Comparison of Bone Marrow Aspirate Concentrate and Allogeneic Human Umbilical Cord Blood-derived Mesenchymal Stem Cells in Patients with Kissing Lesion on Initial Arthrocopy After High Tibial Osteotomy in Medial Unicompartmental Osteoarthritis of Knee

PURPOSE: The purpose of this study was to compare the outcome of cartilage regeneration between bone marrow aspirate concentrate (BMAC) augmentation and the stem cell-based medicinal product (a composite of culture-expanded allogeneic hUCB-MSCs and hyaluronic acid hydrogel [Cartistem]) in medial unicompartmental osteoarthritis of knee METHODS: Out of 81 cases underwent for second look arthroscopy who treated for medial unicompartmental osteoarthritis between 2016 and 2019, 31 cases were kissing lesion which was shown full thickness cartilage defect(over ICRS grade 3B) in medial femoral cartilage and medial tibial cartilage at initial surgery. We retrospectively compared clinical outcomes, including International Knee Documentation Committee (IKDC) subjective score, Knee Society Score (KSS) pain and function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between BMAC group comprising of 25 cases and Cartistem group comprising of 14 cases at minimum of 1 year follow up. Also, cartilage regeneration was graded by International Cartilage Repair Society Cartilage Repair Assessment (ICRS CRA) grading system at secondary arthroscopy. Radiologic measurement including Hip-Knee-Ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed. RESULTS: At the final follow-up, clinical outcomes were improved. However, there were no statistical significances between two groups in clinical outcome and radiologic outcome(p>0.05). Regarding the findings of second-look arthroscopy, Cartistem group was significantly better than BMAC group in medial femoral cartilage and medial tibial cartilage(p=0.002, 0.000). About medial femoral cartilage, grade I cartilage regeneration was found in 0 case, grade II in 10 cases (40%), grade III in 6 cases (16%), grade IV in 9 cases (36%) in BMAC group and grade I cartilage regeneration was found in 1 case (7.1%), grade II in 11 cases (85.7%), and grade III in 1 case (7.1%) in Cartistem group. About medial tibial cartilage, grade I cartilage regeneration was found in 0 case , grade II in 8 cases (32%), grade III in 4 cases (16%), grade IV in 13 cases (52%) in BMAC group and grade I cartilage regeneration was found in 0 case, grade II in 12 cases (85.7%), and grade III in 1 case(7.1%), grade IV in 1 case (7.1%) in cartistem group. CONCLUSION: Clinical outcomes were improved regardless of which augmentation was administered. However, microfracture with Cartistem is more effective for cartilage regeneration than microfracture with BMAC in medial unicompartmental OA. Keywords : High tibial osteotomy, Unicompartmental osteoarthritis, Microfracture, Cartilage regeneration, Bone marrow aspirate concentrate, Cartistem.