全髋关节置换术后髋臼假体外倾角的临床研究

目的　了解广医一院人工全髋关节置换术后髋臼假体外倾角的情况及外倾角大小与聚乙烯磨损的关系。 方法　选取2011年5月前广医一院骨外科THA术后126例145髋患者骨盆前后位X线片，其中男47例，女79例，年龄23~85岁，末次随访时平均年龄60.1岁。采用DR拍摄骨盆前后位照片，测量髋臼外倾角，统计外倾角≥50°及≥55°的发生率。对单侧全髋关节置换患者测量股骨头中心位移，评估髋臼外倾角与聚乙烯磨损的相关性，使用时间超过5年的内衬的线性磨损值与使用时间少于5年的内衬比较有无差异。 结果　126例145髋中61个髋的外倾角大于等于50°，百分率为42.1%（34.1%　~50.1%），大于等于55°者32个，百分率为22.1%(15.3%~28.9%)。外倾角<50°组聚乙烯线性磨损比外倾角≥50°组轻，差异有统计学意义，P<0.001，对107个髋的髋臼外倾角与聚乙烯线性磨损值做散点图及简单线性回归分析，二次多项式曲线拟合效果较好，拟合优度（R Square）为0.697，聚乙烯线性磨损值与髋臼外倾角同向相关，回归方程为■=4.431-0.21x+0.003x2。 结论　人工全髋关节置换术后髋臼外倾角与聚乙烯线性磨损相关，手术中需要采取有效措施防止髋臼假体外倾角过大。

Clinical study of cup abduction angle after total hip aithroplasty

Objective To assess cup inclination of THAs by measuring the abduction angle and to find out if the abduction angle relate to polyethylene wear or not.Methods Cup abduction angle and polyethylene wear were measured on the X-ray with a series of 145 hips undergone THA before 2011 May.The rates of abduction angle greater than 50 degree and 55 degree were calculated.The relationship between cup abduction angle and polyethylene linear wear was evaluated.Results It happened in 32(22.1%,95% CI: 15.3%~28.9%) hips that abduction angle exceeded 55 degree and 61(42.1%,95%CI: 34.1%~50.1%) hips’abduction angle greater than 50 degree.Abduction angle that greater than 50 degree significantly caused polyethylene liner wear.In 107 unilateral THA,positive correlation between abduction angle and liner wear was revealed by a scatter diagram and then a curve estimation was taken.R square was up to 0.697 using Quadratic curve.Regression equation was y=4.431-0.21x+0.003x2.Conclusions Incorrect abduction angle may cause polyethylene wear in THA.Measurement should be made to place the cup at appropriate position.