Micro-Fragmented Adipose Tissue Demonstrates Comparable Clinical Efficacy to Other Orthobiologic Injections in Treating Symptomatic Knee Osteoarthritis: A Systematic Review of Level I to IV Clinical Studies

Purpose: To perform a systematic review of clinical outcomes in patients who underwent treatment with micro-fragmented aspirated tissue for symptoms of knee osteoarthritis. Methods: Medline, Embase, Scopus, and Google Scholar were screened for studies from 2000 to 2023. Risk of bias (ROB) was assessed using the Cochrane Collaboration's tools and the Risk Of Bias In Non-randomised Studies-of Interventions tool. Study quality was assessed with the modified Coleman Methodology Score and Methodological Index for Non-Randomized Studies score. Heterogeneity was assessed using χ² and I² statistics. Results: Twenty-one studies were included. One study had a high ROB, 1 had a critical ROB, 3 had serious ROB, and 16 had a moderate ROB. The mean Coleman score was 58, demonstrating fair study quality; the Methodological Index for Non-Randomized Studies score had a mean value of 13, indicating overall fair quality. Best evidence synthesis revealed moderate evidence. The visual analog scale score improved from 5.2 to 3.2 at 6 and 12 months. Knee injury and Osteoarthritis Outcome Score (KOOS) activities of daily living subscore improved from 58.8 to 70.2 at 6 months and 67.5 at 12 months. KOOS pain subscore improved from 54.3 to 70.2 at 6 months and 72.4 at 12 months. KOOS quality of life subscore improved from 33.1 to 43.6 at 6 months and 42.9 at 12 months. KOOS sports subscore improved from 23.7 to 43.6 at 6 months and 57.4 at 12 months. KOOS symptoms subscore improved from 55.3 to 70.1 at 6 months and 67.9 at 12 months. The Western Ontario and McMaster Universities Osteoarthritis Index score steadily increased from 61.8 at baseline to 78.4 at 12 months. Conclusions: micro-fragmented aspirated tissue injection therapy for the treatment of symptomatic knee osteoarthritis is effective and improves pain and functional outcomes. Moderate study quality combined with a moderate risk of bias, moderate certainty of evidence, and moderate best synthesis evidence reduces external validity. Therefore, the results should be interpreted with a degree of caution. Level of Evidence: Level IV, systematic review of Level I-IV studies.