Hyaluronic Acid Accelerates Tendon-to-Bone Healing After Rotator Cuff Repair:

Background:There is growing evidence that the subacromial injection of hyaluronic acid (HA) is effective for pain relief in rotator cuff tears; however, its effect on tendon-to-bone healing remains unknown.Purpose:To examine the effect of HA on the chondrogenesis of mesenchymal stem cells (MSCs) in vitro and on tendon-to-bone healing in a rotator cuff repair model.Study Design:Controlled laboratory study.Methods:Bilateral complete tears of the infraspinatus tendon were made in rabbits and subsequently repaired. Before closure, 1 mL HA was applied to the repaired site, and phosphate-buffered saline was used in the opposite side as a control. Biomechanical, histological, and immunohistochemical analyses were performed at 4, 8, and 12 weeks after surgery. After euthanizing each animal, the bone marrow was isolated from the femoral bone in the same rabbits. Then, MSCs were cultured in media for chondrogenic differentiation, and the chondral pellet production and cartilage-related gene expression levels in the...