BACKGROUND
Knee replacement typically results in reduced pain and improved function, but it is unclear if these improvements lead to weight loss.
OBJECTIVE
The purpose of this study was to examine weight change patterns pre- and post-operatively among overweight/obese knee replacement patients.
METHODS
The study evaluated 210 overweight/obese patients from the Osteoarthritis Initiative who underwent a knee replacement during an 8 year longitudinal study. Average annual weight changes during 1–2 year intervals prior to, including, and subsequent to knee replacement were categorized as loss (≥−2.5%), maintain (>−2.5% to <2.5%), and gain (≥2.5%). Weight changes across time intervals were compared using logistic regression with generalized estimating equations, adjusting for demographic, health, and knee factors.
RESULTS
On average, patients lost (−0.6 kg/yr) during the interval when the surgery was performed, but weight gain (0.9 kg/yr) in the initial post-operative interval represented an overall net weight gain (0.3 kg/yr) compared to pre- surgery. Continued weight gain (0.3 kg/yr) was also seen among patients with additional follow-ups. Patients were significantly less likely to have a meaningful weight loss in the time interval immediately following the surgery compared to the interval in which the surgery took place (odds ratio=0.37, 95% confidence interval: 0.18, 0.79).
CONCLUSION
Overweight and obese patients initially lost weight during the interval including knee replacement, however they were less likely to lose >2.5% of their weight in the 1–2 years immediately after the surgery. Knee replacement patients may benefit from weight management interventions both pre- and post-operatively.