Morphology and crystal composition of chondrocalcinosis after osteochondritis dissecans.

Three patients, who in their youth had been operated upon for osteochondritis dissecans in the femoral condyles, and who had developed gonarthrosis and chondrocalcinosis 30 years later, were investigated by arthrotomy. Tissue was obtained from the semilunar cartilages, the joint cartilages and the synovialis, for crystal analysis and morphological studies. The calcium deposits were with X-ray diffraction and polarization microscopy, The compound found was mainly calcium pyrophosphate dihydrate. Crystals were seen in all the tissues studies and the deposits could also be seen in micro-radiography. The histological examination demonstrated mainly degenerative, but also regenerative changes in the articular cartilage. On the site of the osteochondritis lesion the fibrous tissue was very rich in crystals. In the semilunar cartilages and the synovialis crystals were also seen.