4. If the patient has only one grade III or IV defect, the size of the defect is ≥ 4 and ≤ 12 cm2 post debridement. If the patient has two grade III or IV cartilage defects the total defect size is ≥ 4 and ≤ 12 cm2 post debridement. The defects must be located on different, non-articulating knee joint areas and both cartilage defects are to be treated with NOVOCART® Inject plus.