title: Radiocapitellar joint contact pressures following radial head arthroplasty.
abstract: OBJECTIVE
  To determine the radial head arthroplasty length that best replicates the native radiocapitellar contact pressure.
  
  
  METHODS
  Eight cadaveric elbows (4 matched pairs) with an average age of 73 years were tested. All specimens were ligamentously stable and without visible cartilage wear. Radiocapitellar contact pressures were digitally analyzed during simulated joint loading at 0°, 45°, and 90° of elbow flexion and neutral rotation in the intact specimens and after ligament-preserving radial head arthroplasty at -2 mm, 0 mm, and +2 mm of the native length. The results were analyzed using 1-way analysis of variance and post hoc Tukey pairwise comparison tests.
  
  
  RESULTS
  Paired analysis demonstrated significantly decreased mean contact pressures when comparing the native versus the minus 2 groups. Significantly decreased maximum contact pressures were also noted between the native and the minus 2 groups. Examining the mean contact pressures showed no significant difference between the native and the zero group and the native and the plus 2 groups. As for the maximum contact pressures, there was also no significant difference between the native and the zero group and the native and the plus 2 group.
  
  
  CONCLUSIONS
  Up to 2 mm of overlengthening may be tolerated under simulated loading conditions without significantly increasing contact pressures of the radiocapitellar joint. Surgeons can use this knowledge along with radiographic parameters and intraoperative examination of elbow stability to gauge the appropriate size of the radial head implant to be used in order to decrease the risk of overstuffing the joint and minimizing radiocapitellar chondral wear.
  
  
  METHODS
  Prognostic IV.
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Michael
authors.initials: M
authors.lastname: Cohn
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY. Electronic address: sergio.glait@nyumc.org.
authors.forename: Sergio A
authors.initials: SA
authors.lastname: Glait
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Anthony
authors.initials: A
authors.lastname: Sapienza
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY.
authors.forename: Young W
authors.initials: YW
authors.lastname: Kwon
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement; D002102:Cadaver; D051224:Capitate Bone / Q000503:physiopathology; D006801:Humans; D008297:Male; D011312:Pressure; D011884:Radius / Q000503:physiopathology; D014955:Wrist Joint / Q000503:physiopathology*
keywords: Arthroplasty; biomechanical analysis; contact pressure; radial head; radiocapitellar joint