Musculoskeletal Pathology II

Question 1

What is a pathological fracture?

Answer 1

Bone fracture caused by disease

Question 2

What is a compound fracture?

Answer 2

bone fragments pierce the skin

Question 3

What is a communiated fracture?

Answer 3

fracture with higher forces than simple fractures

Question 4

What causes a spiral fracture?

Answer 4

twisting forces

Question 5

How does a small gap fracture heal?

<1mm

Answer 5

bone cells migrate from the fracture ends and form lamellar bone at a right angle to the fracture line -> osteonal bone parallel to the long axis of the bone

Question 6

How does a large gap fracture heal?

Answer 6

> 1mm, woven bone fills the gap and must be modeled into osteonal bone

Question 7

Name three potential complications of fractured bone healing

Answer 7

1. inadequate blood supply = some fractures may be left without blood supply
2. large fractures of necrotic bone may be too big to be resorbed and become sequestra

both of these may interfere with healing

Question 8

What may happen if the fracture fragments are not stabilised

Answer 8

movement impairs the callus formation
* impaired neovascularisation

Question 9

What is pseudoarthrosis?

Answer 9

Bone ends become capped and a false joint is formed

Question 10

What is the Salter-Harris Classification?

Answer 10

Grading system of fractures

Question 11

What is Epiphysiolysis?

Answer 11

Separation of the epiphysis from the metaphysis

Question 12

What is valgus deformity?

Answer 12

deviation of the limb laterally

Question 13

What is varus deformity?

Answer 13

deviation of the limb medially

Question 14

What is osteitis?

Answer 14

inflammation of bone

Question 15

What is periosteitis?

Answer 15

inflammation of the bone and periosteum

Question 16

What is a Diskopondylitis?

Answer 16

inflammation of the intervertebral disc and osteomyelitis of the vertebrae

Question 17

What causes aseptic necrosis?

Answer 17

• intramedullary neoplasms
• lesions decreasing venous outflow
• undetermined in some cases

Question 18

What is an oblique fracture?

Answer 18

Bone is broken at an angle

Question 19

What are the 5 stages of fracture healing?

Answer 19

1. Haematoma- bleeding from damaged vessels
2. Undifferentiated mesenchymal cells and neovascularisation
3. Earliest woven bone
4. Primary callus of woven bone and possibly hyaline cartilage
5. Modelling of woven bone into lamellar bone

Question 20

What is rigid fracture repair?

Answer 20

• Requires surgical intervention
• Fractured ends nearly touching eachother- > direct osteonal bridging of the fracture site
• new osteons unite the bone without callus formation

Question 21

What is a Comminuted fracture?

Answer 21

Bone is broken into more than two pieces

Question 22

In what type of fracture may parts of bone be left without a blood supply

Answer 22

Communiated fracture

Question 23

What may occur if fracture fragments are not stablised during healing?

Answer 23

• Movement interferes with the callus formation
• Impaired neovascularisation
• Low blood supply promotes cartilage and fibrous tissue formation
• may cap bone ends and form a false joint
• can also occur with excessive displacement or infection

Question 24

What is epiphylosis in dogs?

Answer 24

anconeal process of the ulna

Question 25

What is epiphylosis in cats?

Answer 25

physeal dysplasia with slipped capital femoral physis

Question 26

What if the physis is severley damaged

Answer 26

formation of a bony bridge between the epiphysis and metaphysis

Question 27

What is osteomyelitis

Answer 27

Involvement of the medullary cavity and bone marrow

Question 28

What are the two main routes of entry for an infectious disease?

Answer 28

1. Directly into the bone
2. Haematogenous (arrives via the bloodstream)

Question 29

What is most infectious bone inflammation due to?

Answer 29

bacteria
* can be life-threatening- often causes simultaneous necrosis with bone removal and production

Question 30

What animal species is haematogenous spread of infection common in?

Answer 30

neonatal horses and livestock

Question 31

What fungi can cause bone inflammation?

Answer 31

• Coccidioides immitis
• Blastomyces dermatitidis

Question 32

What virus can cause bone inflammation?

Answer 32

• Classical swine fever
• Canine adenovirus type 1

Question 33

What protozoa can cause bone inflamation?

Answer 33

Hepatozoon Americanum

Question 34

What is metaphyseal osteopathy?

Answer 34

a type of hypertrophic osteodystrophy
* Disease of young, growing, large-breed dogs
* Severe pain localised to metaphyses of long bones

Question 35

What is the initial metaphyseal osteodystrophy lesion?

Answer 35

fibrinosuppurative osteomyelitis of
trabecular bone

Question 36

What is the chronic metaphyseal osteopathy lesion?

Answer 36

Formation of periosteal new bone
* Remission and exacerbations over weeks-months

Question 37

What is panosteitis?

Answer 37

• Not an inflammatory disease
• Increased density in the medullary cavity of the diaphysis
• proliferation of well-differentiated woven bone and fibrous tissue

Question 38

What three things may cause aseptic necrosis?

Answer 38

• Intramedullary neoplasms
• Decreased venous outflow from the bone
• Ischaemia leading to infarction