Overweight preoperatively impairs clinical outcome after knee arthroplasty

Abstract

BackgroundObesity contributes much to the development of knee osteoarthritis. However, the association between obesity and outcome after knee replacement is controversial. We investigated whether there was an association between the preoperative body mass index (BMI) of patients who underwent total knee arthroplasty (TKA) and their quality of life (QoL) and physical function 3–5 years after surgery.Methods197 patients who had undergone primary TKA participated in a 3–5 year follow-up study. The outcome measures were the patient-reported Short Form 36 (SF-36) and the American Knee Society score (KSS).ResultsOrdinal logistic regression analysis (adjusted for age, sex, disease, and surgical approach) revealed a statistically significant correlation between BMI and 9 of the 14 outcome measures. For all outcome measures, we found an odds ratio (OR) of < 1. A difference in BMI of 1 kg/m2 increased the risk of a lower score from a minimum of 2% (OR = 0.98 (0.93–1.03); p = 0.5) (Mental Component score) to a maximum of 13% (OR = 0.87 (0.82–0.93); p < 0.001) (KSS function score).InterpretationOur findings indicate that TKA patients’ preoperative BMI is a predictor of the clinical effect and patients’ quality of life 3–5 years postoperatively. A high BMI increases the risk of poor QoL (SF-36) and physical function (KSS).

Do Stemmed Tibial Components in Total Knee Arthroplasty Improve Outcomes in Patients With Obesity?

“…In our series, pain at the proximal aspect (defined as the area between the joint line and the 5 cm above) of the tibia was analyzed postoperatively. Pain has been evaluated after TKA in patients with obesity but to our knowledge, the proximal tibial pain that we evaluated has not been studied by others [4,12,[15][16][17]23]. In a previous report, obesity was not associated with a higher risk of moderate to severe pain in patients undergoing primary TKA at 2-or 5-year followup [4].…”

“…Previously published papers regarding BMI and pain after TKA reported controversial results [6,14,[17][18][19]24]. Most previous studies have examined the association of BMI with summary scores (not pain) [4,12,[15][16][17]23], mostly using the KSS total and objective/subjective scores and most reporting lack of an association, whereas few were positive. In one study, however, analyzing the results of 67 patients undergoing TKA for an association of obesity with pain outcomes [17], BMI of 35 to 40 kg/m 2 was associated with higher pain scores in multivariable-adjusted models that included age, gender, and comorbidities.…”

Body Mass Index and Functional Mobility Outcome Following Early Rehabilitation After a Total Knee Replacement: A Retrospective Study in Taiwan

“…In addition, the most obese patients in our study (class III, BMI $35 kg/m 2 ) were combined with the class II obesity patients (30-34.9 kg/m 2 ), whereas most recent studies have included patients with BMIs of .35 kg/m 2 . Because a preoperative BMI of .35 kg/m 2 has been shown to be an independent risk factor for poor post-TKR outcome (12,15,62), future studies are warranted to determine whether severely obese patients with a BMI of .35 kg/m 2 have poorer outcomes following post-TKR rehabilitation compared with obese patients with lower BMIs. Second, the lack of a control group of patients who underwent TKR but did not participate in postoperative rehabilitation prevented us from ascertaining whether intergroup differences in recovery from the TKR surgery itself contributed to the changes in post-TKR outcome measures over time, or whether the changes were solely attributable to the postoperative rehabilitation program.…”

“…A high BMI is associated with limited physical performance and functional mobility in elderly persons or patients with OA (8)(9)(10)(11), and a high preoperative BMI is associated with post-TKR physical disability in obese patients with OA (12). However, the relationship between obesity and post-TKR outcome has not been fully elucidated.…”

“…However, the relationship between obesity and post-TKR outcome has not been fully elucidated. Previous studies have shown that a high BMI is associated with the risk of TKR failure, with regard to both clinical outcome and quality-of-life indicators (12)(13)(14)(15). However, other studies have shown that BMI is not associated with post-TKR outcomes (16,17).…”