Expert Opinion on Allogeneic Bone Marrow-Derived Mesenchymal Stem Cell (BMMSC) Therapy for Knee Osteoarthritis: Clinical Insights, Efficacy, and Safety

BACKGROUND: Knee osteoarthritis (KOA) remains a major cause of disability. Many patients with moderate disease (Kellgren-Lawrence (KL) grade 2-3) continue to experience disease progression, despite receiving guideline-based conservative treatments that primarily offer symptomatic relief. Allogeneic bone marrow-derived mesenchymal stem cells (BMMSCs) have gained attention for their potential anti-inflammatory, immunomodulatory, and chondroprotective effects. This consensus exercise aimed to capture expert perspectives on diagnostic practices, clinical utility, efficacy, safety, and real-world integration of allogeneic BMMSC therapy. METHODS: A structured expert panel comprising experienced orthopedic surgeons reviewed preclinical, clinical, and regulatory evidence supporting allogeneic BMMSCs for KOA. Real-time online polling collected quantitative data on diagnostic approaches, perceived efficacy, safety experience, cartilage-regeneration assessment, and broader orthopedic indications. RESULTS: Most experts (81.8%) relied on physical examination and X-ray (KL grading) for diagnosis, while MRI was used selectively. A majority (72.7%) considered allogeneic BMMSCs effective for KL grade 2-3 KOA. Routine MRI monitoring for cartilage regeneration was uncommon; only 9.0% reported performing post-procedural MRI for visualizing structural improvements. No severe allergic or anaphylactic reactions were reported, and adverse events were described as mild and transient. Regulatory approval and GMP/GLP-certified manufacturing were viewed as key contributors to both clinician and patient confidence and insurance coverage. Experts supported the use of allogeneic MSCs for cartilage defects and, to a lesser extent, avascular necrosis and tendon or ligament injuries. Identified gaps included long-term durability and standardized rehabilitation protocols. CONCLUSIONS: The expert panel found that allogeneic BMMSCs appear to be a safe and effective treatment for grade 2-3 KOA. Additional real-world data and targeted guidelines are needed to better define the role of allogeneic BMMSCs in routine orthopedic practice.