Department of Orthopaedics, Royal Infirmary of Edinburgh, Edinburgh, Scotland.
J Bone Joint Surg Am. 2019 Sep 4;101(17):1575-1585. doi: 10.2106/JBJS.18.01096.
Anterior knee pain is the most common complication of total knee arthroplasty (TKA). The purpose of this study was to assess whether sagittal femoral component position is an independent predictor of anterior knee pain after cruciate-retaining single-radius TKA without routine patellar resurfacing.
A prospective cohort study of 297 cruciate-retaining single-radius TKAs performed in 2006 and 2007 without routine patellar resurfacing identified 73 patients (25%) with anterior knee pain and 89 (30%) with no pain (controls) at 10 years. Patients were assessed preoperatively and at 1, 5, and 10 years postoperatively using patient-reported outcome measures (PROMs), including the Short Form-12 (SF-12), Oxford Knee Score (OKS), and satisfaction and expectation questionnaires. Variables that were assessed as predictors of anterior knee pain included demographic data, the indication for the TKA, early complications, stiffness requiring manipulation under anesthesia, and radiographic criteria (implant alignment, Insall-Salvati ratio, posterior condylar offset ratio, and anterior femoral offset ratio).
The 73 patients with anterior knee pain (mean age, 67.0 years [range, 38 to 82 years]; 48 [66%] female) had a mean visual analog scale (VAS) score of 34.3 (range, 5 to 100) compared with 0 for the 89 patients with no pain (mean age, 66.5 years [range, 41 to 82 years]; 60 [67%] female). The patients with anterior knee pain had mean femoral component flexion of -0.6° (95% confidence interval [CI] = -1.5° to 0.3°), which differed significantly from the value for the patients with no pain (1.42° [95% CI = 0.9° to 2.0°]; p < 0.001). The patients with and those without anterior knee pain also differed significantly with regard to the mean anterior femoral offset ratio (17.2% [95% CI = 15.6% to 18.8%] compared with 13.3% [95% CI = 11.1% to 15.5%]; p = 0.005) and the mean medial proximal tibial angle (89.7° [95% CI = 89.2° to 90.1°] compared with 88.9° [95% CI = 88.4° to 89.3°]; p = 0.009). All PROMs were worse in the anterior knee pain group at 10 years (p < 0.05), and the OKSs were worse at 1, 5, and 10 years (p < 0.05). Multivariate analysis confirmed femoral component flexion, the medial proximal tibial angle, and an Insall-Salvati ratio of <0.8 (patella baja) as independent predictors of anterior knee pain (R = 0.263). Femoral component extension of ≥0.5° predicted anterior knee pain with 87% sensitivity.
In our study, 25% of patients had anterior knee pain at 10 years following a single-radius cruciate-retaining TKA without routine patellar resurfacing. Sagittal plane positioning and alignment of the femoral component were associated with long-term anterior knee pain, with femoral component extension being a major risk factor.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
膝关节置换术后（TKA）前膝痛是最常见的并发症。本研究的目的是评估在不常规行髌骨表面置换的情况下，单半径保留交叉韧带 TKA 后矢状面股骨组件位置是否是前膝痛的独立预测因素。
对 2006 年和 2007 年进行的 297 例单半径保留交叉韧带 TKA 的前瞻性队列研究，在 10 年时发现 73 例（25%）有前膝痛和 89 例（30%）无疼痛（对照组）。患者术前及术后 1、5 和 10 年采用患者报告的结果测量（PROM）进行评估，包括简明健康调查问卷（SF-12）、牛津膝关节评分（OKS）和满意度及期望问卷。评估的前膝痛预测因素包括人口统计学数据、TKA 的适应证、早期并发症、需要在全身麻醉下进行手法松解的僵硬和影像学标准（植入物对线、Insall-Salvati 比、后髁偏心比和前股骨偏心比）。
73 例有前膝痛的患者（平均年龄 67.0 岁[范围 38-82 岁]；女性 48[66%]）的平均视觉模拟评分（VAS）为 34.3（范围 5-100），而 89 例无疼痛的患者的平均 VAS 为 0（平均年龄 66.5 岁[范围 41-82 岁]；女性 60[67%]）。有前膝痛的患者股骨组件的平均屈曲为-0.6°（95%置信区间[CI] = -1.5°至 0.3°），与无疼痛的患者（1.42°[95%CI = 0.9°至 2.0°]）相比差异显著（p < 0.001）。有和无前膝痛的患者的平均前股骨偏心比（17.2%[95%CI = 15.6%至 18.8%]与 13.3%[95%CI = 11.1%至 15.5%]；p = 0.005）和平均内侧胫骨近端角（89.7°[95%CI = 89.2°至 90.1°]与 88.9°[95%CI = 88.4°至 89.3°]；p = 0.009）也有显著差异。10 年时，前膝痛组的所有 PROM 均较差（p < 0.05），OKS 在 1、5 和 10 年时均较差（p < 0.05）。多变量分析证实股骨组件屈曲、内侧胫骨近端角和 Insall-Salvati 比<0.8（髌骨下极）是前膝痛的独立预测因素（R = 0.263）。股骨组件伸展≥0.5°预测前膝痛的敏感性为 87%。
在我们的研究中，在不常规行髌骨表面置换的情况下，单半径保留交叉韧带 TKA 后 10 年时，25%的患者有前膝痛。矢状面股骨组件的位置和对线与长期前膝痛有关，股骨组件伸展是主要的危险因素。
治疗性 IV 级。有关证据水平的完整描述，请参见作者说明。
