Cartilage injury is the biggest headache for orthopedic joint surgeons because the articular cartilage is hyaline cartilage and cannot repair itself to become hyaline cartilage after injury, and there is a higher possibility of secondary osteoarthritis at a later stage. Knee cartilage injury is the most common and is a common cause of osteoarthritis of the knee joint. The mosaic technique for the treatment of localized cartilage injuries and defects of the knee joint was started in 1993 and has shown good results. As the name implies, the technique involves placing normal osteochondral complexes of different diameters in the cartilage defect area like a mosaic. Generally, the skid edge of the knee joint and the intercondylar fossa of the femur are non-weight-bearing areas, which are used as the donor area. A columnar osteochondral complex of 5-12 mm in diameter and 10-20 mm in length is taken with special surgical instruments in an arthroscopic or small incision. The cartilage surface of the recipient area was cleared, the subchondral bone of the defective area was excised, and the donor was placed in the defective area.