Allogenic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Are More Effective Than Bone Marrow Aspiration Concentrate for Cartilage Regeneration After High Tibial Osteotomy in Medial Unicompartmental Osteoarthritis of Knee

Abstract

The purpose of this study was to compare the outcome of cartilage regeneration between bone marrow aspirate concentrate (BMAC) augmentation and allogeneic human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) transplantation in high tibial osteotomy (HTO) with microfracture (MFX) for medial unicompartmental osteoarthritis (OA) of knee in the young and active patient. Between January 2015 and December 2019, the patients who underwent HTO and arthroscopy with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA with kissing lesion which was shown full thickness cartilage defect (≥ International Cartilage Repair Society (ICRS) grade 3B) in medial femoral cartilage and medial tibial cartilage were include in this study. Retrospectively we compared clinical outcomes, including Hospital for Special Surgery (HSS) score, Knee Society Score (KSS) pain and function, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score between BMAC and hUCB-MSCs group at minimum of 1 year follow up. Also, second-look arthroscopy was performed simultaneously with removal of the plate after complete bone union. Cartilage regeneration was graded by International Cartilage Repair Society (ICRS) grading system at second-look arthroscopy. Radiologic measurement including Hip-Knee-Ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed. Out of 150 cases underwent HTO with MFX combined with BMAC or allogeneic hUCB-MSCs procedure for medial unicompartmental OA, 123 cases underwent plate removal and second-look arthroscopy after minimum 1 year after the HTO surgery. 74 cases were kissing lesion in medial femoral cartilage and medial tibial cartilage during initial HTO surgery. Finally, BMAC group comprising of 42 cases and hUCB-MSCs group comprising of 32 cases were retrospectively identified in patients who had kissing lesions and second look arthroscopies with minimum 1 year follow-up. At the final follow-up of mean 18.7 months (SD 4.6 months), clinical outcomes in both groups had improved. However, there were no significant differences between the IKDC, WOMAC, or KSS pain and function scores in the two groups (p>0.05). At second-look arthroscopy, ICRS grade was significantly better in the hUCB-MSC group than in the BMAC group in both medial femoral and medial tibial cartilage (p=0.001 for both). Average ICRS grade of the BMAC group improved from 3.9 preoperatively to 2.8 postoperatively. Average ICRS grade of the hUBC-MSC group improved from 3.9 preoperatively to 2.0 postoperatively. Radiologic findings comparing postoperative HKA angle, posterior tibial slope angle, and correction angle showed no significant differences between the groups (p>0.05). Therefore, it was found that the postoperative correction amount did not affect the postoperative cartilage regeneration results. We found that the hUCB-MSC procedure was more effective than the BMAC procedure for cartilage regeneration in medial unicompartmental knee OA even though the clinical outcomes improved regardless of which treatment was administered.