Intra-articular Injection of Culture-expanded Adipose Tissue-derived Stem Cells for Knee Osteoarthritis: Assessments with Clinical Symptoms and Quantitative Measurements of Articular Cartilage Volume

Background: Intra-articular administration of adipose tissue-derived stem cells (ADSC) is an alternative treatment option for knee osteoarthritis (OA) after conventional treatment fails; however, the clinical results related to the severity of OA grade and changes of cartilage volumes after the administration of ADSC is unknown. This study aimed to determine 1) clinical outcomes after the ADSC administration in knee OA with consideration of radiographic OA grades and 2) changes in cartilage volumes after ADSC administration.

Methods: This observational study included 86 knees from 51 patients who underwent intra-articular administration of cultured ADSC; 47 patients (80 knees) completed follow-up for 6 months (follow-up rate: 93%). The Knee injury and Osteoarthritis Outcome Scores (KOOS) were reported at baseline and 1, 3, and 6 months after the administration. The efficacy rate in the Outcome Measures in Arthritis Clinical Trials-Osteoarthritis Research Society International (OMERACT-OARSI) was evaluated using the KOOS. Cartilage volume of the knee joint was measured using quantitative 3-dimensional magnetic resonance imaging (3D-MRI) software at baseline and 6 months in 52 knees in 31 patients (follow-up rate: 61%).

Results: All items on the KOOS except "sports/recreation" improved significantly at 6 months with more significance in knees with a Kellgren-Lawrence (KL) grade 2 or 3 compared with KL grade 4 knees. The OMERACT-OARSI responder at 6 months was significantly greater in knees with KL grade 2 or 3 (64%) than in knees with KL grade 4 (42%, p = 0.045). Cartilage volume changes varied among patients and were not related to the changes in KOOS after ADSC administration.

Conclusions: Intra-articular administration of ADSC in knee OA improved KOOS at 6 months. The effects were more significant in knees with KL grade 2 or 3 than with KL grade 4. Changes in KOOS were not related to change in cartilage volumes after ADSC administration.