Miscellaneous orthopedic conditions Flashcards
What is an osteochondrodysplasia?
A heritable disease that is characterized by abnormal endochondral or intramembranous ossification (dwarfism).
What are potential causes of retarded growth/dwarfism?
Proportionate: Metabolic disease, endocrinopathy, polysystemic diseases.
Disproportionate: Osteochondrodysplasia, nutritional disease
What minimum database should be performed in a patient with osteochondrodysplasia?
Family and nutritional history, CBC/biochem, urinalysis, radiographs (to document delayed development of epiphyseal growth centers, and abnormal growth morphology), TSH/T4, growth hormone, insulin-like growth factor.
How is a presumptive diagnosis of osteochondrodysplasia made?
Clinical signs, history/family history, evidence of abnormal endochondral +/- intramembranous ossification of rads
What are dystoses?
Group of bone dysmorphologies characterized by abnormal development of individual bones or parts of bones.
What are some types of axial dystoses?
Hemivertebrae, block vertebrae, butterfly vertebrae, transitional vertebrae, spina bifida, facet aplasia, and dens malformation
What are the different classifications of dystoses?
Amelia: complete absence of limb
Hemimelia: absence or partial absence of bone
Dimelia: duplicated limb
Ectrodactyly: congenital digital cleft extending between metacarpal bones
Polydactyly: additional digits
Syndactyly: fused digits
What are the different classifications of amelia?
Thoracic limb: Monobrachia (one limb), abrachia (both limbs)
Pelvic limb: Monopodia, apodia
In which breed might amelia be heritable in?
Beagles
What are the classifications of hemimelia?
What are some examples of hereditary hemimelia?
Bilateral terminal preaxial thoracic limb hemimelia in Chihuahuas, radial hemimelia in DSH and Siamese cats.
What are signs associated with radial hemimelia?
Marked varus and flexural deformity of the elbow and carpus
What are treatment options for radial hemimelia?
Young patient (<4-6 months): external coaptation to allow fusion of the antebrachiocarpal joint in a standing position.
Older patient: conservative therapies or surgery (declawing, reconstruction or amputation [can consider ectoprostheses after amputation]), distraction osteogenesis to repair the radial defect.
Name the dystoses shown in the radiographs.
Is ectrodactyly inherited in dogs and cats?
Possibly in cats, not in dogs
Between which bones is ectrodactyly most frequent reported?
First and second metacarpals
What are treatment options for ectrodactyly?
Young patient (<4-6months): splinting as for hemimelia.
Older patient: conservative or surgical (amputation or reconstruction) treatment.
What conditions are often seen in conjunction with ectrodactyly?
Elbow joint incongruity and luxation, syndactyly, digital contractures, missing carpal bones, short ulna
Is polydactyly considered an inherited trait?
Yes for preaxial (medial) polydactyly in dogs. Considered autosomal dominant in cats.
What are the classifications of syndactyly?
- Simple: interconnection between digits only consists of skin and fibrous tissue.
- Complex: both soft tissues and bone are fused (further subclassified into complicated when other defects are involved, or uncomplicated)
a. Complete: digits are connected along their entire length
b. Incomplete: digits are only partially connected
How is simple syndactyly treated?
Separation of the digits and use of a skin flaps or skin grafts to close the resultant defect.
What is the most likely signalment for a patient with HOD?
Large or giant breed breed, young (2-6 months), male dog (2.3 times more likely than females)
Which bones are most frequently affected by HOD?
Distal radius and ulna, tibia
What are some proposed causes of HOD?
Vitamin C deficiency, overnutrition (both largely refuted), inherited (particularly Weimeraners), infectious, inflammation, vaccinations.