Clinical and arthroscopic outcomes of MSC implantation were encouraging for OA knees in both groups, although there were no significant differences in outcome scores between groups. However, at second-look arthroscopy, there were better ICRS grades in group 2.

Utilizing the described method, MSC implantation for knee OA resulted in better clinical and second-look arthroscopic outcomes than an MSC injection.

Unicomparmental knee arthroplasty (UKA) is a popular alternative to total knee arthroplasty (TKA) and high tibial osteotomy for unicompartmental knee conditions, especially in young patients. However, failure of UKA occurs due to either progressive osteoarthritis (OA) in the other compartment or wear on the polyethylene (PE) insert. This study used finite element (FE) analysis to investigate the effects of PE insert contact pressure and stress in opposite compartments for fixed-and mobile-bearing UKA. Analysis was performed using high kinematics displacement and rotation inputs, which were based on the kinematics of the natural knee. ISO standards were used for axial load and flexion. The mobile-bearing PE insert had lower contact pressure than the fixed-bearing PE insert. With the mobile-bearing UKA, lower stress on the opposite compartment reduces the overall risk of progressive OA in the knee. The fixed-bearing UKA increases the overall risk of progressive OA in the knee due to higher stress on the opposite compartment. However, the PE insert of mobile-bearing showed pronounced backside stress at the inferior surface. ß

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.