Ch 69 - Miscellaneous Orthopaedic Conditions Flashcards
What are the 2 broad categories of constitutional bone and cartilage diseases?
- Osteochondrodysplasias (developmental disorder of chondro-osseous tissue characterised by abnormal endochondral and/or intramembranous ossification
- Dysostoses (Malformation of individual bones, diseases of mesenchymal bone formation)
List the two broad categories of dwarfism and some of their respective causes
- Proportional - Endocrine, metabolic, polysystemic diseases
- Disproportionate - Osteochondrodysplasias and nutritional diseases
What hormones should be tested as a part of a work up of dwarfism?
- T4 and TSH
- GH
- IGF-1
What are the main classifications of growth retardation?
- Osteochondrodysplasia
- Endocrinopathy (GH, T4, DM)
- Congenital disorders of cell metabolism (lipid/glycogen storage disease)
- Nutritional deficiency
- Chronic inflammation (immunodeficiency, intestinal parasites)
- Congenital or acquired major organ failure or insufficiency
What are the only genetic tests available for osteochondrodysplasia?
- Mucopolysaccharidosis
- Osteogenesis imperfecta
What are dystoses?
What are the 2 broad categories?
Dystoses are a group of bone dysmorphologies characterised by the abnormal development of individual bones or parts of bones
- Failure of mesenchymal bone model (anlagen) to form
- Failure f model to transform into cartilage
- Or failure of cartilage to transform into bone
Broad categories:
- Axial (hemivertebrae, block vertebrae etc)
- Appendicular
What are the reported forms of appendicular dystoses?
- Amelia = absense of one or more limbs
- Hemimelia = Complete or partial absense of one of more bones
- Dimelia = duplications of part or all of a limb
- Ectrodactyly = Digital cleft extending between metacarpal bones
- Polydactyly = Presense of one or more extra digits
- Syndactyly = Lack of differentiation between 2 or more digits
How is hemimelia further classified?
- Terminal - If all or some of the bones distal oto a point are absent
- Intercalary - Bones proximal and distal to the absent bone are present
- Transverse - Complete absense of one or more bones across the limbs width
- Longitudinal - Bones along the preaxial (medial) or postaxial (lateral) side of the limb
In what breeds is polydactyly inherited?
- St Bernards and Collies (recessive)
- Cats (dominant)
How can syndactyly be further classified?
- Simple = Interconnection consists of skin and fibrous tissue only
- Complex = Both soft tissues and bones are fuses
- Complete = Digits fused throughout entire length
- Incomplete = Only partial fusion
- Complicated complex syndactyly = Asscoaited with other defects
- Uncomplicated complex syndactyly = No other defects
What is hypertrophic osteodystrophy?
What breeds are overrepresented?
A developmental bone disease of young, rapidly growing dogs causing a zone of disrupted trabeculae in the metaphysis immediatedly adjacent to the physis
Breeds: Weimeraners, Great Danes, Chesapeake Bay Retrievers, Irish Setters, Boxers, GSDs, Goldens, Labs
What bones are most commonly effected by HOD?
What are the classical radiographic signs?
Most commonly distal radius, ulna or tibia
Radiographic signs:
- Lucent line the the metaphysis parallel to narrow area of increased radiodensity immediately adjacent to the physis
- Enlargement of metaphysis “flare”
- Irregular widening of growth plate
Double physis
What factors have been shown to effect outcome of Weimeraners with HOD?
- Treatment with corticosteroids more successful than NSAIDs (100% vs 45.5% remission within 48hr)
- Those with affected litter-mates are more likely to relapse
What small breed dogs have been overrepresented with panosteitis?
Miniature Schnauzers and Scottish Terriers
What is thought the be the pathogenesis of panosteitis?
Vascular congestion and increased intramedullary pressure of 25 - 54mmHg (Normal 6-24), potentially due to protein accumulation
What is the ratio of forelimb to hindlimb involvement for panosteitis?
What are the typical radiographic signs?
- 4:1 FL:HL (ulna 42%, radius 25%, humerus 14%, femur 11%, tibia 8%)
- Increased medullay opacity with granular pattern or with loss of normal trabecular pattern
- Periosteal bone formation
What unique treatment has been reported for panosteitis?
Benzopyron - a proteolytic substance
Resulted in normalisation of intramedullar pressure and remission within days
What is craniomandibular osteopathy?
What breeds are overrepresented?
Unilateral or bilateral symmetric irregular osseous proliferation of mostly the mandibles and/or tympanic bullae. Temporal bones or other skull or long bones may also be affected.
Osteoclastic resorption of lamellar bone, followed by the presense of primitive bone that expands beyond the periosteum
Breeds: Cairn Terriers, WHWT, Scottish Terriers
What is the outcome of surgical treatment of CMO?
Lesions usually recur within 3 weeks, no generally recommended
Over time, lesions usually regress either completely or patially
What breeds are predisposed to Legg-Calve-Perthes disease?
How often is it bilateral?
Toy breeds (Min Poodles) and WHWT and Manchester Terriers
- Bilateral in 12 - 16.5%
What animals are overrepresented for slipped capital physis?
How often is it bilateral?
- Male, neutered overweight cats with delayed physeal closure
- Bilateral 24 - 38%, slow progressive displacement
What are multiple cartilaginous exostoses?
How do they differ in dogs and cats?
- Benign bone disease characterised by multiple cartilage capped bone protuberances arising from surfaces of any bone which developed by endochondral ossification
- Dogs - Young, growing puppies during endochondral ossification, tend to stop when fully grown
- Cats - Develop after skeletal maturity
What is the hypothesised cause of multiple cartilaginous exostoses?
- Failure of the perichondrial ring of Lacroix (peripheral constraint of the growth plate)
What is the normal standing carpal angle in puppies?
What surgical options are there for puppy carpal laxity syndrome if conservative management fails?
Normal Angle 180-190 degrees
Surgical options:
- Tenotomy
- Arthrodesis
What is hypertrophic osteopathy?
Periosteal reaction of the distal extremities as a result of increased peripheral blood flow and vascular congestion in the periosteum due to neuronal stimulation from thoracic neoplasia (usually)
What is disseminated idiopathic skeletal hyperostoses?
DISH - Spinal and extraspinal manifestations of heavy bone formation, most commonly along ventral longitudinal ligament
Boxers overrepresented
What are the three main classifications of bone cysts?
What breed is predisposed to polyostotic cysts?
- Cystic (simple unicameral)
- Aneurysmal
- Subchondral
Dobermans predisposed to polyostotic cysts
What breeds are overrepresented for caudal myopathy?
- Pointers
- Labrador Retrievers
What is the surgical option for recurrent iliopsoas injury?
Tenomyectomy
