Abstract
Knee osteoarthritis (KOA) is a progressive degenerative joint disease with limited treatment options that effectively modify disease progression. This study evaluates the safety and efficacy of allogeneic adipose-derived mesenchymal stromal cells (ADMSCs) injected under ultrasound guidance in patients with symptomatic stage III KOA. In this single-site, randomized, double-blind, placebo-controlled trial, patients were assigned to receive either 2 doses of allogeneic expanded ADMSCs, administered 2 weeks apart (Arm A, mean total dose: 69.58 × 106 ADMSCs), or 2 equal-volume normal saline injections (Arm B). Blinding was maintained for 12 months, after which follow-up of Arm A continued to 60 months. Treatment efficacy was assessed using normalized Knee Injury and Osteoarthritis Outcome Score and Western Ontario and McMaster Universities Osteoarthritis Index at 6, 12, 24, 36, 48, and 60 months, while magnetic resonance imaging (MRI) evaluations were performed at baseline and 12 months. A total of 29 subjects (21 in Arm A, 8 in Arm B) completed the study. Adverse events in Arm A were mild and transient, including localized pain and swelling. Patients in Arm A demonstrated significant improvements in clinical scores compared to baseline, with highly significant differences at 6, 12, 24, and 36 months (P < .0001). MRI assessments at 12 months revealed structural improvement (P < .02). However, clinical improvements declined steadily after 36 months, with scores nearing baseline at 60 months. These findings suggest that allogeneic ADMSC therapy is safe and provides sustained clinical and structural benefits for up to 3 years. Larger trials are needed to optimize dosing and assess long-term efficacy.