COMPARISON BETWEEN SHOULDER COMPUTED TOMOGRAPHY AND CLINICAL FINDINGS IN 89 DOGS PRESENTED FOR THORACIC LIMB LAMENESS

Pathological calcification in canine tendon-derived cells is modulated by extracellular ATP

Tendon calcification is a commonly associated with degenerative tendinopathy of the Achilles tendons in dogs. It is characterised by the formation of calcific deposits and is refractory to treatment, often re-forming after surgical removal. Little is known about its pathogenesis and therefore the aims of this study were to develop an in vitro model of canine tendon calcification and use this model to investigate mechanisms driving calcification. Cells from the canine Achilles tendon were cultured with different calcifying media to establish which conditions were best able to induce specific, cell-mediated calcification. Once optimum calcification conditions had been established, the effect of ATP treatment on calcification was assessed. Results revealed that 2 mM di-sodium phosphate combined with 2 mM calcium chloride provided the optimum calcifying conditions, increasing calcium deposition and expression of osteogenic-related genes similar to those observed in tendon calcification in vivo. ATP treatment inhibited calcification in a dose-dependent manner, reducing calcium deposition and increasing cell viability, while osteogenic-related genes were no longer upregulated. In conclusion, the in vitro model of canine tendon calcification developed in this study provides the ability to study mechanisms driving tendon calcification, demonstrating that ATP plays a role in modulating tendon calcification that should be explored further in future studies.

Orthopedic Imaging: A Practical Clinical Guide

Many imaging options are available to the practitioner both in-house and on a referral basis to help make a definitive diagnosis for orthopedic injuries. To guide treatment, a complete understanding of the nature and extent of the injury is ideal. While a thorough orthopedic physical examination is the first step, a complete diagnostic work-up will include at least one and often more than one imaging modality. The goal of this article is to discuss the imaging options for some of the more common orthopedic issues encountered in dogs to help guide the practitioner through the selection of which should be considered to accomplish a diagnosis.

Prevalence of mineralisation of the tendon of the supraspinatus muscle in non-lame dogs

OBJECTIVES

Mineralisation of the tendon of the supraspinatus muscle has been reported as a common finding in dogs with thoracic limb lameness. It is not clear if the mineralisation is a clinically significant cause, or a secondary effect, of lameness. The aim of this retrospective study was to determine the prevalence of mineralisation of the tendon of the supraspinatus muscle in dogs presented to the clinic for reasons other than lameness and where lameness was not evident at the time of presentation.

MATERIALS AND METHODS

Dogs undergoing CT of the thorax were identified from the clinical records. The dogs selected were those presented for clinical issues other than lameness and with no history of lameness. The CT scans were screened to identify the presence or otherwise of supraspinatus mineralisation. Signalment was recorded on all the cases.

RESULTS

Supraspinatus mineralisation was detected in four out of 99 dogs (4%) with all four cases found in male dogs. Medium to large breed dogs were most frequently affected, with a mean age of 9 years. Unilateral mineralisation of the left thoracic limb only was identified.

CLINICAL SIGNIFICANCE

The prevalence of supraspinatus mineralisation was low in this population of non-lame dogs. This low level when compared to the higher prevalence level found in lame dogs, suggests that supraspinatus mineralisation could be associated with lameness in dogs either as an indirect result of lameness or as a primary cause.

Computed tomographic arthrography is a useful adjunct to survey computed tomography and arthroscopic evaluation of the canine shoulder joint

The aim of this retrospective, methods comparison study was to assess the diagnostic utility of computed tomographic arthrography in the assessment of various intraarticular shoulder pathologies in dogs in comparison with survey computed tomography (CT), using arthroscopic examination as the reference standard. Computed tomography, computed tomographic arthrography, and arthroscopic findings of 46 scapulohumeral joints of dogs with forelimb lameness were reviewed retrospectively. Predefined sites were assessed for the presence or absence of disease. If a lesion was present, a prespecified pathology was designated. Computed tomographic arthrography was found to be a safe technique which provided a superior diagnostic efficacy relative to survey CT for the assessment of the biceps tendon and biceps tendon sheath (sensitivity 71%, specificity 75%, positive likelihood ratio 2.9, negative likelihood ratio 0.38) and humeral head cartilage (sensitivity 65%, specificity 97%, positive likelihood ratio 19, negative likelihood ratio 0.37). Computed tomography and computed tomographic arthrography provided additional diagnostic information to arthroscopy in regard to osteophytosis, subchondral defects, and joint mice. Computed tomographic arthrography alone was of limited diagnostic value for assessment of the medial and lateral glenohumeral ligaments (sensitivity 13% and 0%, specificity 1% and 78%, positive likelihood ratios unmeasurable and 0, negative likelihood ratios 0.88 and 1.29, respectively) and the subscapularis tendon (sensitivity 14%, specificity 98%, positive likelihood ratio 5.7, negative likelihood ratio 0.88). Computed tomographic arthrography is therefore a useful adjunct to survey CT and arthroscopic evaluation of the canine shoulder joint, however, is not a replacement for these techniques.

Pathology of Gray Wolf Shoulders: Lessons in Species and Aging

We examined scapula glenoids (n = 14) and proximal articular humeri (n = 14) of seven gray wolves that were maintained in a sanctuary park setting. Immediately after death, observations were made visually in situ and by radiography. Further observations were made in a museum laboratory setting, prior to and following clearing of soft tissues. Selected dry bone specimens were evaluated using computed tomography. Significant cartilage erosion and osteoarthropathy were identified in all shoulder joints. No single evaluation method yielded maximal information. Plain film radiography revealed only more severe changes. Computed tomography yielded more detail and clarity than standard radiography. Direct examination of articular cartilage informed about joint soft tissue, and dry bone informed about externally visible bone pathology. These data provide a basis for biological, biomedical, ecological, and archaeological scientists to improve retrospective interpretations of bone lesions. They further support developing plausible differential diagnoses for features of ancient and modern animal bones. We noted a dog‐like capacity for wolf longevity in a non‐free‐roaming environment. However, aged wolves' life spans far exceeded those of similar‐sized domestic dogs and breeds, suggesting the possibility of an important species difference that should be explored. We suggest also a hypothesis that the driving force for joint pathology in sheltered non‐domestic species may relate significantly to achieving the longevity that is possible biologically, but is uncommon in the wild because of differential stochastic influences. Anat Rec, 299:1338–1347, 2016. © 2016 Wiley Periodicals, Inc.

Tendon Volume Determination on Magnetic Resonance Imaging of Supraspinatus Tendinopathy

OBJECTIVE

To determine the supraspinatus tendon volume using magnetic resonance imaging (MRI) in dogs with non-calcified supraspinatus tendinopathy (NCST), in dogs with orthopedic disease other than NCST, and in healthy dogs.

STUDY DESIGN

Case series.

ANIMALS

Twenty-two dogs (18 client-owned dogs; 4 purpose-bred dogs).

METHODS

Dogs undergoing shoulder MRI were categorized as NCST if they were diagnosed with NCST only, had histologic confirmed diagnosis, underwent surgical treatment, and were available for follow-up longer than 4 months. Dogs with MRI performed for a forelimb lameness because of a diagnosis other than NCST were categorized as orthopedic control (OC). Healthy dogs from an unrelated study were categorized as healthy controls (HC). Tendon volume was determined from MRI using public domain software and compared across categories.

RESULTS

The study included 9 NCST dogs, 9 OC dogs, and 4 HC dogs. The median tendon volume for NCST was 1,323 mm(3), OC was 630 mm(3), and HC was 512 mm(3). The volume was significantly higher in the NCST than OC (P = .0012) and HC (P = .003). There was no difference between OC and HC (P = .76).

CONCLUSION

Dogs diagnosed with NCST had higher supraspinatus tendon volumes compared to dogs with other orthopedic disorders and healthy dogs.