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

Purpose: 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 cell (hUCB-MSCs) transplantation in high tibial osteotomy (HTO) with microfracture (MFX) for medial unicompartmental osteoarthritis (OA) of the knee in the young and active patient.

Methods: 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 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 the ICRS grading system at second-look arthroscopy. Radiological measurement including hip-knee-ankle (HKA) angle, posterior tibial slope angle, and correction angle were assessed.

Results: Of 150 cases that 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 a minimum of 1 year after the HTO surgery. Seventy-four cases were kissing lesion in medial femoral cartilage and medial tibial cartilage during initial HTO surgery. Finally, the BMAC group composed of 42 cases and hUCB-MSCs group composed of 32 cases were retrospectively identified in patients who had kissing lesions and second-look arthroscopies with a minimum of 1 year of follow-up. At the final follow-up of mean 18.7 months (standard deviation = 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 2 groups (P > .05). At second-look arthroscopy, the ICRS grade was significantly better in the hUCB-MSC group than in the BMAC group in both medial femoral and medial tibial cartilage (P = .001 for both). The average ICRS grade of the BMAC group improved from 3.9 before surgery to 2.8 after surgery. The average ICRS grade of the hUBC-MSC group improved from 3.9 before surgery to 2.0 after surgery. Radiological findings comparing postoperative HKA angle, posterior tibial slope angle, and correction angle showed no significant differences between the groups (P > .05). Therefore it was found that the postoperative correction amount did not affect the postoperative cartilage regeneration results.

Conclusions: 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.

Level of evidence: Level III, retrospective comparative study.