Efficacy of Protein and Essential Amino Acid Supplementation in Lower Limb Surgeries: A Systematic Review and Meta-Analysis.

This study aimed to examine the efficacy and safety of protein and/or essential amino acid (EAA) supplementation in all lower limb surgeries using systematic reviews and meta-analysis of randomized controlled trials (RCTs). We included RCTs that assessed the efficacy of protein and/or EAA supplementation in lower limb surgeries. On June 2, 2023, we searched EMBASE, MEDLINE, the Cochrane Central Register of Controlled Trials, the World Health Organization International Clinical Trials Registry Platform, and ClinicalTrials.gov. The primary outcomes were mobility, patient-reported outcomes (PRO), and acute kidney injury (AKI). The secondary outcomes were exercise capacity, muscle strength, muscle mass, and all adverse events. We performed meta-analyses using the random-effects model. We assessed the risk of bias using the Cochrane risk-of-bias tool and the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation approach. We included 12 RCTs (622 patients). These studies included four on hip fracture surgery, three on total hip arthroplasty, and five on total knee arthroplasty. Protein and/or EAA supplementation may slightly improve PRO (standard mean difference 0.51, 95% confidence interval (CI): 0.22 to 0.80, low certainty of evidence). Nevertheless, it may not improve mobility (mean difference 0.07 m/s, 95% CI: -0.01 to 0.16, low certainty of evidence). No adverse events including AKI were reported. Muscle strength may have increased (standard mean difference 0.31, 95% CI: 0.02 to 0.61, very low certainty of evidence). However, exercise capacity (mean difference 5.43 m, 95% CI: -35.59 to 46.45, very low certainty of evidence) and muscle mass (standard mean difference -0.08, 95% CI: -0.49 to 0.33, very low certainty of evidence) were not improved. While protein and/or EAA supplementation in lower limb surgeries may improve PRO, it is unlikely to affect mobility. Despite this, the medical team and patients might still consider protein and/or EAA supplementation a useful option.