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Osteochondrosis 723

Osteochondrosis Client Education
Sheet
VetBooks.ir Differential Diagnosis Diseases and Disorders

• Chief complaint is usually lameness of various
BASIC INFORMATION
degrees and durations • Shoulder: humeral or scapular fracture;
Definition ○ Unilateral or bilateral biceps tenosynovitis, insertional myopathy,
• Osteochondrosis is an abnormality of endo- ○ May become clinically overt after scapulohumeral luxation
chondral ossification that disturbs the ordered skeletal maturity due to secondary • Elbow: medial coronoid disease, ununited
transition of epiphyseal or physeal cartilage to osteoarthritis anconeal process, ununited medial epicon-
bone. The resultant cartilage thickening inhibits • History may include use of homemade diet or dyle, incongruity, collateral ligament injury,
the ability of nutrients to diffuse to the articular supplemented commercial dog food during fracture
surface, and chondrocyte death ensues. This growth • Stifle: cranial cruciate ligament rupture or
can lead to loosening of the articular cartilage avulsion, meniscal injury, collateral ligament
from the underlying subchondral bone, causing PHYSICAL EXAM FINDINGS injury, extensor tendon avulsion, patella
painful and clinically overt osteochondritis • Lameness may manifest as a short-stepping luxation, femoral or tibial fracture
dissecans (OCD). gait if bilateral. • Tarsus: collateral ligament rupture, fracture
• OCD may lead to osteoarthritis (p. 721), • Joint pain, swelling, crepitus, instability, • Radius curvus syndrome: shortening of ante-
also called degenerative joint disease (DJD), decreased range of motion brachium as in chondrodystrophy, curvature
which is a deterioration of articular cartilage • Occasionally, only joint swelling and fibrosis due to physeal injury
and joint capsule tissues causing decreased are noted
joint function. • Muscle atrophy of the affected limb(s) Initial Database
• It is a common heritable/developmental • Radiographs of the affected and contralateral
disorder in dogs. Etiology and Pathophysiology joints:
• Nutritional excess implicated but not proven ○ Indentation, flattening, or saucer shape
Synonyms as a causal factor of the subchondral bone
Osteochondritis, osteochondritis dissecans ○ Excessive caloric (but not protein) intake ○ Mineralized density may be seen in the
(OCD), osteochondrosis dissecans ○ Increased calcium (or increased vitamin D joint
with normal calcium/phosphorus [Ca/P]) ○ Varying degrees of osteoarthrosis
Epidemiology intake disturbs endochondral ossification ○ Subchondral sclerosis in advanced cases
SPECIES, AGE, SEX in Great Danes, potentially other large ○ Multiple views may be required for
• Large- and giant-breed dogs dogs lesion identification in some joints (e.g.,
• More common in males • At least in horses and pigs, osteochondrosis tarsus)
• First signs may appear at maximal growth begins with failure of the blood supply in • Review dietary history, including food intake
rate (4-8 months of age) growth cartilage, leading to chondrocyte and body condition score
death • Not diagnostic: blood Ca, P, and vitamin D
GENETICS, BREED PREDISPOSITION • Disturbed endochondral ossification leads concentrations
Predisposition among these breeds is seen in to cartilage thickening, resulting in cartilage
certain bloodlines, but the mode of inheritance malnutrition and further chondrocyte Advanced or Confirmatory Testing
is unknown: necrosis • Contrast radiography or CT imaging may
• Border collie, German shepherd, golden • Clefts develop at the junction of viable be necessary. Scintigraphy and MRI are
retriever, Great Dane, Irish wolfhound, and nonviable layers. During normal joint uncommonly used.
Labrador retriever, Newfoundland, rottweiler, motion, vertical fissures develop in the • Arthrocentesis for synovial fluid analysis
Saint Bernard, Bernese mountain dog, others articular cartilage, resulting in the formation when joint effusion is present. Mild increase
of a cartilage flap. in mononuclear cell counts with OCD and
RISK FACTORS • The flap may remain attached to the remain- DJD
• Genetic predisposition ing cartilage tissue or may completely detach • Arthroscopy can be used for diagnosis if
• Rapid growth rate (joint mouse). radiography and CT are inconclusive.
• Excessive dietary calcium (Ca) and calorie • Inflammatory mediators are released, and
intake proposed osteoarthritis results. TREATMENT
• Hormonal effects (i.e., male dogs, calcitonin) • Joints most commonly affected:
• Increased joint loading and trauma from ○ Shoulder: caudal humeral head Treatment Overview
intense exercise ○ Elbow: medial humeral condyle • Surgery (arthrotomy or arthroscopy) is
○ Hock (tarsocrural joint): medial or lateral used to remove the devitalized cartilage
ASSOCIATED DISORDERS trochlear ridges of the talus and help stimulate new cartilage forma-
• Hip dysplasia ○ Stifle: lateral or medial femoral condyle tion. Joint congruity cannot usually be
• Disturbances in endochondral ossification ○ Also identified in the vertebral articular completely restored. Surgery is superior to
also are seen with nontraumatic premature processes and caudal border of glenoid medical management for shoulder OCD;
distal ulnar physis closure and ununited controversy remains about whether medical
anconeal processes, supraglenoid tubercles, DIAGNOSIS or surgical management is better for other
and medial humeral epicondyles joints.
• Medial coronoid disease Diagnostic Overview • Medical management (alone or with surgery)
OCD is suspected based on age (juvenile), aims to reduce inflammation, pain, lameness,
Clinical Presentation breed (large/giant), history, diet, unilateral and improve joint health.
HISTORY, CHIEF COMPLAINT or bilateral lameness, and radiographic signs • Nutrition should be adjusted if necessary.
• Young dogs in good general health of a subchondral bone defect in typical • Modify excessive activity in juvenile large-
(typically) locations. breed dogs.

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