Metacarpal Abduction Orthosis for Patients With the Thumb Carpometacarpal Osteoarthritis

PURPOSE: A specific orthosis to increase radial abduction of the metacarpal of the thumb rather than immobilize it was designed for patients with carpometacarpal (CMC) joint osteoarthritis. This orthosis was designed especially for musicians, who need a large abduction angle of the thumb CMC joint to maintain their hand span to perform music. METHODS: The thumb abduction orthosis was custom-made of flexible polypropylene, leaving the thumb metacarpophalangeal and wrist joints unrestricted and compressing the ulnar side of the thenar muscle to increase the radial abduction angle of the thumb metacarpal. Hand span and grip strength were measured, and clinical symptoms were assessed with the visual analog scale and Quick–Disabilities of the Arm, Shoulder, and Hand score. The Tubiana and Chamagne score was used to assess musical performance. RESULTS: A total of 23 thumbs of 19 professional musicians with CMC joint osteoarthritis were placed in an orthosis. The radial abduction angle of the thumb CMC joint, grip strength, and hand span were significantly increased or enlarged after bracing. Clinical symptoms evaluated by visual analog score, Quick–Disabilities of the Arm, Shoulder, and Hand score, and Tubiana and Chamagne score also improved. CONCLUSIONS: Placement of a metacarpal abduction orthosis improved the hand span and improved patient-reported outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.