title: Assessment of cellular, biochemical, and histologic effects of bipolar radiofrequency treatment of canine articular cartilage.
abstract: OBJECTIVE
  To assess the cellular, biochemical, and histologic effects of bipolar radiofrequency-generated heat on canine articular cartilage.
  
  
  METHODS
  Articular cartilage explants (n = 72) from 6 canine cadavers and cultured articular chondrocytes from 5 canine cadavers.
  
  
  METHODS
  Cartilage explants were randomly assigned to receive no treatment or treatment with focal (3 seconds) or diffuse bipolar radiofrequency. Following treatment, methylene blue permeability assay was performed (n = 12) and remaining samples (60) were cultured. Immediately and 5, 10, and 20 days after treatment, cultured explants were assessed for glycosaminoglycan (GAG) and collagen contents, type II collagen and matrix metalloproteinase (MMP)-13 immunoreactivity, and modified Mankin histologic scores. Liquid culture media were collected every 4 days and GAG content measured. Additionally, cultured chondrocytes were exposed for 3 seconds to media preheated to 37 degrees, 45 degrees, or 55 degrees C. Cell viability was determined via 2 different assays immediately and 24 hours after treatment.
  
  
  RESULTS
  Radiofrequency-treated cartilage had reduced permeability and considerable histologic damage, compared with control samples; most treated samples had reduced collagen II staining and increased MMP-13 immunostaining. Compared with other treatments, less GAGs were released from cartilage after diffuse radiofrequency treatment throughout the study period. Cell viability was significantly different between controls and cells treated at 55 degrees C immediately and 24 hours after heat treatment.
  
  
  CONCLUSIONS
  In this study, bipolar radiofrequency treatment had detrimental effects on normal articular cartilage cells and extracellular matrix with probable long-term clinical consequences. The usefulness of radiofrequency for treatment of osteoarthritic articular cartilage requires further investigation.
authors.affiliation: The Comparative Orthopaedic Laboratory, University of Missouri, Columbia 65211, USA.
authors.forename: James L
authors.initials: JL
authors.lastname: Cook
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Marberry
authors.forename: Keiichi
authors.initials: K
authors.lastname: Kuroki
authors.forename: Keith
authors.initials: K
authors.lastname: Kenter
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002358:Cartilage, Articular / Q000473:pathology / Q000528:radiation effects*; D002470:Cell Survival / Q000528:radiation effects; D002478:Cells, Cultured; D003094:Collagen; D004283:Dog Diseases / Q000532:radiotherapy*; D004285:Dogs; D006025:Glycosaminoglycans; D006358:Hot Temperature / Q000627:therapeutic use; D007150:Immunohistochemistry; D020782:Matrix Metalloproteinases; D010003:Osteoarthritis / Q000532:radiotherapy / Q000662:veterinary*; D000078702:Radiofrequency Therapy
chemical_list: D006025:Glycosaminoglycans; D003094:Collagen; D020782:Matrix Metalloproteinases