Department of Orthopaedics and Rehabilitation, University of Iowa, Iowa, USA.
J Orthop Res. 2011 Nov;29(11):1642-8. doi: 10.1002/jor.21435. Epub 2011 Apr 14.
Instability is a significant concern in total hip arthroplasty (THA), particularly when there is structural compromise of the capsule due to pre-existing pathology or due to necessities of surgical approach. An experimentally grounded fiber-direction-based finite element model of the hip capsule was developed, and was integrated with an established three-dimensional model of impingement/dislocation. Model validity was established by close similarity to results from a cadaveric experiment in a servohydraulic hip simulator. Parametric computational runs explored effects of graded levels of capsule thickness, of regional detachment from the capsule's femoral or acetabular insertions, of surgical incisions of capsule substance, and of capsule defect repairs. Depending strongly upon the specific site, localized capsule defects caused varying degrees of construct stability compromise, with several specific situations involving over 60% decrement in dislocation resistance. Construct stability was returned substantially toward intact-capsule levels following well-conceived repairs, although the suture sites involved were often at substantial risk of failure. These parametric model results underscore the importance of retaining or robustly repairing capsular structures in THA, in order to maximize overall construct stability.
髋关节置换术（THA）中存在一个重要问题，即不稳定，特别是当由于先前存在的病理或手术入路的必要性而导致囊结构受损时。我们研发了一个基于纤维方向的髋关节囊实验基础的有限元模型，并将其与现有的撞击/脱位三维模型相结合。模型的有效性通过与在伺服液压髋关节模拟器中进行的尸体实验结果的高度相似性得到了验证。参数计算运行探索了囊厚度分级、囊与股骨或髋臼附着处的局部分离、囊实质的手术切口以及囊缺损修复的影响。根据具体部位的不同，局部囊缺陷导致了不同程度的构建稳定性受损，在几个特定情况下，脱位阻力降低了超过 60%。在进行了精心设计的修复后，构建的稳定性几乎完全恢复到完整囊的水平，尽管涉及的缝合部位往往存在很大的失效风险。这些参数模型结果强调了在 THA 中保留或修复囊结构的重要性，以最大限度地提高整体构建稳定性。
