骨骺牵张与骨骺板的生物力学性质

本研究是对新西兰幼兔股骨远端骨骺进行体内和体外牵张实验.16只兔右股骨经5～10N力每3天一次牵张.4周后的股骨长度值明显大于左侧和0N组.形态学变化是受牵张的骺板增厚,软骨细胞增殖且无骨骺分离骨折.体外骺板抗断裂测试显示夸张后的骺板强度不低于未经牵张的对照侧.8只动物16根股骨于体外接受20～100N力的牵张,其骺板的塑性变形度随牵张力值的增高而增大,抗断裂强度亦不低于未经牵张的骨骺.这些结果表明适量的牵张力和/或低牵张速率是实现“软骨分离”或骨延长的关键.

CORRELATION BETWEEN EPIPHYSEAL DISRACTION AND BIOMECHANICAL PROPERTIES OF THE EPIPHYSEAL PLATE

The effectiveness of epiphyseal distraction was investigated in vivo and in vitro by forces applied to the distal femoral growth plates of New Zealand white immature rabbits. Distraction forces of 5N and 10N were applied every 3 days to the distal growth plate of the right femur in vivo, in 16 rabbits Four weeks later the length of all distracted femurs was significant longer than both the length of control side and the same one of group ON. Histological study showed hyperplasia of the growth plate, an increase in chondrocytes division rate, and no evidence of epiphyseolysis. The in vitro breaking forces of the growth plate were measured after in vivo distraction. The mean breaking force of the distracted side was not lower than mean values for the undistracted control side. Sixteen femora from 8 rabbits underwent epiphseal distraction in vitro, with 20N, 60N and 100N forces. the mean plastic deformation of the growth plate was great in connection with increasing traction. The subsequence breaking force of these growth plates was no influenced. The results obtained in this study indicated that limb lengthening might be achieved by chondrodiatasis with the proper distraction force and/or a slow distraction rate.