Hip Dysplasia Flashcards
Define hip dysplasia
Complex disease which has been defined as a varying degree of hip laxity, permitting subluxation during early life.
What does hip dysplasia give rise to, which inevitably leads to OA?
Remodeling of acetabulum and femoral head.
There is a direction correlation between what and the development of OA ?
Hip laxity
Which breed type has a low incidence of hip dysplasia?
Sight hounds
Dog Breeds most commonly affected by hip dysplasia? (5)
GSD
Rottweiler
Golden retriever
Labrador
Saint bernard
(Mostly larger breeds)
Cat breeds pre disposed to HD? (3)
Persian
Devon rex
Maine Coon
What is the sex pre disposition to HD?
There isnt one
What genetic trait is HD?
Polygenic
What environment factors influence HD? (5)
Weight
Growth rate
Nutrition
Muscle mass
hormones
What is the heritability range of HD?
0.2-0.6
True or false
At birth all canine hip joints are normal?
True: but they develop abnormally based on the genetics of the dog and environmental influences.
What happens within the hip joint anatomically to create the abnormal HD? (4)
- Loss of joint congruency
- Stretch of ligament of head of femur
- Loss of dorsal acetabular rim
- Subluxation of femoral head
Following the stretch of the joint capsule; what des this lead to? (4)
- Further subluxation and therefore additional remodelling of dorsal acetabular rim + femoral head + articular cartilage degeneration
How does the femoral head become mis shapen with HD?
Acetabulum infills with bone
Femoral neck thickens
Acetabulum = shallower
Femoral head becomes mis shapen
What happens at skeletal maturity which makes the hip joint more stable? (2)
Joint capsule thicken
Improved muscle mass
What causes pain with HD in younger dogs? (5)
Joint laxity
Stretching or tearing of joint capsule
Stretch or tear of ligaments
Stretch or tear of muscle
Microfracture of dorsal acetabular rim
What causes pain with HD in older dogs?
OA
Is HD mono or biphasic?
Monophasic - progresses throughout life
Is bunny hopping seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Immature
Are behaviour changes seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Mature
Is rarely acute lameness Is bunny hopping seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Mature
Is Pelvic swaying when walking seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Immature
Is inactivity stiffness seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Mature
Is apparent weakness of pelvic limbs seen with HD in immature dogs (4-12mo) or mature dogs (>12mo)?
Immature
List clinical signs of HD in immature dogs (4-12mo) (8)
Variable lameness
Apparent weakness of pelvic limbs
Pelvic swaying when walking
Bunny hopping
Difficulty rising
Reluctance to exercise
Difficulty jumping
Difficulty with stairs
List clinical signs of HD in mature dogs (>12mo) (6)
Behaviour change
Difficulty rising
Exercise intolerance
Difficulty jumping
Rare to see acute lame
Inactivity stiff
Why may the greater trochanter be prominent in young dogs?
Poorly developed gluteal m.
With HD when is pain often seen with manipulation?
Extension
When might you be able to feel hip instability?
When hip joints are palpated while the dog is walking
What 3 tests can be performed under GA for HD?
Ortolani
Barlow
Barden
Define ortolani test
In lateral recumbency one hand is placed on the dorsal aspect of the pelvis whilst the other hand holds the stifle. Firm pressure is applied from the stifle in a dorsal direction. At this point, subluxation of the hip may be appreciated. Whilst this pressure is maintained the limb is gently abducted until a clunk is detected (positive Ortolani sign) which is the reduction of the femoral head into the acetabulum. As the limb is adducted with dorsal pressure maintained subluxation of the hip will occur.
With the ortolani test - what is the reduction angle?
The angle between the limb and the table at the time of reduction
With the ortolani test - what is the subluxation angle?
The angle between the table and limb when this occurs
What clinical signs of HD are seen with cats? (3)
less active,
reluctant or hesitant to jump
exhibit behavioural changes.
Define a positive barden test
If the greater trochanter displaces >0.5 cm laterally then the test is considered positive.
What is the Barlow test?
This is the detection of femoral head subluxation and is essentially forms the first part of the Ortolani test.