偏心髋臼旋转截骨术的生物力学机制及初步临床疗效

 目的 探讨偏心髋臼旋转截骨术治疗髋关节发育不良的生物力学机制及其初步临床疗效。方法 取6具经福尔马林防腐处理的女性尸体骨盆标本，建立髋关节生物力学模型，在模型上模拟偏心髋臼旋转截骨术。对骨盆缓慢施加连续纵向压力0~500 N，测量术前和术后载荷100、200、300、400、500 N时的股骨头承重区应变值，计算应力值。2007年7月至2014年10月应用偏心髋臼旋转截骨术治疗髋关节发育不良25例（26髋），男6例，女19例；年龄11~57岁，平均31岁。术后以Harris髋关节评分评价髋关节功能，摄骨盆正位X线片测量头臼指数、中心边缘角（center-edge-angle，CE角）及Sharp角。结果-随着脊柱纵向压力加大，股骨头上的应力值随之增加。偏心髋臼旋转截骨术后应力值在载荷超过300 N后由上升趋势转变为下降趋势，总体呈抛物线状。100~500 N载荷下偏心髋臼旋转截骨术后的应力值与术前差异均无统计学意义。临床随访18例（19髋），随访率72%。随访时间7~85个月，平均40个月。Harris髋关节评分由术前（64.3±7.2）分提高至末次随访时（85.6±5.3）分；头臼指数平均增加36.5%、CE角平均增加33.1°、Sharp角平均减少12.3°，与术前比较差异均有统计学意义。结论-偏心髋臼旋转截骨术具有较好的矫正髋臼畸形的能力，可增大股骨头的髋臼覆盖面和降低承重区压力。

Biomechanical analysis and clinical efficacy of eccentric rotational acetabular osteotomy

Objective To investigate the biomechanical mechanism and report preliminary clinical efficacy of eccentric rotational acetabular osteotomy (ERAO) when conduct treatment for developmental dysplasia of the hip (DDH). Methods Biomechanical model of the hip joint was established on six female cadaveric hips embalmed by formalin and stimulate ERAO was then performed on the model. Vertical force was loaded on the cadaveric spine from 0 N to 500 N and strain value on femoral head was measured preoperatively and postoperatively when loading force on spine reached the point of 100, 200, 300, 400 and 500 N. Stress value were then calculated base on the measurements. Besides, we reported postoperative follow-up cases which were underwent ERAO to treat DDH in our hospital from July 2007 to October 2014. A total of 25 patients (26 hips) were reported, including 6 males and 19 females. Age varies from 11 to 57 years old, and the average age was 31 years old. Postoperative hip function was evaluated by Harris hip score and anteroposterior X-ray of pelvic was taken preoperatively and postoperatively to measure the acetabular-head index (AHI), CE angle and sharp angle. Results Preoperative stress increased when loaded on spine became larger, but postoperative stress changed its increasing trend into decreasing when the load was greater than 300 N (turning point), which showed a parabolic trend. Compared with the preoperative stress under different load varying from 100 N to 500 N, postoperative stress was not statistically significant. Meanwhile, by the end of follow-up period, 18 patients (19 hips) were followed form 7 to 85 months. The average follow-up time was 40 months and the follow-up rate was 72%. Harris hip score improved from preoperative 64.3?7.2 points to 85.6?5.3 points; postoperative AHI increased an average of 36.5%, CE angle increased an average of 33.1? and sharp angle reduced an average of 12.3?. All differences between pre- and post-operative indexes were statistically significant. Conclusion ERAO has the ability to correct the deformity of acetabulum. It enlarges the acetabular coverage of the femoral head and thus reduces the pressure of weight-bearing area.