Chaudhry Harman, Ponnusamy Karthikeyan, Somerville Lyndsay, McCalden Richard W, Marsh Jacquelyn, Vasarhelyi Edward M
Division of Orthopaedic Surgery, Western University, London, Ontario, Canada.
JBJS Rev. 2019 Jul;7(7):e9. doi: 10.2106/JBJS.RVW.18.00184.
Obesity has been associated with a greater burden of symptomatic knee osteoarthritis. There is some evidence that patients with a very high body mass index (BMI) may have a higher risk of complications and poor outcomes following total knee replacement compared with non-obese patients or obese patients with a lower BMI. We hypothesized that increasing degrees of obesity would be associated with deteriorating outcomes for patients following total knee replacement.
We performed a comprehensive systematic review of 4 medical databases (MEDLINE, AMED, Ovid Healthstar, and Embase) from inception to August 2016. We extracted data to determine revision risk (all-cause, septic, and aseptic) and functional outcome scores (Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], Knee Society Score, Oxford Knee Score, EuroQol-5D, and Short Form [SF]-12 Physical Component Summary) in patients with severe obesity (BMI ≥35 kg/m), morbid obesity (BMI ≥40 kg/m), and super-obesity (BMI ≥50 kg/m) in comparison with patients with a normal BMI (<25 kg/m). Meta-analysis was performed using a random effects model.
We screened 3,142 titles and abstracts and 454 full-text articles to identify 40 eligible studies, of which 37 were included in the meta-analysis. Compared with patients with a normal BMI, the risk ratio for an all-cause revision surgical procedure was 1.19 (95% confidence interval [CI], 1.03 to 1.37; p = 0.02) in patients with severe obesity, 1.93 (95% CI, 1.27 to 2.95; p < 0.001) in patients with morbid obesity, and 4.75 (95% CI, 2.12 to 10.66; p < 0.001) in patients with super-obesity. The risk ratio for septic revision was 1.49 (95% CI, 1.28 to 1.72; p < 0.001) in patients with severe obesity, 3.69 (95% CI, 1.90 to 7.17; p < 0.001) in patients with morbid obesity, and 4.58 (95% CI, 1.11 to 18.91; p = 0.04) in patients with super-obesity. There were no significant differences (p > 0.05) in risk of aseptic revision. Based on the Knee Society Scores reported in a single study, patients with super-obesity had outcome scores, expressed as the standardized mean difference, that were 0.52 lower (95% CI, 0.80 lower to 0.24 lower; p < 0.001) than non-obese controls; however, no difference was observed for severe or morbidly obese patients.
The risk of septic revision is greater in patients with severe obesity, morbid obesity, and super-obesity, with progressively higher BMI categories associated with a higher risk. However, the risk of aseptic revision was similar between all obese and non-obese patients. Functional outcome improvements are also similar, except for super-obese patients, in whom data from a single study suggested slightly lower scores. These findings may serve to better inform evidence-based clinical, research, and policy decision-making.
Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
肥胖与有症状的膝关节骨关节炎负担加重相关。有证据表明，与非肥胖患者或体重指数（BMI）较低的肥胖患者相比，BMI非常高的患者在全膝关节置换术后可能有更高的并发症风险和更差的预后。我们推测，肥胖程度增加与全膝关节置换术后患者的预后恶化相关。
我们对4个医学数据库（MEDLINE、AMED、Ovid Healthstar和Embase）从创建到2016年8月进行了全面的系统评价。我们提取数据以确定严重肥胖（BMI≥35kg/m²）、病态肥胖（BMI≥40kg/m²）和超级肥胖（BMI≥50kg/m²）患者与正常BMI（<25kg/m²）患者相比的翻修风险（全因、感染性和无菌性）和功能结局评分（西安大略和麦克马斯特大学骨关节炎指数[WOMAC]、膝关节协会评分、牛津膝关节评分、欧洲五维健康量表和简短健康调查问卷[SF]-12身体成分总结）。使用随机效应模型进行荟萃分析。
我们筛选了3142篇标题和摘要以及454篇全文文章，以确定40项符合条件的研究，其中37项纳入荟萃分析。与正常BMI患者相比，严重肥胖患者全因翻修手术的风险比为1.19（95%置信区间[CI]，1.03至1.37；p=0.02），病态肥胖患者为1.9（95%CI，1.27至2.95；p<0.001），超级肥胖患者为4.75（95%CI，2.12至10.66；p<0.001）。严重肥胖患者感染性翻修的风险比为1.49（95%CI，1.28至1.72；p<0.001），病态肥胖患者为3.69（95%CI，1.90至7.17；p<0.001），超级肥胖患者为4.58（95%CI，1.11至18.91；p=0.04）。无菌性翻修风险无显著差异（p>0.05）。根据一项研究报告的膝关节协会评分，超级肥胖患者的结局评分以标准化平均差表示，比非肥胖对照组低0.52（95%CI，低0.80至低0.24；p<0.001）；然而，严重或病态肥胖患者未观察到差异。
严重肥胖、病态肥胖和超级肥胖患者感染性翻修的风险更大，BMI类别越高风险越高。然而，所有肥胖和非肥胖患者的无菌性翻修风险相似。除超级肥胖患者外，功能结局改善也相似，一项研究的数据表明超级肥胖患者的评分略低。这些发现可能有助于更好地为基于证据的临床、研究和政策决策提供信息。
预后III级。有关证据水平的完整描述，请参阅作者指南。
