Tew M, Waugh W
J Bone Joint Surg Br. 1985 Aug;67(4):551-6. doi: 10.1302/0301-620X.67B4.4030849.
We examine the hypothesis that a knee replacement is most likely to survive successfully if it is stable with a coronal tibiofemoral angle close to 7 degrees of valgus, the accepted normal. The records of 428 knee replacements followed up for one to nine years were analysed. The highest success rate was indeed found in those so aligned at operation and such knees were most likely to remain stable. Nevertheless, half of the failures occurred in knees correctly aligned at operation and two-fifths in knees which had remained stable in this alignment; many failures must have been caused by factors other than malalignment. Some knees, well aligned at operation, deteriorated into severely varus or valgus positions; their failure rate was significantly higher than that for knees which remained normally aligned and higher also than for knees severely varus or valgus from operation onwards. Malalignment, in itself, may not be the most important cause of failure, though it probably does compound failure from other causes.
如果膝关节置换术后稳定，且冠状位胫股角接近7度外翻（公认的正常角度），那么它成功存活的可能性最大。我们分析了428例膝关节置换术患者的记录，这些患者的随访时间为1至9年。确实，手术时如此对齐的患者成功率最高，而且这样的膝关节最有可能保持稳定。然而，一半的失败病例发生在手术时对齐正确的膝关节，五分之二发生在保持这种对齐状态稳定的膝关节；许多失败肯定是由对线不良以外的因素引起的。一些手术时对线良好的膝关节，后来恶化为严重内翻或外翻位；它们的失败率显著高于保持正常对线的膝关节，也高于从手术开始就严重内翻或外翻的膝关节。对线不良本身可能不是失败的最重要原因，尽管它可能确实会加剧其他原因导致的失败。
