骨水泥聚乙烯内衬技术在全髋内衬翻修中的生物力学研究

目的评估骨水泥聚乙烯内衬技术应用于全髋内衬翻修时的生物力学强度。方法 25对金属髋臼及聚乙烯内衬假体随机分为5组(n=5),以标准锁定装置为对照(A组),其余4组应用骨水泥聚乙烯内衬技术固定聚乙烯内衬,分为无钢珠聚乙烯内衬与金属髋臼0°交角组(B组)、带钢珠聚乙烯内衬与金属髋臼0°交角组(C组)、带钢珠聚乙烯内衬与金属髋臼10°交角组(D组)、带钢珠聚乙烯内衬与金属髋臼20°交角组(E组)。通过杠杆试验模拟体内内衬失败情况,测定各组抗杠杆力强度。结果 A～E组抗杠杆力分别为(626.68±206.12)、(915.04±197.49)、(449.02±119.78)、(814.68±53.89)、(1 033.05±226.44)N,组间比较差异有统计学意义(F=8.989,P=0.000)。其中B、E组抗杠杆力大于A组,差异有统计学意义(P<0.05);C、D组抗杠杆力与A组比较,差异无统计学意义(P>0.05)。结论用骨水泥聚乙烯内衬技术将内衬与金属髋臼以≤20°交角固定于金属髋臼内,能提供足够的初始固定强度。

A biomechanical study on polyethylene liner cementing into a fixed acetabular shell in revision total hip arthroplasty

Objective To evaluate the strength of polyethylene linercement interface when cementing a new liner into a fixed acetabular cup in revision.Methods Twenty-five pairs of metal acetabular cups with polyethylene liners were randomly divided into 5 groups: 1 group with standard locking device as control group(group A),other liners were cemented into acetabular cups as 4 experimental groups.According to different intersection angles of metal acetabular cups with polyethylene liners and the polyethylene liners with or without metal ball,the 4 experimental groups were no ball 0°group(group B),0°group(group C),10 group(group D),and 20°group(group E),metal acetabular cups intersected with polyethylene liners without metal ball in group B,with metal ball in groups C,D,and E,respectively.The lever-out biomechanical test reproduced in vivo failure mechanism was then performed to evaluate the lever-out failure strength of liner-cement-metal cup interface.Results The values of liver-out failure force were(626.68 ± 206.12),(915.04 ± 197.49),(449.02 ± 119.78),(814.68 ± 53.89),and(1 033.05 ± 226.44) N in groups A,B,C,D,and E,respectively,showing significant differences for comparison among groups(F=8.989,P=0.000).The values of liver-out failure force in groups B and E were significantly higher than that in group A(P < 0.05),but no significant difference was found between groups C,D and group A(P > 0.05). Conclusion Cementation of polyethylene liner into a malposition shell meeting within 20° can provide enough fixed strength.