Radiographic Evaluation of the Joint Flashcards
What is an osteophyte? Enthesophyte?
periarticular bone formation, typically at the osteochondral junction and in response to joint instability (yellow)
bone formation at the insertion of ligaments, tendons, and joint capsules, typically resulting in Sharpey’s fibers from abnormal stress and strain on these structures (green)
What is effusion? What 2 other things can it not be differentiated from radiographically?
increased fluid/soft tissue opacity within the joints
- soft tissue thickening of synovium from chronic disease
- hemorrhage/pus from septic arthritis
What is subchondral bone? Joint space?
bone immediately beneath cartilage, which can be windows to cartilage health since it cannot be seen radiographically
cartilage surfaces and fluid in the joint
What are 3 things that affect joint space size?
- reduced joint space = cartilage loss
- increased joint space = fluid presence
- artifactual incongruity = positioning
Progression of stifle degenerative joint disease:
- joint effusion
- enthesophyte formation
- joint bodies
- osteophyte formation
- osseous sclerosis
What is the difference between primary and secondary DJD?
cause is thought to be normal wear and tear
associated with some type of instability
What are 4 major causes of secondary DJD?
- ligamentous instability - increased movement causes osteophyte formation for stability, sclerosis for remodeling, enthesophytes in strained tendons/ligaments
- joint incongruity - subluxation
- osteochondrosis
- trauma - ligament rupture
What is subluxation? What is the most common site?
structural displacement of a joint, resulting in abnormal articulation (still in contact with joint)
- coxal (hip) joint —> hip dysplasia
- elbow joint —> elbow dysplasia
Why is a stress radiograph commonly needed in cases of traumatic instability?
force is placed upon the joint in different directions using a wooden spoon or other object to assess for abnormal changes in joint space width
- widening can suggest collateral ligament tear or rupture
Why is assessment of joint spaces commonly complicated?
positioning and non-weight bearing radiography
What soft tissue is important to note in joint spaces?
cranial fat pads and fat in fascial planes can aid in identification
- displacement of fascial planes can suggest joint distension
How should the subchondral bone look?
- sharp and smooth margins
- thin and uniform opacity
- lies immediately deep to cartilage
- indicators of cartilage health
increased opacity = sclerosis
decreased opacity = lysis, destruction
What are 4 possible causes of a widened joint space?
- increased synovial fluid volume in early disease (effusion)
- loss of ligament support
- subchondral bone lysis
- filling of cavity with fibrous tissue or hypertrophied synovium
What is the difference between luxation and subluxation?
LUXATION = complete loss of joint congruity where joint surfaces are not in apposition and have no contact
SUBLUXATION = partial loss of joint congruity and widening where the joint partially articulates
Subluxation:
- incongruity of articular margins
- may require stress radiographs
Where is the chondrosynovial zone?
area at the junction of the articular cartilage and synovial membrane, where instability can result in the formation of painful and uncomfortable osteophytes
