Subchondral Drilling Diameter During CARTISTEM Implantation for Knee Cartilage Defects

This prospective, randomized study at Severance Hospital compares two subchondral drilling techniques during CARTISTEM implantation for symptomatic medial-compartment knee articular cartilage defects. Sixty participants will be allocated 1:1 to drilling with a 2-mm drill alone or sequential drilling with 4-mm and 2-mm drills. CARTISTEM preparation and implantation will be the same in both groups. High tibial osteotomy may be performed when needed to correct alignment. The primary endpoint is the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation score at 12 months after surgery. The study will assess non-inferiority of the 2-mm technique using a prespecified margin of 10.3 points. Secondary assessments include pain and knee function, MRI cartilage repair and subchondral bone findings, radiographic osteoarthritis and alignment, and second-look arthroscopy in participants undergoing plate removal after high tibial osteotomy.

Inclusion Criteria: 1. Age 19 years or older. 2. Knee pain for at least 3 months despite conservative treatment, including medication or physical therapy. 3. Medial-compartment knee arthritis or articular cartilage defects judged to be the main cause of symptoms. 4. Imaging-confirmed medial-compartment cartilage defects for which CARTISTEM implantation has been decided. 5. Voluntary written informed consent by the participant or legally authorized representative after understanding the study. Exclusion Criteria: 1. Surgery for knee cartilage injury within 1 year before screening. 2. Ligament instability requiring simultaneous ligament surgery. 3. Kellgren-Lawrence grade IV osteoarthritis on weight-bearing anteroposterior knee radiographs. 4. Mechanical-axis varus deformity of 5 degrees or greater, unless corrected by simultaneous high tibial osteotomy. 5. Autoimmune or inflammatory arthritis, including rheumatoid arthritis. 6. Inability to undergo MRI. 7. Body mass index of 35 kg/m² or greater. 8. Inability to adequately understand the study explanation, including illiteracy or a language barrier. 9. Age younger than 19 years.