Arthrography and the medial compartment of the patello-femoral joint.

In four groups of patients with normal patellar cartilage, synovitis, patellar chondropathy , and degenerative changes of the patellar surface of the femur, the anatomical relationships within the medial compartment of the patello-femoral joint were examined. Clear differences were observed between these groups in the incidence of visualization of the medial alar plica and the mediopatellar synovial plica. As a consequence, an explanation has been sought for the occurrence of patellar chondropathy and degenerative changes of the patellar surface of the femur. It seems probable that a long-standing traumatic synovitis with effusion, attenuation of the synovial membrane, and the composition of the synovial fluid can lead to patellar chondropathy . The degenerative changes of the patellar surface of the femur are usually secondary to those of the load-bearing patellar facet. Insufficient covering of the cartilage by soft tissue may play a role in chondropathy of the nonload -bearing portion of the patella and the femoral condyle.