Lavage Solution Temperature Influences Depth of Chondrocyte Death and Surface Contouring During Thermal Chondroplasty with Temperature-Controlled Monopolar Radiofrequency Energy

Background: Although radiofrequency energy can smooth and contour cartilage surface, it has deleterious effects on chondrocyte viability. Hypothesis: Monopolar thermal chondroplasty in a 37°C lavage solution, as compared with a 22° lavage solution, will reduce chondrocyte death and result in greater smoothing of the articular cartilage surface. Study Design: Controlled laboratory study. Methods: Sixteen chondromalacic samples from patients undergoing total knee arthroplasty were divided into two groups: 22°C and 37°C lavage solution. Each sample was divided into two equal parts and half of each group was treated for 10 seconds and the other half for 15 seconds. Results: Confocal laser microscopy demonstrated that the depth of chondrocyte death in the 37°C lavage solution group was significantly less (range, 200 to 340 μm) than that in the 22°C solution group for both 10- and 15-second treatment times. Scanning electron microscopy demonstrated that the cartilage surface in the 37°C lavage solution group was smoother than that in the 22°C solution group for the 10-second treatment time. Energy delivery power in the 37°C lavage solution group was significantly lower than in the 22°C solution group for both treatment times. Conclusions: Thermal chondroplasty with 37°C lavage solution resulted in less depth of chondrocyte death and produced smoother surfaces than with 22°C solution for 10 seconds of treatment. Clinical Relevance: Less chondrocyte death would permit increased use of thermal chondroplasty.