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ObjectiveTo compare osteoarthritis scores assigned through radiographic evaluation of 18 anatomic regions in the elbow joint with scores assigned through evaluation of 3-D maximum intensity projection (MIP), 3-D surface rendering (TSR), and multiplanar reconstructed (MPR) CT images, and to evaluate intraobserver and interobserver agreement of radiographic and CT scoring.SampleRadiographic and CT images of 39 elbow joints in 20 dogs.ProceduresImages were anonymized and graded independently by 5 observers. One observer graded 12 elbow joints 3 times. Intraobserver consistency and repeatability, interobserver agreement, consistency among methods, and bias between methods were calculated.ResultsThe most severe changes were observed at the proximal aspect of the anconeal process, and the medial and cranial aspects of the medial coronoid process. Intraobserver consistency was moderate or better for 11/16 regions with MIP images, 11/16 regions with TSR images, 17/18 regions with MPR images, and 14/18 regions with radiographic images. Interobserver agreement was moderate or better for 5/16 regions with MIP images, 9/16 regions with TSR images, 12/18 regions with MPR images, and 6/18 regions with radiographic images. Mean scores from CT-based methods were higher than mean radiographic scores.Clinical relevanceAssessments of osteoarthritis severity in the elbow joints of dogs obtained by examining radiographic images were generally consistent with assessments obtained by examining CT scans. MPR scores were more consistent and more comparable to radiographic scores than were MIP or TSR scores.

ObjectiveTo evaluate the diagnostic value of still images of needle arthroscopy (SNAR), still images of traditional arthroscopy (STAR), and computed tomography (CT) to diagnose medial coronoid process (MCP) pathology.Study designProspective clinical trial.AnimalsDogs (n = 17) presented for evaluation of elbow dysplasia.MethodsFor each case, two SNAR and STAR images of the MCP were reviewed independently and in random order by three board-certified surgeons. Computed tomographic images were reviewed by one board-certified radiologist. Reviewers were blinded to surgical and clinical findings. Surgical findings from real-time TAR with palpation were used as the gold standard. Receiver operating characteristic (ROC) curves and concordance statistics tests for the diagnostic accuracy of MCP fissure, MCP fragment, medial compartment condition, and cartilage score were calculated.ResultsImages of 27 elbows joints were reviewed. For MCP fissure detection, areas under the ROC curves for CT (0.84), STAR (0.73), and SNAR (0.57) did not differ. For the detection of MCP fragment, STAR had a larger area under the ROC curve (0.93) compared with SNAR (0.74, P = .015) and CT (0.54, P

ObjectiveTo describe methods to measure the 3-D orientation of the proximal, diaphyseal, and distal segments of the canine radius by use of computer-aided design software (CADS) and to compare the repeatability and reliability of measurements derived by those methods.Sample31 canine radii with biapical deformities and 24 clinically normal (control) canine radii.ProceduresSelect CT scans of radii were imported into a CADS program. Cartesian coordinate systems for the humerus and proximal, diaphyseal, and distal radial segments were developed. The orientation of each radial segment in the frontal, sagittal, and transverse planes was measured in triplicate by 3 methods. The repeatability and reliability of those measurements were calculated and compared among the 3 measurement methods.ResultsThe mean ± SD within-subject repeatability of radial angular measurements for all 3 methods was 1.40 ± 0.67° in the frontal plane, 3.17 ± 2.21° in the sagittal plane, and 3.01 ± 1.11° in the transverse plane for control radii and 2.56 ± 1.95° in the frontal plane, 3.59 ± 2.39° in the sagittal plane, and 3.47 ± 1.19° in the transverse plane for abnormal radii. Mean ± SD bias between radial measurement methods was 1.88 ± 2.07° in the frontal plane, 6.44 ± 6.80° in the sagittal plane, and 2.27 ± 2.81° in the transverse plane.Conclusions and clinical relevanceResults indicated that use of CADS to assess the 3-D orientation of the proximal, diaphyseal, and distal segments of normal and abnormal canine radii yielded highly repeatable and reliable measurements.

ObjectiveTo assess the accuracy of three-dimensionally (3-D) printed drill guides in constraining the trajectory of drill tracts for implants in canine thoracic vertebrae.Study designExperimental ex vivo study.Sample populationFive canine thoracic vertebral column specimens.MethodsGuides to constrain drill trajectories were designed on the basis of computed tomographic (CT) imaging of six thoracic vertebrae (T8-T13) and were 3-D printed. The guides were used to create drill tracts in these vertebrae by both an experienced and a novice surgeon, and CT imaging was repeated. The entry point and angulation of actual and planned drill tracts were compared for both surgeons. Unintended cortical violations were also assessed by using a modified Zdichavsky classification.ResultsFifty-eight drill tracts were created in 30 vertebrae. Mean entry point deviation was 1.4 mm (range, 0.4-3.4), and mean angular deviation was 5.1° (range, 1.5°-10.8°). There were no differences between surgeons in entry point deviation (P = .07) or angular deviation (P = .22). There were no unintended cortical bone violations, and all drill tracts were classified as modified Zdichavsky grade I.ConclusionThe 3-D printed guides used in the current study yielded drill tracts with small linear and angular errors from intended paths and 100% accuracy for placement within vertebral pedicles and bodies. This technique was conveniently used by both an experienced and a novice surgeon.Clinical significanceThis technique might be immediately applicable to clinical cases requiring thoracic vertebral stabilization and may allow safe and accurate implant placement for surgeons with varying experience levels.

OBJECTIVE To assess 3-D geometry of the humerus of dogs and determine whether the craniocaudal canal flare index (CFI) is associated with specific geometric features. SAMPLE CT images (n = 40) and radiographs (38) for 2 groups of skeletally mature nonchondrodystrophic dogs. PROCEDURES General dimensions (length, CFI, cortical thickness, and humeral head offset), curvature (shaft, humeral head, and glenoid cavity), version (humeral head and greater tubercle), and torsion were evaluated on CT images. Dogs were allocated into 3 groups on the basis of the craniocaudal CFI, and results were compared among these 3 groups. The CT measurements were compared with radiographic measurements obtained for another group of dogs. RESULTS Mean ± SD humeral head version was -75.9 ± 9.6° (range, -100.7° to -59.4°). Mean mechanical lateral distal humeral angle, mechanical caudal proximal humeral angle, and mechanical cranial distal humeral angle were 89.5 ± 3.5°, 50.2 ± 4.5°, and 72.9 ± 7.8°, respectively, and did not differ from corresponding radiographic measurements. Mean humeral curvature was 20.4 ± 4.4° (range, 9.6° to 30.5°). Mean craniocaudal CFI was 1.74 ± 0.18 (range, 1.37 to 2.10). Dogs with a high craniocaudal CFI had thicker cranial and medial cortices than dogs with a low craniocaudal CFI. Increased body weight was associated with a lower craniocaudal CFI. Radiographic and CT measurements of craniocaudal CFI and curvature differed significantly. CONCLUSIONS AND CLINICAL RELEVANCE CT-based 3-D reconstructions allowed the assessment of shaft angulation, torsion, and CFI. Radiographic and CT measurements of shaft curvature and CFI may differ.

OBJECTIVE: To evaluate accuracy of articular surfaces determined by use of 2 perpendicular CT orientations, micro-CT, and laser scanning. SAMPLE: 23 cat cadavers. PROCEDURES: Images of antebrachia were obtained by use of CT (voxel size, 0.6 mm) in longitudinal orientation (CTLO images) and transverse orientation (CTTO images) and by use of micro-CT (voxel size, 0.024 mm) in a longitudinal orientation. Images were reconstructed. Craniocaudal and mediolateral length, radius of curvature, and deviation of the articular surface of the distal portion of the radius of 3-D renderings for CTLO, CTTO, and micro-CT images were compared with results of 3-D renderings acquired with a laser scanner (resolution, 0.025 mm). RESULTS: Measurement of CTLO and CTTO images overestimated craniocaudal and mediolateral length of the articular surface by 4% to 10%. Measurement of micro-CT images underestimated craniocaudal and mediolateral length by 1%. Measurement of CTLO and CT to images underestimated mediolateral radius of curvature by 15% and overestimated craniocaudal radius of curvature by > 100%; use of micro-CT images underestimated them by 3% and 5%, respectively. Mean ± SD surface deviation was 0.26 ± 0.09 mm for CTLO images, 0.30 ± 0.28 mm for CT to images, and 0.04 ± 0.02 mm for micro-CT images. CONCLUSIONS AND CLINICAL RELEVANCE: Articular surface models derived from CT images had dimensional errors that approximately matched the voxel size. Thus, CT cannot be used to plan conforming arthroplasties in small joints and could lack precision when used to plan the correction of a limb deformity or repair of a fracture. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a three-dimensional (3D) quasi-static rigid body canine pelvic limb computer model simulating a cranial cruciate ligament (CrCL) intact and CrCL-deficient stifle during walking stance to describe stifle biomechanics. The model was based on a five-year-old neutered male Golden Retriever (33 kg) with no orthopedic or neurologic disease. Skeletal geometry and ligament anatomy determined from computed tomography (CT), optimized muscle forces, motion capture kinematics, and force platform ground reaction forces were used to develop the model. Ligament loads, tibial translation, tibial rotation, and femoromeniscal contact forces were compared across the intact and CrCL-deficient stifle. The CrCL was found to be the primary intact stifle load-bearing ligament, and the caudal cruciate ligament was the primary CrCL-deficient stifle load-bearing ligament. Normalized tibial translation and rotation were 0.61 mm/kg and 0.14 degrees/kg, respectively. Our model confirmed that the CrCL stabilizes the intact stifle and limits tibial translation and rotation. Model verification was confirmed through agreement with experimentally measured kinematics and previous in vivo, in vitro, and mathematical model studies. Parametric analysis indicated outcome measure sensitivity to ligament pre-strain. Computer modeling could be useful to further investigate stifle biomechanics associated with surgical stabilization techniques. [ABSTRACT FROM AUTHOR]

Objective To report femoral nerve dysfunction caused by focal iliopsoas muscle injury and treated by performing tenectomy of the muscle insertion. Study Design Case report. Animals A 4-year-old, castrated male, English Mastiff. Results Iliopsoas muscle injury caused femoral nerve deficits and severe pain. Focal injury was not detected by ultrasonography or computed tomography but was visible on magnetic resonance (MRI) images. Tenectomy of the insertion of the iliopsoas muscle relieved signs of pain. Conclusions Femoral nerve dysfunction may occur with iliopsoas muscle injury. Clinical Relevance Iliopsoas muscle injury should be considered in patients with hip pain and MRI is a useful test for diagnosis. Tenectomy may be indicated for relief of chronic iliopsoas muscle pain. [ABSTRACT FROM AUTHOR]