Bone Marrow Injection for Knee Arthritis: What the Research Shows It Can Do
The procedure uses a patient's own bone marrow and may improve pain and function, but evidence on its long-term benefits remains limited.
SEOUL, South Korea — Many people with knee arthritis end up in an uncomfortable middle ground. Exercise, pain relievers and standard injections no longer bring enough relief, yet their arthritis is not advanced enough for a knee replacement — or they are not ready for one.
For some of them, a bone marrow injection offers a nonsurgical step in between. Known medically as bone marrow aspirate concentrate, or BMAC, it is made from the patient's own bone marrow, prepared and given in the same visit, and requires no incision in the knee.
"For the right candidate, a bone marrow injection can make a real difference in pain and everyday function," said Yeong Seok Lee, M.D., Ph.D., an orthopedic surgeon at St. Luke's Hospital in Seoul. The treatment is primarily considered for patients with stage 2 or 3 arthritis who have exhausted conservative treatments and are not yet candidates for joint replacement.
Recognized in Korea. In July 2023, Korea's Ministry of Health and Welfare listed BMAC injection for knee osteoarthritis as a new health technology (Notice No. 2023-128). Its evaluation found the treatment safe and effective for relieving pain and improving function in moderate arthritis, defined as Kellgren-Lawrence grade 2 to 3.
What studies have found. Research from several countries points in the same direction:
• In a 2018 study in Heliyon, 121 patients with grade 3–4 arthritis, average age 70, received a single injection. About 11 months later, their average pain score had dropped from 8.3 to 4.5 out of 10, and their Oxford Knee Score for function had risen from 20 to 32 out of 48. No complications were reported.
• A 2024 prospective study of 63 patients with grade 2–3 arthritis reported significant gains in pain and function at mid-term follow-up.
• A 2025 review of the clinical evidence concluded that BMAC relieves symptoms and improves function in the short to medium term, with some studies suggesting it may help delay knee replacement.
Why timing matters. One study found that patients with grade 2 arthritis did better than those with grade 3 or 4.
"Earlier stages tend to respond better," Dr. Lee said. "That is one reason I would rather see an MRI sooner than later. When much of the cartilage is still holding up, the treatment has more to work with."
Questions patients ask.
| Question | Answer |
| Is it surgery? | No. It is a procedure done under local anesthesia, with no incision in the knee. |
| Whose bone marrow is used? | Your own. It is aspirated from the anterior pelvic bone (iliac crest) and concentrated during the same visit. |
| How long does it take? | The procedure itself takes about 40 minutes. A brief hospital stay may follow, with the exact duration determined by the surgeon. |
| What is recovery like? | Mild soreness at the pelvic harvest site and slight swelling in the knee for a few days are common and expected. |
| How long should I plan to stay in Seoul? | About one week is recommended to cover evaluation, the procedure and follow-up. The detailed itinerary will be confirmed after your medical review. |
| Is it right for everyone? | No. It is primarily indicated for moderate (stage 2–3) arthritis and is generally not recommended for severe, bone-on-bone disease. |
What it does not do.Results vary from person to person, and the injection does not regrow a knee. Many published studies did not compare BMAC directly with a placebo, and research on long-term results continues. People who take blood thinners or have certain blood or bone conditions need a careful review first.
At St. Luke's Hospital, every evaluation starts with an MRI that is taken on site and read the same day by a full-time radiologist, so patients know where their knee stands before deciding anything. Those weighing a bone marrow injection against other options can compare the treatments on the hospital's website.
Patients in the United States can send recent X-rays or MRI images for a review from home or email [email protected]. The team replies in English within three business days, and consultations are held directly in English with Dr. Lee.
Next in the series (November 17): A step-by-step approach before knee replacement.
About Yeong Seok Lee, M.D., Ph.D. Dr. Lee is an orthopedic surgeon focused on knee and shoulder care and a Clinical Professor at Sungkyunkwan University School of Medicine (Samsung Medical Center). His research has appeared in The American Journal of Sports Medicine and the Journal of Shoulder and Elbow Surgery.
About St. Luke's Hospital. St. Luke's Hospital is a multi-specialty hospital in Seoul, open 365 days a year, with full-time radiology and anesthesiology specialists and an in-house MRI on site, and about an hour from Incheon International Airport. Its Stem Cell & Joint Preservation Center offers knee care ranging from injections to cartilage procedures and joint replacement.
Media contact: International Team, St. Luke's Hospital · [email protected]
This release is for general information and is not medical advice. Individual results vary.
###
© Copyright IBTimes 2026. All rights reserved.