Adipose tissue-derived versus bone marrow-derived cell concentrates for the injective treatment of knee osteoarthritis: protocol of a prospective randomised controlled trial

Introduction Intra-articular injections of mesenchymal stromal cells concentrates showed promising results in the treatment of knee osteoarthritis (OA). Among these, bone marrow aspirate concentrate (BMAC) has been widely adopted in clinical practice. More recently, microfragmented adipose tissue (MFAT) has been proposed as a more suitable solution. However, there is still no high-level evidence demonstrating the superiority of MFAT to BMAC. The aim of this randomised controlled trial is to compare the safety and clinical outcomes of a single intra-articular injection of BMAC versus a single intra-articular injection of MFAT in patients with knee OA. Methods and analysis 204 patients aged 40-75 years and affected by knee OA are randomised to receive a single injection of BMAC or MFAT in a 1:1 ratio. The primary outcome of the study is the Western Ontario and McMaster University OA index (WOMAC) pain score at 6 months. The secondary outcomes of the study are the WOMAC pain score at 2 months and 12 months and the WOMAC subscales, the total WOMAC score, the International Knee Documentation Committee subjective and objective scores, the Knee Injury and OA Outcome score, the visual analogue scale (VAS) for pain evaluation, the EuroQol VAS and the Tegner score at 2 months, 6 months and 12 months. Moreover, the study aims at demonstrating whether these products have disease-modifying effects: radiographs and magnetic resonance evaluations are performed at baseline and at 12 months of follow-up, while systemic OA biomarkers are evaluated at baseline and after 2 months, 6 months and 12 months. As a tertiary outcome, this study aims at identifying the factors that influence the clinical response, including baseline patient clinical characteristics, biological features of the OA joint, as well as anabolic and anti-inflammatory properties of the injected products. Ethics and dissemination The study protocol has been approved by Emilia Romagna's Ethics Committee Comitato Etico Area Vasta Emilia Centro (CE-AVEC), Bologna, Italy (protocol number: 150/2023/Sper/IOR). Written informed consent is obtained from all participants. The findings of this study will be disseminated through peer-reviewed publications and conference presentations. Protocol version March 2023.