St. Luke's Hospital
Yeong Seok Lee, M.D., Ph.D., explains the knee joint using an anatomical model at St. Luke's Hospital in Seoul. St. Luke's Hospital

SEOUL, South Korea — People researching knee arthritis treatments abroad often come across two names on the same page: bone marrow injection and CARTISTEM®. Both involve cells, and both are discussed before knee replacement. That is where much of the similarity ends.

"These two are often mentioned in the same breath, but they answer different questions," said Yeong Seok Lee, M.D., Ph.D., an orthopedic surgeon at St. Luke's Hospital in Seoul. "One is a same-day injection using the patient's own marrow. The other is a surgical procedure for a specific area of damaged cartilage."

Here is how they compare:

Bone marrow injection (BMAC)CARTISTEM®
What it usesThe patient's own bone marrow, concentrated in the same visitDonor umbilical cord blood stem cells
How it is givenNeedle injection into the knee jointSurgery: applied into a cartilage defect
AnesthesiaLocal anesthesiaAnesthesia given by an anesthesiologist
Generally considered forStage 2–3 arthritis with ongoing pain despite other treatmentsA defined area of deep cartilage damage in stage 2–3 arthritis
RecoveryMost people go home the same day; soreness for a few daysAbout 2–3 months on crutches and about a year of rehabilitation
Suggested stay in SeoulAbout 2 weeksAbout 4 weeks
Regulatory statusRecognized by Korea's Ministry of Health and Welfare as a new health technology for knee osteoarthritis in July 2023Approved in Korea since 2012; not FDA-approved; in a U.S. Phase 3 trial

Stays are rough guides for planning travel; the final plan is set after an individual review.

Neither treatment is a step up from the other. Which one, if either, is worth discussing usually depends on what the MRI shows: whether the damage is concentrated in one area or spread across the joint, how large the damaged area is and how the leg is aligned.

Time matters too. A bone marrow injection fits a shorter trip, while CARTISTEM requires a longer stay and a commitment to about a year of rehabilitation, most of it after returning home.

"The MRI usually decides the conversation," Dr. Lee said. "Where the damage is, how big it is and how much time a patient can give to recovery tell us whether an injection, a cartilage procedure or something else entirely makes sense. Sometimes the honest answer is neither."

CARTISTEM has been approved by Korea's Ministry of Food and Drug Safety since 2012. In the United States it is being studied in a Phase 3 trial. In Japan, the manufacturer has reported Phase 3 results and has said it plans to apply for approval in the second half of 2026.

At St. Luke's Hospital, both treatments are offered by the same orthopedic team, with MRI scans taken and read on site the same day and a full-time anesthesiologist on staff for procedures. Because the hospital also provides rehabilitation, injections and joint replacement, the recommendation can be based on the knee rather than on one treatment.

Patients in the United States can send recent X-rays or MRI images for a review from home through international.slmc.co.kr/medical-review or by email at [email protected]. The team replies in English within three business days, and consultations are held directly in English with Dr. Lee.

Regulatory note: CARTISTEM® is approved for specific uses in South Korea. It is not FDA-approved for commercial use in the United States. Treatment suitability, expected benefits, limitations, risks, and alternatives should be reviewed individually.

Next in the series (November 10): Reading the research on knee cartilage treatments — what it shows and what it does not.

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. international.slmc.co.kr

Media contact: International Team, St. Luke's Hospital · [email protected]

This release is for general information and is not medical advice. Individual results vary.