Henry Ford Hospital Medical Journal


We evaluated a series of 12 biopsies from 11 patients with total knee replacements for severe osteoarthritis. All 12 biopsies showed denervation atrophy, while five cases had significant myopathic changes. Morphometric studies indicated a positive atrophy factor (greater than 150) in the type I myofibers in seven cases, the IIA myofibers in nine cases, and the IIB myofibers in all 12 cases. Type I predominance occurred in six cases, IIA paucity in two cases, and IIB paucity in two cases. The results indicate that patients with severe osteoarthritis of the knee have both significant neuropathic and myopathic changes in quadriceps biopsies. The changes in osteoarthritis of the knee differ from previously reported muscle biopsy results in patients with rheumatoid arthritis, femoropatellar or femorotibial osteoarthrosis, dislocating patella, meniscus tear or chondromalacia.