Centre for Orthopaedic and Trauma Research (COTR), Adelaide Medical School, University of Adelaide, Adelaide, Australia.
Alliance for Research in Exercise, Nutrition & Activity (ARENA), Allied Health & Human Performance Unit, University of South Australia, Adelaide, Australia.
J Orthop Res. 2023 Jun;41(6):1240-1247. doi: 10.1002/jor.25455. Epub 2022 Oct 17.
The aim of this study was to determine the effect of surgical change to the acetabular offset and femoral offset on the abductor muscle and hip contact forces after primary total hip arthroplasty (THA) using computational methods. Thirty-five patients undergoing primary THA were recruited. Patients underwent a computed tomography scan of their pelvis and hip, and underwent gait analysis pre- and 6-months postoperatively. Surgically induced changes in acetabular and femoral offset were used to inform a musculoskeletal model to estimated abductor muscle and hip joint contact forces. Two experiments were performed: (1) influence of changes in hip geometry on hip biomechanics with preoperative kinematics; and (2) influence of changes in hip geometry on hip biomechanics with postoperative kinematics. Superior and medial placement of the hip centre of rotation during THA was most influential in reducing hip contact forces, predicting 63% of the variance (p < 0.001). When comparing the preoperative geometry and kinematics model, with postoperative geometry and kinematics, hip contact forces increased after surgery (0.68 BW, p = 0.001). Increasing the abductor lever arm reduced abductor muscle force by 28% (p < 0.001) and resultant hip contact force by 17% (0.6 BW, p = 0.003), with both preoperative and postoperative kinematics. Failure to increase abductor lever arm increased resultant hip contact force 11% (0.33 BW, p < 0.001). In conclusion, increasing the abductor lever arm provides a substantial biomechanical benefit to reduce hip abductor and resultant hip joint contact forces. The magnitude of this effect is equivalent to the average increase in hip contact force seen with improved gait from pre-to post-surgery.
本研究旨在通过计算方法确定初次全髋关节置换术（THA）后髋臼偏心距和股骨偏心距的手术改变对髋外展肌和髋关节接触力的影响。招募了 35 名接受初次 THA 的患者。患者接受骨盆和髋关节的计算机断层扫描，并在术前和术后 6 个月进行步态分析。使用手术引起的髋臼和股骨偏心距变化来告知肌肉骨骼模型，以估计髋外展肌和髋关节接触力。进行了两项实验：（1）术前运动学中髋关节几何形状变化对髋关节生物力学的影响；（2）术后运动学中髋关节几何形状变化对髋关节生物力学的影响。THA 时髋关节旋转中心的上移和内移对降低髋关节接触力的影响最大，可预测 63%的变异性（p < 0.001）。当比较术前几何形状和运动学模型与术后几何形状和运动学模型时，手术后髋关节接触力增加（0.68 BW，p = 0.001）。增加髋外展肌臂长可使髋外展肌力降低 28%（p < 0.001），髋关节接触力降低 17%（0.6 BW，p = 0.003），无论术前还是术后运动学。未能增加髋外展肌臂长会使髋关节接触力增加 11%（0.33 BW，p < 0.001）。总之，增加髋外展肌臂长可显著改善髋关节外展肌和髋关节接触力的生物力学效益。这种效果的大小相当于从术前到术后改善步态后髋关节接触力平均增加的幅度。
