Department of Orthopaedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
Department of Orthopaedics, LKH Bad Radkersburg, Dr. Schwaiger-Straße 1, 8490, Bad Radkersburg, Austria.
Arch Orthop Trauma Surg. 2023 Jun;143(6):3327-3334. doi: 10.1007/s00402-022-04601-3. Epub 2022 Sep 6.
High BMI is associated with increased risk for knee osteoarthritis, ultimately necessitating total knee arthroplasty (TKA). The aim of this retrospective study was to (1) analyse the amount of postoperative long-term weight loss as reflected by BMI change in TKA patients, (2) identify factors associated with increased change in BMI, and to (3) compare changes with BMI trends of a general population.
Overall, 298 TKA patients [198 females; mean age: 65.1 ± 7.9 years, median follow-up 8.8 (interquartile range: 5.9-10.8 years)] were included in the final evaluation and compared with an age group-matched control group from the general population regarding weight trends between 2006 and 2014. Main variable of interest in both cohorts was body mass index (BMI). Linear regression analyses were performed to assess changes in weight and BMI over time between TKA patients and the general population. Furthermore, mixed linear-effects models were constructed to analyse the potential change in BMI independent from age and gender.
In TKA patients, a significant drop in BMI by 0.8 ± 3.2 points from postoperative to final follow-up was observed (p < 0.001), with reduction being significant independently from age (p = 0.382), gender (p = 0.310), or revision surgery (p = 0.195). In the general population, likewise a significant BMI-decrease by 0.7 ± 6.1 points was observed between 2006 and 2014, with younger people (p = 0.004) and females (p < 0.001) being more likely to reduce BMI. Yet, BMI-decrease between TKA patients and the general population over time was comparable (p = 0.734). Notably, patients with initially higher BMI were significantly more likely to lose weight postoperatively than normal-weight patients (p < 0.001).
Our results point against the notion that TKA patients lose a considerable amount of weight in comparison to the general population as soon as improved joint function and pain relief have been achieved. Thus, individualized patient education programmes should be reinforced, promoting a healthy lifestyle.
高 BMI 与膝关节骨关节炎风险增加有关，最终需要进行全膝关节置换术（TKA）。本回顾性研究的目的是：（1）分析 TKA 患者 BMI 变化反映的术后长期体重减轻量；（2）确定与 BMI 变化相关的因素；（3）并比较 TKA 患者 BMI 变化与一般人群 BMI 趋势的差异。
共纳入 298 例 TKA 患者（198 例女性；平均年龄：65.1 ± 7.9 岁，中位随访时间 8.8（四分位间距：5.9-10.8 年））进行最终评估，并将其与一般人群中年龄匹配的对照组进行比较，以评估 2006 年至 2014 年期间体重变化趋势。两个队列的主要观察变量均为体重指数（BMI）。线性回归分析用于评估 TKA 患者和一般人群随时间的体重和 BMI 变化。此外，还构建了混合线性效应模型，以分析独立于年龄和性别因素的 BMI 潜在变化。
在 TKA 患者中，术后至最终随访时 BMI 显著下降 0.8 ± 3.2 点（p < 0.001），且下降与年龄（p = 0.382）、性别（p = 0.310）或翻修手术（p = 0.195）无关。在一般人群中，同样观察到 2006 年至 2014 年间 BMI 显著下降 0.7 ± 6.1 点，年轻人（p = 0.004）和女性（p < 0.001）更有可能降低 BMI。然而，TKA 患者和一般人群随时间的 BMI 下降相当（p = 0.734）。值得注意的是，与正常体重患者相比，初始 BMI 较高的患者术后体重减轻的可能性显著更高（p < 0.001）。
我们的研究结果表明，一旦关节功能改善和疼痛缓解，TKA 患者与一般人群相比并不会大量减重。因此，应加强个体化的患者教育计划，促进健康的生活方式。
