Leeds Institute of Rheumatic and Musculoskeletal Medicine (LIRMM), School of medicine, University of Leeds, Leeds, UK.
School of Mechanical Engineering, University of Leeds, Leeds, UK.
Proc Inst Mech Eng H. 2022 Jul;236(7):973-978. doi: 10.1177/09544119221092842. Epub 2022 May 21.
Postoperative periprosthetic femoral fracture following hip replacement has been the subject of many varied experimental approaches. Cadaveric samples offer realistic fit and fracture patterns but are subject to large between-sample variation. Composite femurs have not yet been validated for this purpose. We compared the results of composite femurs to cadaveric femurs using an established methodology. In vitro postoperative periprosthetic fracture results using axial-rotational loading were compared between 12 composite femurs and nine fresh frozen femurs, which were implanted with an otherwise identical collarless (6 composite vs 4 cadaveric) or collared (6 composite vs 5 cadaveric) cementless femoral stem using identical methodology. Fracture torque and rotational displacement were measured and torsional stiffness and rotational work prior to fracture were estimated. Fractures patterns were graded according to the Unified Classification System. Fracture torque, displacement, torsional stiffness and fracture patterns for cadaveric and composite femurs were similar between groups. There was a trend for a greater rotational displacement in the cadaveric groups, which lead to a decrease in torsional stiffness and a significantly greater rotational work prior to fracture for all cadaveric specimens (collarless stems: 10.51 [9.71 to 12.57] vs 5.21 [4.25 to 6.04], = 0.01 and for collared stems: 15.38 [14.01 to 17.05] vs 5.76 [4.92 to 6.64], = 0.01). Given comparable fracture torque and the similarity in fracture patterns for fracture trials using composite samples versus cadaveric femurs, the use of composite femur models may be a reasonable choice for postoperative periprosthetic femoral fracture studies within certain limitations.
髋关节置换术后股骨假体周围骨折一直是许多不同实验方法的研究对象。尸体样本提供了真实的拟合和骨折模式，但存在较大的样本间变异。复合材料股骨尚未对此进行验证。我们使用既定的方法比较了复合材料股骨和尸体股骨的结果。通过轴向旋转加载比较了 12 个复合材料股骨和 9 个新鲜冷冻股骨的体外术后股骨假体周围骨折结果，这些股骨用相同的方法植入了相同的无领（6 个复合材料与 4 个尸体）或有领（6 个复合材料与 5 个尸体）非骨水泥股骨柄。测量了骨折扭矩和旋转位移，并估计了断裂前的扭转刚度和旋转功。根据统一分类系统对骨折模式进行分级。尸体和复合材料股骨的骨折扭矩、位移、扭转刚度和骨折模式在组间相似。尸体组的旋转位移有增加的趋势，导致扭转刚度降低，所有尸体标本的骨折前旋转功显著增加（无领柄：10.51 [9.71 至 12.57] 与 5.21 [4.25 至 6.04]，= 0.01；有领柄：15.38 [14.01 至 17.05] 与 5.76 [4.92 至 6.64]，= 0.01）。考虑到骨折试验中复合材料样本与尸体股骨的骨折扭矩相当，且骨折模式相似，在一定限制条件下，使用复合材料股骨模型可能是研究术后股骨假体周围骨折的合理选择。
