Diagnostic imaging of bones 1 and 2

Question 1

What do you need to include in your description of fractures?

Answer 1

• Location: Diaphyseal, physeal, articular
• Orientation: Transverse, oblique, spiral
• Displacement: Distal segment relative to proximal
• Comminuted?
  o This means multiple fragments
• Open/closed?
  o This is part of both the physical exam and radiography (is there gas in the soft tissue?)

Question 2

How would you describe this image?

Answer 2

Mid and distal diaphysis of the tibia with cranial lateral and proximal displacement, it is comminuted and it does not appear to be open

Question 3

How long does it take to see a periosteal response radiographically?

Answer 3

8-10 days

Question 4

What are the 4 A’s of fracture repair?

Answer 4

Alignment, apposition, apparatus and activity

Question 5

Which complication of fracture healing is this image demonstrating?

Answer 5

Non-union - this fracture is not healing and there is no evidence of repair

Question 6

What are the main reasons for non-union?

Answer 6

• Atrophic (avascular) - limited/no vascular supply to support repair
• Hypertrophic - Lots of repair but can occur when the fracture is not immobilised

Question 7

Which complication of fracture healing is this image demonstrating?

Answer 7

Malunion

Question 8

Which complication of fracture healing is this image demonstrating?

Answer 8

Osteomyelitis

Question 9

Do we expect to see differences in fracture repair in a puppy vs an adult dog?

Answer 9

Yes, younger animals are more able to heal fractures more rapidly

Question 10

What would you expect to see in an aggressive bone lesion?

Answer 10

• Poorly demarcated
• Wide zone of transition
• Poorly marginated osteolysis
• Cortex interrupted
• Interrupted irregular periosteal reaction
• No surrounding sclerosis
• Rapid rate of change

Question 11

Give some examples of aggressive bone lesions.

Answer 11

• Malignant neoplasia
• Primary bone tumours
• Metastatic bone lesions
• Round cell tumours
• Osteomyelitis
• Bacterial
• Fungal

Question 11

Give some examples of aggressive bone lesions.

Answer 11

• Malignant neoplasia (Primary bone tumours, Metastatic bone lesions, Round cell tumours)
• Osteomyelitis (Bacterial, Fungal)

Question 12

What would you expect to see in an NON-aggressive bone lesion?

Answer 12

• Well demarcated
• Narrow zone of transition
• Absent or geographic osteolysis
• Cortex may be displaced, remodelled and thin, but not broken
• Solid, smooth periosteal reaction
• +/- Surrounding sclerosis
• Static or slow rate of change

Question 13

Give some examples of NON-aggressive bone lesions.

Answer 13

• Benign neoplasia (Osteoma, Chondroma, Osteochondroma, Multiple cartilaginous exostosis)
• Bone cysts

Question 14

What factors affect fracture healing?

Answer 14

• Vascularity
• Fracture site
• Fracture type
• Fracture reduction
• fracture motion
• age and general health

Question 15

What are the types outlined in the salter-harris classificaiton of bone fractures?

Answer 15

• Type 1 - goes straight through the open growth centre
• Type 2 - through the physis and exit the metaphysis, no articular involvement
• Type 3 - usually articular goes through the epiphysis and goes straight out the physis (rare)
• Type 4 - Articular fracture, goes through epiphysis, involves the physis, exits through the metaphysis
• Type 5 - Crush injury to the physis

Question 16

What is the difference between mono-ostotic and poly-ostotic (both localised and generalised)?

Answer 16

• Mono-osmotic - one bone affected
• Poly-osmotic localised - multiple bones affected, but within the same region
• Poly-ostotic generalised - multiple bones affected, seen in more than one region in the skeleton

Question 17

What are the types of primary malignant bone tumours?

Answer 17

• Osteosarcoma
• Chrondrosarcoma
• Fibrosarcoma
• Haemangiosarcoma
• Liposarcoma

Question 18

Desribe the common features of primary malignant bone tumours.

Answer 18

• Mixed lytic and productive
• long zone of transition
• mono-ostotic

Question 19

Desribe the common features of metastatic bone tumours.

Answer 19

o Highly lytic
o Long zone of transition
o Poly-ostotic, generalised

Question 20

Desribe the common features of osteomyelitits.

Answer 20

• Primarily productive
• long zone of transition
• mono-ostotic
• poly-ostotic (generalised and or localised)

Question 21

What are we looking at here?

Answer 21

Osteoarthrosis - Irregular new bone formation

Question 22

What are we expecting to see in degenerative bone disorders?

Answer 22

Generally purely productive
- Periarticular new bone formation
- Subchondral bone sclerosis
- Soft tissue mineralization

Question 23

What types of bone disorders are younger animals likely to develop?

Answer 23

• Developmental abnormalities such as dysplasia (eg. elbow or hip)
• This usually results in degenerative joint disease

Question 24

Where are you most likely going to see osteochondrosis?

Answer 24

• Medial humeral condyle (distal)
• caudal humeral head
• Lateral and medial trochlear ridges
• lateral and medial femoral condyle
• vertebral articular facets

Question 25

Explain hip dysplasia

Answer 25

• Coxofemoral joint subluxation
• Poor coverage of the femoral heads by acetabulea
• Poor joint congruity
• Osteoathrosis will develop - important to determine the cause. If it is a result of hip dysplasia, then we want to not breed these animals.

Question 26

What do we expect to see in septic arthritis?

Answer 26

• Joint effusion
• With or without subchondral erosion
• Often occurs in joints with substantial arthritis
• SEVERE pain