EVALUATION OF THE RANGE OF MOTION OF A HIP ARTHROPLASTY SYSTEM: A COMPUTER SIMULATION STUDY

ABSTRACT Objective: To date, the literature lacks consensus on the most efficient method to measure the range of motion of an in vitro prosthetic system. In this study, we propose the use of a relatively low-cost online software to measure the range of motion of hip prosthetic implants manufactured in Brazil and compare its results with the current technical standards for hip arthroplasty. Methods: Three different diameters of femoral heads were evaluated (28 mm, 32 mm, and 36 mm). The mean values of the angular displacement of the prosthesis in each motion axis were obtained by computer simulations. Results: The range of motion with each femoral head was 28mm (extension/flexion: 148°, internal/external rotation: 179°, adduction/abduction: 107°), 32 mm (152°/185°/114°), and 36 mm (158°/193°/120°). Conclusion: The computational method showed that the larger the femoral head, the greater the range of motion of the hip joint prosthetic system. Additional clinical studies are necessary to compare the physical results obtained with the values found in this study by computational modeling. Level of evidence V, Experimental study.

摘要
研究目的：迄今为止，学界尚未就体外假体系统活动度的最优测量方法达成共识。本研究拟采用一款成本相对低廉的在线软件，对巴西产髋关节假体植入物的活动度进行测量，并将其测量结果与当前髋关节置换术的技术标准进行对比。
研究方法：本研究评估了3种不同直径的股骨头（28 mm、32 mm及36 mm），通过计算机模拟获取假体在各运动轴上的角位移平均值。
研究结果：各股骨头对应的活动度分别为：28mm组（伸/屈：148°，内/外旋：179°，内收/外展：107°）、32mm组（152°/185°/114°）以及36mm组（158°/193°/120°）。
研究结论：本计算方法结果显示，股骨头直径越大，髋关节假体系统的活动度越高。后续需开展额外临床研究，将本研究通过计算建模得到的数值与实际物理测量结果进行对比。本研究证据等级为V级，属于实验性研究。