Page 571 - ONLINE PROCEEDING BOOK WSAVA 2017
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WSVA7-0306
DIAGNOSTIC IMAGING II
COMMON AND UNCOMMON CAUSES OF LAMENESS IN DOGS – A RADIOLOGIST’S PERSPECTIVE
S. Hecht1
1University of Tennessee, Small Animal Clinical Sciences, Knoxville, USA
COMMON AND UNCOMMON CAUSES OF LAMENESS IN DOGS - A RADIOLOGIST’S PERSPECTIVE
Silke Hecht, Dr. med. vet., Diplomate ACVR, Diplomate ECVDI
Professor in Radiology
C247 Veterinary Medical Center, University of Tennessee College of Veterinary Medicine, Knoxville, TN 37996, USA
shecht@utk.edu
Introduction
Radiographs are the mainstay of the initial evaluation of the orthopaedic small animal patient. If needed, advanced imaging may be performed for a de nitive diagnosis (1).
Principles of Radiographic Evaluation (2)
Usually, radiographs in at least 2 planes of the area of interest are needed. Additional views and comparison radiographs may be necessary for full evaluation. Soft tissues are assessed for swelling, atrophy, super cial defects, presence of foreign material, mineralization,
or areas of decreased opacity indicating fat or gas inclusions. Evaluation of bony structures includes assessment of anatomic conformation and alignment, periosteal and endosteal surface, cortex and medulla for evidence of areas of increased opacity (e.g., new bone proliferation) or areas of decreased opacity (e.g., lysis). Evidence of generalized increased or decreased bone opacity should also be noted. In young animals, growth plates are evaluated for evidence of premature closure or signs of infection. Joint evaluation should include joint space width, joint surfaces and the insertion site of the joint capsule. Soft tissue swelling in the vicinity of a joint should be classi ed as extracapsular or intracapsular which is typically accomplished by visualization
of displacement of local fat planes. Periarticular osteophytosis and joint effusion/capsular thickening is indicative of degenerative joint disease (DJD) which is a common sequela to many different joint diseases.
Bone and Joint Diseases in Young Animals (3, 4) General: Osteochondrosis/osteochondrosis dissecans
(OC/OCD) is a developmental anomaly which predominantly effects young large breed dogs. It can affect various joints and is recognized by focal  attening of the joint surface with associated subchondral sclerosis and with or without the presence of an isolated  ap. Intracapsular soft tissue swelling and DJD may also be observed.
Diseases of the Forelimb: The most common disorders of the scapulohumeral joint in dogs are OC/ OCD and shoulder dysplasia which predominantly
affects Dachshunds and manifests as  attening of
the glenoid cavity, deformity of the humeral head,
and often subluxation and DJD. Elbow dysplasia is common in large breed dogs and encompasses the disease complexes OC/OCD of the medial humeral condyle, fragmentation of the medial coronoid process (FCP)/medial coronoid process disease and ununited anconeal process (UAP). Radiographic  ndings with
FCP include elbow joint incongruity, sclerosis of the
ulnar trochlar notch, blunting of the medial coronoid process, and DJD. An isolated fragment of the medial coronoid process may be seen. Radiographic  ndings with UAP include separation of the anconeal process from parent bone. Additional  ndings include joint incongruity and DJD. Incomplete ossi cation of the humeral condyle predominantly affects Cocker Spaniels and certain hunting breeds. Radiographically, a lucent line may be visible separating the lateral from the medial aspect of the humeral condyle on a craniocaudal
view. This condition often remains undiagnosed until patients present with acute distal humeral fracture after minor trauma. Angular limb deformity is a common developmental anomaly affecting the antebrachium especially in chondrodystrophic dogs due to premature physeal closure of the distal ulna. Radiographic  ndings include cranial curvature of the radius, shortening of the ulna, carpus valgus deformity and elbow joint incongruity with secondary DJD. Congenital elbow luxation is rare and may be dif cult to distinguish radiographically from
a traumatic elbow luxation sustained at young age. Valgus or varus deformity of the carpus is the most common carpal anomaly in young dogs. Incomplete ossi cation of the intermedioradial carpal bone is rarely of clinical signi cance although it predisposes this bone for pathologic fracture after minor trauma.
Diseases of the Hindlimb: Hip dysplasia is a very common condition especially in large breed dogs. Radiographically, incongruity/subluxation of one or both coxofemoral joints are evident. Secondary DJD
is very common. Legg-Calvé-Perthes disease affects small breed dogs. Radiographically, there is widening of the coxofemoral joint, and the femoral head has irregular margins and smaller size compared to normal.
An Urban Experience
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