Preoperative whey protein and exercise ımprove early recovery after total hip arthroplasty: a randomized controlled trial

Abstract Background Total hip arthroplasty (THA) is an effective surgical procedure for treating hip osteoarthritis; however, postoperative recovery may be complicated by impaired functional capacity, delayed mobilization, and prolonged hospital stay. Preoperative multimodal strategies combining nutritional support and exercise may improve recovery outcomes. Objective This study aimed to evaluate the effects of a combined multimodal prehabilitation protocol (preoperative whey protein supplementation plus structured exercise) on metabolic parameters, functional independence, and length of hospital stay in patients undergoing THA. Methods This randomized controlled trial included 71 patients scheduled for total hip arthroplasty (THA). Participants were randomly assigned to either the intervention group (n = 36), which received a 14-day preoperative program consisting of oral whey protein supplementation (25 g/day) and a partially supervised, home-based structured exercise protocol (comprising an initial face-to-face instruction followed by telephone-guided monitoring), or the control group (n = 35), which received standard care. Baseline habitual physical activity levels were recorded for both groups. Data were collected preoperatively and on postoperative days 3 and 5. Functional outcomes were assessed using the Barthel Index, while biochemical markers included C-reactive protein (CRP) and albumin levels. Statistical analyses included ANCOVA (adjusting for age and chronic diseases) and Repeated-Measures ANOVA for longitudinal markers. Results Significant Group × Time interaction effects were observed for CRP ( p < 0.001) and albumin ( p = 0.008), indicating different postoperative trajectories between the intervention and control groups. After adjustment for age and chronic disease status, the intervention group demonstrated significantly higher Barthel Index scores than the control group ( p < 0.001; ηp 2 = 0.31), with a large standardized between-group effect (Cohen’s d = 1.59). Length of hospital stay was significantly shorter in the intervention group (5.11 ± 1.38 vs. 6.94 ± 1.72 days); this difference remained statistically significant after adjustment for age and chronic disease status ( p = 0.004). Conclusion Combined preoperative multimodal prehabilitation integrating whey protein supplementation with structured exercise demonstrates promising efficacy in improving early functional recovery and reducing length of hospital stay in patients undergoing THA. While baseline imbalances necessitate a cautious interpretation of the effect magnitude, this integrated strategy shows strong clinical potential for perioperative optimization. Trial registration : The study was registered at ClinicalTrials.gov (Identifier: NCT07329010) on 25 September 2025.