[Computed tomography based elbow joint morphology and incidence of elbow dysplasia in the red fox (Vulpes vulpes)]. / Computertomografische Morphologie des Ellbogengelenks und Vorkommen der Ellbogengelenkdysplasie beim Rotfuchs (Vulpes vulpes).

OBJECTIVE: Elbow dysplasia (ED) is a common developmental disease of the canine elbow joint and one of the most frequent causes of forelimb lameness in domestic dogs (Canis lupus familiaris). ED is predominantly present in medium to large breed dogs, but has also been described in mixed breed dogs and smaller breeds. In the literature, no information is available concerning the existence of ED in wildlife species. The purpose of the present study was to obtain an overview of the elbow joint anatomy of the red fox as well as to demonstrate the incidence of ED in red foxes. Knowledge regarding the elbow conformation in red foxes may help to understand the effect of anatomical difference onto the pathogenesis of developmental elbow disease. MATERIAL AND METHODS: A total 94 elbow joints of 49 red foxes (Vulpes vulpes) were evaluated using computed tomography (CT) and were compared to canine elbow joints. RESULTS: Apart from size differences and minor species-specific variations, the anatomy of the elbow joints of red foxes and domestic dogs proved to be very similar. In the red foxes, the rounded conformation of the medial coronoid process was shown to be present in 76 % of the individuals. Two elbow joints in 2 red foxes exhibited pathological changes of the medial coronoid process in the CT imaging. CONCLUSION: The prevalence of medial coronoid disease in red foxes amounted to 2.1 % in the presented population. This observation is comparable to the prevalence of elbow dysplasia in small breed dogs. The rounded conformation of the medial coronoid process was found in more than three-quarters of the examined red foxes. This leads to the hypothesis that this conformation of the medial coronoid process could be the original, physiological variant. Selective breeding for such a morphological feature may be an approach to reduce the frequency of canine elbow dysplasia. CLINICAL RELEVANCE: The significance of anatomical characteristics in the development of elbow dysplasia is still unknown. Therefore, research concerning the pathogenesis of medial coronoid disease should set its focus not only on elbow joint anatomy, but also on other influencing factors, such as biomechanics, genetics and environmental parameters.

Improved Computed Tomography Accuracy with a 1-mm versus 2- or 3-mm Slice Thickness for the Detection of Medial Coronoid Disease in Dogs.

OBJECTIVE: Computed tomography (CT) is used complementarily to radiography for the evaluation of medial coronoid disease (MCD). We hypothesized that a slice thickness > 2 mm would significantly affect the image quality and detection of fragmentation of the medial coronoid process. This study aimed to assess CT features indicating direct and indirect evidence of MCD in 168 CT studies with slice thicknesses of 1-, 2- and 3 mm. MATERIALS AND METHODS: The CT studies were blinded in terms of CT slice thickness and patient data and randomly assessed by two independent observers. All dogs underwent arthroscopic evaluation of the elbow joints. Both observers were unaware of the arthroscopic findings. RESULTS: Notably, blurring of the bone contour (p = 0.0001) was significantly influenced by slice thickness; here, a 1-mm thickness yielded a predominantly sharp and well-defined bone contour (observer 1, 91%; observer 2, 79%), whereas 2- (observer 1, 39.3%; observer 2, 56.3%) and especially 3-mm slice thicknesses yielded blurred margins with significantly reduced sharpness (observer 1, 0%; observer 2, 12.5%). The 1-mm slice thickness also yielded the highest fragment detection rate (observer 1, 55.4%; observer 2, 60.4%). Furthermore, the detection of fragment positions and of single fragments and fissures differed substantially with slice thickness. CLINICAL RELEVANCE: The findings of this study support the hypothesis that a CT slice thickness of ≥ 2 mm significantly affects fragment detection. In conclusion, a CT slice thickness of at least 1 mm is recommended for the assessment of MCD of the canine elbow.

Magnetic Resonance Imaging Assessment of Intra-Articular Structures in the Canine Stifle Joint after Implantation of a Titanium Tibial Plateau Levelling Osteotomy Plate.

OBJECTIVES: To determine the effectiveness of magnetic resonance imaging (MRI) in the evaluation of anatomical stifle structures with respect to implant positioning after tibial plateau levelling osteotomy (TPLO) using a titanium plate. METHODS: Selected sagittal and dorsal sequences of pre- and postoperative MRI (1.0 T scanner) of 13 paired (n = 26) sound cadaveric stifle joints were evaluated. The effect of susceptibility artifact on adjacent anatomical stifle structures was graded from 0 to 5. The impact of implant positioning regarding assessment score was calculated using Spearman's rank correlation coefficient. RESULTS: Sagittal turbo spin echo (TSE)-acquired images enabled interpretation of most soft tissue, osseous and cartilage structures without detrimental effect of susceptibility artifact distortions. In T2-weighted TSE images, the cranial cruciate ligament and caudal horn of the medial meniscus could be evaluated, independent of implant position, without any susceptibility artifact in all specimens. T2-weighted fast field echo, water selective, balanced fast field echo and short tau inversion recovery were most markedly affected by susceptibility artifact. CLINICAL SIGNIFICANCE: In selected TSE sequences, MRI allows evaluation of critical intra-articular structures after titanium TPLO plate implantation. Further investigations with confirmed stifle pathologies in dogs are required, to evaluate the accuracy of MRI after TPLO in clinical cases in this context.

Clinical, radiographic, and magnetic resonance imaging findings of gastrocnemius musculotendinopathy in various dog breeds.

OBJECTIVES: To describe clinical, radiographic, and magnetic resonance imaging (MRI) findings in 16 dogs diagnosed with gastrocnemius musculotendinopathy. METHODS: Retrospective evaluation of medical records, radiographs, and MRI results, as well as follow-up completed by telephone questionnaire. RESULTS: Most dogs had chronic hindlimb lameness with no history of trauma or athletic activities. Clinical examination revealed signs of pain on palpation without stifle joint instability. Seven dogs had radiographic signs of osteophyte formation on the lateral fabella. Magnetic resonance imaging revealed T2 hyperintensity and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. Changes were found in the lateral and medial heads of the gastrocnemius. Conservative treatment resulted in return to full function in 11 dogs. Two dogs showed partial restoration of normal function, one dog showed no improvement. Two dogs were lost to follow-up. CLINICAL SIGNIFICANCE: Gastrocnemius musculotendinopathy is a potential cause of chronic hindlimb lameness in medium to large breed dogs. A history of athletic activity must not necessarily be present. Magnetic resonance imaging shows signal changes and uptake of contrast agent in the region of the origin of the gastrocnemius muscle. A combination of T1 pre- and post-contrast administration and T2 weighted sequences completed by a fat-suppressed sequence in the sagittal plane are well-suited for diagnosis. Conservative treatment generally results in return to normal function.