5-6: OCD + Normal Joint Review Slides Flashcards
Explain the mechanism/etiology of OC:
Improper/failure of endochondral ossification
Persisting chondrocytes in the zone of hypertrophy (failure of vascular invasion & ossification)
Cartilage thickening due to failure of EO
What is the source of OC?
Chondrocyte/ECM/Vasculature
Exacerbated by trauma
Stages of progression to OCD/SBC:
Osteochondrosis latens
Osteochondrosis manifesta
Osteochondrosis dessicans or Subchondral Bone Cyst
Osteochondrosis latens:
focal cartilage necrosis
*can heal or progress
Osteochondrosis manifesta
Bone does not occur in the area of focal necrosis (cartilage in place of bone)
Osteochondrosis dessicans:
trauma causes shearing off of cartilage +/- bone
What forces are typically associated with OCD:
gliding forces
What is the pathophysiology of SBC:
Trauma causes cartilage lesion
Joint fluid in lesion-> inflammation-> bone resorption
What forces are typically associated with SBC?
Weight bearing forces
When can you see OCD on radiographs?
when a bone fragment is involved
What are common lameness exam findings for OCD (2)?
Most will have joint effusion and will be positive to flexion
Diagnostics for OCD:
U/S, contrast rats, CT, MRI, NS, PET scan
Rads if bone involvement
Most common site of OCD in the femoropatellar joint:
Lateral trochlear ridge of the femur
Common lesion for OCD in the femoropatellar joint:
Kissing lesion on patella
Common findings with tibiotarsal OCD (2);
minimal lameness
obvious bog spavin- effusion presents early
Common sites of OCD in the tibiotarsal joint:
DIRT
Medial Malleolus of Tibia
DL trochlear ridge of tarsal bone
Anywhere else
Prognosis of metacarpo/metatarso-phalangeal OCD:
Generally good
Subchondral bone cyst definition:
Invaginations of bone adjacent to articular surfaces filled with non mineralized matrix and lined with fibrous tissue
Diagnostics for SBC-
ID on rads- lucency
Common site for Femorotibial SBC:
Medial FT Joint- Medial femoral condyle
Common site for metacarpo/metatarso-phalangeal SBC:
Typically medial condyle
Prognosis of DIRT OCD with surgical tx:
Excellent
Prognosis of OCD/SBC of lateral trochlear ridge of the femur with surgical tx:
fair to good
Prognosis of Medial femoral condyle OCD with surgical tx:
fair
