Nutritional intervention to enhance recovery after arthroscopic knee surgery in adults: a randomized controlled pilot trial

Abstract

Background: Essential amino acid (EAA) and omega-3 fatty acid ingestion independently attenuate leg skeletal muscle disuse atrophy in uninjured persons. However, no data exist regarding the effectiveness of combined EAA and omega-3 fatty acid ingestion to mitigate skeletal muscle disuse atrophy in response to anterior cruciate ligament reconstruction (ACLR) surgery. This pilot trial will explore the feasibility of recruitment and retention of ACLR outpatients from a single center across 18 months to consume either a combination of omega-3 fatty acids and EAAs, or a placebo control, for 4 weeks before and 2 weeks after surgery.

Methods: Thirty adult (≥ 18 years old) ACLR outpatients will be recruited for this single center, double-blind, two-arm randomized controlled feasibility pilot trial. Participants will consume either 5 g⋅day^-1 of omega-3 fatty acids (fish oil) and 40 g⋅day^-1 of EAAs or 5 g⋅day^-1 of a control fatty acid mixture (safflower oil) and 40 g⋅day^-1 of non-essential amino acids (NEAAs). Fatty acid supplements will be consumed 4 weeks before and for 2 weeks after ACLR surgery, whereas the EAAs and NEAAs will be consumed 1 week before and for 2 weeks after ACLR surgery. The primary outcomes are feasibility of recruitment and retention, with the goal to recruit 30 outpatients across 18 months and retain 22 participants upon completion of the study protocol following 12 weeks of data collection. These results will be reported using descriptive statistics, along with reasons and timepoints for study dropout. Secondary exploratory outcomes will be reported using inferential statistics for purposes of hypothesis generation and elucidation of mechanistic targets for future work; no inferences to clinical efficacy will be made. These outcomes include integrated rates of skeletal muscle protein synthesis, skeletal muscle protein content and expression of translation factors, skeletal muscle and erythrocyte phospholipid composition, and measures of skeletal muscle mass, strength, and power.

Impact: This work will set the foundation for a future randomized controlled trial powered to detect an effect of EAA + omega-3 fatty acid intake on skeletal muscle size or function in response to ACLR surgery.

Trial registration: ClinicalTrials.gov, NCT06233825. Registered 31 January 2024. https://clinicaltrials.gov/study/NCT06233825?term=NCT06233825&rank=1.

Keywords: Anterior cruciate ligament; Essential amino acids; Magnetic resonance imaging; Muscle protein synthesis; Omega-3 fatty acids.

Fig. 1

CONSORT flowchart. Intervention is 6 weeks (4 pre-surgery, 2 post) × 5 g⋅day⁻¹ omega-3 FA + 3 weeks (1 pre-surgery, 2 post) × 40 g⋅day⁻¹ EAA. Placebo control is 6 weeks (4 pre-surgery, 2 post) × 5 g⋅day⁻¹ safflower oil + 3 weeks (1 pre-surgery, 2 post) × 40 g⋅day⁻¹ NEAA. ACL, anterior cruciate ligament; ACL-QoL, ACL Quality of Life questionnaire; BIA, bioelectrical impedance analysis; EAA, essential amino acids; GAQ, Get Active Questionnaire; IKDC, International Knee Documentation Committee subjective knee evaluation form; MRI, magnetic resonance imaging; NEAA, non-essential amino acids; PASBQ, Physical Activity Behavior Questionnaire