Impact of Kellgren–Lawrence grade on clinical outcomes following adipose-derived stem cell therapy for knee osteoarthritis: A propensity score–matched retrospective cohort study

Knee osteoarthritis (OA) causes pain and disability, and autologous adipose-derived stem cell (ASC) therapy has emerged as a regenerative treatment option. This retrospective cohort study compared short-term outcomes of intra-articular ASC injections between patients with moderate (Kellgren-Lawrence [KL] 2/3) and severe (KL 4) OA. Among 242 treated patients, 98 in each group were analyzed after propensity score matching for age, sex, and body mass index. Pain (VAS) and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales were evaluated at baseline and 1, 3, and 6 months. Both groups showed significant improvements in pain and function, with KL 2/3 patients exhibiting greater gains in KOOS Total, Activities of Daily Living, Sports/Recreation, Quality of Life, and VAS pain compared with KL 4. KOOS pain and symptoms improved similarly in both groups. Analgesic effects increased over time, and no serious adverse events were observed. Mild transient swelling or discomfort occurred in about 5% to 6% of cases. ASC injections provided meaningful symptom relief and functional improvement, particularly in moderate OA, suggesting that preserved joint structure benefits therapeutic efficacy. In advanced OA, benefits were present but attenuated, indicating limited regenerative potential in end-stage disease.