RECENT ANTERIOR DISLOCATIONS OF THE PROXIMAL INTERPHALANGEAL JOINT

Purpose of the study Recent anterior dislocations of the proximal inte rphalangeal (PIP) joint are uncommon injuries. Chronic and irreducible dislocations have been most often reported. This study aims to precis e the anatomic and radiologic aspects of these lesions about three cas es, and to compare these cases and their treatment with thirteen Gases published in the literature between 1966 and 1994. Material and metho ds Three patients presented an anterior dislocation of the PIP joint a fter direct or twisting traumatism. One had an avulsion of the central slip of the extensor tendon and remained unstable after closed reduct ion needing pin fixation. Two had a longitudinal tear between central and lateral bands of the tendon with an entrapment of the condyle of t he proximal phalanx, and the dislocations were irreducible. After open reduction, the joint was stable. Results The first case showed a limi ted flexion after three months. In the two other cases without rupture , full range of motion was recovered after two months. Discussion Thes e cases have been compared with thirteen cases of recent papers from n ine authors. Two types of anterior dislocations of the PIP joint may b e described. Type I : Without rupture of the central slip of the exten sor tendon. One distal condyle of the proximal phalanx is entrapped be tween the central slip and a lateral band of the extensor tendon, that are separated by a longitudinal partial tear. The deformity is made b y flexion, axial rotation and lateral displacement of the middle phala nx. Open reduction is required and may carry out good functional resul t. Type II : With rupture of the central slip of the extensor tendon. These very unstable lesions need a fixation after closed or open proce dure. The treatment is often lately carried out, and the results not s o good as in type I. Conclusion Two different types of PIP joint anter ior dislocations are described. Earlier diagnosis and surgical treatme nt can allow early rehabilitation and better final functional results.