Stage 3 Knee Arthritis: What to Know About CARTISTEM®, a Cartilage Treatment Approved in Korea and Now in U.S. Trials

SEOUL, South Korea - For many Americans with knee osteoarthritis, the conversation eventually turns to knee replacement. But some people with moderate-to-advanced arthritis, often called stage 3, still have knees that may be worth a closer look first.

One option they may read about is CARTISTEM®, a cell-based cartilage treatment approved in South Korea since 2012 and now being studied in the United States. At St. Luke's Hospital in Seoul, orthopedic surgeon Yeong Seok Lee, M.D., Ph.D., evaluates patients for the treatment and consults with international patients directly in English.

CARTISTEM is made from donated umbilical cord blood stem cells mixed with a gel. Unlike a knee shot, it is placed directly into damaged cartilage during surgery, with the goal of helping the area fill in with new cartilage-like tissue. Recovery includes several weeks on crutches and months of rehabilitation.

The treatment is generally considered for people with stage 2–3 arthritis whose damage is concentrated in one area of the knee. It is usually not suitable for advanced, bone-on-bone arthritis across the whole joint.

[DRAFT QUOTE — to be approved by Dr. Lee] "Stage 3 is the point where many patients feel the only choice left is a replacement," said Dr. Lee. "Our first job is to read the MRI carefully and tell them honestly whether a cartilage procedure makes sense for their knee — and when it doesn't."

CARTISTEM has been approved by Korea's Ministry of Food and Drug Safety since January 2012, and more than 36,000 patients in Korea have received it, according to the manufacturer. It is not approved by the U.S. Food and Drug Administration (FDA) for commercial use. In July 2026, the first patient was treated in a U.S. Phase 3 trial (ClinicalTrials.gov NCT07339111).

[DRAFT QUOTE — to be approved by Dr. Lee] "For American patients, I want it to be clear that this treatment is approved in Korea, not yet in the U.S., and that results differ from person to person," Dr. Lee said.

American patients can begin with a records review from home by sending recent X-rays and MRI images through international.slmc.co.kr/medical-review or by email at [email protected]. The team replies in English within two to three business days. Patients who proceed should plan on a stay of about four weeks in Seoul, confirmed after evaluation.

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.

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 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]

Attachment: Fact Sheet (following pages)

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

###

FACT SHEET · AS OF OCTOBER 8, 2026

CARTISTEM® for Stage 3 Knee Osteoarthritis

Background for journalists and patients — St. Luke's Hospital, Seoul

At a glance

What does "stage 3" knee arthritis mean?

Stage 3 is moderate-to-advanced arthritis on the Kellgren-Lawrence X-ray scale, which runs from 0 (normal) to 4 (severe, often called "bone-on-bone").

At stage 3, an X-ray usually shows a clearly narrowed joint space, several bone spurs and early changes in the bone surface. People often have pain on stairs, morning stiffness and swelling after activity.

Cartilage has almost no blood supply, so it does not repair itself well. That is why many treatments focus on easing symptoms rather than rebuilding tissue.

How CARTISTEM compares with other knee treatments

CARTISTEM is a surgical procedure, not an injection given in a clinic visit. The cells come from cord blood collected with consent after healthy births, so nothing is harvested from the patient's body.

St. Luke's Hospital offers each of these options.

Treatment steps

1. Records review from home. The patient sends recent X-rays and MRI images; the team replies in English.

2. In-person exam in Seoul. The hospital has its own MRI and an on-site radiologist, so scans can usually be reviewed the same day.

3. A look inside the joint. Arthroscopy — a thin camera through small cuts — confirms the size and location of the damage. Final suitability is decided here.

4. Applying CARTISTEM. Under anesthesia, the surgeon makes small holes in the damaged area and fills it with CARTISTEM.

5. Hospital stay and early rehabilitation. Supervised rehabilitation begins before discharge.

Who may be considered — and who may not?

In Korea, CARTISTEM is approved for full-thickness cartilage defects caused by degenerative arthritis or repeated injury. The U.S. Phase 3 trial enrolls adults with Kellgren-Lawrence grade 2–3 arthritis and a defect of roughly 2 to 9 square centimeters.

Recovery

Regulatory history

More than 36,000 patients have received CARTISTEM in Korea, according to the manufacturer (June 2026).

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.

Questions patients can ask

• Is my cartilage damage limited to one area, or spread across the joint?

• What would surgery and recovery look like for my knee specifically?

• What are the risks, and what are my other options?

• How long would I need to stay in Korea, and what is the total cost?

• How will rehabilitation and follow-up work once I am back home?

• Will my U.S. insurance cover any part of it? (Treatment abroad is often not covered.)

Contact for U.S. patients

Replies within 2–3 business days. Payment by card or cash in KRW or USD.