Topographical variation of glycosaminoglycan content and cartilage thickness in canine knee (stifle) joint cartilage. Application of the microspectrophotometric method.

A recently developed microspectrophotometric method was used to measure local changes of thickness and glycosaminoglycan (GAG) content in articular cartilage. The intensity of the GAG stain was recorded from the superficial, intermediate, deep and calcified zones of articular cartilage. At each site of analysis, both the average stain concentration and the total stain content were determined. Of the 10 predefined locations of the Beagle knee (stifle) joint, the thickest cartilage was observed in the medial condyle of the tibia, which also possessed the highest GAG concentration. In the femur, the summits of the condyles had 33% thicker cartilage than the peripheral parts, while the GAG concentration was about equal in both of these regions. The thinnest cartilage and smallest GAG concentration was at the posterior end of the lateral condyle of the femur. The GAG content in the medial condyle and in the patellar surface of the femur was slightly greater than that in its lateral condyle.