股骨后髁偏距与高屈曲后稳定型全膝置换术后膝关节屈曲度的相关性分析

目的 分析股骨后髁偏距与高屈曲后稳定型全膝关节置换术中、术后膝关节屈曲度的相关性,探讨其在股骨假体设计中的意义.方法 前瞻性分析2005年3月至2006年10月使用NexGen LPS-Flex假体行单侧全膝关节置换术的男性(男性组)、女性(女性组)各50例骨关节炎患者临床与影像学资料.对患者手术前、后股骨后髁偏距的改变值与术中及术后2年膝关节屈曲度改善值的相关性进行分析.结果 100例患者术后股骨后髁偏距较术前减小(3.4±3.3)mm,减小程度女性高于男性[女性:(-5.4±3.1)mm,男性:(-1.5±2.0)mm,P<0.05].后髁偏距的改变值与术后2年膝关节屈曲度改善值在患者整体内并无相关性(P>0.05).但若分别在男性与女性组内对其观察,则两者间均呈具有正向相关性(P<0.05);术中患者整体、男性组、女性组内膝关节屈曲度改善值均与后髁偏距的改善值呈正向相关性(P<0.05).结论 重建股骨后髁偏距与高屈曲后稳定型全膝置换术后膝关节屈曲度的获得间存在相关性;使用以西方人解剖参数设计的假体不能充分匹配国人特别是我国女性股骨远端的几何学形态,兼以前参照技术进行前后髁截骨通常会导致其后髁偏距的减少,降低了其获得更大膝关节屈曲度的可能,假体设计有必要考虑不同种族和性别间的解剖差异.

Effect of posterior condylar offset on knee flexion after high-flex posterior-stabilized total knee arthroplasty

Objective To determine the effect of the posterior condylar offset (PCO) on intra- and post-operative knee flexion after total knee arthroplasty (TKA) using a high-flex posterior-stabilized ( PS) fixed-bearing prosthesis and to discuss it's importance in femoral prosthesis design. Methods The clinical and radiographic materials of 100 consecutive patients (100 knees) were prospectively studied, including 50 men and 50 women, who had undergone primary NexGen LPS-Flex TKAs for end-stage osteoarthritis. All operations were performed by a single surgeon using the same operative technique between March 2005 and October 2006. Pearson's regression analysis was used to assess the relationship between the difference in the pre- and post-operative PCO on true lateral radiographs and the change in knee range of flexion (ROF) under non-weight-bearing conditions. Results The decrese of the corrected PCO was (3. 4 ± 3. 3) mm compared with the preoperative value, the restoration of PCO was better in male than female [female ( - 5.4 ± 3. 1) mm vs. male ( - 1.5 ± 2.0) ram, P < 0. 05] . The difference in the corrected PCO after PS TKA demonstrated significantly correlated with the change in 2 years postoperative ROF in male and famel, respectively (P <0. 05). While no statistically correlation was observed in the overall group (P >0. 05). Intraoperatively, the difference in the corrected PCO was significantly correlated with the change in ROF in male, famel, and the overall group, respectively (P < 0. 05). Conclusions Restoration of PCO plays an important role in the optimization of knee flexion after high-flex PS TKA. Femoral components based on Caucasian anatomic characteristics could not match the native anatomy of distal femurs of Chinese population especially female Chinese. Rotated resection of distal femur with anterior referencing technique usually leads to a decreased PCO and therefore reduces maximal obtainable flexion. Sexual dimorphism in humans andanatomic vairations in various ethnic groups should be seriously considered in total knee prosthesis design.