Strain distribution in the proximal human femur after insertion of CF/PEEK femoral stems / 中国矫形外科杂志

ABSTRACT

[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.[Result]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.