髋关节假体置换中股骨头直径及髋臼前倾角的作用

背景：后脱位在人工髋关节置换后并发症中发生率仅次于假体松动,严重影响髋关节的稳定性。目前在临床研究中股骨头直径及髋臼前倾角对髋关节稳定性的影响尚存争议。目的：探讨股骨头直径和髋臼前倾角在人工髋关节置换后对髋关节稳定性的影响。方法：在尸体骨上测量全髋关节置换后影响髋关节后向不稳定的股骨头直径和髋臼前倾角。前倾角在计算机导航引导下安装在0°-20°,其中每个间隔为5°。分别应用直径为28,32,36 mm的股骨头进行实验,观察髋关节屈曲90°内收0°以及屈曲90°内收30°时引起脱位的内旋角度。结果与结论：当髋臼臼杯前倾角从0°增加到15°时,导致髋关节脱位的髋关节内旋角度随股骨头直径增加而增加(P < 0.05)。当髋臼臼杯前倾角度从15°增加到20°时,导致髋关节脱位的髋关节内旋角度随股骨头直径增加而增加的趋势不明显。在髋关节屈曲90°内收0°时,当髋臼臼杯前倾由15°增加到20°,股骨头直径36 mm组相对于28 mm和32 mm组有更高的稳定性(P< 0.01);当髋臼前倾角度大于10°时,股骨头直径32 mm组与28 mm组相比具有更好的稳定性(P < 0.05);当髋臼前倾角小于10°时,此种区别不是很明显。当髋关节屈曲90°内收30°,股骨头直径36 mm组相对于28 mm和32 mm组有更高的稳定性(P < 0.01);当髋臼前倾角度大于10°时,股骨头直径32 mm组与28 mm组相比具有更好的稳定性(P < 0.05);当髋臼前倾角小于10°时,此种区别不是很明显。结果提示髋臼前倾角的增加可减少髋关节后脱位的发生,但是当髋臼前倾角不是很好选择时,应用大直径的股骨头可增加髋关节的稳定性。

Femoral head diameter and acetabular anteversion in hip prosthesis replacement

BACKGROUND:Posterior dislocation after total hip replacement is one of the most common complications that second only to loosen, and can affect the stability of the hip joint seriously. There is controversy on the effect of femoral head diameter and acetabular anteversion on the stability of hip joint in clinical study.OBJECTIVE:To investigate the effect of the femoral head diameter and acetabular anteversion on the stability of hip joint after hip prosthesis replacement.METHODS:The femoral head diameter and acetabular anteversion that affect the posterior instability after hip prosthesis replacement were measured on the cadaveric bone. The acetabular shell was inserted at 0°-20° of anteversion at five degree intervals. The femoral heads with different diameters (28, 32 and 36 mm) were used for experiment, the internal rotation degrees to dislocation caused by hip at 90° flexion and 0° adduction and at 90° flexion and 30° adduction were recorded.RESULTS AND CONCLUSION:When the cup anteversion varied from 0° to 15°, there was an increase in the degree of internal rotation angle that could cause hip dislocation with the increasing of femoral head diameter (P < 0.05). When the cup anteversion varied from 15° to 20°, the increasing trend was not significant. With the hip at 90° flexion and 0° adduction, and the cup anteversion varied from 15° to 20°, the stability of 36 mm group was significantly higher than that of the 28 mm and 32 mm groups (P < 0.01); the stability of 32 mm group was higher than that of 28 mm group when the acetabular anteversion in 10° or more (P < 0.05); there was no significant difference in stability between groups when the anteversion less than 10°. With the hip at 90° flexion and 30° adduction, the stability of 36 mm group was significantly higher than that of the 28 mm and 32 mm groups (P < 0.01); the stability of 32 mm group was higher than that of 28 mm group when the acetabular anteversion in 10° or more (P < 0.05); there was no significant difference in stability between groups when the anteversion less than 10°. The results indicate that the increasing of acetabular anteversion can reduce the occurrence of dip dislocation, but when it is difficult to choice the acetabular anteversion, large-diameter femoral head is preferred to increase the stability of hip joint.