Arthrodesis of the metacarpophalangeal joint of the thumb in children and adults. Adjunctive treatment of thumb-in-palm deformity in cerebral palsy.

A hypermobile hyperextension or hyperflexion deformity of the metacarpophalangeal (MCP) joint associated with thumb-in-palm deformity in 90 patients affected by cerebral palsy was treated by arthrodesis with or without soft-tissue procedures. Twenty-two of these patients were adults with closed physes, and 68 were children or adolescents with open growth plates. The MCP joint fusion was usually accompanied by intrinsic muscle lengthening and/or extrinsic tendon transfer, but occasionally it was the only procedure performed to diminish the thumb-in-palm position. Even in four-year-olds, joint fusion was a predictable procedure to establish stability of that joint without disturbing longitudinal or circumferential growth. Measurable function was improved to a mild or moderate degree in 44 of the 50 children who were followed to maturity. Eighteen of the 68 children were unavailable for follow-up evaluation. Six of the 50 followed patients showed no functional improvement, although arthrodesis of the MCP joint occurred in four of the six. The other two patients were operated on when they were 12 years of age and developed a fibrous union that was painless and stable when they were adults. Even those patients who had no functional improvement did have improved appearance and easier control of the affected hand when it was manipulated by the opposite hand. The children were followed to maturity with age-matched cerebral palsy control patients. There was no significant disturbance in growth of those thumbs that had MCP joint fusion when the physes were open.