股骨距受力状态的光弹性实验研究

A PHOTOELASTIC STUDY OF CALCAR FEMORALE

以三维步态分析中站立相前期、中期和后期三种受力状态作为加载方向,应用光弹“冻结切片法”对正常有股骨距和模拟股骨距受到破坏后股骨上段的应力分布作了比较,并从实验力学角度探讨了临床上有争议的“有肩型”和“无肩型”人工股骨头各自的特点和不足之处。

<ABSTRACT> The study was carried out on the basis of the high quality tubular epoxy resin models of upper femur successfully made by using 'Vacuum Casting Method'. Comparative study on the stress distribution over upper femur between those with normal and those with mimic destructed calcar femorale was made by means of photoelastic freezing slicing tecnique. The loading orientation was chosen from the values of pre-stance, mid-stance and terminal stance period of three dimensional gait analysis. And the clinically debatable problem on the prostheses of femoral head with or without a collar has been studied and discussed from the view point of experimental mechanics. It was demonstrated that calcar femorale plays an important role in the stress distribution of upper femur. When the calcar femorale has been destructed, the stress on the cortex of upper femur was found to be increased greatly, even more than 30 times, the closer to the femoral head the larger would be the increase of stress. Stress concentration was found on the severed end of femoral neck after a model of collared prosthesis was implanted,the stress over other part of the upper femur was decreased simultanously. The stress concentration on the severed end of femoral neck was disappeared while a non-collared prosthesis was used, and the stress of upper femur was much evenly distributed, but in a rather lower magnitude.The stress concentration and low stress may contribute to the cause of bone absorption and osteopenia respectively. There is still no report so far on the study of the inner structure of bone with photoelasticity.We hope that thee xperimental method used in our study will be of valuable help to the biomechanical study of other bones,