Blood Flow Restriction Therapy May Protect Against Bone Loss after ACL Reconstruction

    Patients who undergo anterior cruciate ligament (ACL) reconstruction often experience bone and muscle loss immediately following the procedure. A study presented during AOSSM/AANA Specialty Day found that combining blood flow restriction (BFR) therapy with traditional rehabilitation may slow this bone loss and reduce return-to-function time. 

    “Providing BFR as part of the rehabilitation efforts following ACL surgery appears to help preserve the bone, recover muscle loss, and improve function quicker, according to our research,” said lead author Bradley Lambert, PhD, from the Orthopedic Biomechanics Research Laboratory in the Department of Orthopedics & Sports Medicine at Houston Methodist Hospital.

    The prospective, randomized study included 23 active young patients with a mean age of 23 who were 10 days post-ACL reconstruction. They were divided into 2 groups: standard rehab and standard rehab plus BFR. The 12-week rehab protocol was the same for both groups, but during certain exercises, the BFR group exercised with an 80% arterial limb occlusion using an automated tourniquet. The exercises during which BFR was applied included:

    • Quadriceps contractions in weeks 1 through 3
    • Bilateral leg press in weeks 3 through 12
    • Eccentric leg press in weeks 4 through 12
    • Hamstring curl in weeks 4 through 6
    • Eccentric hamstring curl in weeks 7 through 12

    Bone mineral density, bone mass, and lean muscle mass were measured using dual-energy x-ray absorptiometry before surgery and at rehab weeks 6 and 12.

    The addition of BFR therapy to standard rehab exercises was found to prevent muscle mass loss in the whole leg and thigh in the postoperative limb compared with standard rehab alone. The addition of BFR was also observed to minimize losses in bone mineral content and preserve bone density in the limb compared with standard rehab alone. These findings coincided with improved functional outcomes measured at 8 and 12 weeks. 

    “BFR is a suitable additive therapy to ACL rehabilitation for the purposes of minimizing the loss and enhancing the recovery of muscle, bone, and physical function,” Dr. Lambert said.

    “While further research is needed to fully illuminate the physiologic mechanisms responsible for our results, these findings likely have wide ranging implications for fields outside of ACL rehab alone such as injury prevention, age-related muscle and bone loss, military rehabilitation, and potentially space flight.”  


    Lambert B, Hedt CA, Jack RA, Moreno M, Delgado D, Harris JD, McCulloch PC, Blood Flow Restriction Therapy Preserves Whole Limb Bone and Muscle Following ACL Reconstruction (Paper 06). Presented at the 2019 AOSSM/AANA Specialty Day, March 16, Las Vegas, Nevada.