BackgroundTo evaluate changes in pain, function, and quality of life after treatment with injected micro-fragmented adipose tissue (MFAT) for knee osteoarthritis in a large cohort of individuals treated at multiple centers. MethodsOne hundred ten individuals were recruited from three private outpatient clinics. Participants had to be diagnosed with symptomatic knee OA (defined by persistent knee pain associated with clinical symptoms of OA and/ or classic imaging findings) and who had not received prior knee surgery or treatment with platelet-rich plasma, cortisone, or hyaluronic acid within the previous 6 weeks. Data from 120 knees were included in the analysis. Outcome measures included Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales (pain, symptoms, activities of daily living [ADL], sports and recreation, quality of life [QOL]) and an 11-point Numerical Rating Scale (NRS) for average knee pain over the past week. Outcomes were collected at baseline and 3, 6, and 12 months. ResultsSignificant increases and decreases in KOOS subscale and NRS scores were observed, respectively, in the cohort as a whole (p< .05). Lower BMI was associated with more significant improvements in pain, sports/recreation, and ADL KOOS subscale scores (p< .05). Greater age was associated with more significant improvements in symptoms and QOL subscale scores (p< .05). ConclusionsA single injection of MFAT improved pain, function, and QOL outcome measures up to 12 months in this cohort for more than half of the participants. Greater BMI and lower age negatively influenced outcomes. It is not known whether improvements continue after this timeframe or why many participants reported little-to-no improvement.