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. 2019 Jul 2;14(1):200.
doi: 10.1186/s13018-019-1184-z.

Weight changes after total knee arthroplasty in Chinese patients: a matched cohort study regarding predictors and outcomes

Pengfei Zan  1   2 , Jie J Yao  3 , Kaiyuan Liu  2 , Dong Yang  2 , Weixu Li  4 , Guodong Li  5
Affiliations

Weight changes after total knee arthroplasty in Chinese patients: a matched cohort study regarding predictors and outcomes

Pengfei Zan et al. J Orthop Surg Res. .

Abstract

Background: The purpose of this study was to compare 2-year BMI changes between patients undergoing simultaneous bilateral total knee arthroplasty (TKA), staged bilateral TKA, and unilateral TKA. We also sought to determine the predictors of weight change and whether clinically meaningful weight changes affected outcomes.

Patients and methods: This retrospective, single-institution study included 202 Chinese patients who received simultaneously bilateral TKA, staged bilateral TKA, or unilateral TKA from 2008 to 2015. There were 49 simultaneous bilateral TKAs, 52 staged bilateral TKAs, and a matched 101 unilateral TKAs.

Results: 66.8% (135/202) of patients lost weight after TKA surgery. However, 20.7% (42/202) of patients experienced clinically meaningful weight loss (a BMI decrease of more than 5%). Paired t test showed that 2-year BMI was significantly lower than preoperative BMI (p < 0.001). Weight loss was significantly different between the surgical strategy (p < 0.001). Preoperative BMI and age were predictive of clinically significant weight loss or gain (p < 0.05). Multiple linear regression showed that post-operative weight loss was associated with better Western Ontario and McMaster Universities Osteoarthritis Index and SF-36 scores (p < 0.001).

Conclusion: Patients after TKA experience weight loss. Age and preoperative BMI predict clinically meaningful weight change. Simultaneous bilateral TKA is associated with higher likelihood of weight loss. Clinically meaningful weight loss experiences better patient-reported outcomes.

Keywords: Body mass index; SF-36 score; Total knee arthroplasty; WOMAC score; Weight change.

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Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
Patient flowchart
Fig. 2
Fig. 2
Patients in each BMI class changed with the follow-up time
Fig. 3
Fig. 3
Box plot showed 2-year postoperative BMI stratified by type of surgery
See this image and copyright information in PMC

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