摘要目的 探讨髋关节发育不良全髋关节置换术中髋臼覆盖率对臼杯初始稳定性的影响.方法 取第四代人工合成的半骨盆标本50个,安放直径58 mm的T.O.P髋臼杯假体,通过截除髋臼外上方髂骨制备100%、70%、60%、50%、40%臼杯覆盖率模型,每组10个标本,5个用于扭转力、5个用于拔出力测试.将制备好的半骨盆模型固定于电子万能材料力学试验机和微机控制材料扭转试验机,测试不同臼杯覆盖率组髋臼杯的拔出力和扭转力矩.结果 在髋臼杯拔出力测试中,至臼杯松动时,臼杯覆盖率100%、70%、60%、50%、40%组拔出力分别为(1 560.4±438.7)、(1 467.2±349.8)、(1 137.8±427.4)、(737.4±134.8)、(506.6±119.0)N.随覆盖率减小拔出力逐渐降低,其中臼杯覆盖率100%组高于50%组(P=0.004)和40%组(P=0.001),70%组高于50%组(P=0.002)和40%组(P=0.000);40%组低于60%组(P=0.013)和50%组(P=0.021).在髋臼杯扭转力矩测试中,至臼杯松动时,臼杯覆盖率100%、70%、60%、50%、40%组扭转力矩分别为(28.0± 3.7)、(17.0±2.2)、(9.4±1.1)、(7.6±1.1)、(6.4±1.1)N·m.随覆盖率减小髋臼扭转力矩逐渐减小,其中臼杯覆盖率100%组均高于其他组(P<0.05);除50%组与40%组外,其他两两组间比较差异均有统计学意义(P<0.05).结论 不同髋臼覆盖率影响臼杯的初始稳定性.臼杯覆盖率越大,初始稳定性越高;臼杯覆盖率达到70%以上才能获得足够的初始稳定性,满足日常活动要求,且不增加臼杯松动率.

abstractsObjective To investigate the effects of acetabular coverage on the initial stability of the cup during total hip arthroplasty in developmental dysplasia of hip. Methods There were 50 fourth?generation synthetic hemi?pelvises. The different cup coverage rate (100% group, 70% group, 60% group, 50% group, 40% group) was created in pelvis with 10 specimens per group. The synthetic hemi?pelvis was fixed rigidly to a customized fixture which was placed on the testing table of the material test?ing machine. Pull?out and torque test were conducted by computer?control in torsion testing machine. Results In the acetabular cup pull?out test, the average pull?out force for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 1 560.4±438.7, 1 467.2±349.8, 1 137.8±427.4, 737.4±134.8, 506.6±119.0 N, respectively. The pull?out force was reduced gradually. The pull?out force in 100% group was significantly higher than that in 50% (P=0.004) and 40% (P=0.001) group. The pull?out force in 70% group was significantly higher than that in 50% group (P=0.002) and 40% group (P=0.000). The force in 40% group was signifi?cantly lower than that in 60% group (P=0.013) and 50% group (P=0.021). In the acetabular cup torque test, the average torque for mode of failure in 100%, 70%, 60%, 50%, and 40% group was 28.0±3.7, 17.0±2.2, 9.4±1.1, 7.6±1.1, 6.4±1.1 N·m, respectively. The torque was reduced gradually. The torque in 100% group was significantly higher than that in other groups (P<0.05). There was no significant difference between 50% and 40% group (P>0.05). The torque in other groups were similar (P>0.05). Conclu?sion The present biomechanical study showed that different acetabular cup coverage rate affected the initial stability of the cup. The highest initial stability was observed in the cup with a 100% of cup coverage rate. The cup could not obtain 100% coverage when with acetabular rim defect. We should try our best to make the cup coverage reach to 70%. The 70% coverage rate has suffi?cient initial stability to meet daily activities without increasing the cup loosening rate.