Stifle Joint Rotational Variation in Extended Stifles in Healthy Dogs Undergoing Computed Tomography Examinations.

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 degrees and 1.4 degrees) and intraobserver repeatability was good (within-subject standard deviations 1.4 degrees), but interobserver agreement was poor. Dorsal and sternal positioning produced equivalent results.