Ultrastructural changes in the femoral condylar cartilage of mature American foxhounds following transection of the anterior cruciate ligament.

Skeletally mature male American foxhounds were subjected to surgical transection of the right anterior cruciate ligament; they developed osteoarthritis of this stifle joint. The results were compared with joints from sham operated and nonoperated controls. Articular cartilage from each lateral femoral condyle was viewed by transmission electron microscopy. The ultrastructure of control and of experimental tissues was compared with that of similar, previous studies made in beagles. Both forms of foxhound control tissue were indistinguishable from normal beagle femoral condylar cartilage. Ultrastructural changes observed in the foxhound up to 16 weeks after cruciate ligament surgery were closely similar to those recorded in the beagle; they included alterations of chondrocyte morphology and the deposition of an electron dense cartilage surface coat. However, the degree of cartilage disorganization after 64 weeks was greater than, and qualitatively distinct from, that observed in the beagle.