title: Bipolar radiofrequency in the human meniscus. Comparative study between patients younger and older than 40 years of age.
abstract: OBJECTIVE
  To morphohistologically evaluate the effect of four increasing intensities of bipolar radiofrequency (RF) on the human meniscus and to compare the changes seen in the menisci from patients younger and older than 40 years old.
  
  
  METHODS
  Thirty fresh menisci were divided in two groups. Group 1: 12 menisci from patients younger than 40 y.o.; Group 2: 18 menisci from patients older than 40 y.o. Groups 1 and 2 were divided in four zones and subjected in vitro, for 3 s, to four intensities of bipolar RF energy. The samples were studied macroscopically, and microscopically.
  
  
  RESULTS
  Thermal changes were present between 0 and 4000 microm from the meniscal surface, with an average of 1699 microm (S.D. 740), and was significantly higher on the ablation than the coagulation group (p<0.001). We found a significant difference between the depth of thermal changes in the menisci from patients younger and older than 40 years old at medium intensities of RF energy (p=0.038 and p=0.044).
  
  
  CONCLUSIONS
  Although bipolar RF can cause deep thermal changes (up to 4000 microm) on the human meniscus, this effect depends on the magnitude of the energy applied. When comparing the effect between younger and older patients, the changes were deeper in the older group when RF was applied at medium intensities.
  
  
  CONCLUSIONS
  Based on our findings, we recommend to exert precaution when applying RF energy at medium intensities in the degenerative meniscus, due to a deeper thermal effect in this group.
authors.affiliation: Orthopaedic Surgery Unit, Clínica Alemana de Santiago, Chile. dfigueroa@alemana.cl
authors.forename: D
authors.initials: D
authors.lastname: Figueroa
authors.forename: R
authors.initials: R
authors.lastname: Calvo
authors.forename: A
authors.initials: A
authors.lastname: Vaisman
authors.forename: M
authors.initials: M
authors.lastname: Gallegos
authors.forename: M A
authors.initials: MA
authors.lastname: Carrasco
authors.forename: R
authors.initials: R
authors.lastname: Mardones
authors.forename: I
authors.initials: I
authors.lastname: Delgado
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D017115:Catheter Ablation; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D017075:Laser Coagulation; D008297:Male; D008592:Menisci, Tibial / Q000473:pathology / Q000528:radiation effects*; D008875:Middle Aged