Surgical Applications for Bone Marrow Aspirate Concentrate

Bone marrow aspirate concentrate (BMAC) is an autologous orthobiologic agent that may be of benefit in specific surgical scenarios. Composed of elements isolated from bone marrow, including mesenchymal stromal cells, bone marrow-derived platelets, red and white blood cells, and hematopoietic precursors, BMAC has gained appeal for its potential to slow the progression of chondral degeneration, improve function, and provide symptomatic relief. BMAC is typically prepared during the final stages of a surgical procedure, beginning with bone marrow aspirate harvested from the iliac crest, distal femur, body of the ilium, or proximal humerus and then centrifuged to yield concentrated marrow cells. In a published technique for BMAC use in arthroscopic acetabular labral repair, 120 mL of BMA is harvested from the body of the ilium and then centrifuged to yield approximately 4 to 6 mL of BMAC. The biologic activity of BMAC is 2-fold: (1) mesenchymal stromal cells are pluripotent stem cells that stimulate a robust tissue response for cartilage repair through their potential to differentiate into chondrocytes that induce chondrogenesis, and (2) bone marrow-derived platelets produce growth factors, cytokines, and chemokines that promote collagen synthesis, wound healing, and suppression of proinflammatory cytokines. To date, BMAC has shown promise as an efficacious adjuvant therapy. When comparing patient outcomes, studies have found that patients receiving BMAC achieved lower rates of revision rotator cuff repair, higher functional outcome scores following arthroscopic acetabular labral repair, and significant reductions in pain levels in the context of knee cartilage defects. These findings, however, must be interpreted with caution, as there remains a paucity of randomized controlled trials investigating the mid- and long-term efficacy of BMAC. Overall, as treatments for patients with both progressive chondral degeneration and acute orthopaedic injuries continue to evolve, BMAC serves as promising orthobiologic therapy to improve outcomes.