RESUMO
PURPOSE: To compare a single abdominal microfat (MF) injection mixed or not with platelet-rich plasma (PRP) Low Dose (LD) or High Dose (HD) in order to improve MRI parameters, alleviate pain and enhance functional capacity in knee osteoarthritis. METHODS: Patients with symptomatic grade 2 to 4 knee osteoarthritis according to the International Cartilage Repair Society MRI classification were selected. They were prospectively assessed at baseline and at 3 and 6 months of follow-up. The primary endpoint was change in the maximum of value of cartilage relaxation time in T2 mapping sequences (T2max) at 3 months. Secondary endpoints were MRI grade severity and joint space assessment, Western Ontario and McMaster Universities Arthritis Index score, pain evaluation, knee range of motion, and patients' satisfaction. Adverse events were also collected. The complete cell counts and growth factors content of injected products were assessed to analyze their potential relationship with MRI and clinical outcomes. RESULTS: Three groups of 10 patients received a single injection of 10 cc of a mix (1:1) containing MF-Saline, MF-PRP LD or MF-PRP HD. T2max did not change significantly over the time for any of the groups. All treatments significantly improved knee functional status and symptom relief at 3 and 6 months. All patients were responders in the MF/PRP HD at 3 months and significantly higher compared to MF/PRP LD. Half of the injected PRP in the MF/PRP LD group displayed red blood cell contamination of over 8%, which was correlated with an impairment of T2max. CONCLUSION: A single intra-articular injection of MF with or without PRP is safe and may offer a significant clinical improvement in patients with osteoarthritis. LEVEL OF EVIDENCE: 2; randomized double-blind comparative parallel-group trial (RCT No.: NCT04352075).