Exam 1: Lecture 4 - Surgery of the Hip I Flashcards
what is canine hip dysplasia
hereditary developmental condition of coxofemoral joint that leads to degenerative joint disease
T/F: canine hip dysplasia is considered the most prevalent genetic based ortho disease of dogs
true!
what is the definition of hip dysplasia
abnormal development of hip joint characterized by subluxation or complete luxation of femoral head in younger patients and mild to severe DJD in older patients
what does DJD stand for
degenerative joint disease
how do dogs get DJD
- cartilage damage
- osteophyte formation
- subchondral sclerosis
what is the definition of luxation of hip joint
complete separation between femoral head and acetabulum
what is the definition of subluxation of hip joint
partial or incomplete separation between femoral head and acetabulum
what is does CHD stand for
canine hip dysplasia
what does CHD pain look like in juvenile dogs
articular cartilage wear exposes pain fibers in subchondral bone and laxity causes stretching of soft tissue
what does CHD pain look like in older dogs
due to osteoarthritis
what is the most COMMON signs of CHD
exercise intolerance most common
T/F: clinical signs always correlate with radiographic findings
FALSE, clinical signs often DONT correlate with the rad findings
what is the cause of CHD
hereditary - polygenetic multifactorial
or environmentally influenced
T/F: hips are normal at birth and restricting growth rate reduces onset, severity, and incident of CHD
true!!
what are the observations of CHD
- radiographs and clinical signs may not correlate
- CHD can only be reduced, not eliminated by breeding only dogs with normal hips
- phenotypically normal dogs can produce dysplastic dogs
what is the signalment of dogs with CHD
- sometimes seen in toy breeds and cats
- highest incidence in large breed dogs (bc of rapid weight gain and growth)
what does hip laxity have to do with CHD
- decreases SA of articulation which concentrates stress over a smaller area
- favors the development of CHD
what are the 3 physiologic responses to laxity
- increased joint fluid volume
- proliferative fibroplasia of joint capsule
- increased trabecular bone thickness
what are the 5 mechanical responses to laxity
- joint capsule stretching
- acetabular bone deformation
- periosteal nerve tearing
- sharpey’s fibers rupture, bleed, and form osteophytes
- microfractures of acetabular trabecular cancellous bone
what are the 4 structures that support the hip
round ligament, joint capsule, periarticular musculature, and capsular hydrostatic constraints
T/F: No support structure of the hip is more important than another
true! They are all equally important
What are the clinical signs of CHD in young dogs aged 4-12 months
- most often have sudden onset of unilateral lameness
- abnormal gait (swaying, short stride, bunny hopping)
- pain
- poor muscle development in hind limbs
- joint laxity
- positive ortolani sign
what is the angle of reduction in the ortolani test
point where femoral head slips back into acetabulum when ABDucted
what is the angle of subluxation in the ortolani test
point where femoral head slips out of acetabulum when ADDucted
what part of the ortolani test is shown here
angle of reduction
what part of the ortolani test is this
angle of subluxation
what are the clin signs of CHD in dogs >15 months old
- chronic lameness that is worse after exercise
- often bilateral lameness
- decreased muscle mass in pelvic limbs
- waddling gait/bunny hopping
- rises slowly w difficulty
- shoulder muscle hypertrophy
- difficulty climbing stairs
what is a COMMON differential diagnosis when seeing a young AND old dog for pelvic limb lameness
cranial cruciate injury!!
what are some of the differential diagnoses of young dogs with pelvic lameness
- panosteitis
- osteochondrosis
- physeal separation
- hyperthrophic osteodystrophy
- CCL injury
- patellar lux
- trauma
what are some of the differential diagnoses of older dogs with pelvic lameness
- degenerative myelopathy
- cauda equina neuritis
- intervertebral disk disease
- lumbosacral stenosis
- CCL injury
- polyarthritis
- bone neoplasia
what are the steps to diagnosing CHD
signalment, history, PE, rads
what will we see on a PE of a young dog with CHD
- pain on external rotation
- poorly developed pelvic musculature
- exercise intolerance
- increased laxity by barlow test and ortolani test
what will we see on a PE of a older dog with CHD
- pain on hip extension
- reduced range of motion
- atrophy of pelvic musculature
- exercise intolerance
- crepitus on palpation
T/F: radiographic finding is required for definitive diagnosis
true!
what can you see/evaluate on radiographs to help diagnose CHD
- subluxation/luxation
- acetabular margin
- size, shape, architecture of femoral head/neck
- presence of exostosis or osteophytes
- subchondral bone eburnation
what is the orthopedic foundation for animals (OFA)
made is about 1966 as a not-for-profit foundation
what does the orthopedic foundation for animals (OFA)
- collate and disseminate info on orthopedic disease of animals
- advise, encourage and establish control programs to lower disease incidence
- encourage and finance research
- receive funds and make grants
describe what the OFA dysplasia control registry is/does
- 24 months or older to register
- positioning of specific VD radiographs
- film ID requirements
- evaluated independently by 3 radiologists based on breed, sex, age
- consensus report produced
what do the OFA consensus reports tell yoy
it tells you the levels of hip dysplasia that they are seeing on radiographs
what are the 7 grades of OFA consensus report
- excellent hip conformation (normal)
- good hip conformation (normal)
- fair hip conformation (normal)
- near normal (borderline)
- mild hip dysplaisa
- moderate hip dysplasia
- severe hip dysplasia
T/F: This is the incorrect way to position for radiographs for OFA
false, it is the CORRECT way
describe how to position the pet for OFA radiographs
extend hips and externally rotate tibias (so patellas are directly over trochlear grooves) and be sure pelvis is straight (symmetric obturator foramina)
(i know we havent had DI yet…) BUT what is this V/D rad of an immature dog showing
subluxation of femoral heads and minimal evidence of DJD
what are the 8 criticisms of OFA
- tests non-physiological hip position
- joint laxity is dynamic
- subjective/intra and inter observer variation
- influence of age on reliability
- variation in anesthesia
- hormonal effects on hip laxity
- variation with health status of dog
- lack of uniform reporting
what is the university of penn hip improvement program
made in 1993 at university of pennsylvania
Gail K. Smith stated it and recognized need for accurate and early diagnosis of CHD
what is PennHIP??
stress radiographic diagnostic method using a database/registry and an international network of hip evaluations centers
T/F: PennHIP shows about 2.5x >laxity than seen on hip extended view
true!
T/F: The PennHIP model is not statistically predictive at about 16 weeks of age
FALSE! It is predictive
what is the purpose of the distraction index (DI) for PennHIP
it is the measure of hip laxity….distance ball distracted from hip socket and is expressed as a number between 0 and 1
what are the steps of the PennHIP rad procedure
- sedation/anesthesia
- 3 separate rads with 2 positions
- proper positioning and radiographic technique
- measurement
- report interpretation
what is hip-extended radiograph for PennHIP
hind legs placed in “extension” and hip-extended view to ID radiographic signs of hip osteoarthritis
what part of the PennHIP rad procedure is this view?
hip-extended radiographs
what is compression radiograph for PennHIP
hips placed in neutral stance and femoral heads seated in acetabula
what part of the pennHIP rad procedure is this view
compression radiograph
what is the distraction radiograph in the PennHIP rad procedure
hips placed in same neutral position as the compression radiograph and a special device (distractor) is used to reveal joint laxity
what part of the pennHIP rad procedure is this
distraction radiograph
what is this device
PennHIP distractor
what does a distraction index (DI) of 0.58 mean
means femoral head is out of joint by 58%
what does a distraction index (DI) of 0.75 mean
75% of femoral head os out of joint
what does it mean for a hip with DI=0.50 compared to a hip with DI=0.25
the DI=0.5 is twice as lax as hip with DI=0.25
what does a DI near 0 mean
little joint lax (very tight hips
what does a DI closer to 1.0 mean
high degree of lax (very loose hips)
T/F: Dogs with tighter hips are more likely to develop hip dysplasia than dogs with looser hips
false! Dogs with tighter hips are LESS likely to develop compared to loose hips
what does it mean when threshold level of DI is 0.30
that a DI below 0.30 is very unlikely to develop hip dysplasia
what are the 4 vet requirements for PennHIP
- training
- certification
- mandatory submission of ALL films
- encourage positive ID (microchip or tattoo)
T/F: There is strict quality control of PennHIP measurement and interpertation
true
________ DI = _______ risk for OA later in life
greater DI = greater risk for OA
what are the criticisms of PennHIP
- training requirement (specifically cost/time)
- special equipment
- potential for injury (unfounded)
what are the factors that influence treatment choices of CHS
- patient age
- degree of discomfort
- physical and radiographic findings
- client expectations
- finances
what % of young patients return to acceptable clinical function with medical or conservative management
about 75% of young patients
when should we consider surgical treatment of CHD
- when conservative tx is not effective
- when athletic performance is desires
- slow progression of DJD and enhance probability of good-long term limb fcn
what do we do for short term medical/conservative management
- complete rest for 10-14 days
- moist heat
- PT
- NSAIDs
- potential use of chondroprotective agents??
what do we do for long term medical/conservative management
- weight control
- exercise (walking or swimming)
- NSAIDs
- potential use of chondroprotective agents?
what NSAIDs can be used to treat CHD
- carprofen (rimadyl)
- derocoxib (deramax)
- meloxicam (metacam)
- previcox (firocoxib)
what are the chondroprotective agents that have potential to treat CHD
- parenteral polysulfated glycosaminoglycans (adequan)
- oral glucosamine and chondroitin sulfate (glycoflex, cosequin, etc)
