Excessive radiofrequency application: effects on capsular tissue in an animal model.
Capsular attenuation has been seen after thermal capsulorrhaphy surgery. The purpose of this study was to evaluate the mechanical, histologic, and morphologic effects on capsular tissue after cumulative applications of radiofrequency energy. Ovine patellofemoral capsular tissue was treated with 1, 2, 4, or 8 applications of bipolar radiofrequency energy and then analyzed. No acute capsular ablation or destruction was seen grossly, even in the 8-application group. No definitive visual clues that excessive radiofrequency energy had been applied were seen. There was significant shrinkage and loss of tensile stiffness for all thermal application groups. Given the small sample sizes, post-application failure load, percent relaxation, and stiffness were not observed to be significantly different among the groups. Cumulative applications produced minimal further tissue shrinkage but were accompanied by larger, though not statistically significant, mechanical property losses and increased depth of tissue penetration. These findings suggest that there is no benefit to repeated applications of radiofrequency energy to capsular tissue.
Wolf
Brian R
BR
Department of Orthopaedic Surgery, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA. brian-wolf@uiowa.edu
Heiner
Anneliese D
AD
Albright
John P
JP
Nepola
James V
JV
D000818:Animals; D001696:Biomechanical Phenomena; D017115:Catheter Ablation / Q000379:methods*; D017746:Joint Capsule / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D023421:Models, Animal; D011897:Random Allocation; D019233:Retreatment; D012756:Sheep; D013718:Tensile Strength; D013997:Time Factors