Surgical accuracy in identifying the elbow rotation axis on fluoroscopic images.
OBJECTIVE
To assess the accuracy of surgeons in identifying elbow rotation axis (RA) on fluoroscopic images and to measure the interobserver variability.


METHODS
Five healthy subjects underwent 3-dimensional computed tomography (CT) analysis of their nondominant elbow. Real-time rotation software enabled surgeons to approximate the elbow RA on CT-reconstructed fluoroscopy, which was repeated twice with different starting positions to increase the number of observations. The surgeons used anatomical landmarks of choice. Analysis of variance (ANOVA) was used to determine structural error differences between surgeons, and intraclass correlation coefficients (ICCs) were used to determine the corresponding interobserver variability.


RESULTS
Eight subspecialty-trained trauma surgeons (P.K., N.W.L.S., V.M.d.J., P.J., G.M.K., R.W.P., T.S., B.A.v.D.) participated and attempted to identify the RA on reconstructed fluoroscopy. A total of 15 RA definitions on 5 elbows were recorded per surgeon. The surgeons had a mean rotational error of 5° (range, < 1°-13°) and mean translational error of 1 mm (range, < 1-8 mm), compared with the true elbow RA as measured by the 3-dimensional CT analysis. The ANOVA showed structural differences between surgeons in rotational and translational errors, indicating that some surgeons consistently had more accurately identified the elbow RA than others. The ICC was 0.12 for rotational error and 0.10 for translational error, indicating a large interobserver variability.


CONCLUSIONS
We show in this in vivo study that identification of the elbow RA on fluoroscopy is associated with substantial rotational errors and large inconsistencies among surgeons. Implementation of standardized anatomical landmarks is required to improve surgeons' accuracy. These landmarks should preferably take into account both the coronal and the sagittal planes, using the orientation of the capitellum and trochlea as well as the posterior distal humeral cortex.


METHODS
Diagnostic II.
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway.
J K
JK
Wiggers
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway.
G J
GJ
Streekstra
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway.
P
P
Kloen
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway.
K
K
Mader
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway.
J C
JC
Goslings
Department of Surgery, Trauma Unit, and the Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands; Department of Orthopaedic Surgery, Sentral Hospital Førde, Førde, Norway. Electronic address: n.w.schep@amc.uva.nl.
N W L
NW
Schep
D000328:Adult; D059925:Anatomic Landmarks; D004551:Elbow Joint / Q000000981:diagnostic imaging* / Q000502:physiology / Q000601:surgery; D005471:Fluoroscopy; D064368:Healthy Volunteers; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D015588:Observer Variation; D011857:Radiographic Image Interpretation, Computer-Assisted; D012399:Rotation; D012984:Software; D014057:Tomography, X-Ray Computed
Fluoroscopy; elbow; external fixation; rotation axis