Al-Dirini Rami M A, Huff Daniel, Zhang Ju, Besier Thor, Clement John G, Taylor Mark
College of Science and Engineering, Medical Device Research Institute (MDRI), Flinders University, 1284 South Road, Clovelly Park, Adelaide, 5043, Australia.
DePuy Synthes, Johnson and Johnson, Warsaw.
J Orthop Res. 2018 Apr;36(4):1185-1195. doi: 10.1002/jor.23744. Epub 2017 Nov 1.
For cementless femoral stems, there is debate as to whether a collar enhances primary stability and load transfer compared to collarless designs. Finite Element (FE) analysis has the potential to compare stem designs within the same cohort, allowing for subtle performance differences to be identified, if present. Subject-specific FE models of intact and implanted femora were run for a diverse cohort (21 males, 20 females; BMI 16.4-41.2 kg/m , age 50-80 yrs). Collared and collarless versions of Corail (DePuy Synthes, Warsaw, IN) were sized and positioned using an automated algorithm that aligns the femoral/stem axes, preserves the head-center location, and maximizes metaphyseal fit. Joint contact and muscle forces simulating peak forces in level gait and stair climbing and were scaled to the body mass and applied to each subject. Three failure scenarios were assessed: Potential for peri-prosthetic fibrous tissue formation (stem micromotion), potential for peri-prosthetic bone damage (equivalent strains), and calcar bone remodeling (changes in strain-energy density). Comparisons were performed using paired t-tests. Only subtle differences were found (mean 90th percentile micromotion: Collared = 86 µm, collarless = 92.5 µm, mean 90th percentile interface strains: Collared = 733 µϵ, collarless = 767 µϵ, and similar remodeling stimuli were predicted). The slight differences observed were small in comparison with the inter-patient variability. Statement of clinical significance: Our results suggest that the presence/absence of a collar is unlikely to substantially alter the bone-implant biomechanics nor the initial mechanical environment. Hence, a collar is likely to have minimal clinical impact. Analysis using different femoral stem designs is recommended before generalising these findings. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1185-1195, 2018.
对于非骨水泥型股骨柄，与无领设计相比，领圈是否能增强初始稳定性和负荷传递存在争议。有限元（FE）分析有潜力在同一队列中比较不同的柄设计，从而识别出细微的性能差异（如果存在的话）。针对不同人群（21名男性，20名女性；体重指数16.4 - 41.2kg/m²，年龄50 - 80岁）建立了完整和植入股骨的个体化有限元模型。使用一种自动算法对Corail（DePuy Synthes，印第安纳州华沙）的带领圈和无领圈版本进行尺寸确定和定位，该算法可对齐股骨/柄轴、保持股骨头中心位置并使干骺端贴合最大化。模拟平路行走和爬楼梯时峰值力的关节接触力和肌肉力根据体重进行缩放，并应用于每个受试者。评估了三种失效情况：假体周围纤维组织形成的可能性（柄微动）、假体周围骨损伤的可能性（等效应变）以及股骨距骨重塑（应变能密度变化）。使用配对t检验进行比较。仅发现细微差异（第90百分位平均微动：带领圈 = 86µm，无领圈 = 92.5µm；第90百分位平均界面应变：带领圈 = 733µϵ，无领圈 = 767µϵ，且预测的重塑刺激相似）。与患者间的变异性相比，观察到的细微差异较小。临床意义声明：我们的结果表明，领圈的有无不太可能显著改变骨 - 植入物的生物力学以及初始力学环境。因此，领圈可能对临床影响极小。在推广这些发现之前，建议使用不同的股骨柄设计进行分析。©2017骨科研究协会。由Wiley Periodicals, Inc.出版。《骨科研究杂志》36:1185 - 1195，2018年。
