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C. Thomas Vangsness, Jr., M.D.


Bone marrow aspirate concentrate (BMA/BMAC) is perhaps the most popular “stem cell injection” available today. The treatment involves injecting the patient’s own bone marrow cells into the injured area with the hope that it will help regrow tissue or reduce inflammation. The procedure involves two steps: (1) patients are lightly anesthetized and bone marrow is removed through a needle from the bone, most commonly the iliac crest of the patient’s hip, and then (2) the bone marrow is processed to concentrate the cells. After the bone marrow has been centrifuged (spun in a circle to separate the various blood contents), the BMA/BMAC is put into a syringe and injected into the affected body part.

Bone marrow contains progenitor cells, which are cells that have been “primed” to become specific cells. A small fraction of these cells (about 1% of the total cells in bone marrow) are mesenchymal stem cells, which can become cartilage, bone, and tendon cells. It is thought that these mesenchymal progenitor cells release chemicals that decrease inflammation and help regenerate tissue and other structures in degenerative conditions like knee osteoarthritis and rotator cuff tears.

Studies have shown that BMA/BMAC injections may be successful in relieving pain and improving function for various orthopaedic conditions, including osteoarthritis, tendon injuries and certain spine conditions. We still do not know exactly how these cells function after being injected into the body. BMA/BMAC injections are not covered by insurance or Medicare.