[The appearances of chondropathia patellae on plain films (author's transl)].

The ability to diagnose chondropathia patellae on plain radiographs was studied in 64 patients in whom the disease had been confirmed either by operation or arthroscopy. All cases of stage III chondropathia were diagnosable by radiological examination; in stage I, 67%, and in stage II, 73% could be diagnosed. The diagnosis depends on the co-existence of marginal irregularities, irregularities of the subchondral bone lamellae, spotty diffuse demineralisation, marginal osteophytes, irregularities at the insertion of the quadriceps tendon and soft tissue changes such as joint effusions. These changes are best identified on the so-called "defilée" view. Disalignment of the axis of the patella and post-traumatic defects are of particular importance for the development of chondropathia, but in the present clinical material, the existence of dysplasia of the patella or of the femoral condyle was not associated with a demonstrable increase of chondromalacia.