Bone Marrow Aspirate Concentrate for the Treatment of Knee Osteoarthritis: A Systematic Review

Background: Bone marrow aspirate concentrate (BMAC) has emerged as a therapeutic option for symptomatic knee osteoarthritis (OA). Purpose: To systematically review the literature to evaluate the efficacy of isolated BMAC injection in the treatment of OA of the knee joint. Study Design: Systematic review; Level of evidence, 4. Methods: A systematic review was performed by searching the PubMed, Embase, and Cochrane Library databases up to July 2020 to identify human studies that assessed the clinical outcomes of isolated BMAC injection for the treatment of knee OA. The electronic search strategy used was "bone marrow aspirate concentrate knee osteoarthritis." Results: Eight studies met the inclusion criteria, including a total of 299 knees with a mean follow-up of 12.9 months (range, 6-30 months). Of all patient-reported outcomes assessed across studies, 34 of 36 (94.4%) demonstrated significant improvement from baseline to latest follow-up (P < .05). Five studies evaluating numerical pain scores (visual analog scale and Numeric Rating Scale) reported significant improvements in pain level at final follow-up (P < .01). However, 3 comparative studies evaluating BMAC in relation to other therapeutic injections failed to demonstrate the clinical superiority of BMAC. Conclusion: The BMAC injection is effective in improving pain and patient-reported outcomes in patients with knee OA at short- to midterm follow-up. Nevertheless, BMAC has not demonstrated clinical superiority in relation to other biologic therapies commonly used in the treatment of OA, including platelet-rich plasma and microfragmented adipose tissue, or in relation to placebo. The high cost of the BMAC injection in comparison with other biologic and nonoperative treatment modalities may limit its utility despite demonstrable clinical benefit.