[Chondrosarcoma of the femur neck simulating a normal variant. A difficult diagnostic pitfall]. / Chondrosarcome du col fémoral simulant une variante de la normale. Un redoutable piège diagnostique.

We report a case of chondrosarcoma of the femoral neck wrongly considered as a normal variant during a long time due to the initial aspect on the plain films and its location. Precise radiological criteria must allow the differential diagnosis and will be detailed.

Congenital aplasia of the cruciate ligaments. A report of six cases.

Instability of the knee is frequently found in association with congenital leg-length discrepancy. We have studied six such patients clinically, radiologically and arthroscopically. Clinical signs of knee instability and significant radiological changes were present in all, and at arthroscopy the anterior cruciate ligament was completely absent in four patients and functionless in the other two. This deficiency appears to be a congenital condition which may predispose to meniscus injury or retropatellar pain; it may also lead to subluxation or dislocation of the knee during leg-lengthening procedures.