Abstract
Objective The aim of this study was to evaluate the effect of bipolar radiofrequency (RF) energy
on canine stifle joint fluid temperature.
Materials and Methods A standard stifle arthroscopy was performed on 15 canine large breed cadaveric stifle
joints. A bipolar RF (VAPR III, 2.3-mm side effect electrode; Depuy Mitek, Raynham,
Massachusetts, United States) unit was activated in the joint (1) with or without
direct tissue contact, (2) with or without additional 18-gauge needle outflow and
(3) for 15 and 30 seconds. The joint fluid temperature was monitored with two fibre
optic intra-articular sensors.
Results The stifle joint fluid temperature was significantly higher when there was no contact
between the tissue and RF probe (mean: 58.6°C with 95% confidence interval [CI]: 53.3–64.0°C)
compared with when tissue was contacted (mean: 29.0°C with 95% CI: 26.3–31.6°C). An
18-gauge egress needle had minimal effect on reducing joint fluid temperature. The
temperature was higher during the 30-second application of RF energy than the 15-second
group.
Clinical Significance Bipolar RF energy without firm tissue contact rapidly and significantly increased
joint fluid temperature beyond the level reported to damage chondrocytes (above 45°C).
Caution is required in the use of bipolar RF energy in the canine stifle joint.
Keywords
stifle joint - arthroscopy - radiofrequency energy - temperature - articular cartilage
