Protein Supplementation After ACL Surgery

Overview

The purpose of the study is to assess the longitudinal post-operative care effects of protein supplementation on muscle atrophy in the post-operative period following ACL reconstruction. The main outcome will be muscle size/mass as measured using dual energy x-ray absorptiometry (DEXA) scanning. The primary objective is to assess for any beneficial impact of protein supplementation, with implications of standardizing a recommended protocol for protein supplementation after ACL reconstruction. Secondary outcomes will be to evaluate the survey data from the KOOS JR and Tampa Scale surveys, as well as functional measures recorded during physical therapy.

This study is designed to evaluate non-interventional longitudinal post-operative clinical improvement. The proposed study is a randomized non-interventional, double blind study. Subjects will include patients age 16 to 40 undergoing primary ACL reconstruction for an acute ACL tear. Demographic information including age, sex, BMI, and sport participation will be obtained from patients at the time of recruitment. Subjects will be randomized to one of three categories: 1)placebo, 2)protein supplementation, or 3)protein supplementation with amino acids. The probability is is a 1 in 3 chance to be enrolled in each group. Participants will be provided the supplement drink immediately following surgery and will be asked to consume the supplement 2-times daily following ACL reconstruction for a total of 12 weeks post-op. In addition, participants will be asked to complete a weekly food diary in which they track their diet for 2 week days and 1 weekend day each week for all 12 weeks. This will help account for dietary proteins. Subjects will also be asked to complete the KOOS Jr and Tampa Scale surveys (attached in the application) through Houston Methodist's Redcap system at each time point (Pre-op, 4, 8 and 12 weeks postop). Briefly, BCAAs (particularly leucine) represent primary triggers for the stimulation of protein synthesis via signaling through the mammalian target of rapamycin complex 1 pathway (mTORC1) in skeletal muscle and other tissues. Whey hydrolysate is a complete protein source that is considered to be "fast absorbing." Casein is a complete protein source that is "slow absorbing" relative to whey.9 All protein sources used in this investigation are commercially available nutritional supplements. The placebo will include a crystallite drink. Standard of care clinic assessments such as bilateral muscle strength and stability screening will be performed in all patients at 8 and 12 weeks of rehabilitation. Time to return to sport for those subjects participating in a recreational or professional sport activities will also be recorded. Lastly, quadriceps muscle mass measured through dual energy x-ray absorptiometry (DEXA) scanning. Participants in all 3 groups will undergo DEXA scanning at once pre-operatively, 4 weeks post-op,8 weeks, post-op and 12 weeks post-op following ACL reconstruction. The Tampa Scale and KOOS JR surveys will be administered at each study visit. The purpose of these surveys are to evaluate patient perception of surgery and their injury. As stated in the purpose, these will act as secondary outcomes to this study.