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Reliability of CT measurement of induced radioulnar step in dogs using a circle superimposition technique
Author(s) -
Burton N. J.,
Meakin L.,
Hosworth A.,
Parsons K. J.
Publication year - 2018
Publication title -
journal of small animal practice
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 67
eISSN - 1748-5827
pISSN - 0022-4510
DOI - 10.1111/jsap.12782
Subject(s) - superimposition , intraclass correlation , medicine , ostectomy , ulna , orthodontics , reproducibility , interclass correlation , elbow , cadaveric spasm , anatomy , mathematics , statistics , artificial intelligence , computer science
Objectives To evaluate the reliability of CT measurement of canine elbow axial radioulnar congruence using a duplicated circle superimposition technique. Materials and Methods CT of six cadaveric canine elbows was performed following either: (1) placement of an external fixator on the radius with ostectomy and radial shortening of 1 to 5 mm; (2) radial lengthening of 1 to 5 mm using a radial lengthening system; or, (3) no axial length adjustment. Four observers, on two occasions, blinded to the amount of radial adjustment, placed a circle of best fit of the ulnar trochlear notch on a sagittal image that was duplicated and transposed to the articular contour of the radial head; then the axial distance between circles relative to the dorsal radius was measured. Statistical analysis assessed differences between actual and observer‐assessed radial length adjustment; inter−/intra‐observer interclass correlation coefficients and sensitivity/specificity were calculated to evaluate measurement reliability. Results There was not a significant difference between actual and observer measures of radioulnar congruence. Inter‐ (intraclass correlation coefficient=0.98) and intra‐observer reliability (intraclass correlation coefficient=0.94 to 0.99) were almost perfect for measurement of radioulnar incongruence when compared to the actual radial adjustment. A Bland–Altman plot revealed a 95% confidence interval range of −1.31 to 1.16 mm. Sensitivity and specificity were high for correct identification of congruent elbows and elbows with 1 or 2 mm incongruency. Clinical Significance The duplicated circle superimposition technique provides a simple and accurate means of assessing radioulnar axial incongruence.