Juvenile Bone Disease Flashcards
What are the main 2 disease juvenile bone diseases of the shoulder?
- osteochondrosis
- congenital luxation
What is osteochondrosis? What does this cause?
disturbance in endochondral ossification resulting in pathologic thickening of the cartilage layer
necrosis of the deepest cartilage layers and concussive forces, creating fissures in the articular surface and synovial fluid dissection = joint inflammation
What is osteochondritis dissecans?
secondary cartilaginous flap formation cause by synovial fluid dissection
What is the purpose of endochondral ossification?
replacement of growing cartilage with bone results in bone lengthening
What is the pathophysiology of osteochondrosis (dissecans)?
- failure of endochondral ossification causes thickened cartilage
- malnourished cartilage
- necrosis of cartilage and fissure formation
- continual dissection of synovial fluid causes the production of flaps and joint mice
What are the 5 multifactorial causes of osteochondrosis?
- genetic
- rapid growth
- over-nutrition
- trauma
- hormones
Osteochondrosis dissecans, histology:
How are bones adjacent to the sites of osteochondrosis affected?
kissing lesions form - articular damage from overly thickened cartilage rubbing against normal cartilage (cartilage is no longer smooth)
What dogs are most commonly affected by osteochondrosis? What history is common?
young (5-10 months), male, large or giant breed dogs - Goldens, Labradors —> 50% bilateral disease
stiff after rest
How should radiographs be taken to diagnose osteochondrosis of the shoulder?
at extension - shows the caudomedial area best
What surgical and medical treatments are recommended for osteochondrosis?
arthroscopy/arthrotomy - dissecans removal, curettage, lavage
glycosaminoglycans (fibrocartilage), corticosteroids, NSAIDs
What are the 4 most common locations of osteochondrosis?
- caudal humeral head
- humeral medial condyle
- medial hock
- lateral femoral condyle (stifle)
What is the most common location for osteochondrosis? What signs are associated? What treatment is recommended?
shoulder - caudal humeral head
moderate —> best prognosis of all OCD locations
arthroscopy or arthrotomy fragment removal
What clinical sign is associated with OCD at the elbow? What treatment is recommended? What is a common development?
(medial condyle) - severe lameness
OCD removal by arthrotomy or arthroscopy
osteoarthritis progresses always
What OCD has the worst prognosis? What 3 treatments are recommended?
medial trochlear ridge of the talus - severe lameness, smaller lesions have better prognosis, incomplete recovery and residual DJD common
- open arthrotomy (smaller area, arthroscopy not as easy)
- GAG, corticosteroids, NSAIDs
- arthrodesis if joint is shot
OCD:
site left open, will fill with fibrocartilage
What other joint can be affected by OCD?
theoretically all joints - vertebral end plates are also common
OCD, femoral head:
What new treatment for OCD is being implemented?
osteochondral autograft transfer, commonly from the stifle (available for all OCD sites)
- may not be helpful if graft does not contain cartilage, which creates a defect and causes inflammation
What are the 2 major findings on physical exams in patients with shoulder OCD?
- pain with hyperextension
- infraspinatus and supraspinatus muscle atrophy
What are the 4 major radiographic findings in patients with OCD?
- defect in subchondral bone
- sclerosis
- joint mice within joint
- osteophytosis
What are the 2 major approaches to OCD treatment? How do they compare?
- ARTHROSCOPIC - minimally invasive, technically demanding, high equipment cost
- OPEN - invasive, low cost, high success
OCD:
flap and defect
What approach is used for open treatment of OCD in the shoulder? What 3 things can be done?
cranial/caudolateral approach
- remove joint mice
- curettage of defect down to the subchondral bone
- drill vascular channels
What additional treatment is recommended for open OCD treatment? How are patients maintained following surgery?
glucosamine/chondroitin sulfate
restricted activity for 6-12 weeks
(excellent prognosis in the shoulder!)
What breeds are most affected by congenital shoulder luxation? What direction is most common?
3-8 month old small/toy breeds
medial —> torn medial glenoid ligament
What is most commonly seen on physical exam and radiographs in cases of congenital shoulder luxation?
PE = decreased range of motion
RADS = medial displacement of he humeral head and flattening of the glenoid
What conservative treatment can be used for congenital shoulder luxation?
- NSAIDs
- cage rest
rarely effective
What are the 2 most common surgical treatments of congenital shoulder luxation? What else can be done?
- arthroscopic thermal imbrication
- medio-glenohumeral ligament reconstruction
- bicipital tendon translocation
- arthrodesis
What is a bicipital sling?
surgical translocation of the biceps brachii muscle tendon caudally under an osseous hinge flap of the lesser tubercle and medial joint capsule imbrication
- treats congenital shoulder luxation
- sling applied 2-3 weeks post-operatively
What kind of technique is medio-glenohumeral ligament reconstruction? In what dogs is this recommended?
open - implants include screws and prosthetic
large breeds
What kind of technique is arthroscopic thermal imbrication? In what dogs is this recommended? How does it work?
semi-open, no implants, specialized equipment
small and medium breeds
uses heat to cause focal inflammation and contraction to support the shoulder joint
What equipment is used for shoulder arthrodesis? What does it do?
trans-articular plate or pin
alleviates pain, but causes permanent gait abnormality (still able to bear weight!) —> only done if bone will not stay in its socket
