Diegel P D, Daniels A U, Dunn H K
Division of Orthopedic Surgery, University of Utah School of Medicine, Salt Lake City 84132.
J Arthroplasty. 1989;4(2):173-8. doi: 10.1016/s0883-5403(89)80071-3.
Stress shielding resulting from a stiffness mismatch between bone and femoral prosthesis stems (leading to bone resorption in the proximal femur) is believed to contribute to failure in total hip arthroplasty. In this study, strains were measured under compressive femoral head loads both in the intact femur and after implanting first a collarless steel stem and then a geometrically identical fiber-reinforced polymer composite stem 64% less stiff. Decreasing stem stiffness would be expected increase load transfer from the stem to the proximal medial femur, decreasing the degree of stress shielding. The authors found that proximal medial bone strains were significantly lower with either the steel or composite stem implanted than in the intact case. However, there were no significant differences in strain patterns between the steel and composite stem cases. This apparent insensitivity to prosthesis stiffness may result from factors related to implant geometry and fit.
由于骨骼与股骨假体柄之间的刚度不匹配（导致股骨近端骨吸收）所产生的应力遮挡被认为是造成全髋关节置换术失败的原因之一。在本研究中，分别在完整股骨以及先植入无领钢柄、再植入刚度小64%的几何形状相同的纤维增强聚合物复合材料柄之后，测量了股骨头压缩载荷下的应变。预计柄刚度的降低会增加从柄到股骨近端内侧的载荷传递，从而降低应力遮挡程度。作者发现，植入钢柄或复合材料柄后的近端内侧骨应变均显著低于完整情况下的应变。然而，钢柄和复合材料柄两种情况下的应变模式并无显著差异。这种对假体刚度明显不敏感的情况可能是由与植入物几何形状和贴合度相关的因素导致的。
