Computed Tomographic Evaluation of the Sacroiliac Joints of Young Working Labrador Retrievers of Various Work Status Groups: Detected Lesions Vary Among the Different Groups and Finite Element Analyses of the Static Pelvis Yields Repeatable Measures of Sacroiliac Ligament Joint Strain

Abstract

Musculoskeletal injuries can lead to a working dog being withdrawn from service prior to retirement. During training exercises, young working dogs are often required to perform repetitive tasks, including adoption of an upright posture (or "hupp" task). Non-invasive, quantitative methods would be helpful for supporting research on effects of these repetitive tasks on sacroiliac joints (SIJ). Furthering our understanding of lesions in and biomechanical stresses on the SIJ could provide insight into possible training modifications for minimizing risks of SIJ injury. Aims of this retrospective, secondary analysis, exploratory study were to test hypotheses that (1) mean numbers of SIJ computed tomographic (CT) lesions/dog would differ among work status groups in young working Labrador Retrievers; (2) a methodology for using CT data and finite element analysis (FEA) to quantify SIJ ligament strain in the static canine pelvis would be feasible; and (3) this FEA methodology would yield repeatable measures of SIJ ligament strain. Clinical and CT data for 22 Labrador retriever working dogs, aged 11-48 months, were retrospectively reviewed. Dogs were categorized into three work status groups (Breeder, Detection, Other). A veterinary radiologist who was unaware of dog group status recorded numbers of CT lesions for each SIJ, based on previously published criteria. Mean numbers of SIJ CT lesions/dog were compared among dog work status groups. An a priori FEA model was created from the CT images of one of the dogs using image analysis software packages. Using tissue properties previously published for the human pelvis, various directional loads (n = 8) and forces (48 ligament strain values) were placed

The prevalence of sacroiliac joint CT and MRI findings is high in large breed dogs

“…The intentions of this study were to describe and quantify CT and MRI findings of the SIJ in a sample of large breeds and companion dogs, to report prevalence values, and to determine whether the numbers of SIJ findings were associated with other variables. Criteria for SIJ finding categories were based on previously published studies in dogs for CT and in people for MRI 12,13 14,16,17 . The results supported our first hypothesis that the prevalence of SIJ findings was high in large breed dogs.…”

The appendicular myology of Stegoceras validum (Ornithischia: Pachycephalosauridae) and implications for the head-butting hypothesis

“…It is more likely that the flange served as an attachment site for enlarged sacroiliac ligaments, which would have served to brace the pelvis against lateral impacts from head-butting. In most extant tetrapods, the dorsal and ventral sacroiliac ligaments serve to stabilize the sacroiliac joint and pelvis [ 109 ]. These ligaments are often a source of injury in animals that experience high intensity or high impact activities involving the hindlegs.…”

“…Similar injuries are often found in work animals experiencing abnormally high pelvic stresses. One such example includes dogs working in the police, military, and search and rescue [ 109 ]. These animals are subject to constant high intensity agility training and are often asked to repetitively assume an upright stance which places excessive weight on their hind limbs [ 109 ].…”

“…One such example includes dogs working in the police, military, and search and rescue [ 109 ]. These animals are subject to constant high intensity agility training and are often asked to repetitively assume an upright stance which places excessive weight on their hind limbs [ 109 ]. As a result, many working dogs experience repeated injuries to the sacroiliac joint and ligaments, which often results in pelvic and lower back pain leading to early retirement [ 109 ].…”

“…These animals are subject to constant high intensity agility training and are often asked to repetitively assume an upright stance which places excessive weight on their hind limbs [ 109 ]. As a result, many working dogs experience repeated injuries to the sacroiliac joint and ligaments, which often results in pelvic and lower back pain leading to early retirement [ 109 ]. If pachycephalosaurs participated in high impact head-butting competitions, they most certainly experienced high stress levels focused around their pelves and hind limbs to remain upright.…”