[Ultramicrostructural changes of articular cartilage, subchondral bone and synovium in human osteoarthritis of patellofemoral joint].

Ten patients with patellofemoral joint osteoarthritis (OA) were studied by electron microscope (SEM&TEM) to identify ultramicrostructural changes in the destroyed articular cartilage, subchondral bone and synovium. According to the results obtained, the author suggested that (1) Articular cartilage, subchondral bone and synovium in patellofemoral joint OA were noted to be in various degree of ultramicrostructural changes; (2) The cartilage degeneration in lateral compartment of patellofemoral joint were much more severe than that in medial compartment; (3) The subchondral bone had a strong tendency to undergo selerosis in the form of thicking and confluence of the trabeculae to form massive block of bone, which were not parallel to alteration of cartilage, and the rules of alteration were related to the character of loading; (4) The repair tissues of I-II grade degenerative cartilage were similar to normal cartilage, but those of III-IV grade degenerative cartilage were similar to fibrocartilage in many ways, because the source of repair tissues were different between them; (5) Alteration of synovium revealed only mild non-specific inflammatory changes following the changes of articular cartilage; (6) I-II grade patellofemoral joint OA was treated by conservative methods and III-IV grade OA should be treated by patellofemoral joint resurfacing.