髋关节假体聚乙烯磨损及其影响因素的相关性分析

Correlations between polyethylene wear direction and other influencing factors in total hip arthroplasty

目的 探讨磨损与假体植入参数的相关性.方法 1997年4月至2006年3月对南方医科大学附属南方医院关节与骨病外科58髋Zweymuller双锥面非骨水泥螺旋臼假体进行临床和影像学检查,以计算机辅助测量方法测量髋关节假体聚乙烯内衬的线性磨损,平均随访时间为7.3年.利用股骨头假体中心相对于髋臼杯开口平面轴线的矢量位移,来决定线性磨损的大小和方向.分析髋臼外展角、股骨偏心距、髋臼前倾角对线性磨损方向和大小的影响.结果 平均线性磨损率为（0.17±0.08） mm/年,平均线性磨损方向与髋臼杯轴线的夹角为（34.2±29.3）°.线性磨损方向与外展角存在正相关性（r=0.480,P=0.000）,与术后Harris评分存在负相关性（r=-0.314,P=0.016）.外展角＞45°组的线性磨损方向较外展角＜ 45°组更加偏离髋臼轴心（P=0.001）.术中股骨偏心距得到重建组的线性磨损率小于未得到重建组（P =0.043）.结论 该计算机辅助测量方法适用于各种髋臼杯假体聚乙烯内衬的二维磨损测量.人工全髋关节置换术中合理的髋臼杯外展角和恢复正常偏心距可以减少聚乙烯内衬线性磨损率,增加髋关节假体的稳定性,改善远期效果.

Objective To explore the correlations between polyethylene wear direction and implanted parameters of prosthesis in total hip arthroplasty （THA） by computer-assisted measurement techniques.Methods Retrospective analyses were performed for 58 uncemented THAs from April 1997 to March 2006.The sagittal displacement of femoral head to axis of acetabulum opening plane was examined to determine the direction and degree of linear polyethylene wear.Radiographs were assessed for femoral offset,acetabular abduction,acetabular anteversion and conventional polyethylene wear.The linear polyethylene wear directions were compared between different parameter groups.Results The average linear wear rate was 0.17 ± 0.08 mm/year and the angle between linear wear direction and axis of acetabulum 34.2° （± 29.3 °）.Linear wear direction and acetabular abduction were positively relevant （r =0.480,P =0.000）.Linear wear direction was negatively correlated with postoperative Harris scores （r =-0.314,P =0.016）.Compared with the acetabular abduction of ＜ 45°,the acetabular abduction of 45° or larger was associated with greater decentralization of acetabulum opening plane （P =0.001）.As an independent variable,there were no statistically significant difference in linear wear direction between different acetabular anteversions.And femoral offset had no significant association with linear wear direction （P ＞ 0.05）.Conclusion Reasonable acetabular abduction and femoral offset may decrease linear wear rates,maintain hip stability and improve long-term putcomes.