Engh C A, Sychterz C, Engh C
Anderson Orthopaedic Research Institute, Alexandria, Virginia, USA.
J Arthroplasty. 1999 Aug;14(5):637-44. doi: 10.1016/s0883-5403(99)90091-8.
We performed a postmortem comparison of femurs from two patients who had bilateral cementless total hip arthroplasties with femoral prostheses of different stiffness implanted in their right and left hips. Radiographs of transverse sections of the four femurs demonstrated that all the prostheses were bone ingrown with the most ingrowth occurring distally where the porous coating contacted diaphyseal bone. In both patients, dual-energy x-ray absorptiometry analysis revealed that the femur implanted with the stiffer prosthesis had a 65% to 79% greater loss of proximal periprosthetic bone than the femur implanted with the more flexible prosthesis. One patient, however, had a dramatically greater total loss of bone from side to side than the other patient. In this patient, we believe that it was host factors more than the differences in stem stiffness that affected the bone-remodeling pattern. Although the two femurs with the stiffer prostheses had the greatest bone loss, the two femurs with the more flexible prostheses demonstrated radiographic signs of cantilever bending of the prosthetic stem and failure of proximal osseointegration. We are not aware of any other bilateral human postmortem analysis that so clearly illustrates the effect of stem stiffness on bone remodeling.
我们对两名患者的股骨进行了尸检比较，这两名患者均接受了双侧非骨水泥型全髋关节置换术，其右髋和左髋植入了不同刚度的股骨假体。对这四根股骨横断面的X线片显示，所有假体均有骨长入，其中大部分长入发生在远端，即多孔涂层与骨干骨接触的部位。在两名患者中，双能X线吸收法分析显示，植入较硬假体的股骨近端假体周围骨量的损失比植入较灵活假体的股骨多65%至79%。然而，其中一名患者两侧的骨总量损失比另一名患者明显得多。我们认为，在这名患者中，影响骨重塑模式的更多是宿主因素而非假体柄刚度的差异。尽管两根植入较硬假体的股骨骨量损失最大，但两根植入较灵活假体的股骨显示出假体柄悬臂弯曲和近端骨整合失败的影像学迹象。我们不知道有任何其他双侧人体尸检分析能如此清晰地说明假体柄刚度对骨重塑的影响。
