Postoperative Therapy for Chronic Thumb Carpometacarpal (CMC) Joint Dislocation

Case Report

A right-handed male electrician, age 56 yr, was seen in the hand clinic with a history of pain and deformity in the base of the right thumb. He had noticed these changes for about a year and a half. The patient reported no history of trauma or isolated incident but used his right hand continually at work. For about a year, he had been able to passively “push the bone back into place,” but this adjustment was painful. Pinching with the thumb required considerable effort, making it difficult to use the right hand at work. He was treated with multiple periods of splinting and had received an intraarticular injection. Recently, the thumb had begun to hurt for longer periods, even without use.

Past medical history and review of systems was negative. The patient did not take any medication on a regular basis. Examination revealed a clearly dislocated right thumb CMC joint that could be relocated with pain. The right thumb was about 2 cm shorter than the left thumb and was unstable. The patient did not demonstrate generalized hyperlaxity, although the metacarpophalangeal (MCP) joint of the thumb was unstable, falling into subluxation in flexion during pinch. He could not abduct his thumb and used it only in key pinch. Radiographs demonstrated dislocation with the trapezium tilted radially and evidence of some calcification in the soft tissues. The base of the metacarpal had a rounded appearance (Figure 1).

OPEN IN VIEWER

Figure 1.

Posteroanterior radiograph of the hand illustrating a dislocation of the carpometacarpal joint of the thumb.

The patient was treated surgically to remove the trapezium. Half of the flexor carpi radialis (FCR) was used to suspend the thumb metacarpal through a drill hole, and some of the tendon was used as interposition wound around the intact half of the FCR. The base of the metacarpal was almost completely devoid of cartilage and rounded off. It was decided not to perform an arthrodesis because it was our impression that the alignment would exert shear forces on the fusion mass, create difficulty in bone healing, and load an already compromised MCP joint.

The patient was seen by an occupational therapist 5 days after surgery. At that time mild swelling appeared in the wrist and hand. Pain as evaluated using a visual analog scale was 4/10. The thumb had been lengthened considerably by the surgery and was now the same length as the left thumb.

On initial postoperative evaluation, the wrist was in 30° of flexion and the thumb was in a position of palmar adduction with loss of web space (Figure 2). The MCP and interphalangeal (IP) joints were in neutral. The clinical presentation was explained by tightness of the capsular structures, which had become contracted during the long period of dislocation, and by contracture of the dynamic stabilizers of the CMC joint and the thumb, specifically the flexor pollicis longus (FPL), extensor pollicis longus (EPL), and adductor pollicis, as well as possibly the tendons of the first extensor compartment, which are palmar abductors. Tightness of these structures would explain the position of the joints of the wrist and the thumb as a whole.

OPEN IN VIEWER

Figure 2.

Postoperative photograph showing the small web space and limitation of thumb abduction compared with the unaffected side.

The standard postoperative protocol for this surgical procedure consists of thumb spica splinting for 2–2.5 wk and active ROM and exercises for activities of daily living (ADLs) started immediately thereafter, emphasizing isometric abduction of the thenar muscles initially. Exercises also include active flexion at the CMC joint at first to the radial fingers and gradually toward the little finger and are performed progressively from distal to proximal on the finger. Edema control and scar treatment are implemented as necessary. Strengthening is paced with increasing ROM.

Because of the change in this patient’s anatomy after surgery, the therapeutic protocol took into account the contracted soft tissues that had been pulled out to length and the patterns of thumb use that had developed over years of chronic dislocation. Moreover, the demands of the patient’s job as an electrician necessitated both fine manipulation and gross motor strength, which needed to be addressed as well. In a deviation from the standard protocol, the patient was splinted for a prolonged period to stretch out the soft tissues and emphasis was placed on changing his pattern of thumb use while taking into account his specific functional demands.

The treating therapist (Hani Harel) performed all measurements and tests. The patient was evaluated often during postoperative therapy by the team, including the surgeon (Ronit Wollstein).

The plan included twice-weekly therapy sessions. To maintain tension in the contracted thenar musculature and the adductor pollicis, a thumb spica splint in abduction was constructed. The splint was adjusted periodically using sponge inserts to widen the web space and increase the tension on the thenar musculature and was worn for a total of 6 wk. The original splint extended to the tip of the thumb to include the IP joint, but at 2 wk postsurgery, it was shortened to allow thumb IP joint movement, and the patient was instructed to use the thumb in ADLs to increase the stretch on the thumb musculature. During this period, the splint was inspected often (2×/wk) to make sure no pressure was developing in the area of the palmar CMC joint (Figure 3). The patient was also instructed to use the hand in the splint for activities such as writing, pinch and opposition, and grasp of small objects while gradually advancing from distal to proximal to maintain soft-tissue tension and prevent recurrence of deformity.

OPEN IN VIEWER

Figure 3.

Postoperative splint pulling the thumb into abduction.

At 6 wk postsurgery, the splint was removed during the day, but the patient continued wearing it at night. The size of the web space in the night splint was adjusted at every session. The patient continued therapy with activities tailored to his occupational demands, which included working with a screwdriver and bolts. Emphasis was placed on performing these tasks with the thumb in a neutral position while maintaining the web space. The patient felt increased limitation during activities that required wrist supination; therefore, these types of activities were stressed (e.g., opening doors and jars, using a screwdriver). A dynamic splint was made for use during the day that consisted of a soft Velfoam^® (Velcro USA, Manchester, NH) strap on the wrist with a sling for the thumb (also made out of soft Velfoam) attached to the proximal strap with a rubber band. This passively pulled the thumb out radially into abduction during activities. The patient was also encouraged to work at home and gradually progressed from weeding (strengthening pinch) to using shears (requiring power in adduction but again passively abducting the thumb). He gradually returned to work. At 4 mo, grip strength on the right side was equal to the left (unaffected) side and most pinch strength results were almost equal (Table 1). In addition, the Purdue Pegboard Test (Tiffin & Asher, 1948) results were equal for the right and left sides at 4 mo (Mandell, Nelson, & Cermak, 1984).

The patient’s only complaint at this time was dorsal subluxation of the MCP joint during heavy use. This complaint was addressed with a small splint to the MCP joint that he used while performing heavy tasks. The patient did not use this splint often, and a splint for the IP joint alone was added to limit IP joint flexion and allow further stretching of the EPL and FPL, thus increasing flexion with stretching the extensor in the MCP joint. This addition and consequent improvement in MCP joint flexion to 50° induced a complete disappearance of the dorsal subluxation at the MCP joint.

At 6 mo postsurgery, the patient had returned to full function, with a stable MCP joint during power pinch and grip. Grip strength was stronger in the right hand than in the left (see Table 1). The patient’s retrospective Disabilities of the Arm, Shoulder and Hand score was 100 (Institute for Work and Health, 2006); at 6 mo, it had improved to 78, with recent ipsilateral shoulder symptoms being the main factor limiting function.

Implications for Occupational Therapy Practice

This case has the following implications for occupational therapy practice:

Conclusion

This article describes postoperative treatment after arthroplasty for a chronic thumb CMC joint dislocation. The therapeutic protocol was adjusted to address the soft-tissue contracture and imbalance that existed because of the chronicity of the condition. The main problem was contracture of the dynamic soft tissues affecting the thumb, so therapy included splinting to maintain length and tension. Because the muscles affect all of the joints of the thumb, the patient’s recovery began at the CMC joint and later progressed to the MCP joint. The specific demands of the patient’s occupation necessitated working to change the patterns of thumb use that had been adapted to compensate for a chronically dislocated thumb in work-related activities. Because many of the surgical procedures addressing thumb CMC joint OA involve changing the biomechanics of the joint (shortening, removal of the trapezium, metacarpal osteotomy), it may be beneficial to evaluate the soft-tissue tension and the pattern of thumb use after surgery to treat any deficiencies or inequalities and thus improve functional results.