Radiology of Bone (Q1)

Question 1

What is a Physeal Scar?

Answer 1

An opaque line that may be seen at the site of the physis, after physeal closure

Question 2

Where is the nutrient foramen located?

Answer 2

Diaphysis

Question 3

How does the nutrient foramen appear when visualized end-on? Laterally?

What must it not be mistaken for?

Answer 3

• 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

Question 4

Key points for Good Bone Rads!

Answer 4

• @ 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

Question 5

If you suspect a fissure FX, but don’t see it on your rads what 2 options do you have?

Answer 5

• try a slighlty different projection angle
• Repeat rads in 7-10 d.

Question 6

What can plain rads NOT assess?

Answer 6

Presence of damage to articular cartilage or surrounding ST

Question 7

What may cause diffuse ST swelling?

Answer 7

Cellulitis or Edema

Question 8

What may Focal ST swelling indicate?

Answer 8

• Abscess
• Hematoma
• Tumor or cystic lesion
• Effusion of synovial structure (joint, tendon sheaths or bursa)

Question 9

What can cause calcification of ST?

Answer 9

Dystrophic or 2° to systemic dz.

Question 10

Shift or displacement of fascial planes may indicate ________.

Answer 10

Joint effusion

Question 11

What does the lucent line that represents joint space represent radiographically?

Answer 11

Mainly articular cartilage

(only a very small amt represents synovial fluid)

Question 12

What is the disadvantge of taking joint rads on a recumbent animal (as in SAs)

Answer 12

Does not allow you to reliably assess joint width

Question 13

How can bone destruction be visualized on a radiograph?

Caveat?

Answer 13

• As an area of reduced bone density or increased radiolucency
• Only detectable once ~ 50% of the mineral content has been lost

Question 14

What is scelrosis?

Answer 14

increased bone density due to increased mineral content

Question 15

What does the callus consist of in healing fractures?

Answer 15

Endosteal & periosteal new bone

Question 16

What are Mach lines?

Answer 16

dark lines in areas of 2 bones that overlap & form an optical illusion

(can look like a fracture)

Question 17

What is meant by a Multiple FX?

Answer 17

• fracture lines don’t connect
• Same bone or different bones

Question 18

What is meant by a segmental fx?

Answer 18

2 or more FX lines in the same bone

Question 19

What if affected in a Torus FX?

Answer 19

Concave side of the cortex

Question 20

What is affected in a Greenstick FX?

Answer 20

Convex side of the cortex

Question 21

What is affected in a Chip FX?

Answer 21

no or only one articular surface involved

Question 22

What is affected in a Slab FX?

Answer 22

2 articular sufaces are involved

Question 23

What is an Articular FX?

Who typically gets them?

Answer 23

• a fx w/in the limits of the joint capsule
• Younger animals

Question 24

How are displaced fragments of bone described?

Answer 24

Describe the distal fragment relative to the proximal fragment

Question 25

What is the mnemonic for Assessing **Post-Op Rads**?

Answer 25

**ABCDS** * **A**lignment * **B**one * **C**artilage * **D**evice * **S**oft tissue

Question 26

When should you take follow up rads to asses FX healing in young animals? Mature animals?

Answer 26

* Young → @ 2-3 wk intervals * Mature → @ 4-6 wk intervals (depending on the nature of FX & fixation & the clinical condition of the patient)

Question 27

What does the **6 A's** stand for?

Answer 27

* Apposition * Alignment * Angulation * Apparatus * Activity of bone healing * Architecture of the bone * Soft Tissue

Question 28

What is **delayed union**? What can cause it?

Answer 28

* 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

Question 29

What classifies **non-union**?

Answer 29

* ~ 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

Question 30

List the 3 kinds of **Non-viable non-unions**.

Answer 30

* **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**

Question 31

List the 2 kinds of **Viable Non-Unions**.

Answer 31

* **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

Question 32

What may non-unions lead to?

Answer 32

formation of false joints/pseudoarticulation (one fragment ends up concave, the other convex)

Question 33

What type of union can lead to DJD in adjacent joints?

Answer 33

Mal-union

Question 34

What things can lead to **excessive callus formation**?

Answer 34

* movement @ the FX site * infection * periosteal stripping * incorporation of bone grafts

Question 35

Who gets "Rhino horn" or "Bucket Handle callus"? Where? Significance?

Answer 35

* Young animals * caudal cortex of a fractured femur * not clinically significant

Question 36

What is a DDX for osteomyelitits?

Answer 36

instability @ fracture site causing exuberant callus

Question 37

What is FX disease?

Answer 37

a clinical syndrome w/ joint stiffness, mm. atrophy & osteopenia

Question 38

What tends to occur when metallic implants were used or healing was complex?

Answer 38

neoplastic transformation | (tumor develops at FX site years later)

Question 39

What can result from rxn to metallic implants?

Answer 39

Metallosis (sterile, chronic, proliferative osteomyelitis)

Question 40

What is the most common joint abnormality seen in SA & equine practice?

Answer 40

Osteoarthritis