Joints Flashcards
define OCD
Disease that affects the normal endochondral ossification of growth plates.
Necrotic cartilage develops a fissure undermining cartilage and forming a cartilage flap –> seepage of synovial fluid under flaps causes subchondral bone pain and inflam –> secondary OA
define OC
endochondral ossification disturbed –> cartilage continues to grow w/out being transformed into bone causing it to become abnormally thick
pathogenesis of OC in articular cartilage
- nutrition to articular cartilage is by diffusion of nutrients from the synovial fluid –> OC causes cartilage to become too thick –> no nutrients and necrosis of basal layers –> edochondral ossification fails in that area –> subchondral defects in epiphysis
rad findings of OCD
- radiolucent defect in the subchondral bone
- subchondral bone sclerosis
- a cartilage flap is only visible if mineralised
sequelae of OC of growth plate cartilage
- does not lead to necrosis of cartilage because nutrition from blood vessels not synovial fluid
- may cause some disturbance in growth often not clinically significant
- important if occurs in radius/ulna –> asynchronous growth results in incongruity of elbow + antebrachial growth deformities
aetiology of OC
- hereditary
- males > females (2:1)
- overnutrition/rapid growth
- mature size >25kg
hx/sig of OC
large breed dogs, 4-8mo w/ progressive intermittent lameness worsened by exercise
if suspect OC always radiograph…
both limbs!
tx of OCD
- debride necrotic cartilage down to healthy bleeding subchondral bone –> forage underlying subchondral bone to encourage revasc and healing
- healing bone replaces necrotic cartilage
- articular cartilage replaced by fibrocartilage
which OCD type/location has the best prognosis?
the shoulder
where does OCD occur in the shoulder?
caudal aspect of humeral head
breeds predisposed to shoulder OCD?
Great Dane, GSD, Newfie, Bernese Mt Dog
radiographic findings of shoulder OCD?
- radiolucent defect cd aspect of humeral head
- loss of convex shape/flattening + assoc. subchondral bone sclerosis
- +/- jt mouse
what rad view to diagnose shoulder OCD?
- laterals (bilateral)
shoulder OCD ddx
- elbow dz
- panosteitis
- sesamoid dz
- metaphyseal osteopathy
- Soft tissue injury
when is surgical treatment of shoulder OCD indicated?
if lameness/pain apparent
sx approaches to OCD lesions?
- open arthrotomy
- arthroscopically (preferred)
which part of the stifle is commonly affected by OCD
lateral condyle of femur
stifle OCD breed assoc.
young, large breed dogs esp. retrievers
rad findings of stifle OCD
- radiolucent concavity in either femoral condyles
- subchondral sclerosis + flattening of condyle
- stifle DJD
prognosis of hock OCD
-poor as high motion, low tolerance joint and reformation of trochlear ridge is unrealistic thus progression of OA inevitable
3 types of elbow disease
- FCP
- OCD
- UAP
how useful are rads to investigate elbow disease
- all types of elbow disease show evidence of OA
- can diagnose OCD (Cr.Cd view) and UAP from x-rays
- cannot diagnose FCP
what is FCP
disease of the medial part of coronoid process of ulna resulting in progressive OA and ‘kissing’ lesion on adjacent medial humeral condyle
where do you palpate to feel elbow effusion?
lateral elbow btwn lateral epicondyle + olecranon
normal should be convex
tx of FCP
subtotal coronoidectomy + tx of kissing lesion (like OCD)
+ ongoing NSAIDs/OA management
typical stance of dog w/ bilateral elbow disease
- base narrow
- Supination
- Elbow abduction
where does elbow OCD occur?
medial humeral condyle
what rads do you take if you suspect elbow OCD?
Bilateral
- lateral
- flexed lateral
- Cr. Cd views
how do you definitively diagnose elbow OCD?
rads – radiolucent concavity on trochlear ridge of medial humeral condyle + secondary OA
earliest rad. signs of elbow OA secondary to OCD?
osteophytes on anconeal process
later rad. signs of elbow OA secondary to OCD?
articular and periarticular osteophytes, subchondral bone sclerosis, jt space narrowing, jt effusion
tx of UAP
if early in dx before major degenerative change an ulna osteotomy + lag screw repair
– recheck 10wks = complete union of AP w/ good congruity + callus healing of ulna osteotomy
what rad view to diagnose UAP?
laterals
what imaging to diagnose FCP?
CT
Hip dysplasia aetiology
- Genetic: most common heritable ortho problem in dogs - schemes exist to prevent breeding
- Environment: XS exercise/weight gain/ growth while immature, obese, large breeds
define hip dysplasia
abnormal development of coxofemoral joint characterised by subluxation in young animals - leads to DJD in older animals
2 presentations of hip dysplasia
- younger growing dogs w/ pain of instability + sublux
- older dogs w/ chronic OA, reduced ROM, crepitus
what stance/gait characteristics are indicative of hip dysplasia?
- waddling
- weight shifted forwarded
- poorly developed HL muscles
hip joint laxity tests are only reliable in dogs as what age?
> 16wks
why may older dogs w/ hip dysplasia not display hip laxity?
due to chronic OA changes and stabilisation of hip joint
a positive ortolani test indicates
the dog has hip dysplasia
why are PennHip rads taken?
To assess degree of sublux of femoral head (50% of fem head in acetabulum)
- stimulate position of hips when standing
what are the 4 surgical approaches to hip dysplasia
- Juvenile pelvic symphysiodesis
- Triple/Double pelvis osteotomy
- Total hip replacement
- Femoral head excision arthroplasty
when are preventation sx approaches indicated in a dog with hip dysplasia?
- young (6-8monts) w/ no DJD
age requirement for juvenile pubic symphysiodesis?
<20wks old
age req. for triple/double pelvis osteotomy?
5-12mo
triple/double pelvic osteotomy goal
axially rotates and lateralises the acetabulum resulting in increased dorsal coverage of the femoral head
when are salvage sx indicated to tx hip dysplasia?
only if dog does not response to WET therapy
complications of THR
- infection
- aseptic loosening of implants
- dislocation
success rate of THR
80-90%
femoral head excision arthroplasty ideal candidates are…
<15kg
what causes Legg-Calve-Perthes disease?
interuppted blood supply to femoral epiphysis –> avascular necrosis of epiphysis (femoral head) –> femoral head collapses and remodels –> incongruity and DJD results
signalment/presentation for Legg-Calve-Perthes-Disease
- 6-10mo, small (<10kg)
- WHWT, cairns
- slowly progressive HL lameness, usu. unilateral
rad signs of chronic Legg-calve-perthes disease
collapse and remodelling of femoral neck w/ femoral head deformity + DJD
tx and px of legg-calve-perthes disease
quite good as femoral head excision arthroplasty to tx –> small dogs respond well
use of cartrophen and NSAIDs is…
contraindicated
ddx of Hip dysplasia in young animals
- OCD of stifle/hock
- panosteitis
- Cruciate disease
- patella lux
- hypertrophic osteodystrophy
- neurologic disease
ddx of hip dysplasia in mature animals
- cruciate disease
- polyarthropathy
- neoplasia
- neuro: degen myelopathy, IVDD
how does obesity affect OA?
- inflammatory mediators released from adipose tissue –> higher serum and synovial fluid leptins (pro-inflam) + lower adiponectin (anti-inflam)
- increased mechanical stress does not significantly contribute to OA
what weight loss % is associated with improvement of lameness in dogs?
8.5-11% weight loss
what analgesics are indicated to tx OA?
- NSAIDs
- Amantadine
- Grapiprant
- Paracetamol
- Gabapentin
what salvage surgery options exist for advanced/severe OA not responsive to WET tx?
- joint replacement
- arthrodesis
- femoral head osteotomy
