title: Inter- and intra-observer errors in identifying the transepicondylar axis and Whiteside's line.
abstract: OBJECTIVE
  To assess inter- and intra-observer errors in identifying the transepicondylar axis and Whiteside's line in a cadaveric model mimicking total knee arthroplasty.
  
  
  METHODS
  Four cadaveric knees with intact soft tissues were used. The knees were exposed anteriorly using the Insall approach, with the patella everted laterally. Three observers (2 surgeons and one trainee) took turns to identify the anatomic landmarks of the transepicondylar axis and Whiteside's line. Each observer repeated the process 20 times. Each identification was photographed and referenced with the true values obtained from the knees after they were stripped of all soft tissue. Inter- and intra-observer errors in the anatomic landmarks were compared.
  
  
  RESULTS
  Inter-observer error was significant with both the transepicondylar axis and Whiteside's line (p<0.001, one-way ANOVA). The intra-observer variation was greater for Whiteside's line than the transepicondylar axis (standard deviation, 4.2 vs 2.5 degrees). The maximum potential errors in the transepicondylar axis and Whiteside's line were 13 degrees and 24 degrees, respectively.
  
  
  CONCLUSIONS
  The accuracy of rotational alignment of the transepicondylar axis and Whiteside's line were operator-dependent, and their intra-operative reproducibility was low.
authors.affiliation: Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong. yanchunhoi@yahoo.com.hk
authors.forename: C H
authors.initials: CH
authors.lastname: Yan
authors.forename: W P
authors.initials: WP
authors.lastname: Yau
authors.forename: T P
authors.initials: TP
authors.lastname: Ng
authors.forename: W H
authors.initials: WH
authors.lastname: Lie
authors.forename: K Y
authors.initials: KY
authors.lastname: Chiu
authors.forename: W M
authors.initials: WM
authors.lastname: Tang
mesh_terms: D019645:Arthroplasty, Replacement, Knee; D002102:Cadaver; D002983:Clinical Competence; D004838:Epiphyses; D005269:Femur; D006801:Humans; D019300:Medical Errors; D008953:Models, Anatomic; D020370:Osteoarthritis, Knee / Q000175:diagnosis* / Q000601:surgery*; D015203:Reproducibility of Results