title: Effects of radiofrequency energy on human articular cartilage: an analysis of 5 systems.
abstract: BACKGROUND
  Previous radiofrequency work has not rigidly controlled energy application to the articular cartilage, giving uncertain results published to date.
  
  
  OBJECTIVE
  At minimal settings, radiofrequency probes cause cell death in measurable areas when applied to human articular cartilage.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Simulating operating room conditions, 5 commercially available radiofrequency probes were attached to a customized jig to standardize a minimal contact pressure of each probe tip to 2.0 g. Keeping all variables the same, probes were placed on specific points of fresh grade II human cartilage with treatment times of 1 and 3 seconds at the manufacturer's recommended settings. Grade III cartilage was also tested with a treatment time of 3 seconds, and grade II cartilage was studied with the probe held 1 mm off the cartilage surface. Cartilage was blindly analyzed by confocal microscopy using a live/dead cell viability assay to determine the extent of cell death.
  
  
  RESULTS
  Radiofrequency probes produced significant cellular death in the form of a half-circle into the cartilage to variable depths. For treatment times of 1 and 3 seconds, cell death measurements ranged from 404 to 539 mum and 1034 to 1283 mum, respectively. One probe failed to show any effect, with minimal evidence of cell death or cartilage smoothing. When probes were kept a 1.0-mm distance above the cartilage, no cell death or cartilage smoothing was noted. Radiofrequency treatment of grade III cartilage penetrated to the subchondral bone. There was no statistically significant difference between the damage caused by monopolar and bipolar probes when tested under these rigidly controlled conditions.
  
  
  CONCLUSIONS
  These results showed significant cellular death at these minimal conditions to the underlying chondrocytes with radiofrequency probes. Surgeons using this technology need to be aware of the power and dangerous potential these probes can have on articular cartilage.
authors.affiliation: Keck School of Medicine, University of Southern California, Los Angeles, California, USA.
authors.forename: Sean
authors.initials: S
authors.lastname: Caffey
authors.forename: Edward
authors.initials: E
authors.lastname: McPherson
authors.forename: Brian
authors.initials: B
authors.lastname: Moore
authors.forename: Thomas
authors.initials: T
authors.lastname: Hedman
authors.forename: C Thomas
authors.initials: CT
authors.lastname: Vangsness
mesh_terms: D000368:Aged; D001178:Arthroplasty / Q000295:instrumentation; D002358:Cartilage, Articular / Q000166:cytology* / Q000000981:diagnostic imaging*; D017115:Catheter Ablation; D016923:Cell Death; D019902:Chondrocytes / Q000528:radiation effects*; D006801:Humans; D006979:Hyperthermia, Induced; D008875:Middle Aged; D000078702:Radiofrequency Therapy; D011877:Radionuclide Imaging