髋臼方位与全髋置换术后脱位的关系

The effect of position and orientation of the cup on dislocation after total hip arthroplasty

目的研究人工全髋置换术后髋臼方位对髋关节脱位的影响,并为临床提供评价标准。方法测量318例(326髋)X线片的髋臼外展角、前倾角及股骨头旋转中心垂直位置,通过平均2.7年随访来确定上述3因素与术后髋脱位的关系,并进行统计学处理。结果在最近随访时,326髋有10髋发生脱位。外展角≥55°,较<55°脱位发生率有显著性差异;股骨头旋转中心垂直位置≥30mm,较<30mm脱位发生率也有显著性差异;前倾角≥15°和<15°相比,脱位发生率没有显著性差异;前倾角与外展角没有交互作用。结论髋臼方位不当与全髋置换术后的脱位明显相关;外展角<55°,股骨头旋转中心垂直位置<30mm及合适的前倾角可以提供较稳定的髋关节,明显降低术后髋脱位的发生率。

Objective A group of patients who had undergone total hip arthroplasty were followed up radiologically to explore the effects of abduction angle, the anteversion angle and the height of the femoral head center on dislocation, because these measurements could be used as a basis to evaluate current practice and to seek improvements. Methods A series of 326 hip joints (318 patients) were followed up routinely. The average follow up period was 2.7 years. 10 was found to have dislocation. The abduction angle, the anteversion angle and the height of the femoral head center were measured. The results were statistically analyzed, with a P value less than 0.05 indicating significant difference. Results The abduction angle of 55°or larger was found to be associated with greater risk of dislocation, compared with the abduction angle of less than 55°. Meanwhile, cups with the femoral head center superior placement greater than 30 mm resulted in more dislocation, compared with those less than 30 mm. As an independent variable, the anteversion angle had no significant association with dislocation. Conclusions Based on the results of the current study, the abduction angle and the height of the femoral head center should be considered as prerequisites for maintaining hip stability and decreasing the risk of dislocation. We believe that hips with the abduction angle of less than 55°and the height of the femoral head center less than 30 mm can decrease the risk of dislocation.