Abstract
Objectives The aim of this study was to evaluate stifle joint rotational stability in response
to body position and repositioning in dogs undergoing computed tomography (CT).
Materials and Methods Nine dogs (18 stifles) with no history or clinical signs of stifle injury undergoing
CT examinations for other reasons were included in the study. Dogs were positioned
in alternating dorsal and sternal recumbency with the pelvic limbs extended caudally
and unrestrained, for a total of four examinations. Scans included the entire tibia
and distal femur. Using defined landmarks on the tibia and femur, stifle joint rotational
angles were measured from multiplanar reconstructions made by two independent observers,
and repositioning effects and intra- and interobserver agreement evaluated.
Results Repositioning produced repeatable stifle joint rotational angles (pooled within-subject
standard deviations of 0.9° and 1.4°) and intraobserver repeatability was good (within-subject
standard deviations 1.4°), but interobserver agreement was poor. Dorsal and sternal
positioning produced equivalent results.
Clinical Significance The results indicate that little rotation occurs in the healthy extended canine stifle
joint during positioning for CT and support CT as a method for assessing limb alignment
around the stifle joint, provided that the limb distal to the femorotibial joint is
unrestrained. Clinically, it is likely that measured changes in rotational angles
across (and distant to) the stifle joint are real, rather than being due to rotation
artefact during imaging.
Keywords
computed tomography - dogs - stifle joint
