integrity of circulation to the injured area and hastens the resolution of the inflammatory process.15,16 The rehabilitation regimen then begins two to three days following the surgery. Early controlled motion at this time inhibits the formation of peritendinous scarring, which correlates with collagen synthesis occurring at the wound site.16 Before motion is initiated, the postoperative bulky dressings and plaster splint are removed, and a thermoplastic dynamic flexion-assist splint is fabricated. The dorsal splint is designed to allow 3 to 5 mm of tendon glide at the repair site, thus inhibiting the formation of adhesions that interfere with normal tendon excursion. The wrist and MCP joints are positioned in flexion. This posture protects the newly repaired tendon and controls tension at the tenorrhaphy site. The degree of wrist and MCP joint flexion desired by the referring surgeon may vary. In general, for tendon repairs in zone I through zone IV (Fig. 1), a wrist position of 45 degrees of flexion with 40 degrees of MCP joint flexion is sufficient to prevent adhesions that prevent tendon gliding.1,3,5 The thermoplastic dorsal splint also should allow for complete active extension of the IP joints. For flexor tendon repairs in zone V (Fig. 1), the splint is designed to position the wrist in 20 degrees of flexion and the MCP joints in 60 degrees of flexion. The increase in MCP joint flexion is sufficient to prevent tension at the repair site. This position also minimizes the peritendinous scar adhesions at the wrist, which may limit the degree of active wrist extension in the later stages of the rehabilitation regimen. Once the dorsal splint is fitted to the patient, with the wrist and digits in the desired position, two 2.54-cm wide pieces of soft strapping material are measured. One strap is measured and cut to fit around the volar surface of the forearm at the proximal end of die splint, and the second strap is measured and cut to fit across the palm at the level of the distal palmar crease (DPC). A 5.08-cm length of strapping then is measured and cut to fit across the volar wrist crease, and a lengthwise cut is made at both ends of the strap. This split-tail design effectively secures the forearm in the splint and prevents the dorsal cap from slipping out of position. The three straps attach to Velcro hook tabs,' which are secured to both the radial and ulnar sides of the splint at the previously mentioned positions (Fig. 3). Following the fabrication of the thermoplastic dorsal splint and die application of the straps, a palmar pulley dynamic traction system is constructed. A 2.54-cm safety pin is fastened to the DPC strap perpendicular to the line of pull of the involved digit(s) at the level of the DPC. A 10lb test nylon monofilament line is then run through the eye of the safety pin and attached distally to a small clothing hook glued to the fingernail of the involved digit(s). The distal end of the nylon monofilament is then secured to a set of two #18 rubber bands: one circumferentially intact (double) rubber band and one rubber band that is cut to form a single length band. The monofilament must be long enough to allow for full extension of the involved digit(s) without interfacing with the safety pin and the junction of the monofilament and the rubber bands. The proximal ends of the rubber bands are anchored to a hook at the proximal portion of the thermoplastic splint (Fig. 4). The palmar pulley system increases the passive flexion of the IP joints of the involved digit(s) by pulling the fingertip to the DPC of the hand. This system, in turn, maximizes tendon excursion and inhibits DIP joint extension contractures. The thermoplastic dorsal splint with the palmar pulley dynamic traction system is worn by the patient 24 hours per day for the first 28 days following the surgical repair. The splint is removed only by the therapist for splint modification and supervised treatment sessions. Early controlled active extension exercises are initiated following the fabrication and application of the thermoplastic dorsal splint and the palmar pulley dynamic traction system. Prior to initiating the active extension exercise, the patient is instructed to remove the double rubber band from the proximal anchor site on the dorsal splint (Fig. 4). The single rubber band remains anchored at all times. The patient is instructed to actively extend the involved digit(s) against the tension of the single rubber band (Fig. 5). Ten repetitions of this exercise are to be completed by the patient once every waking hour. At the end of each exercise session, the patient is instructed to reattach the double rubber band. At no time, however, should both the single band and the double band be removed from the anchor point. The prescribed regimen of controlled motion is sufficient to minimize the formation of peritendinous scarring and to allow for adequate wound healing between exercises. The use of active extension against a resistance "is based on the finding that contraction against resistance of one group of muscles results in synergistic relaxation of its antagonist," p446) thus minimizing the stress on the repaired tendon and reducing the risk of rupture. The double-band-single-band modification to the palmar pulley system permits a near-constant tension approximately 65-75 g) while the involved digit(s) is (are) both at rest and in full active extension. This modification allows for greater ease in performing the exercises, which may influence the patient's positive compliance with the exercise regimen.8 In addition to the active extension exercises, a regimen of therapist assisted passive exercises is initiated. The therapist passively flexes the MCP joints of the involved digit(s) into full flexion 90") while simultaneously extending both the proximal interphalangeal (PIP) and DIP joints passively (Fig. 6). Ideally, these therapist assisted passive exercises are performed on a daily basis during the first postoperative week and on alternate days during the second postoperative week in an effort to safeguard against contractures at the IP joints. At no time during the first 28 postsurgical days should the wrist or the MCP joints be extended during simultaneous IP joint extension of the involved digit(s). Explicit instructions are given to the patient not to actively flex the involved digit but to allow the palmar pulley system to passively pull the digit(s) into the flexed, resting position. Any individual who accompanies the patient to the therapy sessions also is educated about the exercise program. The patient is also instructed not to perform the passive exercises, which reduces the risk of any potential complications from overzealous movement of the involved digit(s). For the first two postoperative weeks, treatment sessions include 1) wound care based on the surgeon's specifications, 2) splint monitoring and modification as indicated, 3) therapist assisted passive ROM exercises of the PIP and DIP joints, 4) verbal instructions and visual demonstrations of the home exercise program, and 5) monitoring of patient compliance with the rehabilitation program, The importance of the home exercise program and the need for patient compliance are continuously emphasized by the therapist and the surgeon until the patient consistently expresses and demonstrates a proper understanding of the rehabilitation regimen. Stage H Weeks 3 and 4) The second stage of die rehabilitation program takes place during postoperative weeks 3 and 4. During Stage II, the patient continues to perform the home exercise program of active extension against the single rubber band of the palmar pulley system. The therapist-assisted passive ROM exercises are eliminated if the patient demonstrates complete active extension of the IP joints of the involved digit(s). If the patient displays any IP joint extension lag of the involved digit(s), however, the therapist assisted exercises are continued. The thermoplastic dorsal splint and the palmar pulley traction device are still worn 24 hours a day and removed only by the therapist during supervised treatment sessions. Ideally, the patient is treated three times a week throughout Stage 11. During each treatment session, the therapist performs wound care, adjusts the splint and traction device as necessary, assesses ROM within the confines of the splint, and monitors patient compliance. Stage M (Weeks 5 and 6) On day 1 of postoperative week 5, active flexion exercises and patient assisted passive flexion exercises are initiated. Prior to beginning active flexion exercises, the patient is taught and must demonstrate, on the uninvolved hand, the gentle active flexion exercise. This procedure reduces the incidence of forceful active flexion, which may rupture the newly repaired tendon when the exercises are initiated with the involved hand. The rubber-band traction is removed. The patient is instructed to actively and gently flex the involved digit(s) into the palm, attempting to touch the DPC with the fingertip(s). Once that flexed position is achieved, it is held for 10 seconds. The patient then is told to actively extend the digit(s) within the limitations of the dorsal splint. Second, the patient is taught a passive flexion exercise that consists of using the unaffected hand to simultaneously move the involved digit(s) into full passive MCP, PIP, and DIP joint flexion. This exercise is performed 10 times every waking hour, thus inhibiting the formation of tendon tightness. if the patient does not demonstrate complete active flexion to the DPC, the rubber bands are reattached and the palmar pulley system is used through the fifth postoperative week. If complete active flexion is achieved, the dynamic traction system is discontinued. The dorsal splint remains in place, however, until the end of the fifth week. On day 1 of week 6, the dorsal splint is modified to place the wrist in a neutral position with the MCP joints in 20 degrees of flexion. This modification serially increases wrist and MCP joint extension so as not to place undue tension on the repaired tendon. The prescribed home program during weeks 5 and 6 consists of the active flexion and extension exercises and the patient assisted passive flexion exercises. At the end of the fifth week, the patient is permitted to use the involved hand in light activities, which allows the patient to incorporate an activity pattern of reflexive flexion rather than the cortical movements associated with a prescribed exercise regimen. Noncortical movement patterns inhibit any improper use of the extensor mechanism, which may occur when the patient strains to maximally flex the repaired tendon.20 To avoid excessive stress on the repaired tendon, the patient is instructed not to pick up or use objects heavier than the weight of a checker or an empty cup until the completion of the sixth postoperative week. The dorsal splint is removed and its wear is discontinued at the end of week 6. During postoperative weeks 7 to 12, the patient is treated once a week to monitor progress with the rehabilitation regimen and to detect, at an early stage, the formation of any unexpected loss of ROM. The activity level using the involved hand is slowly increased. At the beginning of week 7, the patient may begin using the involved hand in light activities of daily living including personal hygiene, dressing, and feeding. Heavy lifting over 5 lb is not allowed until the completion of the 12th postoperative week. At the beginning of the eighth postoperative week, isolated blocking exercises are initiated to encourage active isolated PIP and DIP joint flexion of the involved digit(s), thus encouraging isolated motion of the flexor digitorum superficialis tendon and the flexor digitorum profundus tendon.21,22 Deep friction massage over the scar is encouraged at this time to assist in breaking down scar adhesions that may still be developing. Conclusion This article describes the use of the Washington Regimen of early controlled motion in the rehabilitation of flexor tendon repairs of the hand. in their multicenter study, Chow et al noted 80% excellent results, 18% good results, and 2% fair results. No subjects they rated demonstrated poor results. Similarly, in Chow et al's 1987 report on flexor tendon repairs in the no man's land,"382% of the digits treated using the Washington Regimen of early controlled motion achieved excellent results. Sixteen percent were rated good, 2% were rated fair, and none were rated poor. The percentages of good to excellent results achieved in clinical investigations, suggest this six-week regimen of early controlled motion is effective in inhibiting the formation of peritendinous scarring, joint contractures, and other complications that commonly occur secondary to flexor tendon repairs. Patient compliance is crucial throughout the rehabilitation process. if the patient demonstrates an unwillingness or inability to comply with the program during the preoperative counseling session or early in the rehabilitation program, this regimen is not recommended. Feasible alternatives should be discussed with the referring surgeon. Although the Washington Regimen was originally used for flexor tendon injuries in zone 11 of the hand, it appears to be equally successful, using minimal modifications, for use following flexor tendon injuries in other zones of the hand. This regimen also has been used with great success following tendon repairs of the thumb and flexor tendon grafting.