title: Comparison of mechanical debridement and radiofrequency energy for chondroplasty in an in vivo equine model of partial thickness cartilage injury.
abstract: OBJECTIVE
  The purpose of this study was to develop a long-term model of cartilage injury that could be used to compare the effects of radiofrequency energy (RFE) and mechanical debridement as a treatment.
  
  
  METHODS
  Partial thickness fibrillation of patellar cartilage was created in 16 mature ponies. Three months after the initial surgery all injured patellae were randomly selected to receive one of the four treatments (n = 8/treatment): (1) control, (2) mechanical debridement with a motorized shaver, (3) TAC-CII RFE probe, and (4) CoVac 50 RFE probe. The ponies were euthanized 22 months after treatment. Macroscopic appearance of the cartilage surface was scored, vital cell staining was used to determine chondrocyte viability and light microscopy was used to grade the morphometric changes within the cartilage. Mechanical properties (aggregate modulus, Poisson's ratio and permeability) also were determined and compared to normal uninjured cartilage.
  
  
  RESULTS
  There were no differences in the cartilage surface scores among the treatment groups and control samples (P > 0.05). The maximum depth of cell death and the percentage of dead area in control and mechanical debridement groups were significantly less than those in both RFE groups. There were no significant differences in maximum depth and the percentage of dead area between the two RFE treatment groups. Histologic scores demonstrated better cartilage morphology for the control and mechanical debridement groups than those of RFE groups. However, even with full thickness chondrocyte death, the matrix in the RFE treated sections was still retained and the mechanical properties of the treated cartilage did not differ from the mechanical debridement group.
  
  
  CONCLUSIONS
  RFE caused greater chondrocyte death and more severe morphological changes compared to untreated degenerative cartilage and mechanical debridement in this model.
authors.affiliation: Comparative Orthopaedic Research Laboratory, Department of Surgical Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI 53706-1102, USA.
authors.forename: R B
authors.initials: RB
authors.lastname: Edwards
authors.forename: Y
authors.initials: Y
authors.lastname: Lu
authors.forename: R K
authors.initials: RK
authors.lastname: Uthamanthil
authors.forename: J J
authors.initials: JJ
authors.lastname: Bogdanske
authors.forename: P
authors.initials: P
authors.lastname: Muir
authors.forename: K A
authors.initials: KA
authors.lastname: Athanasiou
authors.forename: M D
authors.initials: MD
authors.lastname: Markel
mesh_terms: D000818:Animals; D001182:Arthroscopy / Q000379:methods*; D002357:Cartilage Diseases / Q000601:surgery*; D002358:Cartilage, Articular / Q000378:metabolism* / Q000601:surgery; D006736:Horses; D000078702:Radiofrequency Therapy; D011897:Random Allocation