To determine whether microfracture with bone marrow aspirate concentrate (BMAC) improves functional outcome and cartilage regeneration better than microfracture alone in patients undergoing high tibial osteotomy (HTO) for medial unicompartmental osteoarthritis (OA).
Among 436 patients treated with HTO for medial unicompartmental OA with varus deformity between 2010 and 2016, clinical outcomes were retrospectively compared between the microfracture alone group (group I, 43 cases) and microfracture with BMAC augmentation group (group II, 48 cases). Of these, 64 patients underwent a second-look arthroscopic assessment. Clinical outcomes were compared based on the Knee Society Score (KSS), International Knee Documentation Committee (IKDC) subjective score, and Western Ontario and McMaster Universities Arthritis Index (WOMAC). Cartilage regeneration was assessed according to Koshino's staging system and the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system.
At the last follow-up, there were no significant intergroup differences in terms of KSS for pain and function (p > 0.05). Moreover, WOMAC scores were similar between the two groups (p > 0.05). Regarding second-look arthroscopy findings, according to Koshino's staging system, there was no significant intergroup difference in terms of defect coverage (p = 0.187). However, group II showed a significantly better mean CRA score than group I (p = 0.035).
There were no significant differences in clinical outcomes and cartilage regeneration between the groups. However, the CRA score was significantly higher with BMAC augmentation and microfracture than microfracture alone. Therefore, BMAC augmentation had a synergistic effect for a better cartilage regeneration, although studies with a longer follow-up might help to confirm whether microfracture with BMAC augmentation would ensure better clinical outcomes than microfracture alone for the treatment of knee OA.