Purpose

The aim of this study was to examine and evaluate the factors associated with changes in limb alignment 10 years after total knee arthroplasty (TKA). The hypothesis was that bone morphology and immediate postoperative alignment could be correlated with long-term post-operative alignment changes following TKA.

Methods

This study retrospectively analysed 136 consecutive primary TKA cases for varus deformity, performed from 2006 to 2008, that could be followed for at least 10 years postoperatively. Anteroposterior long-leg weight-bearing radiographs were obtained within 1 month and at least 10 years after surgery. The hip–knee–ankle (HKA) angle immediately after surgery was compared with that 10 years later; factors correlating with the change in HKA angle (δHKA) were evaluated.

Results

The mean HKA angles were significantly different between immediate and long-term postoperative assessments (0.1° ± 1.9° vs. 1.2° ± 2.9°, p < 0.001). Furthermore, a significant difference was observed in the outlier ratio (> 3° deviation from the 0° of HKA angle) (10% vs. 24%, p = 0.002). δHKA strongly correlated with a higher preoperative tibial plateau tip-to-proximal tibial shaft (TPTPS) angle, higher postoperative HKA angle, lateral distal femoral angle, and lower postoperative medial proximal tibial angle.

Conclusion

Varus deformity in the proximal part of the tibia, immediate postoperative varus alignment, and varus position of the femoral and tibial components may lead to varus progression in limb alignment in the long term, even 10 years after TKA; the surgeon should, therefore, weigh the risks of leaving a varus alignment during surgery. Moreover, if the preoperative TPTPS angle is high, the alignment may become varus after TKA, even in patients who have acquired neutral alignment.

Level of evidence

IV.

中文翻译：

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胫骨近端内翻畸形和术后立即进行内翻矫正可导致全膝关节置换术后长期内翻的内翻发展。

目的

这项研究的目的是检查和评估与全膝关节置换术（TKA）十年后的肢体对齐变化有关的因素。假设是骨形态和术后立即对齐可能与TKA后长期术后对齐变化有关。

方法

这项研究回顾性分析了2006年至2008年间连续进行的136例原发性TKA内翻畸形病例，这些病例术后至少可以随访10年。术后1个月内和至少10年后获得前后长腿负重X光片。手术后立即与10年后比较髋-膝-踝（HKA）角；评估与HKA角度变化（δHKA）相关的因素。

结果

术后立即评估和长期术后评估的平均HKA角显着不同（0.1°±1.9°与1.2°±2.9°，p  <0.001）。此外，观察到异常值比率有显着差异（与HKA角的0°偏离> 3°）（10％对24％，p  = 0.002）。δHKA与术前胫骨平台尖端至近端胫骨干（TPTPS）角较高，术后HKA角较高，股骨远端外侧角以及术后内侧近端胫骨角较低密切相关。

结论

从长期来看，甚至在TKA后10年，胫骨近端的内翻畸形，术后立即进行内翻对准以及股骨和胫骨组件的内翻位置都可能导致四肢内翻的内翻发展。因此，外科医生应权衡在手术过程中保持内翻对准的风险。此外，如果术前TPTPS角度高，即使在获得中性对准的患者中，对准也可能在TKA后内翻。

证据水平

IV。