Baseline magnetic resonance imaging findings associated with short-term clinical outcomes after intraarticular administration of autologous adipose-derived stem cells for knee osteoarthritis

Introduction: This study aimed to determine the association between the baseline magnetic resonance imaging (MRI) findings and clinical outcomes after articular injection of adipose-derived mesenchymal stem cells (ASCs) for knee osteoarthritis (KOA). Methods: This retrospective study included 149 patients with varus-type KOA treated with a single intraarticular ASC injection. All patients underwent a MRI evaluation before treatment. Patients were categorized following the MRI Osteoarthritis Knee Score (MOAKS) system cartilage score into the mild, moderate, or severe KOA groups. Additionally, joint effusion and synovitis, bone marrow lesions (BMLs), and meniscal extrusions were graded with the MOAKS. Knee Osteoarthritis Outcome Score (KOOS) was obtained at baseline, 1-, 3-, 6-, and 12-month posttreatment. The responder rate in the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International was assessed with the KOOS. Multivariate logistic regression analyses were conducted to determine factors associated with the responder rate. Results: All KOOS subscales significantly enhanced with the greatest improvement from baseline to 6 months which plateaued between 6 and 12 months. The responder rate was 65.4 % in the mild/moderate KOA compared to 35.2 % in the severe KOA at 12 months. Lower OA grade (odds ratio [OR]: 0.52; 95 % confidence interval (CI): 0.31–0.88; P = 0.015), smaller BMLs in medial femoral condyle (OR: 0.36; 95 % CI: 0.14–0.94; P = 0.037), and less meniscal extrusion (OR: 0.31; 95 % CI: 0.11–0.89; P = 0.029) were associated with higher responder rate at 6 months in multivariable logistic regression analysis. The factors associated with higher responder rate at 12 months included lower OA grade (OR: 0.42; 95 % CI: 0.25–0.73; P = 0.002) and younger age (OR: 1.04; 95 % CI: 1.00–1.08; P = 0.042). Conclusions: ASC treatment for KOA enhanced short-term clinical outcomes. MRI findings, including cartilage lesions, BMLs, and meniscal extrusion, were associated with responder rate, helping physicians identify which patients may benefit from this therapy.