Radiographic Determination of Canine Femoral Alignment in the Sagittal Plane: A Cadaveric Pilot Study

Introduction: Although alignment of the canine femur in the frontal plane has been reported, a standardized methodology has not yet been established for evaluation in the sagittal plane. The objective of this study was to establish a reliable methodology for radiographic determination of alignment of the femur in the sagittal plane. We hypothesized that the proposed methodology would result in high repeatability of measurements within and among three observers when measuring a population of canine femurs.

Materials and Methods: Femoral specimens were collected from the University’s veterinary anatomy laboratory and sagittal plane radiographs obtained. Utilizing the centre of rotation of angulation methodology, the anatomic and mechanical axes, joint orientation lines, and joint orientation angles were determined in the sagittal plane. Three observers measured the alignment and associated angles for all femurs on three separate days. Inter- and intraobserver reliability were measured using two-way mixed intraclass correlation coefficients (ICC) with associated 95% confidence intervals.

Results: Twenty-nine canine femora were measured. A high degree of correlation was present both among and between observers for all angles, as defined by ICC > 0.8 for each.

Discussion/Conclusion: The hypothesis was accepted, as strong correlation was observed within and among observers for all measurements suggesting the described methodology is appropriate for reliable measurement of the canine femur in the sagittal plane. Limitations of this study include the use of cadaver bones without associated soft-tissues and a small sample size. These results suggest this methodology could be considered for planning sagittal plane deformity correction.

Acknowledgment: There was no proprietary interest/funding for this project.