Poster 266: The Effect of Bone Marrow Aspirate Concentrate Augmentation on ACL Reconstruction Allograft Volume and PROMs

OBJECTIVES: Prior studies have correlated MRI-calculated tendon volume with biomechanical properties of ACL allografts in porcine models. Bone marrow aspirate concentrate (BMAC) has been shown to improve biomechanical graft strength in other animal studies. We sought to assess the effects of BMAC on ACL bone-tendon-bone (BTB) allograft volume and PROMs. METHODS: The study population included 66 patients with both a 3-month and 9-month MRI from an IRB-approved, double-blinded, randomized control trial comparing patients undergoing ACL reconstruction (ACLR) with BTB allograftBMAC. The primary outcome was tendon volume at 9 months, with a secondary outcome of change in tendon volume between 3-9 months. Knee Injury and Osteoarthritis Outcome Score Junior (KOOS-Jr), Tegner activity scale, and International Knee Documentation Committee (IKDC) were obtained pre-operatively and at 1 year. RESULTS: The final analysis included 32 BMAC study patients (BMAC volume=2.420.90 mL, soak time=17.83.15 mins) and 34 control patients. Baseline demographics, physical exam features, and PROs did not vary between groups. Average 9-month tendon volume was 773280 mm(3) in BMAC patients and 743224 mm(3) in controls (P=0.634). Mean change in tendon volume between 3-9 months was 1175 mm(3) in BMAC patients and -21120 mm(3) in controls (P=0.552). Tendon volume was not associated with KOOS-Jr (beta=7.26 mm(3)/point, 95 % Confidence Interval [CI]=-13.21-27.72, P=0.476), Tegner (beta=-0.53 mm(3)/point, 95% CI=-2.40-1.45, P=0.596), or IKDC (beta=5.18 mm(3)/point, 95% CI=-10.59-20.95, P=0.513). There was a nonsignificant, negative correlation between tendon volume and KT-1000 translation (beta=-0.56 mm(3)/cm, 95% CI=-1.15-0.04, P=0.065). CONCLUSIONS: In this study, BMAC did not affect tendon volume at 9 months after ACLR. PRO-scores were not significantly associated with tendon volume. Both BMAC patients and controls showed improvements in KOOS Jr, Tegner, and IKDC. Biomechanical and histologic studies are warranted to better elucidate the relationship between BMAC augmentation, PRO scores, and ligamentization in ACL allograft reconstruction.