目的 建立患者简化盆骨模型并模拟髋臼周围截骨术(periacetabular osteotomy，PAO)，探究PAO对站立位下骶髂关节受力的影响。方法 对患者髋关节模型前方中心边缘角(anterior center edge angle，ACEA)与外侧中心边缘角(lateral center edge angle，LCEA)进行调节，得到除术前的 27 个模拟术后模型。在单腿和双腿站立两种情况下，对各模型进行有限元计算分析，探究骶髂关节软骨受力变化规律与分布情况，并结合髋关节受力情况进行分析。结果 单腿站立时，正常人骶髂关节软骨最大应力为 18。2 MPa，随着 ACEA 增大，患者骶髂关节软骨von Mises应力从 34。5 MPa降低到 19。8 MPa，骶髂软骨整体应力呈现下降趋势。髋臼软骨最大von Mises应力从4。767 MPa降低到 2。7 MPa。但在ACEA=36°前，髋臼软骨整体应力呈现下降趋势;在ACEA=36°后开始增大，应力分布明显改善。双腿站立时，患者病侧骶髂关节软骨最小 von Mises应力为 2。8 MPa，最大 von Mises 应力为6。5 MPa。正常侧受力未有太大变化，双侧受力差值逐渐减小。结论 PAO不仅能使髋关节受力情况得到改善，也能使骶髂关节的受力情况得到好转，但是骶髂关节的改善规律和髋关节并不相同。在手术前，根据髋关节与骶髂关节进行综合性规划，能为医师手术做参考，对髋臼发育不良患者治疗得到更好效果具有重要意义。
Effects of Periacetabular Osteotomy on Stress of Sacroiliac Joints in Standing Position
Objective A simplified pelvic model of a patient was established,and periacetabular osteotomy(PAO)was simulated to investigate its effects on the stress in the sacroiliac joints in the standing position.Methods The anterior center edge angle(ACEA)and lateral center edge angle(LCEA)of the patient's hip model were adjusted,and 27 postoperative models were obtained.Finite element calculations and analyses of each model were performed during single-leg standing and double-leg standing.Furthermore,an investigation of the stress variations and distributions on the sacroiliac cartilage was conducted in combination with a hip joint stress analysis.Results During single-leg standing,the maximum stress on the sacroiliac cartilage of a healthy individual was 18.2 MPa.With an increase in the anterior center edge angle(ACEA),the von Mises stress of the sacroiliac cartilage decreased from 34.5 MPa to 19.8 MPa.The maximum von Mises stress in the acetabular cartilage decreased from 4.767 MPa to 2.7 MPa.Before the ACEA attained 36°,the maximum von Mises stress exhibited a downward trend.After it attained 36°,the stress distribution began to increase,and the stress distribution improved significantly.During double-leg standing,the minimum and maximum von Mises stresses on the sacroiliac cartilage of the affected leg side were 2.8 and 6.5 MPa,respectively.The sacroiliac cartilage stress on the normal leg side did not vary significantly,and the stress difference between the two leg sides decreased gradually.Conclusions PAO can improve the hip joint stress and sacroiliac joint stress.Additionally,the improvement of sacroiliac joint stress is identical to that of hip joint stress.Prior to surgery,a comprehensive planning of the hip and sacroiliac joints can be used as a reference by doctors.This is of high significance for patients with developmental dysplasia of the hip(DDH)to achieve better outcomes.
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