Implantation of mesenchymal stem cells in combination with allogenic cartilage improves cartilage regeneration and clinical outcomes in patients with concomitant high tibial osteotomy.

Objective: This study aimed to compare the clinical, radiological, and second-look arthroscopic outcomes of implanting mesenchymal stem cells (MSCs) alone and together with allogenic cartilage in patients treated with concomitant high tibial oteotomy (HTO) for varus knee osteoarthritis.

Methods: Eighty patients treated with cartilage repair procedures and concomitant HTO were prospectively randomized into two groups: MSC implantation (MSC group), and MSC implantation with allogenic cartilage (MSC-AC group). Clinical outcomes were evaluated using the Lysholm Score and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at preoperative and every follow-up visit. Radiological outcomes were evaluated by measuring the femorotibial angle and posterior tibial slope. During second-look arthroscopy, cartilage regeneration was evaluated according to the Kanamiya grade.

Results: Clinical outcomes at the second-look arthroscopy (mean 12.5 months [MSC group] and 12.4 months [MSC-AC group]) improved significantly in both groups (P < 0.001 for all). Clinical outcomes from the second-look arthroscopy to the final follow-up (mean 27.3 months [MSC group] and 27.8 months [MSC-AC group]) improved further only in the MSC-AC group (P < 0.05 for all). Overall, the Kanamiya grades, which were significantly correlated with clinical outcomes, were significantly higher in the MSC-AC group than in the MSC group. Radiological outcomes at final follow-up revealed improved knee joint alignments relative to preoperative conditions but without significant correlation between clinical outcomes and Kanamiya grade in either group (n.s. for all).

Conclusions: Implantation of MSCs with allogenic cartilage is superior to implantation of MSCs alone in cartilage regeneration accompanied with better clinical outcomes. Methods: Therapeutic study, level II.