Bone Marrow Aspirate Concentrate (BMAC)

BMAC is usually considered for people with mild to moderate knee, hip or shoulder arthritis who still have pain after exercise therapy, weight management, medicines and often a simpler injection such as PRP. It is not a good fit for severe bone-on-bone arthritis, an unstable or misaligned joint, active infection, blood or marrow disorders, or active cancer. You should also be comfortable with a self-pay treatment whose benefits are not proven.

Most people find BMAC uncomfortable but manageable. The skin and bone surface are numbed, but you may feel pressure and a brief, sharp pulling sensation for a few seconds as the marrow is drawn^[12]. Light sedation is often offered. Afterward, both the back of the pelvis and the treated joint are usually sore for several days.

Not according to current research. In a randomized trial of 90 people with knee arthritis, BMAC and PRP improved pain and function equally for 12 months^[10], and a systematic review found no study showing BMAC to be clinically superior to PRP or other injections^[8]. BMAC adds a bone marrow harvest and usually costs more, so PRP is often the simpler first choice.

BMAC helps some people, but the evidence is limited. Studies report improvements in pain and function at short- to mid-term follow-up, yet BMAC has not outperformed PRP, other injections or placebo in comparative studies^[8]. For cell injections in general, a Cochrane review found only a slight improvement over placebo, based on low-certainty evidence^[7]. It is reasonable to try only with realistic expectations.

Improvement, when it happens, usually appears within the first few months, though some people do not improve at all. In a randomized trial, people who received BMAC for knee arthritis had better scores by one month, and the improvement lasted through 12 months^[10]. Soreness in the first week can mask any early benefit, so we usually judge the result after a few months.

No — BMAC is not a stem cell treatment approved by the FDA^[2]. It contains a small number of mesenchymal stromal cells — about 0.001% of the nucleated cells in marrow^[9] — along with platelets and growth factors. The FDA has not approved any regenerative medicine product for orthopedic conditions^[2]. BMAC is prepared from your own marrow in the same visit with minimal processing, which is different from lab-grown or donor cell products.

The main downsides are cost, uncertain benefit and, with unapproved products, real safety risks. The FDA has received reports of blindness, tumor formation and infections after unapproved stem cell products^[1]. With BMAC, which uses your own marrow, the usual risks are soreness, bruising and rarely infection or bleeding^[12]. Long-term safety of cell injections for arthritis is still not well understood^[7].

Bring a list of every medicine and supplement you take. You may be asked to stop NSAIDs such as ibuprofen and naproxen beforehand. Do not stop a prescribed blood thinner on your own — we will review it with the doctor who prescribed it^[6]. Eat a light meal, wear loose clothing and arrange a ride home if you will have sedation.

Recovery is usually quick but sore. Expect aching at the back of the pelvis and in the treated joint for several days. Most people walk out the same day, return to desk work within a day or two, and build up activity over the next few weeks, often with physical therapy. Use ice and acetaminophen, and call us for fever, spreading redness or severe pain.

It can be, but there is little research on repeat BMAC injections. If the first injection helped and the benefit fades, your physician may discuss repeating it or switching to PRP, which is simpler. If BMAC did not help after several months, repeating it is unlikely to change the result, and we will discuss other options.

BMAC is generally not covered by insurance and is usually self-pay; we do not post prices because the cost depends on the joint and imaging used. Wellpoint Federal (formerly National Government Services), the Medicare contractor for New York, considers PRP — including PRP combined with stem cells — experimental for musculoskeletal and joint conditions^[4]. Workers’ compensation and no-fault carriers follow their own rules. We give you a written estimate before treatment.

Alternatives include exercise therapy and weight management, a cortisone or hyaluronic acid injection, and PRP. For a painful bone marrow lesion seen on MRI, subchondroplasty may help. Nerve-targeted treatments such as genicular nerve ablation for the knee or hip radiofrequency ablation can reduce arthritis pain, and joint replacement remains an option.