Partial patellectomy induces a decrease in the proteoglycan content in the remaining patellar articular cartilage. An experimental study in rabbits.

We studied the alterations and distribution of the proteoglycan (PG) content of the remaining patellar articular cartilage after unilateral partial patellectomy in 13 rabbits. Sagittal sections of the patella were prepared and stained with Safranin O for quantification of changes in the PG content of the patellar articular cartilage using a commercially available imaging analysis system. Our findings suggest that partial patellectomy results in a decreased PG content in the remaining patellar articular cartilage. In addition, the postoperative development of metaplasia in the scar tissue next to the healing interface may represent a compensatory response, which could prevent a further reduction in the PG content and hence the development of osteoarthritis in the remaining patellar articular cartilage.