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Static Progressive Forearm Rotation Contracture Management Orthosis Design: A Study of 28 Patients

Nicole M. Parent-Weiss, CO, OTR, FAAOP,
Jeffrey C. King, MD

ABSTRACT

Loss of forearm rotation can lead to significant loss of upper limb function. Operative treatment to improve rotation of the forearm at both the proximal radioulnar joint and distal radioulnar joint has been reported. There are limited orthosis designs available to address this clinical problem and limited information about the efficacy of conservative management of forearm rotation stiffness. A unique orthosis design was fabricated to provide static progressive motion for forearm rotation motion: supination and pronation. The orthosis design consisted of a custom-molded polyethylene hinged elbow orthosis with a dual offset channel overlapping an adjustable rotation component. Attempts were made to align the anatomical axis for forearm rotation motion with the mechanical axis of the orthosis. All orthoses used were adjustable from full supination to full pronation range of motion. A study was carried out to track the progress and results of 28 patients with loss of forearm rotation. Patients with synostosis or malunion of forearm fractures were excluded. Patients were included if they had 50° or less of supination, pronation, or both. Average initial supination was 33.2°, and final supination averaged 68.1°. Average gain was 36.5°. Twenty-three patients (92%) gained motion, 17 (68%) gained a functional arc. Initial pronation averaged 49.3°, and final pronation was 74.0°. Average pronation gain was 25.8°. This report describes the design details and the fit criteria and challenges. It also demonstrates the effectiveness of this type of static progressive stretching to improve forearm stiffness related to soft tissue contracture. (J Prosthet Orthot. 2006;18:63–67.)

Designs of upper limb orthoses vary from simple prefabricated three-point pressure systems to more elaborate high temperature (fabricated from plaster mold of patient) designs. All orthosis designs with articulations share a common goal of attempting to match the anatomical axis to the mechanical axis to provide simultaneous movement along the same plane of motion. One of the more difficult upper limb axes of motion to mimic in a mechanical design is the motion of forearm rotation: pronation and supination. The anatomical axis for forearm rotation is defined as a longitudinal axis that extends from the ulnar head to the radial head. The anatomical axis extends the entire length of the forearm ( Figure 1 ). The custommolded orthosis design effectively moved the patient's forearm through the entire range of motion-full supination to full pronation-with adequate limitation of substitution by circumferentially encompassing the forearm with a molded forearm cuff attached to the adjustable rotation component.

Operative treatment to improve rotation of the forearm at both the proximal radioulnar joint (PRUJ) and distal radioulnar joint (DRUJ) has been reported. ^1–4 However, there is limited information about the efficacy of conservative management of forearm rotation stiffness. Nonoperative management alone is not effective in loss of forearm rotation related to mechanical malalignment or bony block. ³ Causes of stiffness amenable to conservative treatment include elbow trauma from fracture/ dislocation, isolated radial head injury, and reconstructive procedures, such as radial head resection, arthroplasty, or ligament reconstruction. Distal radius fractures, ulna fractures, DRUJ or wrist ligament reconstruction procedures can lead to rotation stiffness that can be treated with orthoses, provided the limitation is not bony in nature. Although the reported functional range of motion (ROM) for forearm rotation is 100°, centered in neutral rotation, ⁵ individual needs can vary. For example, the increasing use of keyboards places a premium on forearm pronation, whereas for a guitar player, maximal supination is critical. The concept of positioning the shortened tissue at or near the end of its currently available range of motion is referred to as low load, prolonged stretch therapy, and is most effectively accomplished with the use of orthoses. ⁶ The force can be applied via different techniques, including static progressive stretching, dynamic splinting, or static serial casting. Technical challenges to designing effective forearm stretching orthoses include difficulty with aligning the axis of rotation, short lever arms with which to apply stretching force, and soft tissue containment.

Connective tissue of the capsule demonstrates viscoelastic properties. ⁶ The collagen latticework has a high tensile resistance to rapidly applied loads but demonstrates the properties of creep and stress relaxation in response to sustained loads. This plastic elongation has been attributed to the "separation of the attachments at the points of contact of adjacent collagen fibers in the connective tissue meshwork," ⁷ rather than from the actual ductility of the collagen fibers. This material property of capsular tissue forms the basis for the use of stretching orthoses.

Static progressive orthotic management (SPOM) uses the principle of stress relaxation. By definition, the amount of force required to maintain tissue at a given length decreases with time. ^6,8 Serial casting uses the same principles but is much more labor and time intensive. ^9,10 An incrementally adjustable orthosis controlled by the patient allows a set force to be applied that slightly exceeds the elastic limit of the tissue, resulting in relaxation and stretch. The tissue elongation occurs via reorganization of the collagen matrix and the breaking and reforming of the attachments of the fibers at greater distances. Properly applied, there is little inflammation of the tissue, resulting in minimal pain, improved compliance, and much better acceptance by the patients. SPOM allows for infinite adjustability and control of tissue tension and joint position compared with dynamic splinting. ⁶ SPOM has been effectively applied to address elbow flexion contractures ^11–13 but has received limited attention for forearm rotation.

Loss of joint motion may be related to capsular contracture, shortening of the musculotendinous units through spasm, cocontraction, or contracture, or changes of the articular surface and/or bony blocks. The latter two causes are not addressed in this study. The connective tissue of the capsule is loose areolar tissue with a meshwork structure. The collagen, elastin, and reticular fibers are loosely connected by ground substance and by chemical bonds. The mobility of this tissue is determined by the distance between the points of attachment of the collagen fibers. ⁷ There exists potential energy in the collagen lattice with a tendency for the fibers to contract and reorganize unless countered by an opposing force. The normal mobility of the elbow or wrist joint provides the opposing force to these tissue changes. Thus, when the joint is immobilized, these forces are restricted, allowing for shortening, primarily by fiber reorganization, which leads to the thickening and increased stiffness of the capsular tissue readily seen in contracted joint capsule. Trauma, edema, or ischemia exacerbates this process by stimulating the production of additional collagen fibers via active fibroblastic activity. These conformational changes may occur in as little as 3 days. ⁷ The purpose of this study is to evaluate the results of the use of a static progressive orthosis for improvement of forearm rotation caused by soft tissue contracture and to demonstrate the effectiveness of this new design of orthosis.

PATIENTS AND METHODS

Twenty-eight patients (15 men, 13 women; average age, 41.2 years; range 23–64 years) received treatment with static progressive orthoses. Half (14) had stiffness related to the PRUJ, 13 had stiffness related to the DRUJ, and 1 had stiffness related to both. Causes of stiffness included elbow fracture/dislocation (6), isolated radial head injury (3), status post radial head resection (5), distal radius fracture (10) wrist ligament reconstruction (2), and ulna fracture (2). Six patients received their orthoses following surgery for postoperative stiffness. Patients with synostosis or malunion of forearm fractures were excluded. Functional range of motion was defined as 50° supination and 50° pronation.⁵ Patients were included if they had 50° or less of supination, pronation, or both. All 28 patients were seen initially for evaluation and molding in preparation for fabrication. Average time from date of surgical release or date of injury to placement of orthosis was 7.6 weeks, with a median of 8 weeks (range, 2–12 weeks). Rotation splinting was continued for at least 3 months, or until a plateau was achieved.

Evaluation included determination of elbow joint location at an approximation of the difference between the location of the center of the medial and lateral epicondyles. Any bony abnormalities or prominence of surgical hardware were noted in the mold. The patients underwent the molding process in a position of 80° flexion and neutral forearm rotation (when applicable and patient tolerated this position). If a patient was unable to achieve this molding position, the mold was taken at a position as close to this as possible to facilitate joint alignment of the rotation component. Negative molds were filled and positive molds were modified with minimal plaster addition or removal. Approximation of soft tissue compression, especially on the humeral section, was reduced on the positive mold to achieve an intimate fit. True anatomical shape of the forearm was not compromised with plaster modification.

The mechanical joint at the elbow consisted of two options depending on the presence of a flexion or extension contracture in conjunction with the forearm rotation contracture. If the secondary flexion/extension contracture were present, a static progressive joint was used to address this limitation with the same protocol ( Figure 2 ). If no secondary limitation existed, a free range joint was used at the elbow ( Figure 3 ).

Although unable to directly mimic the anatomical axis of the forearm ( Figure 1 ) with the mechanical axis of the orthosis, the rotation component included movement of the entire forearm component around the static humeral/elbow section of the orthosis. The shape of the forearm section of the orthosis remained accurate to the exact shape of the patient's forearm. The outside of the forearm component had several layers of additional polyethylene added to produce a smooth round surface over which the rotation motion would glide smoothly and without resistance ( Figure 4 ). The total contact nature of the forearm component was used to most closely approximate the anatomical axis of rotation and prevent substitution by radiocarpal rotation, which is likely with a less-than-intimate fit between the forearm component and the patient's forearm. All orthoses were adjustable from full supination to full pronation ROM ( Figure 5 ). Dual offset slots were meticulously cut into the overlapping component to facilitate integrity of the rotation component itself and allow full ROM in directions of both pronation and supination.

Custom orthoses were fit to patients within 1 week of initial presentation. Range-of-motion measurements were taken during each follow-up appointment and entered as data. Patients were seen at 4-week intervals. Range-of-motion measurements used for data analysis were all performed by one physician with a standard technique. We standardized the measurement of forearm rotation by referencing the longitudinal axis of the humerus, rather than to "vertical," to eliminate the error associated with shoulder internal and external rotation. ¹⁴ Patients underwent aggressive hand therapy in conjunction with orthotic management. Passive ROM and/or manipulation were not performed by the therapist. Orthoses were adjusted as needed for fit problems, decreases in swelling, or increases in muscle tone. However, with the use of 1/8-inch polyethylene material for humeral and forearm shells, a certain amount of patient adjustment to compensate for decreases or increases in volume was allowed.

Detailed written donning instructions were provided to all patients. A written wearing schedule was provided and explained verbally at the time of orthosis fitting. The protocol for the determination of the wearing schedule began with the most severe limitation being addressed during sleep (6–8 hour session). Three daily wearing sessions of 3 to 4 hours each were alternated between the more severe limitation and the opposing motion ( Table 1 ). The orthosis was removed for 1 to 2 hours between wearing sessions, and functional use of the forearm and skin maintenance were encouraged. Patients were instructed to apply the orthosis in a neutral, mid-arc position, then apply rotation force in the desired direction until a strong stretching sensation was felt. They were then instructed to relax the stretch slightly, and set the position. This submaximal stretch protocol enhanced patient compliance, while providing for the stress relaxation response. Degree markings were not provided on the orthosis because patients were encouraged to apply the stretch that was tolerable at each session.

RESULTS

Duration of splinting was 12 to 24 weeks. Average initial supination was 33.2° (range, 0° – 48°), and final supination averaged 68.1° (range, 10° –90°). Average gain was 36.5° (range, .20° – 80°). Twenty-three (92%) patients gained motion; 17 (68%) gained a functional arc. Initial pronation averaged 49.3° (range, 0° –90°), and final pronation was 74.0° (range, 40° –90°). Average pronation gain was 25.8° (range, 10° – 69°). All gained pronation, and 87% achieved a functional arc ( Table 2 ). Complications included radial sensory nerve neurapraxia in two patients. Only two patients in this series required surgery for failure to achieve functional rotation.

DISCUSSION

The efficacy of static progressive splinting SPOM for the treatment of elbow flexion/extension contracture has been well documented. ^11,12,15 Serial casting is a more labor-intensive form of SPOM, which has been successful as well. ^9,16 Despite the documented results of conservative management of elbow flexion/ extension contracture with SPOM, there are no reported results with the use of SPOM to treat rotation contracture of the forearm. We are reporting the only known large series of patients with forearm contracture effectively treated with static progressive orthoses.

Green and McCoy ¹⁵ reported the effective treatment of 12 of 15 patients with elbow flexion contracture with turnbuckle splinting. The demographics of the patients are similar to those in this study. Treatment was initiated later, at an average of 5.3 months after injury or operation. Failure to obtain an acceptable correction occurred in three patients, all of whom had intraarticular incongruity. Bonutti et al. ¹¹ reported an average increase of 31° in elbow ROM in 20 patients with elbow flexion/ extension contracture. Only 8 of 20 obtained a "functional" arc of motion (30°–130° of elbow flexion/extension) The static progressive device was worn for only two 30-minute periods per day. Patient compliance and satisfaction were high, despite the limited functional results. More recently, Gelinas et al. ¹² reported the result of turnbuckle splinting for the treatment of elbow flexion/extension contracture in 22 patients. They demonstrated improvement in the ROM of 19 of 22 patients, although a functional arc was obtained in only 11 of 22. Three patients experienced no improvement, with one patient ultimately undergoing surgery to improve ROM.

We are reporting the design of a static progressive orthosis and the only known series of patients treated with SPOM for forearm rotational stiffness. Patients with diminished forearm rotation from PRUJ and/or DRUJ causes have been included, and improvement was noted in each group. Ongoing data collection with more patients is under way, with the hope that these different groups can be compared to determine if efficacy and prognostic differences exist. These orthoses are well tolerated by the patients, and self-reported compliance is high. Although the initial cost of custom-made orthoses can be high, the combination of demonstrated effectiveness, as well as unlimited pre- and postoperative use, make this device cost effective when compared with the monthly rental charges required for commercially available SPOM rotation orthoses. There was noticeable difference in the amount of time required for patients to wear the orthoses. All patients were told the minimum amount of time for orthotic treatment would be 3 months. They were also told that this time would extend until improvements in range of motion plateaued. This time varied between 3 and 12 months.

One potential weakness of the study was the inclusion of multiple diagnoses, including PRUJ and DRUJ causes for rotation loss. Pre- and postoperative orthosis use also is included. Despite this varied population, we thought the universal improvement of forearm rotation across this disparate group warranted the inclusion of these varying diagnoses/situations.

We have demonstrated the ability of this static progressive orthoses to reliably obtain/maintain a functional arc of forearm rotation in a variety of conditions. Treatment with this orthosis is well tolerated by the patients, and patient compliance is high. Additional studies are in progress to evaluate this device for the correction of proximal versus distal forearm rotation problems, as well as the efficacy for specific diagnosis. This static progressive stretching orthosis design provides an effective treatment modality for improving rotation of the forearm axis.

ACKNOWLEDGMENTS

The authors thank James Evans, RTPO, for extensive contributions to current design. Charles Cassidy, MD for the original patient referral and Jan Linhart for early design contributions.

Correspondence to: Nicole M. Parent-Weiss, University of Michigan Medical Center, Orthotics & Prosthetics, 1D220 Box 0784, 1500 East Medical Center Drive, Ann Arbor, MI 48109; e-mail: .

NICOLE M. PARENT-WEISS, CO, OTR, FAAOP, is a Certified Orthotist and University Hospital Acute Care Team Leader at the University of Michigan Orthotics & Prosthetics Center, Ann Arbor, Michigan.

JEFFREY C. KING, MD, is Associate Professor, Department of Orthopaedic Surgery, Health Care Midwest, Kalamazoo, Michigan.

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