Metacarpophalangeal Joint Dislocations
Habib Olapade
UK pre law student; Falsely imprisoned in TX intending to move to CA, HI, or UK upon release.
Dorsal metacarpophalangeal dislocations most commonly involve either the index or little finger. Here, the volar plate is ruptured proximally from the metacarpal by a hyperextension injury. Traction across the subluxated metacarpophalangeal joint can turn a reducible joint into an irreducible, dislocated joint. Once the joint is dislocated, the volar plate is interposed between the dislocated articular surfaces. In this instance, open reduction can be accomplished with either a palmar or dorsal approach. If the palmar approach is used, care should be taken to avoid injury to the radial digital nerve in the index finger as well as the ulnar digital nerve in the small finger. The A1 pulley is incised to release the tension of the flexor tendons on the volar plate. If the dorsal approach is used, the volar plate is longitudinally incised. After the operation, the metacarpophalangeal joint is immobilized in about thirty degrees of flexion for three to five days. Splinting with active motion is then continued for three weeks. By way of contrast, if the joint is subluxed and the volar plate has not been interposed, closed reduction can be achieved with joint flexion. Although lateral dislocations of the metacarpophalangeal joint are rare, isolated radial collateral ligament ruptures can occur. These injuries should also be immobilized in thirty degrees of flexion for three weeks and the fingers should be protected from ulnar stress for an additional three weeks. Unstable index and middle finger radial collateral ligament tears should be surgically repaired.