Sodium (23Na) MRI was employed for the evaluation of patients with ICRS Grade I-II cartilage defects at 7T. 23Na data from defect, weight-bearing, and non-weight-bearing region of femoral cartilage were obtained at baseline, 8-days, 3-months and 6-months follow-up. Significantly lower 23Na values were found in defect than in weight-bearing and non-weight-bearing regions at all time-points. While 23Na values in weight-bearing and in non-weight-bearing regions were stable over time, a significant decrease was found in the defects. 23Na-MRI allows noninvasive follow-up of changes in the cartilage GAG content and thus might be particularly useful for the evaluation of cartilage regenerating therapies.