Radiographic determination of normal canine femoral alignment in the sagittal plane: A cadaveric pilot study

Objective To establish a reliable methodology for radiographic determination of alignment of the normal canine femur in the sagittal plane. Study design Cadaveric pilot study. Sample population Twenty‐nine cadaveric canine femurs. Methods Femoral specimens were collected from the University of Missouri veterinary anatomy laboratory, and standardized sagittal plane radiographs were obtained. The anatomic and mechanical axes, joint orientation, lines and joint orientation angles were determined in the sagittal plane by using the center of rotation of angulation methodology. Landmarks were clearly described to allow repeatability and reliability of measurements. Three observers with various degrees of experience measured two centers of rotation of normal angulation, the anatomic caudoproximal femoral angle, and the mechanical caudodistal femoral angle for all femurs on three separate days. Interobserver and intraobserver reliability were measured by using two‐way mixed intraclass correlation coefficients (ICC) with associated 95% CI. Results Twenty‐nine medium to large breed canine femora were measured. A high degree of correlation was present both among and between observers for all measurements performed, as defined by an ICC >0.8 for each. Conclusion The described methodology was reliable and repeatable for measurement of angulation of grossly normal canine femora in the sagittal plane when performed by observers with varying degrees of clinical experience, as evidenced by a high degree of correlation for all values measured. Clinical significance This methodology may be used for standardized evaluation of alignment of canine femora in the sagittal plane.