半月板のコラーゲン構造が摩擦・力学特性に及ぼす影響

抄録

The knee joint menisci play important roles in weight bearing, stress dispersion and stabilization. It is reported that the loss of its mechanical function due to injury and aging-related degeneration occasionally results in osteoarthritis (OA). Cartilage damage incident to knees suffering from OA is more severe on the femoral side than on the tibial side, probably due to differences in the tissue structure, frictional and mechanical properties between tibial and femoral sides of menisci. In the present study, medial meniscus from porcine knee was divided into three regions (anterior, middle and posterior) and coronal sections were examined histologically with hematoxylin-eosin staining. Then, porcine medial menisci explants were harvested from six locations including the femoral and tibial sides at three regions. Indentation tests were performed on the explants at a compression rates of 5, 30, and 100 μm/s. In addition, reciprocating friction tests were performed on the explants at a sliding speed of 5 mm/s. Histological examination indicated that the entire meniscus was surrounded by collagen-like fibril tissues and that the thickness of the tissues was 97.9±30.3 μm and 181±29.4 μm in femoral and tibial sides, respectively. Equivalent elastic modulus of the meniscus surface was significantly higher in tibial side than in femoral side at a high compression rate. In contrast, the coefficient of dynamic friction of the meniscus was smaller in tibial side than in femoral side. These results indicated that the surrounding tissue of the menisci influences in tibial side its frictional and mechanical properties.