Palpation and dorsal acetabular rim radiographic projection for early detection of canine hip dysplasia: a prospective study.

OBJECTIVE: To determine the value of 2 diagnostic methods: (1) the reduction angle (RA) using the Ortolani maneuver and (2) the dorsal acetabular slope (DAS) from the dorsal acetabular rim (DAR) radiographic projection, to predict osteoarthritis (OA) in dogs with hip dysplasia. STUDY DESIGN: Prospective study. SAMPLE POPULATION: Dogs (n = 73). METHODS: Hip-extended ventrodorsal (VD) radiographic projections, RA, and DAS were evaluated when dogs were 6, 12, and 24 months of age. VD projections were qualitatively scored for OA. RA was determined using the Ortolani maneuver in dorsal recumbency and DAS using the DAR projection. Distraction index (DI) measurements from the compression-distraction radiographic projections (PennHIP method) were also performed at 6 months of age. Statistical analyses were used to establish the range of values of normal and abnormal RA and DAS, to document the temporal variation in RA and DAS, to compare the ability of the different methods to predict coxofemoral OA, to determine the influence of pure passive laxity and of the DAS on the occurrence of an Ortolani sign and on the magnitude of the RA, to establish the relationship between the DAS and subsequent development of passive laxity and coxofemoral OA, and to evaluate the influence of the DAS and RA on the occurrence of coxofemoral OA with severe, moderate, and minimal coxofemoral passive joint laxity, respectively. RESULTS: VD, RA, DAS, and DI methods of coxofemoral joint evaluation correlated significantly with the status of the coxofemoral joints at 2 years of age. The risk of occurrence of coxofemoral OA increased, as the RA, DAS, or DI increased. There was a significant positive linear relationship between RA and DI (P = .015, r(2) = 0.32), RA and DAS (P = .0078, r(2) = 0.38), and DAS and DI (P = .015, r(2) = 0.33). A negative Ortolani sign was at all times significantly predictive of absence of coxofemoral OA at 2 years of age. DAS best predicted coxofemoral OA for DI ≥ 0.7, whereas RA best predicted coxofemoral OA for 0.3 < DI < 0.7; however, RA proved to be the best overall predictor of coxofemoral OA. CONCLUSION: RA measured at 6 months of age in dorsal recumbency was the best predictor of coxofemoral OA at 2 years of age.

Radiographic abnormalities in cats with feline bronchial disease and intra- and interobserver variability in radiographic interpretation: 40 cases (1999-2006).

OBJECTIVE: To determine prevalence of various radiographic signs in cats with feline bronchial disease (FBD) and evaluate intra- and interobserver variability in radiographic interpretation for examiners with variable degrees of experience in radiographic interpretation. DESIGN: Retrospective case series. ANIMALS: 40 cats with FBD and 40 control cats without thoracic disease. PROCEDURES: Radiographic abnormalities in cats with FBD were scored by consensus of 2 radiologists. Radiographs of control cats and cats with FBD were examined twice by 5 other individuals, and diagnostic accuracy and observer agreement were assessed. RESULTS: In cats with FBD, the most common radiographic signs were bronchial (n=37) and unstructured interstitial (30) lung patterns, lung hyperinflation (31) and hyperlucency (21), aerophagia (19), and lung soft tissue opacities (11). Ratios of lung inflation on ventrodorsal views were significantly higher in cats with FBD. For the 5 examiners, sensitivity ranged from 71% to 89% and specificity ranged from 43% to 74%. Intraobserver agreement was good (N=0.47 to 0.60), but the agreement between examiners was only poor to good (N=0.22 to 0.70). For most examiners, significant associations were found between examiner diagnosis (correct vs incorrect), level of examiner certainty, and bronchial pattern severity. CONCLUSIONS AND CLINICAL RELEVANCE: Findings suggested that several radiographic abnormalities can commonly be seen in cats with FBD but highlighted the limitations of thoracic radiography. Examiner diagnosis and level of confidence were significantly associated with severity of a bronchial pattern.

Radiographic detection of thoracic lesions in adult cows: a retrospective study of 42 cases (1995-2002).

Medical records of 42 cows that underwent both thoracic radiographic and postmortem examinations within a period of 7 days were reviewed to develop an evaluation grid to interpret bovine thoracic radiographs and to determine the sensitivity and the specificity of thoracic radiographs for detection of thoracic lesions, based on postmortem examination. Most cows (64%) had clinical signs of respiratory disease, whereas 19% showed signs of cardiac problems. The sensitivity and specificity of radiographs for identifying cows with thoracic lesions were 94% and 50%, respectively. In this study, with a prevalence of thoracic lesions of 86%, the positive- and negative-predictive values were 92% and 57%, respectively. This study provides an evaluation grid that allows standardization of the reading of bovine thoracic radiographs and the identification of most thoracic lesions. Bovine thoracic radiographs are useful in detecting thoracic lesions in cows.

Sensitivity and specificity of radiographic detection of canine elbow incongruence in an in vitro model.

Canine elbow incongruence is believed to be the consequence of underdevelopment of the radius. The purpose of this study is to determine the sensitivity and specificity of radiography to detect elbow incongruence in an in vitro model and to assess the optimal elbow angle and radiographic beam position. Five normal cadaveric canine left forelimbs were used. A four-pin, type 1 external fixator with a linear motor side bar was fixed to the cranial part of the radius of each limb and a 1 cm segment of bone was removed from the mid-diaphysis to allow radial shortening. Each elbow was subjected to the same protocol. They were radiographed at two different angles (90 degrees and 135 degrees) of flexion, with 10 different radiographic beam positions (centered on the humeral condyle, 3 cm cranial, 3 cm caudal, 3 cm distal, 3 cm proximal, 3 cm cranio-proximal, 3 cm cranio-distal, 3 cm caudo-proximal, 3 cm caudo-distal and on the shoulder joint) and at four different level of radial shortening (0, 1, 2 and 3 mm). In addition, a radiographic view centered on the elbows flexed at 135 degrees was made after simulating weight bearing. The acquired digital images were independently evaluated by three evaluators unaware of the elbows status. The elbows were judged normal, incongruent or borderline based on specific criteria. The sensitivity for detection of elbow incongruence at and beyond 2 mm was excellent at 90 degrees (median = 100% for all views) and good at 135 degrees (median = 80%) of flexion with no difference between examiners. The sensitivity at 1 mm of incongruence was unchanged at 135 degrees but was reduced at 90 degrees of flexion (median = 60%) with a significant difference between the evaluators. The specificity was significantly different between the evaluators and ranged from 70% to 90% at 90 degrees of flexion and from 50% to 80% at 135 degrees. The lowest specificities at 90 degrees were obtained with the proximal displacements of the X-ray beam. Simulating weight bearing significantly decreased the sensitivity at 1 mm (from 80% to 50%) and 3 mm (from 100% to 80%) of incongruence and slightly increased the specificity (from 55% to 65%). Radiography is a sensitive and specific test to detect moderate-to-severe radio-ulnar incongruence (2 mm and over) if the elbow is flexed at a 90 degrees angle regardless of the radiographic beam position. Finally, canine elbow incongruence appeared reduced after an in vitro weight-bearing simulation.

Comparison of multistage versus one-stage destabilization of a type II external fixator used to stabilize an oblique tibial osteotomy in dogs.

OBJECTIVE: To compare the biomechanical effects of multistage versus one-stage destabilization of a type II external skeletal fixator (ESF) used to stabilize an oblique unstable tibial osteotomy in dogs. STUDY DESIGN: In vitro, in vivo, and ex vivo experimental study. ANIMAL POPULATION: Twelve healthy adult dogs. METHODS: The biomechanical characteristics of the type II ESF used in this study were determined. This fixator was applied to both tibiae of two groups of 6 dogs to stabilize a 2-mm-wide oblique osteotomy. One fixator on each dog remained unchanged throughout the 11-week study (control group). The fixator on the opposite limb was destabilized late and acutely in one group of dogs (single-stage) and early and progressively in the other (multistage). Clinical examination, radiographic examination, and force-plate analysis were used to evaluate the results. All dogs were euthanatized at 11 weeks. All tibiae were scanned to determine the cross-sectional area of the callus in the center of the osteotomy and subjected to biomechanical tests to determine mean pull-out strength of pins and callus strength and stiffness. RESULTS: Stiffness of the type II ESF used in this study was 578 N/mm in axial compression, 0.767 Nm/deg in torsion, 261 N/mm in medio-lateral bending, and 25 N/mm in cranio-caudal bending. Peak vertical forces of the hindlimbs were significantly lower at 2.5 and 5 weeks than before surgery. Peak vertical forces of the hindlimbs did not change before and after destabilization. No significant differences could be detected between the two destabilization sequences or between all control tibiae and pooled destabilized tibiae with regards to radiographic evaluation of the healing osteotomy, cross-sectional periosteal callus area, mean pull-out strength of transfixation pins, callus strength, and callus stiffness. CONCLUSIONS AND CLINICAL RELEVANCE: Bone healing of unstable osteotomies stabilized with a type II ESF is not significantly enhanced by staged destabilization of the fixation as performed in this study.