PURPOSE Lower limb malalignment is a strong predictor of progression in knee osteoarthritis. The purpose of this study is to identify the individual alignment variables that predict progression in early to moderate osteoarthritis of the knee. METHOD A longitudinal cohort study using data from the Osteoarthritis Initiative. In total, 955 individuals (1329 knees) with early to moderate osteoarthritis (Kellgren-Lawrence grade 1, 2 or 3) were identified. All subjects had full-limb radiographs analysed using the Osteotomy module within Medicad® Classic (Hectec GMBH) to give a series of individual alignment variables relevant to the coronal alignment of the lower limb. Logistic regression models, with generalised estimating equations were used to identify which of these individual alignment variables predict symptom worsening (WOMAC score > 9 points) and or structural progression (joint space narrowing progression in the medial compartment > 0.7mm) over 24 months. RESULTS Individual alignment variable were associated with both valgus and varus alignment (mechanical Lateral Distal Femoral Angle, Medial Proximal Tibial Angle and mechanical Lateral Distal Tibial Angle). Only the Medial Proximal Tibial Angle was significantly associated with structural progression and none of the variables was associated with symptom progression. The odds of joint space narrowing progression in the medial compartment occurring at 24 months increased by 21% for every one degree decrease (more varus) in Medial Proximal Tibial Angle (p < 0.001) CONCLUSIONS: Our results suggest that the risk of structural progression in the medial compartment is associated with greater varus alignment of the proximal tibia. LEVEL OF EVIDENCE Level III, retrospective cohort study.

中文翻译：

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胫骨近端的内翻对准与膝关节早期至中度内翻性骨关节炎的结构进展有关。

目的下肢错位是膝骨关节炎进展的有力预测指标。这项研究的目的是确定可预测膝盖从早期到中度骨关节炎进展的个体比对变量。方法采用骨关节炎倡议组织的数据进行纵向队列研究。总共确定了955例早期至中度骨关节炎（Kellgren-Lawrence 1、2或3级）的个体（1329膝）。所有受试者均使用Medicad®Classic（Hectec GMBH）中的截骨术模块分析了全肢X线照片，以提供一系列与下肢冠状位相关的个体位准变量。使用具有广义估计方程的Logistic回归模型来确定这些个体比对变量中的哪些预测症状恶化（WOMAC得分> 9分）和/或结构性进展（内侧隔室中关节间隙变窄的进展> 0.7mm）超过24个月。结果个体对准变量与外翻和内翻对准相关（机械外侧股骨角，内侧近端胫骨角和机械外侧胫骨角）。仅内侧近端胫骨角与结构进展显着相关，而变量均与症状进展无关。结论：24个月内发生的内侧间隔关节间隙变窄的几率，随着胫骨后内侧角每减小1度（内翻幅度增加），其增加21％（p <0.001）。结论：我们的结果表明，内侧隔室结构性进展的风险与胫骨近端的更大内翻对准相关。证据水平III级，回顾性队列研究。