What Is Bone Marrow Aspirate Concentrate (BMAC)?
Bone marrow is the soft tissue inside your bones. To make BMAC, a small amount of marrow is drawn with a needle, usually from the iliac crest, the ridge at the back of the pelvic bone. The sample is spun in a centrifuge, a machine that separates it into layers, and the concentrated layer is then injected into the joint or tendon being treated.
The concentrate contains a rich mix of cells and proteins, including growth factors involved in the body's natural healing response and stem-like cells, which is why BMAC is often described as a "stem cell" treatment. Studies of knee arthritis and tendon problems have reported improvements in pain and function, and BMAC gives active patients another option to explore before considering surgery.
A same-day outpatient procedure using local anesthetic and ultrasound guidance. Your physician will explain where and how it is done.
Who Is a Candidate?
BMAC may be worth discussing if you have a joint or tendon problem that has not improved enough with physical therapy, activity changes, bracing or standard injections, and you would like to consider another non-surgical option before surgery. Conditions it may be considered for include:
- Mild to moderate knee osteoarthritis
- Hip arthritis in people who are not ready for, or not yet candidates for, joint replacement
- Chronic tendon problems (tendinopathy) and some partial tendon tears around the shoulder, hip or knee
BMAC is not a replacement for surgery when a tendon is fully torn or a joint is severely damaged. It is generally not used if you have an active infection, active cancer, certain bleeding disorders, or a problem at the pelvic bone that makes the marrow draw unsafe. Dr. Adelman, who is dual board-certified in family medicine and sports medicine (CAQSM) with advanced expertise in interventional musculoskeletal ultrasound, provides non-surgical care for arthritis and sports injuries and uses orthobiologic treatments where appropriate. She will review your history and imaging and talk with you honestly about whether BMAC makes sense for you.
What to Expect
BMAC is done as a single same-day visit. You lie on your stomach while the skin and the surface of the bone over the back of the pelvis are numbed with a local anesthetic, a medicine that numbs only the area being treated. A needle is then used to draw a small amount of marrow. Most people feel pressure and a brief deep ache during the draw.
While the sample is concentrated in the centrifuge, the treatment area is cleaned and numbed. Your physician uses diagnostic ultrasound to see the joint or tendon on a screen in real time and guide the needle to the right spot. The visit takes longer than a PRP injection, and your physician may ask you to arrange for someone to drive you home.
Risks and Side Effects
Because BMAC comes from your own body, allergic reactions are unlikely. Possible side effects include:
- Soreness at the harvest site, where the marrow was drawn, for several days
- Bruising or bleeding at the harvest or injection site
- A flare of pain, swelling or stiffness at the injection site for several days
- Infection, which is uncommon
- Rare nerve injury near the harvest or injection site
Your physician will review these risks with you, along with any medicines, such as blood thinners, that may need to be adjusted beforehand.
Recovery
Most people return to light daily activities within a few days but are asked to limit heavy use of the treated joint or tendon for a period, sometimes with a brace or crutches. Your physician will usually ask you to avoid anti-inflammatory medicines such as ibuprofen or naproxen for a period before and after the procedure, since they may interfere with the response.
Improvement typically builds gradually over several weeks to a few months as your body responds. A guided exercise program is an important part of the plan. Our physical therapists work in the same office and share your chart, so therapy can be timed around your procedure.
Physical therapy happens in our office, with therapists who share your chart. Learn about on-site physical therapy.
Insurance and Cost
BMAC is usually not covered by Medicare or commercial insurance plans, so most patients pay for it themselves. Our team can explain the cost before you decide. Your office visit and any imaging may still be billed to your insurance as usual.
When to Talk to a Specialist
Call our office if a joint or tendon problem has lasted more than a few months despite therapy and other care, or if you want to understand your non-surgical options before considering surgery. After hours, call our main number to reach the answering service.
After the procedure, go to the emergency room or call 911 for fever, spreading redness, warmth or drainage at the harvest or injection site, which can be signs of infection.
