Optimising body weight in people with obesity prior to knee or hip arthroplasty: a feasibility study utilising a dietitian-led low inflammatory diet

Background: Weight loss is recommended for people with obesity prior to undergoing total knee or hip arthroplasty. This study aimed to determine the feasibility of implementing a dietitian-led low-inflammatory weight-loss diet for people with obesity awaiting arthroplasty. Secondary aims were to report weight change, patient-reported outcomes, diet compliance, surgery deferment and diet acceptability. Methods: Eligible participants were enrolled across two sequential periods; Usual Care (UC) was recruited, followed by an intervention period with a dietitian-led weight-loss programme (DT). Assessments occurred at baseline, 6-month and pre-surgery (11–12 months from baseline). Predefined diet feasibility outcomes included: (i) recruitment rate ≥60%, (ii) ≥60% of DT group reporting ≥10% improved compliance with low-inflammatory diet by pre-surgery, (iii) all DT participants attending ≥60% of dietitian consultations, (iv) proportion of DT group losing ≥5% weight double that of UC by pre-surgery. Results: Ninety-seven people participated (UC, n = 47, DT, n = 50). Baseline variables were similar between groups. None of the diet feasibility criteria were fulfilled: 52% of eligible people consented; 57% of DT group improved diet compliance; 72% of DT Group attended ≥60% of dietitian appointments; 31.4% of DT group lost ≥5% weight (compared to 20.6% of UC). Compared to UC group at pre-surgery, DT group demonstrated modest weight loss (−1.7 kg (95%CI -3.5,0.2) versus −0.4 kg (−2.5,1.6)), and decreased waist circumference (−4.8 cm (−6.9,-2.8) versus −2.2 cm (−5.2,0.7)). Three DT participants declined surgery due to improved symptoms. Conclusion: Utilisation of a dietitian-led low-inflammatory weight-loss diet was not feasible in this cohort. Suboptimal diet compliance likely explains the modest weight loss results.