Risk of osteonecrosis of the femoral condyle after arthroscopic chondroplasty using radiofrequency: a prospective clinical series

Abstract

Radiofrequency (RF) energy can be used for treatment of intraarticular pathologies in knee joint. RF energy was found to be superior to mechanical techniques in smoothening the articular surface (chondroplasty), shortening the operation time and reducing the blood loss. As RF produces thermal energy it has been reported to be responsible for the postoperative osteonecrosis however, there is no clinical evidence in the literature supporting that RF causes osteonecrosis. The current study searches for an answer whether surgical arthroscopic modalities using RF energy causes osteonecrosis. We hypothesize in the presented study that chondroplasty with RF has no effect on increasing the incidence of osteonecrosis in knee joint. In a prospective clinical trial, arthroscopic chondroplasty was performed in 50 patients with degenerative changes of the articular cartilage, stage II and III according to Outerbridge. To be included in the study, the patients had to meet the following criteria: (1) Preoperative MRI and plain film radiographs showing no evidence of osteonecrosis. (2) Patients had to be symptomatic for at least 6 weeks before the preoperative MRI. (3) Arthroscopically confirmed stage II or III. Preoperative MRI was taken in all patients. For chondral lesions bipolar RF energy system (VAPR-DePuy Mitek, Norwood, USA) was used. The patients were examined at the end of the sixth month and we performed MRI. Fifty patients with an average of age 45.54 (between 18 and 64) (SD, 10.63). During arthroscopy, together with chondropathy 22 patients pure medial meniscus tears, 7 patients medial and lateral meniscus tears, 7 patients pure lateral meniscus tears, 2 patients medial plica, and 3 patients synovial hypertrophy were detected. Among all 50 patients, osteonecrosis were detected at only 2 (4%) in the postoperative period. Until now it was not clear that RF energy causes osteonecrosis; however, according to this study if proper method is used, bipolar RF energy used for arthroscopic chondroplasty does not causes subchondral osteonecrosis.