Lecture 4: Surgery of the Hip 1 (Exam 1) Flashcards
(49 cards)
What is canine hip dysplasia (CHD)
A Hereditary dev condition of the coxofemoreal (hip) joint that leads to degenerative joint disease (DJD)
What is the most prevalent genetic based ortho disease of dogs
Canine Hip Dysplasia (CHD)
Define hip dysplasia
Abnorm dev of hip joint characterized by subluxation or complete luxation of the femoral head in younger px & mild to severe DJD in older px (Hip laxity!)
What can be found w/ DJD
- Cartilage damage
- Osteophyte formation
- Subchondral sclerosis
Define luxation of the hip joint
Complete separation btw/ the femoral head & acetabulum
Define subluxation
Partial or incomplete separation btw/ femoral head & acetabulum
What cause hip dysplasia pain in juvenile dogs
- Articular cartilage wear exposes pain fibers in the subchondral bone
- Laxity causes stretching of soft tissue
What causes hip dysplasia pain in older dogs
Osteoarthritis
Describe the clinical signs in canine hip dysplasia
- Exercise intolerance is the most common sign
- Clinical signs often don’t correlate w/ radiographic findings
- Some dogs w/ mod or severe dysplasia are asymptomatic
Describe the etiopathogenesis of hip displasia
- Hereditary: polygenetic multifactoral
- Envi influenced
- Hips are norm at birth
What will reduce onset, severity, & incidences of CHD
Restricting growth rate
T/F: CHD can be reduced & eliminated by breeding only dogs w/ norm hips
False; it is only reduced & not eleiminated
Describe the signalment of CHD
- Sometimes seen in toy breeds & cats (bony changes rare)
- Highest incidence in large breed dogs
- Rapid weight gain & growth causes probs w/ dev of supporting soft tissue which contributes to hip laxity
Describe hip laxity
- Decreases SA of articulation (concentrating stress over a smaller area)
- Favors the dev of CHD
What are the physiologic responses to laxity
- Increased joint fluid vol
- Proliferative fibroplasia of joint capsules
- Increased trabecular bone thickness
What is the mechanical response to laxity
- Joint capsule stretching
- Acetabular bone deformation
- Periosteal nerve tearing
- Sharpey’s fibers rupture, bleed, & form osteophytes
- Microfractures of acetabular trabecular cancellous bone
What structures act together to support the hip
- Round ligament
- Joint capsule
- Periarticular musculature
- Capsular hydrostatic constraints
What are the clinical sx in young dogs (4 - 12 M)
- Most often: sudden onset of unilateral lamenes
- Abnorm gait (swaying, short stride, or bunny hopping)
- Pain
- Poor muscle dev in the hind limbs
- Joint laxity
- Positive ortolani sign
what is the angle of reduction
Point where femoral head slips back into the acetabulum when abducted
What is the angle of subluxation
Point where the femoral head slips out of the acetabulum when adducted
What are the clinical signs in adult dogs ( > 15 M)
- Chronic lameness that is worse after exercise
- Often bilateral lameness
- Decreased muscle mass in pelvic limbs
- Waddling gait/bunny hopping
- Crepitus & pain on palpation
- Rises slowly w/ difficulty
- Shoulder muscle hypertrophy
- Difficulty climbing stairs
What can be found in both a young dog & older dog differential dx
Cranial cruciate injury
What is a major sign of laxity in the PE of young dogs
- Barlow test (first part of ortolani test subluxation)
- Positive ortolani sign (reduction of the femoral head)
Which organizations say radiography is req for definitive dx
- Ortho foundation of animals (OFA)
- Univ of Pennsylvania Hip Improvement Program (PennHIP)
