Interobserver repeatability of measurements on computed tomography images of lax canine hip joints from youth to maturity

Abstract

Objectives To determine interobserver repeatability of measurements on computed tomography (CT) images of lax canine hip joints at different ages and in the presence of degenerative joint disease at maturity. Study Design Longitudinal observational investigation. Animals Sibling crossbreed hounds. Methods Pelvic CT was performed at 20, 24, 32, 48, 68, and 104 weeks of age. Measures were performed on 3 contiguous two-dimensional (2D) transverse CT images of both hips at each time point by 3 investigators. Center-edge angle (CEA), horizontal toit externe angle (HTEA), ventral (VASA), dorsal (DASA), and horizontal (HASA) acetabular sector angles, acetabular index (AI), and percent femoral head coverage (CPC) were measured. Interobserver repeatability was quantified with the intraclass correlation coefficient (ICC). Satisfactory repeatability was considered when ICC≥0.75. Results DASA, CEA, and CPC were repeatable in all age groups. HASA and HTEA were repeatable for all but 1 time point. At 20 weeks of age, all measures but AI were repeatable, and at 104 weeks of age, DASA, CEA, CPC, and HASA were repeatable. Measures were repeatable in hips with and without degenerative changes with the exceptions of AI and HASA in normal hips and VASA and HTEA in osteoarthritic hips. Conclusions Most 2D CT measurements examined were repeatable regardless of age or joint disease. Clinical Relevance Two-dimensional CT measures may augment current techniques for assessing joint changes in lax canine hips. © 2009 by The American College of Veterinary Surgeons.