Total Mankin score of histological cartilage damage. The assessment was carried out at the weight bearing area of medial femoral condyle. HEALTHY (n = 7), OA (n = 7), OP (n = 8) and OPOA (n = 8) knees. OA: osteoarthritis; OP: osteoporosis. Results are expressed as mean ± SEM; *P < 0.05 vs. HEALTHY, #P < 0.05 vs. OA, &P < 0.05 vs. OP.