Thrall Chapter 19 fracture healing and complications

Question 1

1) Which of the statements below are true of intramembranous ossification (more than one may be correct)?
a) It begins with mesenchymal cells that differentiate into osteoblasts that form a matrix, which then becomes calcified
b) It progresses by the formation of a cartilage model derived from the mesenchyma that is then replaced by bone
c) It occurs at the epiphyses of bones
d) It occurs primarily in the bones of the calvarium and mandible

Answer 1

a,d

Question 2

2) Which region of endochondral ossification is the weakest zone and the most common location for physeal fractures?
a) The resting zone containing immature cells of the epiphyseal side of the physis
b) The cell growth and proliferation zone
c) The cell hypertrophy zone
d) The provisional calcification or ossification zone

Answer 2

c- middle layer

Question 3

3) Which statements are true regarding indirect (secondary) bone healing?
a) It involved endochondral ossification only
b) It occurs in fractures where there is no movement between the fragments
c) The first step is characterized by haematoma formation and inflammation
d) Undifferentiated mesenchymal cells from soft tissues and the periosteum are recruited to help with healing

Answer 3

c,d

Question 4

4) What is the incidence of non-union fracture in dogs?
a) 0-6%
b) 6-10%
c) 10-14%
d) 14-18%

Answer 4

a

Question 5

5) In the image below what is indicated by the arrow?
a) A neoplastic process
b) Osteomyelitis
c) Sequestrum formation
d) Callus formation due to periosteal stripping at the time of injury

Answer 5

d

Question 6

6) Which of the following fractures more commonly occurs in cuboidal bones?
a) Slab
b) Avulsion
c) Spiral
d) Transverse

Answer 6

a

Question 7

7) Which of the following factors is the most common cause of delayed union in veterinary patients?
a) Inadequate nutrition
b) Excessive rigidity of repair
c) Excessive motion at the fracture site
d) Endocrinopathies

Answer 7

c

Question 8

8) Which is the most common site for growth plate closure after a salter harris type fracture?
a) Proximal ulnar physis
b) Distal ulnar physis
c) Distal femoral physis
d) Proximal radial physis

Answer 8

b

Question 9

9) Which zone of endochondral ossification is closest to the epiphysis?
a) Cell growth and proliferation
b) Resting
c) Ossification
d) Preliminary calcification
e) Cell hypertrophy

Answer 9

b (resting, proliferation, hypertrophy, calcification, ossification)

Question 10

10) For distraction osteogenesis, intentional mechanical gradual widening is used to lengthen the bone, how much is the gap widened per day?
a) 4mm
b) 3mm
c) 2mm
d) 1mm

Answer 10

d

Question 11

11) From the primary centre of ossification of a long bone, what type of ossification is occurring in the initial stage of bone growth?
a) Distraction
b) Endochondral
c) Intramembranous
d) Secondary

Answer 11

c

Question 12

12) What is the incidence of non-union fracture in cats?
a) 0-5%
b) 0.85-7%
c) 0.85- 4.3%
d) 4-7.56%

Answer 12

c

Question 13

13) Which of the below is the definition for oligotrophic nonunion?
a) Moderate callus formation that is less than the amount seen with hypertrophic non- union.
b) Little or no callus, with bridging of the fracture fragments with fibrous tissue. Scintigraphy may be needed to assess blood supply to the fracture gap
c) A radiolucent fracture gap with no evidence of callus and rounded sclerotic bone edges.

Answer 13

B, A is moderate hypertrophic nonunion, C is dystrophic non-union