Radiofrequency chondroplasty is not recommended for the treatment of concomitant grade ii patellar cartilage defects. Issue 1 (April 2020) - Koller, U.; Springer, B.; Rentenberger, C.; Szomolanyi, P.; Waldstein-Wartenberg, W.; Windhager, R.; Trattnig, S.; Apprich, S.