Proof of concept: hip joint damage occurs at the zone of femoroacetabular impingement (FAI) in an experimental FAI sheep model.

OBJECTIVE: In ovine hips chondrolabral damage as seen in cam-type femoroacetabular impingement (FAI) can be induced via an intertrochanteric varus osteotomy. However, it is yet to proven whether the observed cartilage damage is caused by a dynamic cam type impingement. Thus we asked, (1) whether actual cartilage damage observed after FAI induction in ovine hips occurs at the predicted, computed zone of FAI; (2) whether the extent of cartilage damage increases with ambulation time in this animal model? DESIGN: In this experimental, controlled, comparative study 20 sheep underwent unilateral FAI induction through an intertrochanteric varus osteotomy. Preoperatively sheep underwent computed tomography to generate three-dimensional models of the osseous pelvis and femur. The models were used to predict impingement zones before and after simulated varus osteotomy using range of motion (ROM) analysis. Sheep were sacrificed after 14-40 weeks of ambulation. At sacrifice cartilage was inspected and (1) location of actual damage and computed impingement zones were compared; (2) Cartilage damage was compared between short- and long ambulation groups. RESULTS: (1) The average location and the extent of peripheral and central cartilage lesions did not differ with the computed impingement zones (all P > 0.05). (2) Grades of central, posterior cartilage damage were more severe in the long-compared to the short ambulation group (2.2 ± 1.8 vs 0.4 ± 0.5; P = 0.030). CONCLUSIONS: In this experimental ovine FAI model the surgical induction of an osseous impingement conflict between the femur and acetabulum causes cartilage damage at the zone of simulated FAI.

Femoral osteochondroplasty can be performed effectively without the risk of avascular necrosis or femoral neck fractures in an experimental ovine FAI model.

OBJECTIVE: The experimental induction of cam-type femoroacetabular impingement (FAI) in sheep is established. To tap the full potential of this ovine model, one should be able to perform a femoral osteochondroplasty safely. This study was based on previous cadaver experiments on the blood supply to the ovine femoral head and on the biomechanical strength of the proximal femur following offset creation. We hypothesized that offset creation in this ovine FAI model does not lead to (1) avascular necrosis (AVN) of the ovine femoral head or (2) iatrogenic femoral neck fractures and (3) can be performed effectively. DESIGN: In this experimental, controlled, prospective study nine sheep underwent unilateral FAI induction through an intertrochanteric, varus osteotomy. Seventy days following FAI induction, femoral osteochondroplasty was performed. Sheep were sacrificed after another 140 days. Radiographs, computed tomography (CT) scans and MRI were acquired. Histologic samples were stained with hematoxylin-eosin. (1) The multimodal Association Research Circulation Osseous (ARCO) classification was used for assessment of AVN. (2) Femoral neck fractures were assessed with the multimodal imaging approach. (3) Pre- and postoperative (=after sacrifice) alpha angles and femoral neck diameters were compared. RESULTS: (1) No signs for AVN according to the ARCO classification or (2) for femoral neck fractures were detected. (3) Mean alpha angles and femoral neck diameters decreased significantly (p < 0.001) superiorly by at least 30° respectively 4 mm after the offset creation. CONCLUSIONS: Femoral osteochondroplasty can be performed effectively and without the risk of AVN or femoral neck fractures in this ovine FAI model.

Long-term palliation of right-sided congestive heart failure after stenting a recurrent cor triatriatum dexter in a 10½-year-old pug.

A 10½-year-old, male neutered, pug presented with increasing ascites over two months. Echocardiography revealed cor triatriatum dexter with no concurrent cardiovascular anomalies, subsequently confirmed by computed tomography angiography. Balloon dilation of the perforated intra-atrial membrane under fluoroscopic guidance resulted in the transient resolution of all clinical abnormalities, but six months later stenosis and ascites recurred. After repeated balloon dilation, a stent was placed across the membrane. The dog remains asymptomatic fourteen months after the second procedure. One noteworthy feature of this case is the onset of congestive heart failure due to a congenital defect only at more than 10 years of age.

A case series highlighting the role of different gamma-herpesviruses in Equine Multinodular Pulmonary Fibrosis.

INTRODUCTION: This case series describes three cases of equine multinodular pulmonary fibrosis (EMPF) diagnosed at the Clinic for Equine Internal Medicine at the University of Zurich between 2012 and 2017. Current information on etiology and treatment options are presented. Two horses showed mild signs of chronic lower respiratory tract disease and one horse was presented with acute signs of disease including recurrent fever spikes and tachypnea. Diagnosis was achieved by physical examination, radiographic findings, and PCR testing for equine herpesviruses (EHV) of bronchoalveolar lavage (BAL) fluid or lung tissue obtained by biopsy. All horses were euthanized due to continuing deterioration after attempted treatment. Post mortem histological examination of lung tissue showed severe multifocal diffuse to confluent fibrosis in two cases and in another horse a discrete nodular fibrosis pattern. Panherpes nested PCR revealed the presence of equine herpesvirus 5 (EHV-5) DNA in lung tissue of one horse whereas in two other horses, asinine herpes virus 5 (AHV-5) was detected. EMPF should be considered as a differential diagnosis in horses with acute and chronic respiratory disease, including horses non-responsive to treatment for equine asthma.

INTRODUCTION: Cette série de cas décrit trois cas de fibrose pulmonaire multinodulaire équine (EMPF) diagnostiqués à la Clinique de médecine interne équine de l'Université de Zurich entre 2012 et 2017. Des informations actuelles sur l'étiologie et les options de traitement sont présentées. Deux chevaux présentaient de légers signes de maladie chronique des voies respiratoires inférieures et un cheval présentait des signes aigus de maladie, notamment des pics de fièvre récurrents et une tachypnée. Le diagnostic a été obtenu grâce à un examen physique, des résultats radiographiques et des tests PCR pour les virus herpès équins (EHV) du liquide de lavage broncho-alvéolaire (BAL) ou du tissu pulmonaire obtenus par biopsie. Tous les chevaux ont été euthanasiés en raison d'une détérioration continue après une tentative de traitement. L'examen histologique post mortem du tissu pulmonaire a montré une fibrose multifocale diffuse à confluente sévère dans deux cas et chez un cheval un type de fibrose nodulaire discret. La PCR par Panherpes a révélé la présence d'ADN de virus herpès équin 5 (EHV-5) dans le tissu pulmonaire d>un cheval alors que chez deux autres chevaux, le virus de l>herpès asinien 5 (AHV-5) a été détecté. L'EMPF doit être considéré comme un diagnostic différentiel chez les chevaux souffrant d'une maladie respiratoire aiguë et chronique, y compris les chevaux ne répondant pas au traitement de l'asthme équin.