Blood flow restriction training in rehabilitation following anterior cruciate ligament reconstructive surgery: A review

Anterior cruciate ligament (ACL) rupture is a highly prevalent orthopedic injury, resulting in substantial skeletal muscle atrophy because of changes in muscle protein balance and satellite cell abundance. Neural activation problems also contribute to strength loss, impacting upon a patients' physical function and rehabilitative capacity. Heavy loads typically required for muscle hypertrophy and strength adaptations are contraindicated because of graft strain and concomitant cartilage, meniscal, and bone pathologies associated with ACL reconstruction. Strength of the quadriceps is a fundamental component for the ability to reduce shearing and torsional strains on the ACL with ground contact, and forms a critical component of ACL rehabilitation. Given the dangers of early postoperative heavy-loading, low-load blood flow restriction (BFR) training may provide an alternative rehabilitation tool for practitioners. Passive BFR can attenuate early muscle atrophy and strength loss, and may be more effective with the addition of novel, complementary therapies such as neuromuscular electrical stimulation. Upon ambulation, aerobic, and resistance exercise with BFR can stimulate muscle hypertrophy and strength adaptations and resolve activation problems. This may occur through increasing muscle protein synthesis and satellite cell proliferation, decreasing muscle protein breakdown and improving muscle activation by altered recruitment patterns. Thus, BFR training may provide an effective rehabilitation tool that does not place heavy loads and force through the tibiofemoral joint. This may reduce the risk of damaging the graft, cartilage, meniscus, or other intra-articular structures, providing thorough screening before use is followed by correct, evidence-informed application.