A surgical system includes a surgical generator and at least one energy delivery device. The surgical generator includes at least one energy output stage configured to deliver energy, a controller configured to control the energy output, and sensor circuitry. The energy delivery device(s) is coupled to the surgical generator, configured for insertion into a synovial joint, and configured to supply energy through synovial fluid in the synovial joint. In a sensing mode, the sensor circuitry is configured to sense at least one electrical parameter of the energy and the controller is configured to determine a parameter of the synovial fluid based thereon. The controller is further configured, in a treatment mode, to control the energy based upon the at least one determined parameter of the synovial fluid to treat tissue of the synovial joint.