Blood Flow Restriction Following ACL Reconstruction

Recovery from anterior cruciate ligament (ACL) reconstruction involves early physical therapy to promote muscular development. Traditional training regimens are based on the concept that muscle growth is induced with high resistance exercises of at least 65-70% of 1-repetition maximum. Achieving a high resistance level can be challenging in the early post-surgical patient who may be limited by pain, muscle atrophy, diminished proprioception, and psychological factors. Increasing evidence has suggested that Blood Flow Restriction (BFR) in resistance training, while transmitting a decreased load (25-50% of 1-repetition maximum) across the surgical site, may provide an additional benefit of inducing muscular development similar to that of high intensity exercises . Augmenting exercises with BFR involves an external pressure cuff applied to the proximal portion of the extremity, which is inflated to a pressure that restricts venous outflow while allowing arterial inflow to continue. This creates a physiologic environment for the patient to gain the hypertrophic effect of high resistance training, though at a lower and safer intensity. Studies suggest that BFR stimulates muscular development through an increase in metabolic stress, muscle fiber recruitment, cell swelling, and protein synthesis.