Weight Loss Intervention Before Total Knee Replacement: A 12-Month Randomized Controlled Trial

Abstract

Background and Aims: Obesity is an increasing problem in patients after total knee replacement. The aim of this study was to investigate whether a weight loss intervention before primary total knee replacement would improve quality of life, knee function, mobility, and body composition 1 year after surgery. Material and Methods: Patients scheduled for total knee replacement due to osteoarthritis of the knee and obesity were randomized to a control group receiving standard care or to an intervention group receiving 8-week low-energy diet before total knee replacement. Patient-reported quality of life, 6-Min Walk Test, and body composition by dual-energy X-ray absorptiometry were assessed before intervention for the diet group, and within 1 week preoperatively for both groups, and the changes in outcome from baseline to 1 year after total knee replacement were compared between groups. The number of participants was lower than planned, which might introduce a type-2 error and underestimate the trend for a better outcome after weight loss. Results: The analyses are based on a total of 76 patients, 38 in each group. This study showed major improvement in both study groups in quality of life and knee function, though no statistically significant differences between the groups were observed 1 year after total knee replacement. The average weight loss after 8-week preoperative intervention was 10.7 kg and consisted of a 6.7 kg reduction in fat mass. One year after total knee replacement, the participants in the diet group managed to maintain the weight reduction, whereas there was no change in the control group. Conclusion: The results suggest that it is feasible and safe to implement an intensive weight loss program shortly before total knee replacement. The preoperative intervention resulted in a 10% body weight loss, improved body composition, lower cardiovascular risk factors, and sustained s-leptin.

Core Outcome Measurement Instruments for Clinical Trials of Total Knee Arthroplasty: A Systematic Review

“…Responsiveness was examined in almost all tools by various methods. With the definition of responsiveness used in this study, the KOOS [40,73,79], OKS [13,30,42,90], GDS [73], HADS [10,17,52,82,87] and NRS pain [83] had positive ratings for responsiveness to change. In TKA patients, at 6 months, the MIC scores for improvement in pain and physical function for the WOMAC were approximately 23 and 19, respectively, which were higher than the MDC [79].…”

“…Content validity was assessed for 9 (69%) of the 13 tools ( Figure 2 and Table A4). The Knee Injury and Osteoarthritis Outcome Score (KOOS) [54], OKS [30,42], State-Trait Anxiety Index (STAI) [72], Geriatric Depression Scale (GDS) [73] and Hospital Anxiety and Depression Scale (HADS) [10,17,52,82,87] had positive ratings based on several studies. The WOMAC [8,18,34,63,79], New Knee Society Score (KSS) [29,70], SF-36 [7,8,27,34,75,88], SF-12 [7,28,34,38,88] and Pain Catastrophizing Score (PCS) [82] had indeterminate (doubtful) ratings regarding the lack of clear and complete documentation of the item selection process.…”

“…For most of the remaining studies, the Cronbach α was determined, and studies involving the SF-36 [34,35], SF-12 [7,28,38,88] and PCS [82] showed values of ≥0.7 for all subscales. Although the HADS [10,17,52,82,87] had a positive rating based on several studies, it may show reduced validity in some populations (e.g., older people).…”

“…Construct validity was assessed in all tools. The KOOS [37,40,73,78,79], WOMAC [8,18,34,63,79,89], OKS [30,42], GDS [73], HADS [10,17,52,82,87], SF-36 [7,8,27,34,35,75,88], SF-12 [7,28,34,38,88], and pain by a numeric rating scale (NRS pain) [83] had positive ratings based on some studies. The KSS [29,70] and PCS [82] received indeterminate ratings mostly due to the lack of pre-defined hypotheses and confirmation of less than 75% of the hypotheses.…”

“…Based on more than one study, the KOOS [37,40,73,78,79], WOMAC [8,18,34,63,79,89], OKS [30,42,90], SF-36 [7,8,27,34,35,75,88], and SF-12 [7,28,34,38,88] had positive ratings. The HADS [10,17,52,82,87] and HSS [51,69] had indeterminate ratings in nearly all studies because some subscales did not meet the 15% cut-off point.…”