Interobserver and intraobserver error in distal femur transepicondylar axis measurement with computed tomography.
On 2 separate occasions at least 1 week apart, 6 independent observers studied errors in identification of the transepicondylar axis (TEA) using computed tomography in 10 cadaveric knees. The reference surgical TEA was established by dissection of specimens. We found an average error of 2.6 degrees (external rotation) when the TEA was identified by computed tomography. The error was significantly smaller when the TEA was identified by using a conventional axial image than when a 3-dimensional reconstruction image was used (P < .001, paired t test). No significant intraobserver error (P = .814, Wilcoxon rank test) was found when the measurement was performed using conventional 2-dimensional computed tomography images. However, significant interobserver difference was evident (P < .001, Friedman test).
Department of Orthopaedic and Traumatology, Queen Mary Hospital, The University of Hong Kong, Hong Kong.
Chester Lie
CL
Wai Hung
Yau
Y
Wai Pan
Chiu
C
Kwong Yuen
Leung
L
Hon Bong
Lisa Wong
LW
Lei Sha
Simon Wong
SW
Ho Man
D019645:Arthroplasty, Replacement, Knee; D005269:Femur / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000706:statistics & numerical data*; D021621:Imaging, Three-Dimensional / Q000706:statistics & numerical data*; D007719:Knee Joint / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D015588:Observer Variation; D011859:Radiography; D015898:Tomography Scanners, X-Ray Computed