利用有限元方法对髋臼弧形截骨术进行术前规划

目的对已截骨的髋臼块进行不同角度旋转,以模拟手术中髋臼块需调节的不同角度,通过分析髋关节周围软骨接触应力以及接触面积确定最佳角度,为髋臼截骨提供个体化方案。方法建立髋关节发育不良(development dysplasia of hip,DDH)和正常有限元模型,探讨发育不良髋臼形态特征以及应力集中原因。对DDH模型模拟截骨术,通过髋臼块的向前方和侧方旋转的不同角度组合得到共计20个截骨术后骨盆模型,对比分析模型在模拟单腿站立情况下最优结果的差异。结果正常模型髋臼软骨最大接触压力为7.85 MPa。DDH模型髋臼软骨最大接触压力为13.42 MPa,模拟截骨术后最优解接触压力下降至8.49 MPa,且接触力分布改善更明显。结论改变前侧旋转角度可以明显改善接触压力分布和大小并且远离术前病变区域,对术后效果有积极影响。手术前基于每位患者的实际情况制定个性化截骨方案对于手术效果至关重要。

Preoperative Planning of Acetabular Arc Osteotomy Using Finite Element Method

Objective In order to simulate different angles of acetabular blocks that need to be adjusted during operation, the optimal angle was determined through analyzing the contact stress and contact area of cartilage around the hip joint, so as to provide an individual scheme for acetabular osteotomy. Methods The finite element models for development dysplasia of hip (DDH) and normal pelvis were established to investigate morphological characteristics of the acetabulum and the causes of stress concentration. To simulate osteotomy for the DDH model, a total of 20 postoperative osteotomy models were obtained through the combination of different angles for anterior rotation and lateral rotation of acetabular blocks, and the differences in optimal results of the models during simulated one legged-standing were compared and analyzed. Results The maximum contact pressure of acetabular cartilage in normal model was 7.85 MPa. The maximum contact pressure of acetabular cartilage in DDH model was 13.42 MPa. The optimal contact pressure after simulated osteotomy decreased to 8.49 MPa, and the contact distribution was improved more significantly. Conclusions Changing the anterior rotation angle can significantly improve the contact pressure distribution and size, as well as stay away from the preoperative lesion area, which has a positive impact on postoperative outcomes. Personalized osteotomy plan based on actual situation of each patient before the operation is crucial for the surgical effect.