This in vitro investigation characterized temperature changes associated with radiofrequency (RF) energy induced heating of bovine articular cartilage using temperature-controlled, monopolar (Vulcan RF system and Vulcan, TAC-S Electrothermal Probe) and bipolar (VAPR II RF system and VAPR TC RF electrode) electrosurgical equipment. The RF generators were used at the same setting (set temperature 70 degrees C; 30 W). The cartilage tissue sample was placed in a saline bath maintained at room temperature. Temperatures were recorded using fluoroptic thermometry at the RF electrode-tissue interface at 1-s intervals before, during deliver of RF energy (1- and 2-s), and after (1- to 3-s). For both electrosurgical systems the mean RF electrode-tissue interface temperatures were significantly ( P<0.05) higher than the mean baseline value during delivery of RF energy (monopolar, highest mean temperature, 65.7 degrees C; bipolar, highest mean temperature, 54.1 degrees C). In general, during and after the deliver of RF energy, the monopolar RF system produced tissue temperatures that were significantly ( P<0.05) higher than those produced by the bipolar RF system. Neither electrosurgical system exceeded the set temperature of 70 degrees C. These findings provide basic tissue temperature characteristics for the newly developed, temperature-controlled RF devices applied to articular cartilage.