[Recent palmar dislocations of the proximal interphalangeal joint]

Recent anterior dislocations of the proximal interphalangeal (PIP) joint are uncommon injuries. Chronic and irreducible dislocations have been most often reported. This study aims to precise the anatomic and radiologic aspects of these lesions about three cases, and to compare these cases and their treatment with thirteen cases published in the literature between 1966 and 1994.

Three patients presented an anterior dislocation of the PIP joint after direct or twisting traumatism. One had an avulsion of the central slip of the extensor tendon and remained unstable after closed reduction needing pin fixation. Two had a longitudinal tear between central and lateral bands of the tendon with an entrapment of the condyle of the proximal phalanx, and the dislocations were irreducible. After open reduction, the joint was stable.

The first case showed a limited flexion after three months. In the two other cases without rupture, full range of motion was recovered after two months.

These cases have been compared with thirteen cases of recent papers from nine authors. Two types of anterior dislocations of the PIP joint may be described. TYPE I: Without rupture of the central slip fo the extensor tendon. One distal condyle of the proximal phalanx is entrapped between the central slip and a lateral band of the extensor tendon, that are separated by a longitudinal partial tear. The deformity is made by flexion, axial rotation and lateral displacement of the middle phalanx. Open reduction is required and may carry out good functional result.

With rupture of the central slip of the extensor tendon. These very unstable lesions need a fixation after closed or open procedure. The treatment is often lately carried out, and the results not so good as in type I.

Two different types of PIP joint anterior dislocations are described. Earlier diagnosis and surgical treatment can allow early rehabilitation and better final functional results.