Comparative outcome analyses of subchondral vs intra-articular bone marrow aspirate concentrate in primary osteoarthritis knee: A double-blinded randomized controlled trial protocol.

Abstract

Background: Knee osteoarthritis (OA) imposes a substantial burden through pain, functional limitation, and progressive cartilage loss. Bone marrow aspirate concentrate (BMAC) has emerged as a promising regenerative therapy for OA due to its rich composition of mesenchymal stromal cells (MSCs) and bioactive factors. While intra-articular BMAC injections provide short-term symptomatic relief, recent literature suggests that targeting the subchondral bone-an area crucial to OA progression-may offer superior and longer-lasting clinical benefits.

Aim: To compares the outcomes of subchondral vs intra-articular BMAC injections in patients with primary knee OA.

Methods: In this unicentric, double-blinded, randomized controlled trial, 30 patients with radiologically confirmed primary knee OA (Kellgren-Lawrence grades II and III) will be equally randomized to receive either subchondral (Group A) or intra-articular (Group B) BMAC injections. BMAC will be harvested from the posterior iliac crest, processed using a standardized centrifugation protocol to yield a product with > 85% cell viability, and administered under image guidance. The primary outcome is the change in pain intensity at 12 months as measured by the Visual Analog Scale (VAS). Secondary outcomes include functional improvement assessed by Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores, structural changes evaluated through advanced magnetic resonance imaging using (MRI) the whole-organ MRI Score, and safety as determined by the incidence of adverse events.

Results: This study aims to evaluate pain reduction at 12 months post-injection, using the VAS as the primary outcome. Secondary outcomes include functional improvement (KOOS, WOMAC, IKDC), cartilage regeneration (T2 cartigram), adverse event incidence, patient satisfaction (standardized questionnaires, Likert scale), and quality of life (EQ-5D). Ethical considerations follow the Declaration of Helsinki and Good Clinical Practice, with institutional review board approval and participant informed consent ensured. Confidentiality and data security comply with regulations, and a data safety monitoring board oversees trial safety. Results will be shared via peer-reviewed journals, presentations at international orthopedic conferences, and detailed summaries for stakeholders and participants. The trial is registered under clinical trial registry of India/2024/04/065284. Findings emphasize patient-centered advancements in knee osteoarthritis management.

Conclusion: This trial aims to refine regenerative strategies for knee OA by comparing subchondral vs intra-articular BMAC injections, addressing long-term efficacy, safety, and treatment standardization to guide targeted interventions. This trial will provide critical insights into the comparative efficacy and safety of subchondral vs intra-articular BMAC injections in treating primary knee OA.