Variation of actin filament length in dogs.

As the smallest functional unit of force production, the sarcomeres are important in determining muscle function. Actin filament lengths, which are important in determining optimal sarcomere length for a species, have not yet been reported in dogs. This study aims to provide a species-specific value for actin filament length in dogs, while examining intraspecies, intermuscular and intramuscular variations. Muscle samples were taken from the tibialis anterior muscle, the lateral gastrocnemius muscle head and the medial gastrocnemius muscle head in 10 dogs including a Labrador, a Belgian Malinois, a Caucasian Shepherd, German Shepherds and some mixed-breed dogs. Actin filament lengths were determined through transmission electron microscopy. Mean actin filament length across all muscle samples was 0.90 ± 0.01 µm. The low intraspecies variation, combined with a lack of important inter- and intramuscular variation found in this study, affirms the use of a species-specific optimal sarcomere length of 1.89 µm for canine muscles.

Musculotendon excursion potential, tendon slack and muscle fibre length: the interaction of the canine gastrocnemius muscle and tendon.

Although the form-function relation of muscles and tendons has been studied extensively, little in vivo data exist on the musculotendon properties of the gastrocnemius complex in dogs. Using a combination of ultrasound and 3D motion tracking, musculotendon parameters were obtained in vivo from the lateral gastrocnemius muscle and the gastrocnemius tendon in nine healthy Labrador Retrievers. These parameters include musculotendon length and excursion potential, tendon slack length, muscle belly length, muscle fibre length, pennation angle and architectural index. This study also examined the variation of muscle and tendon length contributions to musculotendon length, as well as the relation between musculotendon excursion potential and muscle fibre length or tendon length. To facilitate comparison between dog breeds, the femur length as a potential scaling parameter was examined. In the Labrador gastrocnemius musculotendon complex, the tendon contributes 41% (± 9%) of musculotendon length. In longer musculotendon complexes, the contribution of the muscle belly increases while the tendon contribution decreases. Longer muscle belly and musculotendon complexes were, however, associated with shorter muscle fibres. No significant relations were found between musculotendon excursion potential and muscle fibre length or tendon slack length, and femur length did not prove to be a reliable scale factor for the length-related musculotendon parameters examined in this study. Longer musculotendon complexes exhibit relatively longer muscle bellies, which are in turn associated with shorter muscle fibre lengths. This trade-off between gastrocnemius muscle belly length and muscle fibre length might have the advantage that muscle volume stays constant regardless of the length of the limbs.

A prospective follow up of age related changes in the subchondral bone density of the talus of healthy Labrador Retrievers.

BACKGROUND: During growth, the skeletal structures adapt to the increased loading conditions and mature to a fully-grown skeleton. Subchondral bone density reflects the effect of long-term joint loading and it is expected to change over time. The aim of this study was to describe the long-term changes in the density distribution of the subchondral bone of the talus of healthy Labrador Retrievers in a prospective study. RESULTS: The subchondral bone density distribution was evaluated using computed tomographic osteoabsorptiometry (CTOAM). Visually, all joints showed very similar density distribution patterns. No significant differences in the topography of the density maxima were found between t1 and t2. The mean density, maximum density, and maximum area ratio (MAR) were significantly increased with increasing age. CONCLUSIONS: The subchondral bone density of the talus of healthy Labrador Retrievers increases with increasing age. It is likely an adaptive response of the subchondral bone due to increased joint loading during growth.

The Influence of the Size, Age and Sex on the Computed Tomographic Measured Size of the Pituitary Gland in Normal Horses.

The objective of this study was to examine the influence of the size, age and sex of the horse on the size of the pituitary gland and determine the possibility of using the pituitary gland height-to-brain area ratio (P:B ratio) to allow comparison of different sized and aged horses. Thirty-two horses without pituitary pars inter-media dysfunction that underwent a contrast-enhanced computed tomographic (CT) examination were included in a cross-sectional study. On the CT images, the pituitary gland height was measured and the P:B ratio was calculated. These measurements were correlated to the size, age and sex of the horses. The pituitary gland height was significantly associated with the size (P < 0.001) and the age (P < 0.001), but not with the sex (P = 0.40), of the horses. No significant association was found between the P:B ratio and the size (P = 0.25), the age (P = 0.06) or the sex (P = 0.25) of the horses. In conclusion, the pituitary gland size varies between different sized and aged horses. The use of the P:B ratio is a valuable metric for making comparisons between the pituitary glands of these horses.

Bone density of elbow joints in Labrador retrievers and Golden retrievers: Comparison of healthy joints and joints with medial coronoid disease.

The aims of this study were: (1) to determine the inter-observer repeatability of particular regions of the canine elbow joints; (2) to assess the effect of age, bodyweight and breed on bone density in healthy young dogs; (3) to compare Hounsfield units (HU) and bone density (BD) measurements between normal elbow joints and diseased elbow joints; and (4) to determine the sensitivity and specificity for HU and BD measurements in specific regions in the canine elbow joint. Regions with the highest repeatability were located at the medial coronoid process (MCP) base and apex, and at the level of the humerus, on the sagittal and sagittal oblique planes of the elbow joint. Age and breed were significantly associated with several regions of interest; conversely, none of the measurements were associated with bodyweight. Increased HU and BD values in the MCP base and apex regions are likely to be related to medial coronoid disease. Labrador retrievers had higher HU and BD values than Golden retrievers and an increase in BD was found in older animals. Cut-offs determined with receiver operating characteristic plots of the MCP base and apex suggested fairly good sensitivity and specificity (base: area under the curve 0.85, sensitivity 75.0%, specificity 88.8%; apex: area under the curve 0.89, sensitivity 80.0%, specificity 92.5%).

Subchondral bone density distribution of the talus in clinically normal Labrador Retrievers.

BACKGROUND: Bones continually adapt their morphology to their load bearing function. At the level of the subchondral bone, the density distribution is highly correlated with the loading distribution of the joint. Therefore, subchondral bone density distribution can be used to study joint biomechanics non-invasively. In addition physiological and pathological joint loading is an important aspect of orthopaedic disease, and research focusing on joint biomechanics will benefit veterinary orthopaedics. This study was conducted to evaluate density distribution in the subchondral bone of the canine talus, as a parameter reflecting the long-term joint loading in the tarsocrural joint. RESULTS: Two main density maxima were found, one proximally on the medial trochlear ridge and one distally on the lateral trochlear ridge. All joints showed very similar density distribution patterns and no significant differences were found in the localisation of the density maxima between left and right limbs and between dogs. CONCLUSIONS: Based on the density distribution the lateral trochlear ridge is most likely subjected to highest loads within the tarsocrural joint. The joint loading distribution is very similar between dogs of the same breed. In addition, the joint loading distribution supports previous suggestions of the important role of biomechanics in the development of OC lesions in the tarsus. Important benefits of computed tomographic osteoabsorptiometry (CTOAM), i.e. the possibility of in vivo imaging and temporal evaluation, make this technique a valuable addition to the field of veterinary orthopaedic research.

Assessment of medial coronoid disease in 180 canine lame elbow joints: a sensitivity and specificity comparison of radiographic, computed tomographic and arthroscopic findings.

BACKGROUND: Diagnostic imaging is essential to assess the lame patient; lesions of the elbow joint have traditionally been evaluated radiographically, however computed tomography (CT) has been suggested as a useful technique to diagnose various elbow pathologies. The primary objective of this study was to determine the sensitivity and specificity of CT to assess medial coronoid disease (MCD), using arthroscopy as gold standard. The secondary objective was to ascertain the radiographic sensitivity and specificity for MCD compared with CT. METHODS: For this study 180 elbow joints were assessed, of which 141 had been examined with radiography, CT and arthroscopy; and 39 joints, had radiographic and CT assessment. Sensitivity and specificity were calculated for CT and radiographic findings using available statistical software. RESULTS: Sensitivity and specificity of CT using arthroscopy as gold standard resulted in high values for sensitivity (100 %) and specificity (93 %) for the assessment of MCD. For the radiographic evaluation, a sensitivity of 98 % and specificity of 64 - 69 % using CT as the technique of reference, were found. DISCUSSION: These results suggest that in case of doubt during radiographic assessment, CT could be used as a non-invasive technique to assess the presence of MCD. CONCLUSION: Based on the high sensitivity and specificity obtained in this study it has been considered that CT, rather than arthroscopy, is the preferred noninvasive technique to assess MCD lesions of the canine elbow joint.

Low-Field Magnetic Resonance Imaging and Multislice Computed Tomography for the Detection of Cervical Syringomyelia in Dogs.

BACKGROUND: Syringomyelia (SM) is defined as the presence of fluid-containing cavities within the parenchyma of the spinal cord. Sagittal magnetic resonance (MR) images have been described as the preferred technique for visualizing SM in dogs and humans. OBJECTIVE: To investigate whether computed tomography (CT) can be used to diagnose SM. ANIMALS: Thirty-two client-owned dogs referred for investigation of the cervical spine on magnetic resonance imaging (MRI) and CT. METHODS: Two reviewers retrospectively analyzed sagittal and transverse T1-weighted spin echo (T1WSE) MR images and CT images from each dog for the presence of SM and, if SM was present, the width (mm, syrinx width [SW]) was measured. The results were analyzed statistically. RESULTS: For the presence of SM there was a moderate interobserver agreement for MR (81%, κ = 0.54) and almost perfect agreement for CT (94%, κ = 0.87). There was a moderate intramodality agreement for both observers (observer 1 81%, κ = 0.59; observer 2 81%, κ = 0.57). For measurement of SW the repeatability was the best on the midsagittal T1WSE images (95% repeatability coefficient <0.52 mm) and the reproducibility was the best on midsagittal images in both modalities (95% limits of agreement -0.55-0.45; P = 0.002). CONCLUSION AND CLINICAL IMPORTANCE: Both techniques can be used to detect SM. Midsagittal MR and CT images are best used for measuring SW. Computed tomography can be used as a diagnostic tool for SM when MRI is not available, but CT cannot replace MRI as the standard screening technique for the detection of SM in Cavalier King Charles Spaniel for breeding purposes.

Low-field MRI and multislice CT for the detection of cerebellar (foramen magnum) herniation in Cavalier King Charles Spaniels.

BACKGROUND: Cavalier King Charles Spaniels (CKCS) have a high prevalence of Chiari-like malformation (CM). Herniation of the cerebellum into the foramen magnum is a key diagnostic feature for CM. Midsagittal MR images are the preferred technique for visualizing cerebellar herniation (CH). OBJECTIVE: To investigate whether CT can be used to diagnose CH. ANIMALS: Fifteen client-owned CKCS dogs referred for investigation of the brain and cranial cervical spine on MRI and CT. METHODS: Two reviewers retrospectively analyzed midsagittal T1WSE and T2WSE MR images and midsagittal pre- and postcontrast 2D multiplanar reformatted CT images from each dog for the presence of CH. And, if present, the length (mm, CHL) of the herniation was measured. The results were analyzed statistically. RESULTS: There was no significant difference between the different observers and techniques for the detection of CH and measurement of CHL. Overall, the CHL was longer on the CT images. CONCLUSION AND CLINICAL IMPORTANCE: Both techniques are useful for detecting CH and measuring CHL. Because CHL does not have a known direct impact on the clinical presentation of CM, CT can be used as a diagnostic tool in a routine clinical practice for CM in CKCS when MRI is not available. We emphasize that MRI is the standard screening technique in CKCS for breeding purposes to detect the presence of CM and SM and, at the current time, CT cannot replace MRI.

Diagnostic imaging and endoscopic finding in dogs and cats with gastric tumors: a review.

Medical imaging is an essential part of the diagnostic workup of many gastrointestinal disorders. This paper reviews imaging and endoscopy of gastric tumors in dogs and cats and the techniques used. The appearance of the normal as well as the various aspects of gastric tumors are described for these different modalities. Plain radiography is widely available but has limited diagnostic value. Contrast radiography has higher sensitivity but is laborious and time-consuming. Ultrasonography (if an adequate acoustic window is available), endosonography and endoscopy are the most appropriate modalities for diagnosing gastric tumors. They are especially useful when obtaining samples for cytologic or histopathologic examination, because the imaging modalities do not always differentiate between inflammatory or infectious conditions and neoplastic disorders. Hydro-helical CT was found helpful for evaluating the location and local invasiveness of the lesion. Ultrasonography and endoscopy are useful modalities for taking adequate biopsies.

L'imagerie diagnostique est un élément important du diagnostic de nombreuses affections gastro-intestinales. Cet article donne un aperçu des diverses techniques d'imagerie qui peuvent être utilisées pour identifier des tumeurs gastriques chez le chien et le chat. On décrit aussi bien les aspects physiologiques que les altérations pathologiques. Des clichés radiographiques sont en général facilement disponibles, ils n'ont toutefois qu'une valeur diagnostique limitée. Les études utilisant des moyens de contraste ont une meilleure valeur diagnostique mais nécessitent du temps et de travail. L'échographie (pour autant qu'on dispose d'une fenêtre acoustique adéquate), l'endosonographie et l'endoscopie sont les techniques diagnostiques les plus sûres pour identifier les tumeurs gastriques. Comme les techniques d'imagerie ne permettent pas toujours de différencier entre inflammation et tumeur, elles sont particulièrement utiles pour prélever des échantillons pour la cytologie ou l'histopathologie. Le scanner hydro-hélical est utile pour définir la localisation et l'extension d'une lésion, alors que l'échographie et l'endoscopie servent avant tout à effectuer des biopsies adéquates.

The effects of positioning, reason for screening and the referring veterinarian on prevalence estimates of canine hip dysplasia.

Although the prevalence of canine hip dysplasia (HD) has been the subject of a number of published studies, estimates vary widely. This study evaluated several possible causes for these differences. Sixty Belgian, Dutch and German veterinarians were asked to submit all hip radiographs obtained for screening purposes (irrespective of HD status) over a 2-year period, resulting in a database of 583 dogs. Each set of radiographs was accompanied by information on the reason for screening (breeding soundness examination, clinical complaint, assistance dogs, or other reasons), and dog breed, date of birth and age. Dog positioning exerted an effect at multiple levels. The agreement among different observers regarding correct or incorrect positioning was limited and incorrect positioning itself reduced the inter-observer agreement for radiographic hip conformation. Dysplastic dogs were more commonly positioned incorrectly than non-dysplastic dogs. The clinical complaint population had a high prevalence of dysplastic dogs (>70%) compared with the breeding population (11%) and the assistance dogs (6%). There was a significantly lower prevalence of HD among cases referred by veterinarians who frequently submitted hip-extended radiographs for evaluation (P = 0.002) compared to those who refer less frequently. However, this was likely to be selection bias, as radiographs that were from dogs suspected to be dysplastic were not submitted by frequent senders. The prevalence of dysplastic dogs varied widely between breeds (16.7-71.4%). Dogs diagnosed with dysplasia were significantly older than dogs considered healthy (P = 0.001) and dogs classified as borderline dysplastic (P = 0.035). Inter-observer agreement for hip conformation was moderately low, resulting in >7% variation in prevalence estimates for dysplasia.

Computed tomography atlas of the normal cranial canine abdominal vasculature enhanced by dual-phase angiography.

This study was performed to provide a detailed atlas of the normal arterial and venous canine vasculature in the cranial abdomen by dual-phase computed tomographic angiography. Five adult beagles were positioned in dorsal recumbency on a multislice helical CT scanner. An unenhanced survey CT scan from the diaphragm to the pelvic inlet was performed. Bolus-tracking software was used for the dual-phase angiogram, and contrast medium was administered in a cephalic vein. The arterial phase was scanned from the mid-abdomen to the cranial aspect of the diaphragm; the portal phase was scanned a few seconds after the arterial phase in the opposite direction. The DICOM studies from all dogs were analysed. Representative images were selected and anatomic structures labelled. Maximum intensity projections and three-dimensional images were generated using software techniques. A detailed atlas of the venous and arterial vasculature of the cranial canine abdomen was created with the help of bolus-tracking dual-phase computed tomographic angiography (CTA). Practitioners can use this anatomic atlas with its detailed venous and arterial phase CT angiograms of the canine cranial abdomen to compare normal versus abnormal vascular anatomy.

Comparing Norberg angle, linear femoral overlap and surface femoral overlap in radiographic assessment of the canine hip joint.

OBJECTIVES: The aim of this study was to compare Norberg angle, linear femoral overlap and surface femoral overlap in radiographs of hips accepted for official hip dysplasia screening. METHODS: Radiographs of 100 dogs (200 hips) were reviewed. The three measurements were performed in each hip according to previously described methods and thereafter correlated. RESULTS: Intra- and inter-observer reliability was very high (all >85%). The linear correlation between Norberg angle and linear femoral overlap or surface femoral overlap was 0·40 and 0·41, respectively. The linear correlation between linear femoral overlap and surface femoral overlap was 0·84. CLINICAL SIGNIFICANCE: Norberg angle cannot be compared with surface femoral overlap or linear femoral overlap, and a mathematical formula could not be computed for the comparison.

Intramodality and intermodality agreement in radiography and computed tomography of equine distal limb fractures.

REASONS FOR PERFORMING STUDY: Computed tomography (CT) is increasingly accessible in equine referral hospitals. OBJECTIVES: To document the level of agreement within and between radiography and CT in characterising equine distal limb fractures. STUDY DESIGN: Retrospective descriptive study. METHODS: Images from horses that underwent radiographic and CT evaluation for suspected distal limb fractures were reviewed, including 27 horses and 3 negative controls. Using Cohen's kappa and weighted kappa analysis, the level of agreement among 4 observers for a predefined set of diagnostic characteristics for radiography and CT separately and for the level of agreement between the 2 imaging modalities were documented. RESULTS AND CONCLUSIONS: Both CT and radiography had very good intramodality agreement in identifying fractures, but intermodality agreement was lower. There was good intermodality and intramodality agreement for anatomical localisation and the identification of fracture displacement. Agreement for articular involvement, fracture comminution and fracture fragment number was towards the lower limit of good agreement. There was poor to fair intermodality agreement regarding fracture orientation, fracture width and coalescing cracks; intramodality agreement was higher for CT than for radiography for these features. POTENTIAL RELEVANCE: Further studies, including comparisons with surgical and/or post mortem findings, are required to determine the sensitivity and specificity of CT and radiography in the diagnosis and characterisation of equine distal limb fractures.

Primary and concomitant flexor enthesopathy of the canine elbow.

OBJECTIVES: To report the characteristics of two types of flexor enthesopathy, primary and concomitant, based on different diagnostic techniques. MATERIALS AND METHODS: Over a period of three years a prospective study was performed on dogs admitted for the complaint of elbow lameness. Based on the radiographic findings a selection of dogs underwent a complete series of different imaging modalities. With each technique, pathology of the medial epicondyle and the presence of other elbow disorders were recorded. All joints with signs of flexor pathology apparent with at least three techniques were selected. A distinction was made between primary and concomitant flexor enthesopathy based on the absence or presence of other elbow disorders. RESULTS: Primary flexor enthesopathy was diagnosed in 23 joints and concomitant flexor enthesopathy in 20 joints. In 43% of the joints with primary and in 75% of the joints with concomitant flexor enthesopathy, pathology at the medial epicondyle was demonstrated by all techniques. All joints with concomitant flexor enthesopathy had a diagnosis of medial coronoid disease, osteochondritis dissecans, or both. CLINICAL SIGNIFICANCE: Pathology at the medial epicondyle is a sign of flexor enthesopathy. It may be present as the only sign in a joint with primary flexor enthesopathy or concomitant with other elbow pathology. In both groups flexor lesions can be demonstrated with different imaging techniques. The distinction between the primary and concomitant form is based on the presence or absence of other elbow pathology, mainly medial coronoid disease. Recognizing both types is important for a correct treatment decision.

Anaesthetic arthrography of the shoulder joint in dogs.

OBJECTIVE: To evaluate the use of intra-articular anaesthesia combined with positive contrast arthrography (collectively called 'anaesthetic arthrography' [AA]) in the shoulder in order to identify and confirm the source of pain in lame dogs. METHODS: Anaesthetic arthrography was performed in 30 dogs with shoulder joint lameness with a mixture of contrast medium (iohexol: 240 mg I/ml) and a local anaesthetic (mepivacaine 2%: 20 mg/ml). The effect of intra-articular anaesthesia was evaluated by an objectified visual scoring system and the arthrograms were evaluated for their diagnostic value. RESULTS: This study showed that AA was positive in 28 out of 30 dogs. Dilution of the contrast medium with a local anaesthetic produced an arthrogram of good quality for each shoulder joint. In 16 out of 18 cases of osteochondritis dissecans, a cartilage flap could be identified following arthrography. In all cases the flap was not identified from plain radiographs. Biceps brachii tendon pathology was diagnosed on arthrography in seven dogs but was missed in two dogs. Calcification at the caudal rim of the glenoid cavity was diagnosed in three dogs, but was of clinical importance in only two dogs. In addition one infection was diagnosed during synovial aspiration. CONCLUSION: Anaesthetic arthrography of the shoulder is a simple, safe, and reliable diagnostic test to confirm shoulder joint pain and simultaneously identify a lesion. This procedure may be of particular importance in cases of occult shoulder joint lameness when clinical findings and plain radiographs are inconclusive.

Arthroscopic treatment of fragmented coronoid process with severe elbow incongruity. Long-term follow-up in eight Bernese Mountain Dogs.

The purpose of this study was to investigate the long-term treatment results of fragmented coronoid process (FCP) in joints with a radio-ulnar step greater than 3 mm. Treatment of these patients only consisted of fragment removal, without correction of the incongruity. The eight Bernese Mountain Dogs (11 joints) included in this study showed obvious clinical signs of elbow disease and were diagnosed with severe elbow incongruity and concomitant FCP in the time period from 1999-2003. At that time, elbow radiography, computed tomography, and arthroscopy were performed. The mean follow-up period was 5.6 years. The follow-up consisted of a telephone questionnaire combined with a clinical and radiographic re-evaluation at our clinic. The questionnaire revealed that all dogs were either free of lameness or only lame following heavy exercise. One dog sporadically required medication after heavy exercise. The owner satisfaction rate was 100%. The clinical re-evaluation did not reveal any signs of pain or lameness in all cases. Range-of- motion was decreased in nine of the 11 elbows. Radiographs revealed an increase in severity of osteoarthritis in every case.In this case series, arthroscopic fragment removal without treatment of incongruity was demonstrated to be a valuable treatment option and may provide a satisfactory long-term outcome.

Radiographic findings of the medial humeral epicondyle in 200 canine elbow joints.

OBJECTIVES: To determine the frequency and radiographic aspect of medial humeral epicondylar lesions as a primary or concomitant finding and to evaluate the association with osteoarthritis. METHODS: Medical records of dogs diagnosed with elbow lameness were reviewed. Inclusion criteria for this study were a complete clinical examination, a complete set of digital radiographs and a final diagnosis made by computed tomography or magnetic resonance imaging and arthroscopy. Changes of the medial humeral epicondyle were recorded and correlated with the radiographic osteoarthritis and final diagnosis. RESULTS: Eighty of the 200 elbows showed changes of the medial humeral epicondyle. In 12 of these 80 elbows, changes of the medial epicondyle were the only findings within the joint, and these elbows were diagnosed with primary flexor enthesopathy. In the remaining 68 elbows, other concomitant elbow pathologies were found. In those cases of concomitant epicondylar changes, high grades of osteoarthritis were recorded, while most elbows with primary flexor enthesopathy showed a low grade of osteoarthritis. CLINICAL SIGNIFICANCE: Changes of the medial humeral epicondyle are often considered clinically unimportant and are regarded as an expression of osteoarthritis. This study showed the relatively frequent presence of epicondylar changes of which the majority were considered concomitant to a primary elbow problem. If changes of the medial humeral epicondyle are the only pathologic finding (primary flexor enthesopathy) they should be considered as the cause of lameness and not as a sign of osteoarthritis.

Primary flexor enthesopathy of the canine elbow: imaging and arthroscopic findings in eight dogs with discrete radiographic changes.

OBJECTIVE: To describe the radiographic, ultrasonographic, computed tomography (CT), magnetic resonance imaging (MRI), and arthroscopic findings in eight dogs with elbow lameness caused by primary flexor enthesopathy. STUDY DESIGN: Clinical study. ANIMALS: Eight client-owned dogs. METHODS: In all dogs, lameness was localized to the elbow by clinical examination. Radiographic examination, ultrasound, CT and MRI were performed prior to arthroscopy. In seven dogs, surgical treatment and subsequent histopathology were performed. RESULTS: Primary enthesopathy of the medial epicondyle was diagnosed in eight dogs (13 joints) by combining the minimal radiographic changes with specific ultrasonographic, CT, MRI and arthroscopic findings at the medial epicondyle. In all joints, any other pathology could be excluded. Histopathology of the affected tissue revealed degeneration and metaplasia in the flexor muscles. CONCLUSIONS: Primary flexor enthesopathy at the medial epicondyle is an unrecognized condition and is a possible cause of elbow lameness in the dog. Diagnosis is based on specific imaging and arthroscopic findings. CLINICAL RELEVANCE: The most important cause of elbow lameness in dogs is medial coronoid disease. Often this condition presents with minimal radiographic and arthroscopic changes. In these cases, primary enthesopathy of the medial epicondyle should be considered as a differential diagnosis, in order to make the correct treatment decision.