Macdonald W, Carlsson L V, Charnley G J, Jacobsson C M
Department of Biomaterials/Handicap Research, University of Göteborg, Sweden.
Proc Inst Mech Eng H. 1999;213(1):33-9. doi: 10.1243/0954411991534780.
Pre-clinical testing of the fixation of press-fit acetabular components of total hip prostheses relies on cadaver or synthetic bone, but the properties and geometry of bone models differ from those of physiological bone. Cup designs use varied mechanisms for initial stability in bone; therefore, using different analogues and tests is appropriate. Press-fit cup stability was tested in the following: firstly, polyurethane (PU) foam modelling cancellous support; secondly, glass-fibre reinforced epoxide (GFRE) tubes modelling acetabular cortical support; thirdly, cadaveric acetabula. Three commercial cups [Harris-Galante II (H-G-II), Zimmer; Optifix, Smith & Nephew, Richards; porous coated anatomic (PCA), Howmedica] and an experimental cup with enhanced rim fixation were tested in three modes: direct pull-out, lever-out and axial torque. The fixation stabilities measured in the PU and the GFRE models showed trends consistent with those in cadaver bone, differing in the oversizing and cup geometry. The experimental cup was significantly more secure in most modes than other cups; the H-G II and Optifix cups showed similar stabilities, lower than that of the experimental cup but greater than that of the PCA cup (analysis of variance and Tukey's highly significant test; p < 0.001). The stabilities measured in cadaver bone more closely approximated those in GFRE. The use of several bone analogues enables separation of fixation mechanisms, allowing more accurate prediction of in vivo performance.
全髋关节假体压配式髋臼部件固定的临床前测试依赖于尸体或合成骨，但骨模型的特性和几何形状与生理骨不同。髋臼杯设计在骨中实现初始稳定性的机制各不相同；因此，使用不同的模拟物和测试方法是合适的。通过以下方式测试压配式髋臼杯的稳定性：首先，用聚氨酯（PU）泡沫模拟松质骨支撑；其次，用玻璃纤维增强环氧树脂（GFRE）管模拟髋臼皮质支撑；第三，用尸体髋臼。测试了三种商用髋臼杯[Harris-Galante II（H-G-II），Zimmer公司；Optifix，Smith & Nephew公司旗下的Richards品牌；多孔涂层解剖型（PCA），Howmedica公司]以及一种边缘固定增强的实验性髋臼杯，测试采用三种模式：直接拔出、杠杆拔出和轴向扭矩。在PU和GFRE模型中测得的固定稳定性显示出与尸体骨中一致的趋势，但在尺寸过大和髋臼杯几何形状方面存在差异。实验性髋臼杯在大多数模式下比其他髋臼杯明显更稳固；H-G II和Optifix髋臼杯显示出相似的稳定性，低于实验性髋臼杯但高于PCA髋臼杯（方差分析和Tukey高度显著检验；p < 0.001）。在尸体骨中测得的稳定性更接近GFRE中的稳定性。使用多种骨模拟物能够区分固定机制，从而更准确地预测体内性能。
