Computed Tomographic Determination of Tibial Torsion in the Dog

Abstract

The goal of this study was to develop a method for computed tomographic (CT) measurement of tibial torsion, and to compare this technique with direct anatomic measurement of tibial torsion in cadaveric canine tibiae. Paired hind limbs of 10 cadaveric dogs were mounted on a custom-designed limb holding apparatus. One-millimeter thick, contiguous, transverse CT slices were obtained from the distal femur to the proximal tibia and 2 mm CT slices were obtained from the distal tibia to the proximal tarsus. The tibiae were freed of soft tissues and digital photographic images of the proximal and distal articular surfaces were obtained with the camera lens aligned perpendicular to the long axis of the tibia. Multiple proximal and distal tibial axes were identified on the images; two proximal and two distal axes were found to be repeatable in all specimens in both the direct and CT methods. The torsion angle was calculated by determining the difference between the axis angles for each pair of proximal and distal axes. There was no significant difference in torsion angle identified between the direct photographic and CT method for any pair of proximal and distal axes. CT determination of tibial torsion is a rapid and accurate method, and warrants investigation in clinical patients.

Evaluation of Osteotomy Accuracy and Rotational and Angular Alignment for Cranial Closing Wedge Ostectomy Performed With and Without Alignment Aids

“…CT scans were used to assess tibial torsion as described previously . Briefly, 0.6 mm thick, contiguous, transverse CT slices were acquired from the proximal and distal 2 cm of all tibiae including at least 4–6 slices of the distal aspect of the femur and proximal aspect of the tarsus.…”

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) …”

Assessing torsion of the medial cortex of the canine tibia using computed tomography multiplanar reconstruction

“…We adopted the threshold of 10° based on a previous CT study of tibial torsion in normal large breed NCD dogs, which found that the standard deviation of the mean was 5° (Aper et al . ), suggesting that 95% of dogs will be within ±10° of the population mean. The authors are unaware of studies in dogs assessing the clinical significance of tibial rotational malalignment.…”