Abstract
BACKGROUND: Complications of bone marrow aspirate concentrate (BMAC) injections for knee osteoarthritis (OA) are not well known and were investigated through comparison to other injections. METHODS: PubMed, Embase, Cochrane, and Web of Science databases were searched for randomized controlled trials (RCTs) comparing isolated BMAC injections to other injectables for knee OA. Demographics, complications, and comparator injectable treatments were collected. Complication rates and number needed to harm (NNH) were calculated for BMAC. DerSimonian-Laird random-effects models evaluated differences in pooled early (≤7 days) and late (>7 days) complication rates using odds ratios. RESULTS: Six RCTs were identified with 860 patients, 334 of whom received BMAC injections. The mean follow-up was 13 months. The overall complication rates among BMAC and comparison groups were 41.91 % and 41.25 %, respectively (p = 0.85). The NNH for BMAC was 152. Knee effusion was the most common complication of BMAC (18.26 %). Early and late complication rates for BMAC were not significantly different from other injectables (hyaluronic acid [HA], steroids, platelet-rich plasma, stromal vascular fraction, mesenchymal stromal cells, or saline) (early p = 0.09, I (2) = 0; late p = 0.46, I (2) = 0), nor specifically compared to HA (early p = 0.76, I (2) = 0; late p = 0.66, I (2) = 0). CONCLUSIONS: Complication rates of BMAC injections are not significantly different from other injectables, nor specifically from HA for knee OA. Compared to other injections, 152 patients would need to receive a BMAC injection for one additional patient to experience a complication.