Purpose 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). Conclusion Implantation of MSCs with allogenic cartilage is superior to implantation of MSCs alone in cartilage regeneration accompanied with better clinical outcomes. Level of evidence Therapeutic study, level II.

Background: Cartilage repair procedures using mesenchymal stem cells (MSCs) can provide superior cartilage regeneration in the medial compartment of the knee joint when high tibial osteotomy (HTO) is performed for varus knee osteoarthritis (OA). However, few studies have reported the factors influencing the outcomes of MSC implantation with concomitant HTO. Purpose: To investigate the outcomes of MSC implantation with concomitant HTO and to identify the prognostic factors that are associated with the outcomes. Study Design: Case series; Level of evidence, 4. Methods: A total of 71 patients (75 knees) were retrospectively evaluated after MSC implantation with concomitant HTO. Clinical and radiological outcomes were evaluated, and magnetic resonance imaging (MRI) was used to assess cartilage regeneration. Statistical analyses were performed to determine the effect of different factors on clinical, radiographic, and MRI outcomes. Results: Clinical and radiographic outcomes improved significantly from preoperatively to final follow-up ( P < .001 for all), and overall cartilage regeneration was encouraging. Significant correlations were found between clinical and MRI outcomes. However, radiographic outcomes were not significantly correlated with clinical or MRI outcomes. Patient age and number of MSCs showed significant correlations with clinical and MRI outcomes. On multivariate analyses, patient age and number of MSCs showed high prognostic significance with poor clinical outcomes. Conclusion: MSC implantation with concomitant HTO provided feasible cartilage regeneration and satisfactory clinical outcomes for patients with varus knee OA. Patient age and number of MSCs were important factors that influenced the clinical and MRI outcomes of MSC implantation with concomitant HTO for varus knee OA.

No abstract

Background: A cell-based tissue engineering approach that uses mesenchymal stem cells (MSCs) has addressed the issue of articular cartilage repair in knees with osteoarthritis (OA). Purpose: To evaluate the midterm outcomes, analyze the survival rates, and identify the factors affecting the survival rate of MSC implantation to treat knee OA. Study Design: Case series; Level of evidence, 4. Methods: We retrospectively evaluated 467 patients (483 knees) who underwent MSC implantation on a fibrin glue scaffold for knee OA with a minimum 5-year follow-up. Clinical outcomes were determined based on the International Knee Documentation Committee (IKDC) and Tegner activity scale results measured preoperatively and during follow-up. Standard radiographs were evaluated using Kellgren-Lawrence grading. Statistical analyses were performed to determine the survival rate and the effect of different factors on the clinical outcomes. Results: The mean IKDC scores (baseline, 39.2 ± 7.2; 1 year, 66.6 ± 9.6; 3 years, 67.2 ± 9.9; 5 years, 66.1 ± 9.7; 9 years, 62.8 ± 8.5) and Tegner scores (baseline, 2.3 ± 1.0; 1 year, 3.4 ± 0.9; 3 years, 3.5 ± 0.9; 5 years, 3.4 ± 0.9; 9 years, 3.2 ± 0.9) were significantly improved until 3 years postoperatively and gradually decreased from 3- to 9-year follow-up ( P < .05 for all, except for Tegner score at 5 years vs 1 year [ P = .237]). Gradual deterioration of radiological outcomes according to the Kellgren-Lawrence grade was found during follow-up. Survival rates based on either a decrease in IKDC or an advancement of radiographic OA with Kellgren-Lawrence scores were 99.8%, 94.5%, and 74.5% at 5, 7, and 9 years, respectively. Based on multivariate analyses, older age and the presence of bipolar kissing lesion were associated with significantly worse outcomes ( P = .002 and .013, respectively), and a larger number of MSCs was associated with significantly better outcomes ( P < .001) after MSC implantation. Conclusion: MSC implantation provided encouraging outcomes with acceptable duration of symptom relief at midterm follow-up in patients with early knee OA. Patient age, presence of bipolar kissing lesion, and number of MSCs were independent factors associated with failure of MSC implantation.