Purpose

This study aimed at determining whether overcorrection after open wedge high tibial osteotomy (OWHTO) would be predicted by the magnitude of preoperative medial and lateral coronal soft tissue laxity around the knee joint.

Methods

Overall, 68 knees of 62 patients who underwent OWHTO for primary medial osteoarthritis were retrospectively reviewed. The mechanical hip–knee–ankle (HKA) axis, weight-bearing line (WBL) ratio, medial proximal tibial angle (MPTA), joint line obliquity, coronal subluxation, and joint line convergence angle (JLCA) were measured on full-weight-bearing long-standing HKA radiographs preoperatively and at 1 year postoperatively. The varus valgus stress angle was measured on preoperative radiographs. The correction amount due to soft tissue factors was calculated as the difference between the WBL ratio on postoperative 1-year radiographs and that on virtually corrected preoperative radiographs with the same amount of MPTA at 1 year postoperatively. The patients were grouped according to the presence or absence of a ≥ 10% overcorrection of WBL ratio (overcorrection or expected correction). Multiple logistic regression analysis was performed to identify the preoperative risk factors of overcorrection.

Results

The average WBL ratio was corrected from 19.0 ± 13.5% preoperatively to 61.6 ± 9.1% postoperatively (P < 0.001). The average MPTA changed from 85.1 ± 1.7° preoperatively to 93.6 ± 2.6° postoperatively, resulting in an average tibia correction angle of 8.6 ± 3.1°. The average estimated correction from soft tissue factors was 5.8 ± 7.4% of the WBL ratio. Soft tissue correction of the WBL ratio > 10% was confirmed in 17 patients (28%). The preoperative JLCA and valgus stress angle were significantly greater in the overcorrection group than in the expected correction group: 5.0 ± 1.7° vs. 3.4 ± 1.9° (P = 0.003) and 2.4 ± 1.0° vs. 1.3 ± 1.2° (P = 0.002), respectively. Among the radiologic parameters, the presence of both ≥ 4° JLCA and ≥ 1.5° valgus stress angle was the only significant risk factor for overcorrection from soft tissue factors (P = 0.006; odds ratio, 30.2).

Conclusions

The magnitude of both medial and lateral coronal soft tissue laxity was a predictor of overcorrection from soft tissue factors after OWHTO. Overcorrection was more likely to occur in cases with both ≥ 4° JLCA and ≥ 1.5° valgus stress angle.

Level of evidence

III.

中文翻译：

---

术前内侧和外侧松弛的增加是开放楔形高位胫骨截骨术矫正过度的预测指标。

目的

这项研究旨在确定是否可以通过术前膝关节周围内侧和外侧冠状软组织松弛的程度来预测开楔高位胫骨截骨术（OWHTO）后的过度矫正。

方法

总体而言，回顾性分析了62例因原发性内侧骨关节炎接受OWHTO手术的患者的68膝。机械性髋-膝-踝（HKA）轴，负重线（WBL）比，胫骨近端内侧角（MPTA），关节斜度，冠状动脉半脱位和关节线会聚角（JLCA）均按全重测量-术前和术后1年携带长期的HKA X光片。在术前X线片上测量内翻外翻应力角。由软组织因素引起的校正量计算为术后1年X线片的WBL比率与术后1年MPTA量相同的虚拟校正前X线片的WBL比率之差。根据是否存在≥10％的WBL比过度校正（过度校正或预期校正）将患者分组。进行了多元逻辑回归分析，以确定术前过度矫正的危险因素。

结果

平均WBL比率从术前的19.0±13.5％校正为术后的61.6±9.1％（P  <0.001）。平均MPTA从术前的85.1±1.7°变为术后的93.6±2.6°，因此平均胫骨矫正角为8.6±3.1°。软组织因子的平均估计校正量为WBL比率的5.8±7.4％。在17例（28％）患者中证实了WBL比率> 10％的软组织矫正。过度矫正组的术前JLCA和外翻应力角明显大于预期矫正组：5.0±1.7°vs. 3.4±1.9°（P  = 0.003）和2.4±1.0°vs. 1.3±1.2°（P = 0.002）。在放射学参数中，同时存在≥4°JLCA和≥1.5°外翻应力角是从软组织因子过度矫正的唯一重要危险因素（P  = 0.006；优势比，30.2）。

结论

OWHTO后，内侧和外侧冠状软组织松弛的程度是软组织因子过度矫正的预测指标。≥4°JLCA和≥1.5°外翻应力角的情况下，更可能发生过度矫正。

证据水平

三，