Impact of monopolar radiofrequency energy on subchondral bone viability

• Published in: Knee surgery, sports traumatology, arthroscopy : official journal of the ESSKA Vol. 18; no. 5; pp. 673 - 680
• Main Authors: Balcarek, Peter, Kuhn, Anke, Weigel, Arwed, Walde, Tim A., Ferlemann, Keno G., Stürmer, Klaus M., Frosch, Karl-Heinz
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.05.2010; John Wiley & Sons, Inc
• Subjects: Analysis; Animal subjects; Animals; Bone Regeneration - radiation effects; Bones; Diathermy - adverse effects; Energy; Experimental Study; Female; Femur - surgery; Investigations; Knees; Labeling; Medicine; Medicine & Public Health; Microscopy; Mineralization; Necrosis; Orthopedics; Rabbits; Radiation Injuries, Experimental; Radio frequency; Radio Waves - adverse effects; Sports; Surgery; Techniques; United States > US; Germany; Osteonecrosis; Thermal chondroplasty; Radiofrequency energy; Monopolar
• ISSN: 0942-2056; 1433-7347; 1433-7347
• DOI: 10.1007/s00167-009-0949-z

The purpose of this study was to analyze the impact of monopolar radiofrequency energy treatment on subchondral bone viability. The femoral grooves of six chinchilla bastard rabbits were exposed bilaterally to monopolar radiofrequency energy for 2, 4 and 8 s, creating a total of 36 defects. An intravital fluorescence bone-labeling technique characterized the process of subchondral bone mineralization within the 3 months following exposure to radiofrequency energy and was analyzed by widefield epifluorescence optical sectioning microscopy using an ApoTome. After 2 s of radiofrequency energy exposure, regular fluorescence staining of the subchondral bone was evident in all samples when compared to untreated areas. The depth of osteonecrosis after 4 and 8 s of radiofrequency energy treatment averaged 126 and 942 µm at 22 days ( P  < .05; P  < .01). The 4 s treatment group showed no osteonecrosis after 44 days whereas the depth of osteonecrosis extended from 519 µm at 44 days ( P  < .01), to 281 µm at 66 days ( P  < .01) and to 133 µm at 88 days ( P  < .05) after 8 s of radiofrequency energy application. Though radiofrequency energy may induce transient osteonecrosis in the superficial zone of the subchondral bone, the results of this study suggest that post-arthroscopic osteonecrosis appears to be of only modest risk given the current clinical application in humans.