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- Author or Editor: Jason A. Osborne x
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Abstract
Objective—To compare 5 radiographic views for the detection of osteochondritis dissecans (OCD) in dogs with signs of elbow joint pain.
Animals—53 dogs (100 elbow joints) with forelimb lameness and signs of elbow joint pain.
Procedures—Mediolateral (ML), flexed ML, craniocaudal (CC), craniolateral-caudomedial oblique (Cr15L-CdMO), and distomedial-proximolateral oblique (Di35M-PrLO) radiographic views of the 100 elbow joints were obtained. Four examiners graded radiographs with regard to elbow joint OCD. Joints were assessed by use of arthroscopy. Receiver operating characteristic (ROC) curves, kappa measure of agreement, and Fisher exact tests for association between median diagnostic value and actual status were computed.
Results—47 joints had an abnormal medial aspect of the humeral condyle (MAHC), and among them, 11 had OCD. The presence of fractures of the medial coronoid process was significantly and positively correlated with the presence of abnormalities of the MAHC (r = 0.40), but was negatively correlated with the presence of OCD (r = −0.32). At 95% specificity, median sensitivities to detect OCD were 57% for Cr15L-CdMO, 56% for CC, 10% for flexed ML, 7% for ML, and 4% for Di35M-PrLO views. The areas under the ROC curves were significantly larger for the Cr15L-CdMO and CC views than for the ML, flexed ML, and Di35M-PrLO views for the detection of OCD. Only the Cr15L-CdMO and CC views allowed accurate detection of OCD.
Conclusions and Clinical Relevance—In dogs with signs of elbow joint pain, the Cr15L-CdMO view is excellent and the CC view was good for detection of OCD.
Abstract
Objective—To assess the effect of computed tomography (CT) scan protocols (radiation amounts) and fabrication methods on biomodel accuracy and variability.
Sample—Cadaveric femur of a Basset Hound.
Procedures—Retroreconstructions (n = 158) were performed of 16 original scans and were visually inspected to select 17 scans to be used for biomodel fabrication. Biomodels of the 17 scans were made in triplicate by use of 3 freeform fabrication processes (stereolithography, fused deposition modeling, and 3-D printing) for 153 models. The biomodels and original bone were measured by use of a coordinate measurement machine.
Results—Differences among fabrication methods accounted for 2% to 29% of the total observed variation in inaccuracy and differences among method-specific radiation configurations accounted for 4% to 44%. Biomodels underestimated bone length and width and femoral head diameter and overestimated cortical thickness. There was no evidence of a linear association between thresholding adjustments and biomodel accuracy. Higher measured radiation dose led to a decrease in absolute relative error for biomodel diameter and for 4 of 8 cortical thickness measurements.
Conclusions and Clinical Relevance—The outside dimensions of biomodels have a clinically acceptable accuracy. The cortical thickness of biomodels may overestimate cortical thickness. Variability among biomodels was caused by model fabrication reproducibility and, to a lesser extent, by the radiation settings of the CT scan and differences among fabrication methods.
Abstract
Objective—To assess the impact of partial immersion in water on vertical ground reaction force (vGRF) and vGRF distribution in dogs.
Animals—10 healthy adult dogs.
Procedures—Weight placed on each limb of each dog was measured 3 times (1 scale/limb). Dogs were then immersed in water to the level of the tarsal, stifle, and hip joints, and vGRFs were measured. Coefficients of variation for triplicate measurements were calculated. Mixed-effects ANOVAs were used to compare the vGRF for thoracic versus pelvic limbs and the vGRF at various immersion levels as well as the vGRF distributions among limbs at various immersion levels.
Results—Mean ± SD vGRF before immersion was 249 ± 34 N. It was significantly decreased by 9% after immersion to the tarsal joints (227 ± 32 N), by 15% after immersion to the stifle joints (212 ± 21 N), and by 62% after immersion to the hip joints (96 ± 20 N). The vGRFs were significantly higher for the thoracic limbs than for the pelvic limbs before immersion and at all immersion levels. Dogs placed 64% of their weight on the thoracic limbs before immersion. That ratio did not differ significantly after immersion to the tarsus (64%) or stifle (63%) joints, but was significantly larger after immersion to the hip joints (71%).
Conclusions and Clinical Relevance—vGRF decreased as the depth of immersion increased. The thoracic limb-to-pelvic limb vGRF ratio was unchanged in dogs after immersion to the tarsal or stifle joints, but it increased after immersion to the hip joints.
