膝关节单髁置换术保留圆角截骨技术的生物力学研究

Biomechanical Study for Radial-Corner Shape Reserved Osteotomy in Unicompartmental Knee Arthroplasty

摘要: 目的：研究单髁膝关节置换术(Unicompartmental Knee Arthroplasty, UKA)中保留圆角截骨不同钻孔半径和膝关节屈曲角度下的生物力学特性，为优化手术方案提供理论依据。方法：基于膝关节CT和MRI图像，构建了在膝关节屈曲0˚、30˚和60˚状态下常规截骨与保留圆角截骨不同钻孔半径(1~6 mm)的有限元模型，以分析胫骨的应力分布特征。结果：保留圆角截骨钻孔半径2~6 mm模型中，胫骨近端截骨区皮质骨的最大von Mises应力相比钻孔半径1 mm模型分别在膝关节屈曲0˚时减少了10.11%、17.69%、18.56%、29.03%、35.16%；屈曲30˚时减少了1.73%、14.40%、17.80%、25.00%、38.98%；屈曲60˚时减少了5.87%、15.16%、18.38%、19.67%、22.39%。相同条件下，胫骨近端截骨区松质骨的最大von Mises应力变化趋势与皮质骨相似。在保留圆角截骨的不同钻孔半径设置下，胫骨近端截骨区皮质骨和松质骨的整体高应力分布区域，与相同膝关节屈曲角度下的常规截骨模型基本一致。结论：保留圆角截骨通过优化截骨面的几何形状，可以有效改善胫骨近端截骨区的应力分布，减少应力集中风险，有效降低了胫骨应力性骨折的风险，为临床上在膝关节单髁置换术中选择合适的手术方案提供理论依据。

Abstract: Objective: To explore the biomechanical characteristics of unicompartmental knee arthroplasty (UKA) under varying radii of radial-corner shape reserved osteotomy and knee flexion angles, to provide a theoretical basis for optimizing surgical protocols. Methods: Based on CT and MRI images of knee joint, finite element models of conventional osteotomy and radial-corner shape reserved osteotomy (1~6 mm radius) under the knee flexion of 0˚, 30˚ and 60˚ were constructed to analyze stress distribution characterization of tibia. Results: In the radial-corner shape reserved osteotomy models (2~6 mm radius), the maximum von Mises stress in the cortical bone of the proximal tibial osteotomy region was reduced by 10.11%, 17.69%, 18.56%, 29.03%, and 35.16% at 0˚ flexion; by 1.73%, 14.40%, 17.80%, 25.00%, and 38.98% at 30˚ flexion; and by 5.87%, 15.16%, 18.38%, 19.67%, and 22.39% at 60˚ flexion, compared to the 1 mm radius model. Under the same conditions, the maximum von Mises stress in the cancellous bone of the proximal tibial osteotomy region exhibited a similar trend to that observed in the cortical bone. Under different radii in the radial-corner shape reserved osteotomy, the overall high-stress distribution regions in the cortical and cancellous bone of the proximal tibial osteotomy region were largely consistent with those in the conventional osteotomy model at the same knee flexion angles. Conclusion: The radial-corner shape reserved osteotomy, by optimizing the geometric configuration of the osteotomy surface, effectively improved stress distribution in the proximal tibial osteotomy region, reduced the risk of stress concentration, and significantly mitigated the risk of stress fractures in the tibia. These findings provide a theoretical basis for selecting appropriate surgical protocols in clinical UKA procedures.