Letter to the Editor regarding the Article "Effects of Intra-articular Bone Marrow Aspirate Infiltration in the Treatment of Knee Osteoarthritis: A Clinical Study Comparing BMA versus Corticosteroid and Genicular Block." Rev Bras Ortop 2025;60(2):s00451809512. DOI:10.1055/s-0045-1809512

Dear Editor-in-Chief of the Brazilian Journal of Orthopedics and Traumatology, Dr. Geraldo Motta,

After carefully reading the article by Clazzer et al.,¹ we consider it pertinent to make some comments regarding the design and interpretation of the results presented.

1. Methodological Aspects

   This study, although prospective and randomized, has significant limitations. Fifteen patients were lost to follow-up, resulting in only 35 subjects evaluated over 6 months. This reduction compromises the originally planned statistical power. Furthermore, there is no detailed sample size calculation for relevant clinical outcomes, nor are the randomization criteria clearly described.

2. Conceptual Confusion about the Intervention

   The authors describe the intervention group as being treated with bone marrow aspirate (BMA). However, according to their own methodology, the BMA was mixed with dexamethasone and injected intra-articularly. This point is critical because the literature indicates that glucocorticoids negatively affect mesenchymal stem cells, decreasing their viability, proliferation, and chondrogenic differentiation.² Such conduct contradicts the principles of regenerative medicine and makes it difficult to attribute the outcomes to BMA alone.

3. Interpretation of Results

   Clinical findings showed a significant difference only in the pain domain of the Western Ontario and McMaster Universities Arthritis Index (WOMAC) after 6 months, with no significant improvement in stiffness or function. Even so, the authors conclude that BMA represents a viable therapeutic option. We consider this statement premature, as it relies on limited outcomes and short follow-up. Unfortunately, we have noted that the Instagram page of the Brazilian Society of Orthopedics and Traumatology mistakenly claims that the study resulted in an improvement in pain and function.

   Final Considerations

   We acknowledge the relevance of the study and the search for therapeutic alternatives for knee osteoarthritis. Nevertheless, we believe that result interpretation requires care due to methodological limitations and the conceptual inconsistencies associated with the simultaneous use of corticosteroids and BMA. The publication of this letter aims to stimulate critical and constructive debate on orthobiologic therapies, highlighting the need for scientific rigor and conceptual clarity in the field.

References

• ¹ Clazzer R, Pinto DM, Krause MVdA, Rolim TLV, Oliveira RLd, Lima DAd. [Effects of Intra-articular Bone Marrow Aspirate Infiltration in the Treatment of Knee Osteoarthritis: A Clinical Study Comparing BMA versus Corticosteroid and Genicular Block.]. Rev Bras Ortop 2025;60(02):s00451809512. Doi: 10.1055/s-0045-1809512
  » https://doi.org/10.1055/s-0045-1809512
• ² Csaki C, Schneider PR, Shakibaei M. Mesenchymal stem cells as a potential pool for cartilage tissue engineering. Ann Anat 2008;190 (05):395-412. Doi: 10.1016/j.aanat.2008.07.007
  » https://doi.org/10.1016/j.aanat.2008.07.007

Edited by

• Editor-in-Chief:
  Geraldo da Rocha Motta Filho.

Publication Dates

• Publication in this collection
  20 July 2026
• Date of issue
  2026