title: The effect of metallic radial head arthroplasty on radiocapitellar joint contact area.
abstract: OBJECTIVE
  This study determined the effect of metallic radial head arthroplasty on radiocapitellar joint contact area.
  
  
  METHODS
  The contact area of eight intact radiocapitellar joints was assessed during simulated compressive loading. Subsequently, the same experiments were repeated after reconstruction with three different radial head implant sizes.
  
  
  BACKGROUND
  There has been an increasing use of metal radial head implants relative to silicone implants. However, the contact characteristics with the metal reconstruction have not been determined.
  
  
  METHODS
  A 100 N compressive load was applied to the radiocapitellar joint at three different flexion angles for the native joint and three different sizes of a metal head implant. An impression material was employed to quantify joint contact area.
  
  
  RESULTS
  Following metallic radial head arthroplasty, the contact area decreased by approximately two-thirds relative to the native radiocapitellar joint (P<0.001). Smaller implant sizes resulted in slightly larger contact areas (P<0.05). In addition, contact area decreased as joint flexion angle increased (P<0.04).
  
  
  CONCLUSIONS
  Selection of radial head implant size is likely not a significant factor with regard to contact area mechanics of the radiocapitellar articulation.
  
  
  CONCLUSIONS
  The effect of radial head implant size on the contact area produced with the native capitellum is not known. This study shows that the design or selection of a metallic radial head implant from the viewpoint of size is likely not an important factor with regard to minimizing joint contact stresses.
authors.affiliation: Bioengineering Research Laboratory, Division of Orthopaedic Surgery, Hand and Upper Limb Centre, Lawson Health Research Institute, St. Joseph's Health Care London, The University of Western Ontario, 268 Grosvenor Street, ON, N6A 4L6, London, Canada.
authors.forename: Victor S
authors.initials: VS
authors.lastname: Liew
authors.forename: Ian C
authors.initials: IC
authors.lastname: Cooper
authors.forename: Louis M
authors.initials: LM
authors.lastname: Ferreira
authors.forename: James A
authors.initials: JA
authors.lastname: Johnson
authors.forename: Graham J W
authors.initials: GJ
authors.lastname: King
mesh_terms: D000368:Aged; D001178:Arthroplasty / Q000295:instrumentation*; D004551:Elbow Joint / Q000503:physiopathology* / Q000601:surgery; D019544:Equipment Failure Analysis / Q000379:methods*; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007595:Joint Prosthesis / Q000145:classification; D008297:Male; D008670:Metals; D011312:Pressure; D011475:Prosthesis Failure; D011885:Radius Fractures / Q000601:surgery; D013314:Stress, Mechanical; D016474:Weight-Bearing
chemical_list: D008670:Metals