Surgery of the Hip I (4) Flashcards
Dr. Gilley
What is canine hip dysplasia?
hereditary developmental condition of coxofemoral joint (hip) that leads to degenerative joint disease (DJD)
What is hip dysplasia?
abnormal development of hip joint characterized by subluxation, or complete laxation, of femoral head in younger patients & mild to severe DJD in older patients
What are characteristics of Degenerative Joint Disease?
- cartilage damage
- osteophyte formation
- subchondral sclerosis
What is luxation of the hip joint?
complete separation between femoral head and acetabulum
What is subluxation of the hip joint?
partial or incomplete separation between femoral head and acetabulum
What is hip dysplasia pain due to in young dogs?
- articulate cartilage wear exposes pain fibers in subchondral bone
- laxity causes stretching of soft tissue
What is hip dysplasia pain due to in older dogs?
osteoarthritis
What are the causes of hip dysplasia?
hereditary: polygenetic multifactorial
- environmentally influenced
What is the most common sign of hip dysplasia? What is a caveat to findings here?
exercise intolerance
clinical signs often don’t correlate with radiographic findings
What can make hip dysplasia better?
restricting growth rate
What is the signalment of hip dysplasia?
large breed dogs
What are the effects of hip laxity?
decreases SA of articulation and concentrates stress over a smaller area
What are physiologic responses to laxity?
increased joint fluid volume
proliferate fibroplasia of joint capsule
increased trabecular bone thickness
What is the mechanical response to laxity?
- joint capsule stretching
- acetabular bone formation
- periosteal nerve tearing
What are the supports of the hip?
- round ligament
- joint capsule
- periarticular musculature
- capsular hydrostatic constraints
What are clinical signs of hip dysplasia in young dogs?
sudden onset unilateral lameness, abnormal gait
What is the angle of reduction regarding the Ortolani test?
point where femoral head slips back into acetabulum when abducted
What is the angle of subluxation regarding the Ortolani test?
point where femoral head slips out of acetabulum when adducted
What are clinical signs of hip dysplasia in adult dogs?
biltateral lameness
What are your differentials with an abnormal gait with young dogs?
cranial cruciate injury
What are your differentials with an abnormal gait with older dogs?
What do you see upon physical exam with a dog with hip dysplasia?
increased laxity by Ortolani test
What is a positive Ortolani test?
reduction of the femoral head after subluxate the femoral joint
What might you see on physical exam with an older dog with hip dysplasia?
For hip dysplasia ______ is required for definitive diagnosis
radiography
What may you see on radiography with hip dysplasia?
- subluxation/luxation
- acetabular margin
- size, shape, & architecture of femoral head and neck
- presence of exostosis or osteophytes
- subchondral bone eburnation
What are the disadvantages in registering for the OFA dysplasia control registry?
24 months or older
evaluated independently by 3 radiologists
How do you position a patient to send to the OFA?
- extend hips and internally rotate tibias
- be sure the pelvis is straight
What does this radiograph show?
VD radiograph of immature dog with subluxation of femoral heads and minimal evidence of DJD
What does this radiograph depict?
advanced hip dysplasia and osteophyte formation
What are the criticisms of the OFA?
What are the advantages of PennHIP?
statistically predictive at 16 weeks of age
distraction index: distraction view very reliable to show laxity
measures maximal passive hip laxity
What is the radiographic procedure for PennHIP?
What are the 3 types of PennHIP radiographs?
- hip-extended radiograph
- compression radiograph
- distraction radiograph
What is the PennHIP hip-extended radiograph?
- hind legs placed in extension
- hip-extended view to identify radiographic signs of hip osteoarthritis
What is the compression radiograph regarding PennHIP?
- hips placed neutral stance position
- pfemoralheads seated in acetabula
What is the distraction radiograph regarding PennHIP?
- hips placed same neutral position as compression radiograph
- special device (distractor) used to reveal joint laxity
What device is this?
PennHIP distractor - acts as a fulcrum to push femoral heads out
Label 1-3
- hip-extended radiograph
- compression radiograph
- distraction radiograph
What is the distraction index meaning the femoral head is out of the joint?
DI = 0.58, or 58%
What is the distraction index meaning the hip is out of the joint?
DI = 0.75
What is distraction index?
measure of hip laxity
- expressed as number between 0 and 1
What does it mean if the distraction index is near 0?
little joint laxity (very tight hips)
What does it mean if the distraction index is closer to 1?
high degree of laxity
Dogs with [tighter/looser] hips less likely to develop hip dysplasia than dogs with [tighter/looser] hips
tighter
looser
How do you treat CHD?
- medical or conservative management
- surgical treatment
What is short-term medical management for hip dysplasia?
What is long-term management of hip dysplasia?
