[Polyepiphyseal dysplasias and chondrodysplastic rheumatism]

The hip is the commonest site of polyepiphyseal dysplasia. These genotypic diseases are characterised by the presence of a moderate dysmorphic syndrome associated with developmental anomalies of the epiphyses. Metaphyseal and spinal alterations are absent or minor. The joint symptoms associated with these diseases have a polymorphic clinical and radiological expression. Osteoarthritis, the commonest manifestation, has several specific signs which distinguish it from "common" osteoarthritis: early onset, severity, dissemination and involvement of non-weight-bearing joints. Osteochondromatous formations, related to fragmentation of the epiphyses, are present in approximately one third of patients and may sometimes be responsible for joint locking. Progressive tendon retraction of the extremities has been exceptionally reported. Recurrent acute arthritis is more frequent, affecting joints with a radiological appearance often similar to that of metabolic joint disease with subchondral bone changes and occasionally calcified margins.