Radiology of Bone (Q1) Flashcards
What is a Physeal Scar?
An opaque line that may be seen at the site of the physis, after physeal closure
Where is the nutrient foramen located?
Diaphysis
How does the nutrient foramen appear when visualized end-on? Laterally?
What must it not be mistaken for?
- End-on→well defined, circular radiolucency w/ smooth, thin radio-opaque rim
- Laterally → linear lucent gap w/ a sclerotic border in the bone cortex
- Don’t mistake for a FX or lytic lesion
Key points for Good Bone Rads!
- @ least 2 views → 90° to each other (orthogonal views)
- Include joints above & below the injured bone
- Examine growth plates for injury in skeletally immature animals
- Repeat rads in 3 wks
- Compare to the contralateral limb if suspect subtle changes may have occured
- Stressed projections → if concerned about joint stability
If you suspect a fissure FX, but don’t see it on your rads what 2 options do you have?
- try a slighlty different projection angle
- Repeat rads in 7-10 d.
What can plain rads NOT assess?
Presence of damage to articular cartilage or surrounding ST
What may cause diffuse ST swelling?
Cellulitis or Edema
What may Focal ST swelling indicate?
- Abscess
- Hematoma
- Tumor or cystic lesion
- Effusion of synovial structure (joint, tendon sheaths or bursa)
What can cause calcification of ST?
Dystrophic or 2° to systemic dz.
Shift or displacement of fascial planes may indicate ________.
Joint effusion
What does the lucent line that represents joint space represent radiographically?
Mainly articular cartilage
(only a very small amt represents synovial fluid)
What is the disadvantge of taking joint rads on a recumbent animal (as in SAs)
Does not allow you to reliably assess joint width
How can bone destruction be visualized on a radiograph?
Caveat?
- As an area of reduced bone density or increased radiolucency
- Only detectable once ~ 50% of the mineral content has been lost
What is scelrosis?
increased bone density due to increased mineral content
What does the callus consist of in healing fractures?
Endosteal & periosteal new bone
What are Mach lines?
dark lines in areas of 2 bones that overlap & form an optical illusion
(can look like a fracture)
What is meant by a Multiple FX?
- fracture lines don’t connect
- Same bone or different bones
What is meant by a segmental fx?
2 or more FX lines in the same bone
What if affected in a Torus FX?
Concave side of the cortex
What is affected in a Greenstick FX?
Convex side of the cortex
What is affected in a Chip FX?
no or only one articular surface involved
What is affected in a Slab FX?
2 articular sufaces are involved
What is an Articular FX?
Who typically gets them?
- a fx w/in the limits of the joint capsule
- Younger animals
How are displaced fragments of bone described?
Describe the distal fragment relative to the proximal fragment
What is the mnemonic for Assessing Post-Op Rads?
ABCDS
- Alignment
- Bone
- Cartilage
- Device
- Soft tissue
When should you take follow up rads to asses FX healing in young animals? Mature animals?
- Young → @ 2-3 wk intervals
- Mature → @ 4-6 wk intervals
(depending on the nature of FX & fixation & the clinical condition of the patient)
What does the 6 A’s stand for?
- Apposition
- Alignment
- Angulation
- Apparatus
- Activity of bone healing
- Architecture of the bone
- Soft Tissue
What is delayed union?
What can cause it?
- longer than expected time for a FX to heal but evidence of bone activity occuring
- Disuse, instability, poor reduction, poor nutrition, old age, infection, poor vascularity, large intramedullary pin, presence of a sequestrum, neoplasia
What classifies non-union?
- ~ 10-12 wk post FX
- Healing has visibly ceased & FX ends aren’t united
- FX ends are smooth & medullary cavity appears closed
- Predisposed to by infection or movement at the FX site
List the 3 kinds of Non-viable non-unions.
- Atrophic non-union → no callus, pointed bone ends & bone ends not in contact
- Dystrophic/necrotic non-union → often have devitalized intermediate fragments
- Defect non-union
List the 2 kinds of Viable Non-Unions.
-
Hypertrophic non-union
- both ends are plump & parallel
- new bone present around FX end but FX has not been crossed
- Elephant’s foot appearance
-
Oligotrophic non-union
- little or absent callus
What may non-unions lead to?
formation of false joints/pseudoarticulation
(one fragment ends up concave, the other convex)
What type of union can lead to DJD in adjacent joints?
Mal-union
What things can lead to excessive callus formation?
- movement @ the FX site
- infection
- periosteal stripping
- incorporation of bone grafts
Who gets “Rhino horn” or “Bucket Handle callus”?
Where?
Significance?
- Young animals
- caudal cortex of a fractured femur
- not clinically significant
What is a DDX for osteomyelitits?
instability @ fracture site causing exuberant callus
What is FX disease?
a clinical syndrome w/ joint stiffness, mm. atrophy & osteopenia
What tends to occur when metallic implants were used or healing was complex?
neoplastic transformation
(tumor develops at FX site years later)
What can result from rxn to metallic implants?
Metallosis
(sterile, chronic, proliferative osteomyelitis)
What is the most common joint abnormality seen in SA & equine practice?
Osteoarthritis
