An interventional study of 2-mm subchondral drilling and Sequential 4-mm and 2-mm subchondral drilling in Osteoarthritis, Knee and Articular Cartilage Defects of the Knee, sponsored by Yonsei University. Recruiting at 1 site in South Korea. Open to participants aged 19 Years and older. Per ClinicalTrials.gov, last updated 2026-10-19.
Sponsored by Yonsei University · Not applicable, Interventional, and Treatment
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.
Eligible adults with persistent knee pain and medial-compartment cartilage defects scheduled for CARTISTEM implantation will be recruited at the Department of Orthopedic Surgery, Severance Hospital. Computer-generated randomization will allocate 60 participants equally between two parallel groups. Recruitment is planned for one year, follow-up for 12 months after surgery, and the overall research period for three years after approval.
The experimental group will undergo subchondral drilling with a 2-mm drill alone. The active comparator group will undergo sequential drilling with 4-mm and 2-mm drills. Both groups will receive allogeneic human umbilical cord blood-derived mesenchymal stem cells mixed with sodium hyaluronate hydrogel and implanted into the drilled holes and over the cartilage defect. High tibial osteotomy may accompany implantation when clinically indicated.
Baseline assessments include demographics, clinical scores, standing knee radiographs, lower-limb alignment radiographs, and MRI. Arthroscopy at surgery will document lesion location, size, and ICRS lesion grade. IKDC, pain VAS, Lysholm, and KOOS assessments are scheduled at 3, 6, and 12 months. Radiographic assessments are scheduled at 6 and 12 months, and MRI at 12 months. Second-look arthroscopy is limited to participants undergoing plate removal after concomitant high tibial osteotomy.
Non-inferiority will be assessed using the between-group difference in the 12-month IKDC score and its 95% confidence interval, with a 10.3-point margin. Adverse events will be assessed at postoperative visits.
Participants are masked to the allocated drilling technique. Assessors of secondary imaging, arthroscopic, and histological outcomes are masked to allocation and evaluate coded participant information. The operating surgeon is aware of allocation. No biopsy or genetic analysis is planned.
Research funding: MEDIPOST; total study budget: KRW 60,000,000.
3,391 studies on the registry are indexed under Osteoarthritis, Knee; 628 are open to participants now.
This study's planned enrollment of 60 is below the median of 69 across 2,808 interventional studies indexed under Osteoarthritis, Knee.
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Exclusion Criteria:
Subchondral drilling with a 2-mm drill alone, followed by CARTISTEM implantation. High tibial osteotomy may be performed when needed for alignment correction.
Procedure: 2-mm subchondral drilling
Sequential subchondral drilling with 4-mm and 2-mm drills, followed by the same CARTISTEM preparation and implantation. High tibial osteotomy may be performed when needed.
Procedure: Sequential 4-mm and 2-mm subchondral drilling
Under general or spinal anesthesia, the cartilage defect is exposed and prepared. Subchondral holes are drilled with a 2-mm drill alone. Allogeneic umbilical cord blood-derived mesenchymal stem cells are mixed with sodium hyaluronate hydrogel, placed into the drilled holes, and applied over the defect. The same cell product preparation is used in both arms. High tibial osteotomy may precede implantation when indicated.
Also known as: 2-mm subchondral drilling with CARTISTEM implantation, Small-diameter subchondral drilling, CARTISTEM implantation
Under general or spinal anesthesia, the cartilage defect is exposed and prepared. Subchondral holes are made using sequential 4-mm and 2-mm drilling. The same allogeneic umbilical cord blood-derived mesenchymal stem cell and sodium hyaluronate hydrogel preparation is implanted into the holes and over the defect. High tibial osteotomy may precede implantation when indicated.
Also known as: Sequential 4-mm and 2-mm subchondral drilling with CARTISTEM implantation, Combined-diameter subchondral drilling; CARTISTEM implantation.
IKDC Subjective Knee Evaluation score at 12 months after surgery
The IKDC Subjective Knee Evaluation score assesses participant-reported knee symptoms and function on a 0-100 scale. Higher scores indicate better function and fewer symptoms. The primary non-inferiority comparison uses the 12-month between-group difference and its 95% confidence interval, with a prespecified margin of 10.3 points.
Time frame: 12 months after surgery. Additional protocol measurements occur at 3 and 6 months.
Pain visual analog scale
Knee pain assessed using a 10-cm visual analog scale (VAS), recorded from 0 to 10: 0 = no pain; 10 = worst imaginable pain. Higher scores indicate greater pain. Scores and changes from baseline are assessed.
Time frame: Baseline and 3, 6, and 12 months after surgery
Lysholm knee score
Patient-reported knee symptoms and function measured using the Lysholm knee score, ranging from 0 to 100; higher scores indicate better knee function.
Time frame: Baseline and 3, 6, and 12 months after surgery
Knee injury and Osteoarthritis Outcome Score (KOOS)
The original 42-item Knee injury and Osteoarthritis Outcome Score (KOOS) assesses pain, symptoms, activities of daily living, sport/recreation, and knee-related quality of life. Each of the five subscales is scored separately from 0 to 100; higher scores indicate fewer symptoms and better function.
Time frame: Baseline and 3, 6, and 12 months after surgery
MOCART 2.0 knee score
MRI assessment of cartilage repair using the MOCART 2.0 knee score, ranging from 0 to 100; higher scores indicate more favorable repair tissue morphology.
Time frame: 12 months after surgery
Subchondral edema assessment
Subchondral edema assessed on MRI using the relevant MOCART 2.0 subscale.
Time frame: 12 months after surgery
Presence of subchondral cysts
Presence or absence of subchondral cysts on MRI.
Time frame: 12 months after surgery
Presence of subchondral insufficiency fracture
Presence or absence of subchondral insufficiency fracture on MRI.
Time frame: 12 months after surgery
ICRS Cartilage Repair Assessment
ICRS Cartilage Repair Assessment at second-look arthroscopy during plate removal in participants with concomitant high tibial osteotomy. Defect filling, integration with adjacent cartilage, and macroscopic appearance are each scored from 0 to 4 and summed to a total of 0 to 12; higher scores indicate better cartilage repair. Overall repair is classified from Grade I (normal) to Grade IV (severely abnormal).
Time frame: At second-look arthroscopy during plate removal, planned at 12 months
Kellgren-Lawrence grade
Radiographic osteoarthritis assessed using the Kellgren-Lawrence grade, ranging from 0 to 4; higher grades indicate more severe osteoarthritis.
Time frame: Baseline and 6 and 12 months after surgery
Hip-knee-ankle angle
Lower-limb alignment measured as the hip-knee-ankle angle, in degrees, on standing full-length radiographs.
Time frame: Baseline and 6 and 12 months after surgery
Plan to share: Undecided — The plan to share individual participant data with other researchers has not yet been determined.
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From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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