A better understanding of imaging characteristics of equine stifle osteoarthritis (OA) may allow earlier detection and improve prognosis. Objectives of this ex vivo, prospective, methods comparison study were to (1) describe the location and severity of naturally acquired OA lesions in the equine stifle using ultrasound (US), radiography (XR), computed tomography (CT), and macroscopic evaluation (ME); (2) compare the diagnostic performance of each imaging modality with ME; and (3) describe subchondral bone mineral density (BMD) in equine stifle joints with OA using CT. Radiographic, CT, and US evaluations were performed on 23 equine cadaver stifles and compared with ME. Significant associations were found between osteophyte global scores for all imaging modalities (CT, P ˂ 0.0001; XR, P = 0.005; US, P = 0.04) vs. ME osteophyte global scores. Osteophytes were detected most frequently in the medial femorotibial (MFT) joint. A specific pattern of osteophytes was observed, with a long ridge of new bone at the insertion of the MFT joint capsule cranially on the medial femoral condyle. A novel caudo-10°proximo-5°lateral-cranio-disto-medial oblique radiographic projection was helpful for detection of intercondylar osteophytes. Multiplanar CT reformatted images were helpful for characterizing all osteophytes. Osteophyte grades at most sites did not differ among modalities. Low sensitivity/specificity for subchondral bone sclerosis and flattening of femoral condyles suggested that these signs may not be reliable radiographic and CT indicators of equine stifle OA. Equine stifle OA was associated with a decrease in BMD and specific sites of focal subchondral bone resorption/cyst formation were found in some specimens.

This study is the first to describe normal equine meniscal morphology and lesions. Meniscal lesions were identified in all segments and on both articular surfaces. Meniscal degeneration significantly correlated with OA severity in the equine medial femorotibial joint. The relationship between OA and meniscal pathology remains to be elucidated.

Measurements of mJSW in the medial compartment of femorotibial joints, the most common site of osteoarthritis in horses, were reproducible and optimal with a caudoproximal-craniodistal oblique radiographic projection made at 10° from the horizontal.

Pericardial defect is a rare condition, with risk of cardiac chamber strangulation or incarceration. Surgical correction is recommended when clinical signs are unmanageable and to decrease the risk of thromboemboli. A 15-year-old, 4.1-kg, spayed female Shih Tzu dog presented to the hospital with a 6-month history of weakness and syncope episodes. The dog had been diagnosed with degenerative mitral valve disease 9 years earlier. Thoracic radiographs, echocardiography and computed tomography indicated a left auricular herniation through a pericardial defect. Clinical signs were temporarily controlled with pimobendan, benazepril and clopidogrel, until the syncope episodes returned along with atrial fibrillation (unresponsive to oral digoxin). Surgical correction (auriculectomy and partial pericardiectomy) was performed via thoracotomy. Atrial fibrillation reverted to normal sinus rhythm following surgery and recovery was uneventful. The patient survived, arrhythmia-free, for 25 months postoperatively. Syncope episodes never resolved.

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