Open simultaneous double dislocation of the metacarpophalangeal and interphalangeal joints of the thumb with ulnar collateral ligament avulsion

Abstract

Double dislocations of the thumb at the metacarpophalangeal joint (MCPJ) and interphalangeal joint (IPJ) occurring at the same time are seldom seen in medical practice. The sporadic occurrence of this interesting injury makes it difficult to formulate a clear management protocol. We report an unusual combination of injury involving the right thumb of a 60-year-old man, where the IPJ was dislocated dorsally with a volar dislocation of the MCPJ. It was an open injury with avulsion of the ulnar collateral ligament of the MCPJ. The dislocation was treated successfully by closed reduction in the casualty department, under a ring block. The ulnar collateral ligament was repaired later in the operating theatre. At six months' follow-up, the patient had a full painless range of movement in his thumb with no instability. To our knowledge, this is the first reported case of a thumb double dislocation where the injury was open at both joints. This is also the first case where a volar dislocation of the MCPJ was treated successfully by closed reduction, with an excellent functional outcome.