Hip Dysplasia Flashcards
hip dysplasia
- general concept of how it is acquired and what it is,
- breeds
- Inherited
- Developmental
> Hip laxity and instability
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Most prevalent in large breed dogs but exist in small dogs and cats - bulldog 71.8
- pug 70
- st. bernard 49%
- Rottweiler 21.1
- GSD
- Golden
- Lab
hip dysplasia
- are the notable at birth?
- biomechanics
- genetics
- primary risk factor
- joint fluid
- hip laxity vs dysplasia
- Hip Development
> Normal at birth - Biomechanics
> Subluxation: decreased Area, increased Force = DJD - Genetics: 100’s of genes
- Joint Laxity > Primary risk factor for HD
- Joint Fluid > High volume ~ increased passive laxity
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All dogs with hip dysplasia have hip laxity
Not all dogs with hip laxity will develop clinical signs of hip dysplasia
Hip Dysplasia contributing factors
- hormonal factors
- weight / growth factors
- nutrition
- other
Hormonal factors
* Estrogens
* Relaxin?
* Neutering after 12 months
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Weight and growth
* Overweight
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Nutrition
* Vitamin C
* Vitamin D
* Calcium
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* Environmental factors
hip dysplasia pathophysiology / development
- Normal at birth
- Clinical laxity and instability at 2-4 months
- Subluxation of the femoral head and development of DJD
hip dysplasia clinical signs
- timing of peak lameness, improvement
- ways it can present
- Peak lameness: 5-12 months of age or adult
> Improvement often seen from 12-16 m
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bilateral - Difficulty rising, jumping
- Bunny hopping gait
- Aggressive, pain of pelvic limb
- Non-neurological wobbly gait
- Muscle atrophy
- Exercise intolerance
hip dysplasia PE observations, tests
Decreased range of motion of hip joints and pain
* Pain on hip Extension
* Pain on hip Abduction
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Demonstration of joint laxity (generally predictable at 4-5 months)
* Ortolani sign
* Barlow Test
* Barden Test
Ortolani’s Test
Flex the hips and knees to 90 degree, then apply an anterior pressure over the greater trochanter and gently adduct the leg with your thumbs. If the hip was dislocated, a distinctive clunk will be heard as the hip relocates. This would be Ortalani’s test positive.
hip dysplasia radiographs
- rule outs
- uses
- relationship to clinical signs
- Confirm the diagnosis
> Rule out other diseases (LS, tumour,…) - Measure laxity
> Provide prognosis ? - Select or rule out a specific treatment
- Monitor the progression of DJD
> Purpose ?
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There is little correlation between radiographic signs and clinical signs: Treatment should NOT be based solely on radiographs
OFA Screening
- Assessment criteria, grades and what they mean?
- Sn, Sp?
Assessment criteria
* Degree of subluxation (+/-unreliable)
* Osteoarthritis
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normal:
* GradeI= Excellent conformation
* GradeII=Good
* GradeIII=Fair
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* GradeIV=Borderline
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Dysplastic:
* GradeV=Mild
* GradeVI=Moderate
* GradeVII=Severe
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Not mandatory to send radiographs
* Accuracy of ventrodorsal projections
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8 Mo: Sn 38%, Sp 96%
12 Mo: Sn 70-80%
24 Mo: Sn 90%
PENN-HIP (Hip Improvement Program)
- what is this?
- Hip extended radiographs and compression/distraction radiographs
- More repeatable measurement of hip laxity
- Better correlation between Distraction Index (DI) and clinical disease
- Mandatory to send radiographs, training required
- Still based on phenotype and not genotype
PENN-HIP Radiographs - distraction index use
- what can it help predict?
- breed?
- how is it used?
- DI is the most reliable predictor at 16-18 weeks for osteoarthritis at 12 months
- DI is breed-specific
- DI does not “fail” dogs… decision is up to the breeder
hip dysplasia
- what proportion of dogs will not show signs at 4y?
- radiographs proprtional to clinical signs?
- 76% of dogs will not show obvious signs at 4y
- There is little correlation between radiographic and clinical signs
(Treat the patient not the radiographs)
hip dysplasia conservative therapy
Conservative therapy
* Weight loss
* Exercise modification, Physiotherapy
* NSAIDS
* Chondroprotective drugs
hip dysplasia surgical options
- preventative, non-preventative, and who they are for
- salvage
Preventative: Young dogs only
* Juvenile pubic symphysiodesis (JPS)
* Double/Triple pelvic osteotomy
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Non-Preventative: Adult dogs
* Total Hip Replacement
* Denervation of the joint Capsule
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Slavage
* Femoral Head and Neck Excisional Arthroplasty (FHO)
Juvenile Pubic Symphysiodesis candidates
<20 weeks of age
With MILD-moderate subluxation
Juvenile Pubic Symphysiodesis
- what is it?
- age group?
- concerns
- results
Use electrocautery to close pubic symphysis
- 12-20 weeks of age only
* Ethical concerns (may hide dysplasia)
NEUTER or Hemoclip
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Results?
* Good for mild dysplasia
* Variable for moderate dysplasia
* Poor for severe dysplasia
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* Dysplasia rarely diagnosed at 16 weeks
Triple/Double Pelvic Osteotomy
- what is this?
- candidates?
Rotates the acetabulum to improve femoral coverage
* 6-8 Mo to 1 Year of age
* No osteoarthrosis
* Mild-Moderate subluxation
Triple/Double Pelvic Osteotomy prognosis
- Good to excellent ?
- Progressive osteoarthritis
> Especially if wrong case selection - Very limited numbers
Total Hip Replacement
- techniques, results
- complications, complication rate?
Techniques: cemented or non-cemented
* >85% to 90% good-excellent results
* Now available for all sizes (even cats)
* Best return to function
* $$$
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Complications are serious
* Up to 25% complication rate
* Aseptic loosening
* Septic loosening
* Luxation
* Fracture
Not for everyone!
Hip Denervation
- purpose
- method
- efficacy?
- Alleviate the pain by selective denervation of the acetabulum
- Periosteal scraping
- Efficacy questionable
(Forceplate improvement in only 50% in one study) - Long term?
Femoral Head and Neck Ostectomy (FHO)
- when is this done? who is it for?
- contraindications
- prognosis, outcomes, recovery
Salvage procedure
* Cannot be reversed!
* Can be done in large dogs
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Relative contraindications
* Large/Heavy animals
* Severe limb muscle atrophy
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Prognosis
* 60%-83% acceptable function
* Not normal
> Excellent in small dogs and cats
> The larger the dog, the less predictable the results
* Better outcome with more severe OA
* Prolonged recovery
hip dysplasia timeline for procedures
Medical: 6 mo +
JPS: 16-20 wks
TPO: 6-12mo
Denerv: adult / old
THR: adult
FHO: old
