Poster 328: Pre-Operative Low-Intensity Blood Flow Restriction Training Does Not Improve Quadriceps Strength or Hypertrophy After Anterior Cruciate Ligament Reconstruction

OBJECTIVES: The purpose of this study is to evaluate the effect of low-intensity blood flow restriction (LI- BFR) training utilized in a pre-rehabilitative setting for patients undergoing anterior cruciate ligament reconstruction (ACLR) on postoperative outcomes by minimizing postoperative atrophy and impairment of the quadriceps. We hypothesize that postoperative strength and hypertrophy of the quadriceps will be greater in a population that undergoes preoperative LI-BFR training than that of a population that undergoes low-intensity sham control (LI-SHAM) training. METHODS: Twenty-eight subjects undergoing primary ACLR underwent 2 weeks of either a BFR intervention or a SHAM intervention at a rate of 2 sessions per week before surgery. Quadriceps strength and cross-sectional area were measured as well as other exploratory outcomes were measured before and after the intervention before surgery and at 5 different time points after surgery, through 6 months postoperative. Quadriceps strength was assessed through handheld dynamometry and a leg press test and quadriceps cross-sectional area was assessed using musculoskeletal ultrasound imaging. RESULTS: Adjusting for sex, time, and strength/hypertrophy at baseline, there were no significant differences found between treatment groups for the primary endpoints. Compared to 24-48 hours pre- op, this suggests that the post-op average hypertrophy remains significantly lower through 24 weeks post-op, while leg strength is similar at 24 weeks post-op as measured by handheld dynamometer and even significantly larger at 24 weeks as measured by the leg press test. CONCLUSIONS: A 2-week preoperative program of LI-BFR training may not be effective to improve postoperative quadriceps strength and hypertrophy after ACLR.