Histologic appearance of "pristine" articular cartilage in knees with unicompartmental osteoarthritis.

This prospective study evaluated the histologic appearance of the "unaffected" lateral compartment articular cartilage in 15 knees with medial compartment degenerative arthritis undergoing unicompartmental arthroplasty or total knee arthroplasty between the ages of 54 and 65 years. The biopsy specimens were compared to a control group of patients between the ages of 25 and 45 years who were having routine arthroscopic meniscectomy. These patients had an intercondylar notch biopsy at the time of their arthroscopic procedure. A decrease in proteoglycan, breakdown of calcification, clonal grouping of chondrocytes, and/or hypocellularity was noted in the biopsy specimens of the "pristine" appearing lateral compartment in patients with isolated medial compartment disease indicative of progressive osteoarthritis.