聚醚醚酮髋股骨头假体置换术后股骨近段的力学分析

Strain distribution in the proximal human femur after insertion of CF/PEEK femoral stems

[目的]探讨复合材料在全髋股骨头假体中的应用前景,旨在寻找能与股骨紧密结合、增加股骨近端应力传递的新型假体,期望进一步提高全髋关节置换术的远期疗效。[方法]5对人体新鲜尸体股骨平均分成左右2组,1组行钴铬钼合金(CoCrMo)股骨头假体置换术,另1组行碳纤维增强聚醚醚酮(CF/PEEK)假体置换术。在假体和近端股骨表面粘贴应变片,模拟单肢站立施加载荷。首先记录正常股骨产生的应变分布,然后行2种假体的股骨头置换术,再记录2组标本所产生的应变分布。[结果]股骨应变在假体植入后,从近端到远端逐渐增加,变化形式与完整股骨的应变形式相似,并且在假体远端最大。2种假体植入后,股骨内外侧表面的应变皆减少;但CF/PEEK假体组产生的应变形式和大小比CoCrMo合金假体组更接近正常股骨。[结论]CF/PEEK复合材料股骨头假体能提供术后即刻稳定性和良好的近端载荷传递,因此能进一步减少应力遮挡、骨吸收、骨萎缩,最终避免假体松动失败。

[ Objective] To develop a new femoral prosthesis that can integrate with femur compactly and increase proximal femoral stress transfer, and further improves the long-term curative effect of total hip arthroplasty. [ Method] Five pairs of human cadaver femora were divided equally into two groups one of which received a cobalt - chrome molybdemum alloy （CoCrMo） implant and the other a carbon fiber reinforced polyetheretherketone composite （CF/PEEK） implant. Six strain-gauge rosettes were attached to the external surface of each implant and proximal femora. The loading conditions simulated single - limb stance and the strains were recorded first with the femora intact and then with the femoral components of two different designs implant inserted. [ Resultl After the insertion of a femoral component, the normal pattern of a progressive proximal-to-distal increase in strains was similar to that in the intact femur and the strain was maximum near the tip of the prosthesis. On the medial and lateral aspects of the proximal femur, thc strains were reduced after implantation of both types of implant. The pattern and magnitude of the strains, however, were closer to those in the intact femur after insertion of the CF/PEEK stem than that of CoCrMo stem. [ Conclusion] Our findings suggest that the CF/PEEK stem can provide immediate postoperative stability, better proximal loading transfer in the metaphysis and further reduce stress shielding, bone resorption and osteanabrosis,thus prevent the implant from failuri.