Osteochondroma of the capitate causing rupture of the extensor digiti minimi: case report.

Osteochondromas usually arise from the metaphyses of long bones. Involvement of the carpal bones is extremely rare. We report a case of an osteochondroma originating from the dorsal capitate in a 51-year-old man. Attritional rupture of the extensor digiti minimi tendon resulted from mechanical irritation as it coursed over the mass. Surgical excision of the mass with tendon transfer of the extensor digiti minimi was subsequently performed.