Background

Little attention has been focused on risk factors for undergoing bilateral total knee arthroplasty (TKA) after primary unilateral TKA among patients with knee osteoarthritis (OA). This study investigated the differences in characteristics between groups with and without additional TKA for the contralateral knee among patients with knee OA who underwent primary unilateral TKA.

Methods

Seventy-six patients who underwent primary unilateral TKA were included in this study. We defined patients who underwent additional TKA for the contralateral knee within one year of the primary TKA as a bilateral TKA group, and patients who did not undergo bilateral TKA as a unilateral TKA group. Femorotibial angle (FTA), percentage of mechanical axis (%MA), Kellgren–Lawrence (KL) grade, range of motion, Japan Orthopaedic Association (JOA) score, 10 m-walking time, C-reactive protein, estimated glomerular filtration rate, and serum albumin levels were selected as independent variables including covariates of age, sex, and body mass index for predicting bilateral TKA. We compared differences in variables between the two groups using the t-test or Mann–Whitney U-test and general linear models. A multivariate stepwise logistic regression model was also used to determine which variables correlated with bailateral TKA.

Results

In pairwise comparisons, the KL grade, FTA, %MA, JOA score, and knee flexion angle in the contralateral knee were significantly worse in the bilateral TKA group than in the unilateral TKA group after controlling for covariates (P < 0.01, respectively). A stepwise logistic regression revealed that significant contributors to undergoing the contralateral TKA were FTA (OR = 1.47, P < 0.001) and knee flexion angle (OR = 0.96, P = 0.022) of the contralateral knee.

Conclusions

Severe varus deformity and limitations of flexion in the contralateral knee were found to be risk factors for undergoing additional TKA within one year of primary unilateral TKA among patients with knee OA.

中文翻译：

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单侧全膝关节置换术后对侧全膝关节置换的危险因素

背景

对于膝骨关节炎(OA)患者初次单侧全膝关节置换术 (TKA) 后进行双侧全膝关节置换术 (TKA) 的危险因素很少受到关注。本研究调查了接受初次单侧 TKA 的膝关节 OA 患者中，对侧膝关节进行或未进行额外 TKA 的组之间的特征差异。

方法

本研究纳入了 76 名接受初次单侧 TKA 的患者。我们将首次 TKA 后一年内对对侧膝关节接受额外 TKA 的患者定义为双侧 TKA 组，将未接受双侧 TKA 的患者定义为单侧 TKA 组。股胫角 (FTA)、机械轴百分比 (%MA)、Kellgren–Lawrence (KL) 分级、运动范围、日本骨科协会 (JOA) 评分、10 m 步行时间、C 反应蛋白、估计肾小球滤过率，并选择血清白蛋白水平作为自变量，包括年龄、性别和体重指数的协变量，用于预测双侧 TKA。我们使用 t 检验或曼-惠特尼 U 检验和一般线性模型比较了两组之间变量的差异。还使用多元逐步

结果

两两比较中，控制协变量后，双侧 TKA 组的 KL 分级、FTA、%MA、JOA 评分和对侧膝关节屈曲角度均显着差于单侧 TKA 组（分别P  < 0.01）。逐步逻辑回归显示，进行对侧 TKA 的重要因素是对侧膝关节的 FTA（OR = 1.47，P  < 0.001）和膝关节屈曲角度（OR = 0.96，P  = 0.022）。

结论

研究发现，膝关节 OA 患者在初次单侧 TKA 后一年内，对侧膝关节严重内翻畸形和屈曲受限是接受额外 TKA 的危险因素。