The goal of this clinical trial is to learn if a new treatment works to help regrow knee cartilage in people with knee cartilage damage. The main questions it aims to answer are:

Does the treatment help the knee work better and lower pain more than the standard surgery?

Is the treatment safe and does it help grow stronger new cartilage?

Researchers will compare participants who get the standard surgery (microfracture) to participants who get both the standard surgery and the new treatment. This is to see if the new treatment leads to a better and faster recovery.

Participants will:

Have a surgery to treat their knee cartilage damage.

Visit the clinic for check-ups to see how well their knee moves.

Take imaging tests, like an MRI, so researchers can look at the new cartilage.

Inclusion Criteria:

• Adults aged 19 years to <65 years at the time of consent.
• Cartilage lesion severity of the target knee is ICRS grade 3 or 4.
• Focal cartilage defect size in the target knee is ≥5 cm² and ≤10 cm².
• The target knee is clinically considered to require microfracture, or microfracture with high tibial osteotomy (HTO).
• Able and willing to provide written informed consent after receiving a full explanation of the study.

Exclusion Criteria:

• Traumatic or secondary osteoarthritis (Secondary OA) in the target knee.

• Inflammatory arthritis in the target knee (e.g., rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, reactive arthritis, systemic lupus erythematosus, gout, pseudogout, Behçet's disease, etc.).

• Currently receiving immunosuppressive therapy or having a serious systemic disease (e.g., severe cardiovascular disease; long-term use of immunosuppressants; cancer patient receiving chemotherapy; systemic autoimmune disease; severe liver or kidney disease; uncontrolled endocrine disease, etc.).

• Advanced severe osteoarthritis in the target knee (Kellgren-Lawrence [KL] grade 4).

• Lower-limb malalignment that may affect the surgical plan (e.g., varus deformity with varus angle ≥15°).

• Within 5 years prior to Visit 1, a history of osteomyelitis of the target knee, a diagnosis of malignancy, or recurrent malignancy (participants with benign tumors may be eligible if the investigator judges that there will be no impact on study conduct during the study period).

• Body mass index (BMI) ≥35 kg/m².

• Clinically significant knee instability in the target knee that is not expected to be improved by the study procedure (e.g., complete or partial tears of major ligaments such as the anterior cruciate ligament, posterior cruciate ligament, medial collateral ligament, or lateral collateral ligament).

• Prior surgery for treatment of a cartilage defect in the target knee (diagnostic arthroscopy only is allowed).

• History of major structural surgery of the target knee (diagnostic arthroscopy only is allowed). Participants with prior HTO may be eligible at the investigator's discretion if the knee structure is stable without critical defects.

• Intra-articular injection of any biologic or pharmacologic agent into the target knee within 3 months prior to Visit 1 (e.g., hyaluronic acid, corticosteroids, platelet-rich plasma, autologous cell therapy, cytokine inhibitors, etc.).

• Use of systemic corticosteroids within 1 month prior to Visit 1.

• Participant or partner is a woman of childbearing potential and the participant does not agree to use an effective method of contraception during the study period, including any of the following:

  1. Sterilization procedure of the participant or partner (vasectomy; bilateral oophorectomy and salpingectomy/tubal ligation; hysterectomy)
  2. Intrauterine device (IUD), including copper IUD or hormone-releasing intrauterine system
  3. Non-oral hormonal contraception or spermicide used in combination with a barrier method
  4. Cervical cap or diaphragm used in combination with a male condom

• Pregnant or breastfeeding.

• Participation in another clinical trial and receipt of an investigational medical device within 6 months prior to Visit 1.

• Any other condition that, in the opinion of the principal investigator (or delegated study staff), makes the participant unsuitable for participation in the study.