Measurement of Femoral Torsion in Dogs Using a Biplanar Method

Abstract

The authors defined the concept of femoral torsion using three axes and two planes. Two techniques were used to measure the femoral anteversion angle on 30 femurs of 15 adult mixed breed dogs. The conventional fluoroscopic technique was compared to the right angle triangle technique. The mean angle for each technique was 30.80 and 31.31 degrees, respectively. The right angle triangle technique, using conventional radiographs, appeared as reliable, accurate, and reproducible as the fluoroscopic method and is recommended for clinical use.

Computation of Femoral Canine Morphometric Parameters in Three‐Dimensional Geometrical Models

“…Our results on femoral angles (Table ) differ from available information in the literature as all past works are based on 2D assessments (Table ) . Reasons for differences in femoral angles computed in projected planes (Table ) are principally due to the definition of 3D axes.…”

“…The literature contains several definitions and various methods to compute femoral head and neck axis . Consequently, different values of angles related to this axis have been reported.…”

“…Radiographs for each articulated hind limb were performed with digital radiographic equipment (Kodak Point of Care CR‐360 System, Carestream Health, Inc, Rochester, NY), obtaining cranio‐caudal and sagittal projections for each femur. The appropriate positioning of femora was carefully evaluated, taking into account guidelines suggested by the literature . All angles were also measured from radiographic images, adopting the methods proposed by Dudley et al for FTA, while the guidelines proposed by Tomlison et al were adopted for the measurements of all other angles …”

“…The morphologic evaluation of canine femur has been limited, until recently, to multiple orthogonal radiographs . However, the femur has a complex 3‐dimensional (3D) configuration, and biplanar radiographic imaging is limited in accurately assessing and quantifying bone deformities .…”

Repeatability and Reproducibility of Measurements of Femoral and Tibial Alignment Using Computed Tomography Multiplanar Reconstructions

“…Radiographic measurement protocols are described for distal femoral varus, known as the anatomic lateral distal femoral angle (aLDFA), angle of anteversion (AA), proximal tibial varus or valgus, which is expressed as the mechanical medial proximal tibial angle (mMPTA)), and tibial torsion . Protocols are also described for measurements using computed tomography (CT) for aLDFA, AA, tibial torsion, and tibial tuberosity displacement (TTD) …”