The purpose of this study is to investigate the safety and feasibility of implanting autologous cartilage mini-grafts (or Cartibeads) into cartilage defects in the knee and ankle.

Cartibeads are engineered from autologous articular chondrocytes (from the patient's own cartilage cells). A small cartilage biopsy (~50 to 150 mg according to lesion size to be treated) is collected from a minimal weight bearing zone of the patient's articulation. Chondrocytes are extracted from the biopsy and expanded in culture. Our patented, standardized methodology then allows expanded cells to recover their capacity of producing hyaline matrix and to form cartilage mini-grafts (Cartibeads). These grafts are beads of 1 to 2 mm in diameter and have similar characteristics to native hyaline cartilage.

Autologous Cartibeads are implanted into the patient's cartilage defect. Patients are then followed for 12 months for assessment of study endpoints, with safety being the primary outcome.

Key inclusion criteria:

• Cartilage focal lesion(s) ≥ 1.5 cm2 and ≤ 10 cm2
• ICRS grade 3 or 4
• Pain for 3 months or more
• Aged over 18 years

Key exclusion criteria

• Inability to undergo MRI
• Cartilage specific surgery within 12 months from baseline
• Cartilage therapeutic injection within 3 months from baseline
• Radiologically apparent degenerative joint disease (K&L grade >1)
• Chronic inflammatory arthritis and/or infectious arthritis