TKA假体植入位置对膝关节解剖和应力的影响及其个体化优化方法的研究

Total knee arthroplasty (TKA) is an effective treatment method for severe knee osteoarthritis(OA), but TKA knee still has a series of postoperative complications. Except the prosthesis design and the misoperation, whether the complications are also related to the basic principles of prosthesis implantation position mismatching the knee anatomical structures? The preliminary study of the applicant in intact knee under TKA simulation found that the stress of medial compartment of TKA knee was significantly higher than that of lateral compartment. Meanwhile, clinical TKA failure also occurs in the knee medial compartment. Further study found that abnormal anatomical structure change occurred in intact knee under TKA simulation, and coincided with abnoraml stress distribution. It was speculated that there was a relationship between TKA prosthesis implantation position and the occurrence of TKA complications, and it could optimize stress distribution of TKA knee through individual adjustment of position parameters of prosthesis implantation. The plan of this project is to apply simulation method to further research the common characteristics of the changes of anatomical structure and stress distribution between osteoarthritic knee and intact knee under TKA treatment, and clarify the internal relationship between TKA prosthesis implantation position and postoperative complications. Then, to further study the method of optimizing stress distribution of TKA knee by individually adjusting the TKA prosthesis implantation position parameters for individualized TKA preoperative plan and TKA intraoperative navigational positioning.

全膝关节置换术（TKA）是治疗重度膝骨关节炎（OA）的有效手段之一，但TKA术后仍出现一系列并发症。除假体设计、操作失误等方面外，是否还与假体植入位置同膝关节解剖结构之间存在不匹配有关？申请人在对正常膝TKA术后仿真研究发现，内侧间室应力明显高于外侧间室，临床TKA失败也多发生在膝内侧间室；进一步发现正常膝TKA术后存在异常解剖结构变化，并与应力分布不均相吻合。推测TKA假体植入位置与术后并发症的发生有关，通过个体化调整假体植入位置参数能够优化TKA膝应力分布。本项目拟应用仿真方法深入研究重度OA膝和正常膝TKA术后解剖结构变化和应力分布改变的共性特征，阐明TKA假体植入位置与术后并发症的内在关联；研究通过个体化调整TKA假体植入位置参数优化TKA膝应力分布的方法，为临床制定个体化TKA术前计划和TKA术中定位提供理论依据。

本项目利用活体正常和重度骨关节炎（Osteoarthritis, OA）膝关节CT和MRI影像数据，通过多种仿真软件构建了具有个体化解剖学特征的膝关节和全膝关节置换术后（Total knee arthroplasty，TKA）膝三维模型，评估TKA假体与膝关节解剖结构的匹配程度，进而采用有限元分析的方法研究膝关节生物力学行为，并通过正交试验方法优化TKA假体植入定位参数。通过对正常膝、TKA正常膝和TKA重度OA膝的解剖学测量，系统地评估了TKA假体与膝关节解剖结构的匹配程度。发现TKA正常膝和TKA重度OA膝具有相同的解剖学变化趋势：股骨假体相对于高分子聚乙烯衬垫偏内、偏前；内侧副韧带短缩，外侧副韧带延长；髌骨内倾；关节线内高外低。这一解剖学变化趋势是由TKA假体植入位置同膝关节解剖结构之间存在不匹配引起的，与膝关节退变严重程度无关。通过对正常膝、TKA正常膝和TKA重度OA膝进行应力分析，发现正常膝接触面积较大，但接触应力、韧带应力远小于TKA正常膝和TKA重度OA膝，尤其是内侧间室。这一生物力学行为变化与TKA术后膝关节解剖学变化趋势相关联，与膝关节退变严重程度无关。从而证明TKA导致了假体之间不匹配、韧带张力不平衡、膝关节线位置变化和髌骨内倾等问题，继而引起TKA膝的应力分布异常，这些均与TKA假体植入位置同膝关节解剖结构之间存在不匹配有关。在此基础上，通过对TKA膝进行有限元分析，并结合正交试验方法，分别从矢状位、冠状位和轴状位获得个体化股骨假体和胫骨假体植入定位最优参数组合，使聚乙烯衬垫上表面的接触压峰值最小，减少了磨损，延长了假体使用寿命。通过有限元分析结合正交试验方法，可个体化调整TKA假体植入定位参数优化TKA膝生物力学行为，改善了TKA膝的解剖结构异常，为个体化TKA术前计划、TKA术中定位和TKA术后疗效评价提供理论依据。