Fractures

Question 1

Before 75 years, which fracture is most common? [1]

After 75 years, which fracture is most common? [1]

Answer 1

Before 75: wrist fracture (colle’s or colles like)

After 75: Hip fractures

Question 2

Difference between open / closed fracture? [1]

Displacced v undisplaced? [1]

Answer 2

Closed: bone fragments do not pierce skin

Open/compound: do pierce skin

Displaced: not in anatomical position

Question 3

Compression force is most likely to cause what type of fracture? [1]

Answer 3

Impacted fracture

Question 5

Transverse fracture is usually caused by what type of force? [1]

Answer 5

Usually caused by directly applied force to fracture site (e.g. object dropped on you)

Question 6

Name two places that have retrograde blood supply

Answer 6

Scaphoid
Head of femur

Question 7

What happen to blood spply if fracture scaphoid in waist? [1]

Answer 7

Waist: becomes avasuclar and dies

Question 8

what type of force cause a spiral or oblique fracture? [1]

Answer 8

Caused by violence transmitted through limb from a distance (twisting movements)

Can create sharp edges that lacerate tissue / vasculature

Question 9

Which disease increases the likilihood of crush / compression fractures? [1]

Answer 9

osteoporosis

Question 10

Which type of bone is compressed in a crush injury? [1]

Where in the body do these occur? [1]

Answer 10

A compression fracture is a type of broken bone that can cause your vertebrae to collapse, making them shorter.

Cancellous / trabeculae bone

Question 11

How does a burst fracture occur? [1]

Answer 11

E.g. if jump of a building

Occurs in short bones e.g. vertebra from strong direct pressure such as impaction of disc

Force transmitted from lower limb into vertebral column

Question 12

Burst fractures are most common in which vert layers? [2]
Why are burst fractures so problematic? [1]

Answer 12

Most common at thoracic/lumbar junction

Broken bone can impinge vertebral column and damage spinal cord

Question 13

Burst fractures are most common in which vert layers? [2]
Why are burst fractures so problematic? [1]

Answer 13

Most common at thoracic/lumbar junction

Broken bone can impinge vertebral column and damage spinal cord

Question 14

What type of force causes an avulsion fracture? [1]

What are avulsion fractures characterised by? [1]

Answer 14

Avulsion fracture: caused by traction; when a piece of bone attached to a tendon or ligament gets pulled away from the main part of the bone.

Question 15

Describe charactersitics of a fracture dislocation/subluxation [1]

Answer 15

Fracture involves a joint: results in mal-alignment of joint surfaces

A complete dislocation happens when the bones in your joint are totally separated and pushed out of place

Question 16

A colles fracture is what type of fracture? [1]

Answer 16

Impacted

Question 17

Describe the characteristics of an impacted fracture [1]

Answer 17

Bone fragments are impacted (forced, pushed) into each other

Question 18

What are characteristics of a comminuted fracture [2]

Answer 18

Two or more bone pieces - high energy trauma

Question 19

What are characteristics of a stress fracture [2]

Answer 19

Abnormal stress on normal bone (fatigue fracture - e.g. too much walking)
OR

Normal stress on abnormal bone (insufficiency fracture) - e..g Pagets disease

Question 20

Stress fractures are difficult to assess on an x-ray. State 3 other imaging techniques used to assess a stress fracture [3]

Answer 20

Bone scintigraphy becomes positive at same time or sooner than plain films
Low false positive
CT and MRI scans

Question 21

Describe characteristics of torus fracture [2]

Answer 21

In children

Children have lots of woven bone
Axial loading causing trabecular compression; bulging of the cortex

Incomplete fractures of the shaft of a long bone that is characterised by bulging of the cortex. They result from trabecular compression due to an axial loading force along the long axis of the bone

Question 22

Describe characteristics of greenstick fracture [2]

Answer 22

Occurs in children: bones soft and bend without fracturing completely

Question 23

Salter-Harris fractures are used to classify which type of fractures? [1]

Answer 23

Fractures of the epiphyseal growth plate

Question 24

Why are fractures of the epiphyseal growth plate problematic? [1]

Answer 24

Can cause growth plate to ossify early; particularly bad if have two bones in parralel (e.g. tibia and fibula)

Question 25

Describe the mechanism of bone healing after a fracture [5]

Answer 25

Fracture hematoma:
* Blood from broken vessels forms a clot 6-8 hours after injury
* Creates hypoxia; low pH
* Dead cells present cause pro-inflam cytokines
* Swelling

Fibrocartilaginous callus
* Angiogensis occurs (due to previous hypoxia)
* Fibroblasts and osteogenic precursors invade procallus
* Chondroblasts makes fibrocartilage

Inflammatory, granulation and soft callus
* Organisation and resorption of clot as new capillaries form
* Fibroblasts enter and differentiate as chondrocytes
* Chondrocytes produce collagen that bridges fracture site cartilage and trabecular bone laid down

Bony callus
* osteoblasts make woven bone
* Excess bone can form and create a bridge or a pseudo-arthrosis especially in the foot

Bone remodelling
* Osteoclasts remodel woven bone into compact bone and trabecular bone
* Often no trace of fracture line on X-rays.

Question 26

State what is represented by blue, the dot and the hashtage in this bone remodelling

Answer 26

= remodelling

Blue = calcified cartilage
dot = woven bone
hashtag = remodelling