Thermal chondroplasty with bipolar and monopolar radiofrequency energy: Effect of treatment time on chondrocyte death and surface contouring

Purpose: The purpose of this study was to evaluate chondrocyte viability and surface contouring of articular cartilage using confocal laser microscopy (CLM) and scanning electron microscopy (SEM), respectively, during different treatment time intervals with monopolar and bipolar radiofrequency energy (RFE). Type of Study: In vitro analysis using chondromalacic human cartilage. Methods: Forty-two fresh osteochondral sections from patients undergoing partial or total knee arthroplasties were used to complete this study. Each of 36 sections was divided into 2 distinct 1-cm(2) regions that were treated with either bipolar or monopolar RFE. Six sections were maintained as untreated controls. Six RF treatment time intervals were evaluated: 5, 10, 15, 20, 30, and 40 seconds (6 specimens per time interval per group). After treatment, each specimen was processed for CLM and SEM. Results: CLM demonstrated that the depth of chondrocyte death in the monopolar RFE treatment group was significantly less than the bipolar group at each of the same time intervals (P < .05). SEM showed that each RFE device began to contour and smooth the articular surface after 15 seconds of treatment. Conclusions: When applying thermal chondroplasty, a broad treatment time range could result in variable degrees of cartilage smoothness and significant chondrocyte death.