碳纤维增强聚醚醚酮股骨头假体置换术后的即刻稳定性

目的探讨碳纤维增强聚醚醚酮(CF/PEEK)复合材料股骨头假体全髋关节置换术后的即刻稳定性。方法8对新鲜成人尸体股骨平均分成两组,一组行钴铬钼合金股骨头假体置换术,另一组行CF/PEEK复合材料假体置换术。用位移传感器测量骨与假体之间的微动,模拟单肢站立施加载荷(200～1000N),并记录假体在股骨髓腔内的下沉幅度、旋转角度及界面间的相对运动。结果两种假体置入后,近端微动比远端大,CF/PEEK组的近端微动比钴铬钼合金组小,两者平均相差42%;远端的微动量都较小,但两者之间差异有极显著性意义(P<0.01)。CF/PEEK复合材料组的扭转角比钴铬钼合金组小38%,差异有极显著性意义(P<0.01),前者的抗扭刚度比后者大39%以上。结论CF/PEEK复合材料股骨头假体全髋关节置换术后的即刻稳定性优于钴铬钼合金假体,证明CF/PEEK复合材料股骨头假体在初次全髋置换术中切实可行。

The initial stability of CF/PEEK femoral stem after total hip replacement

Objective To explore the initial stability of a carbon fiber reinforced polyetheretherketone composite (CF/PEEK) stem in human femurs after total hip replacement. Methods 8 pairs of human cadaveric femurs were used to test the CF/PEEK prosthesis versus a conventional cementless stem of cobalt-chrome molybdemum alloy(CoCrMo). The bone-femoral prosthesis interface motion was measured in vitro using displacement transducers. Combined axial and torsional loads and simulated single-leg stance loading were applied. Subsidence, rotation and interface motion were measured with load cycles up to 1 000 N. Results The extent of the micro-motion in the proximal femoral region was larger than that in the distal femoral region. The CF/PEEK composite prosthesis showed less dynamic micro-motion in the proximal region compared with the CoCrMo alloy prosthesis stem, with the average difference being 42%. The extent of the distal micro-motion in the 2 groups was small but the difference was significant (P< 0.01). The torsional angle in CF/PEEK composite prosthesis group was smaller than that in CoCrMo alloy prosthesis group, with the difference being 38%(P< 001). The anti-torsional stiffness of the former was greater than that of the latter and the difference was 39%. Conclusions The initial stability of a CF/PEEK femoral stem is superior to that of a CoCrMo femoral stem. The data set for initial stability justifies the clinical use of a CF/PEEK femoral stem in primary hip replacement.