The volar approach to open reduction of the complex dislocation of the
index metacarpophalangeal joint as described by Kaplan proved to have
certain disadvantages. Digital nerves are easily damaged during exposure
and there is a limited view of the entrapped fibrocartilaginous volar plate
dorsal to the metarcarpal head. A direct dorsal longitudinal incision
through the skin and extensor tendon gives full exposure. The volar plate
attached to the proximal phalanx and trapped over the dorsal aspect of the
metacarpal head is in full view. The volar plate is split longitudinally
and the dislocation reduces spontaneously as the flexor tendons and
lumbrical muscle slip by the metacarpal head. The advantages of this
approach as compared with the volar approach are: (1) there is full
exposure of the fibrocartilaginous volar plate, the main structure blocking
reduction; (2) digital nerves are not as apt to be damaged; and (3)
accurate reduction and fixation of the osteochondral fracture of the
metacarpal head, frequently seen with this dislocation, is possible.