Cortex - general trauma 2 (this is the more important stuff from this section)

Question 1

Define what is meant by the term fracture

Answer 1

It is the medial term for a brake in the bone

Question 2

Describe the different ways in which fractures can be classified:

• Mechanisms in which they occur?
• How the fracture itself can be classified?

Answer 2

• They can occur due to direct trauma (e.g. direct blow) or indirect trauma (e.g. due to twisiting or bending forces)
• Can be partial / incomplete (eg unicortical fracture from a stress fracture - break in only one cortex) or complete.
• High energy (eg RTA, gunshot, blast, fall from height) or low energy (eg trip, fall, sports injury).

Question 3

What are the two main different ways in which bone healing can occur ?

Answer 3

Primary or secondary bone healing

Question 4

Describe the process of primary bone healing and when primary bone healing usually occurs

Answer 4

• Usually occurs when there is minimal fracture gap e.g. in hairline fractures and when there fixed with screws and plates
• The bone simply bridges the gap with new bone from osteoblasts

Question 5

When does secondary bone healing occur ?

Answer 5

• This is the most common type of bone healing
• Occurs due to gap at the fracture site, this requires scaffold for new bone to be laid down
• Involves an inflammatory response with recruitment of pluropotential stem cells which differentiate into different cells during the healing process

Question 6

Describe the different stages of secondary bone healing

Answer 6

1. Fracture occurs
2. Haematoma occurs with inflammation from damaged tissues
3. Macrophages and osteoclasts remove debris and resorb the bone ends
4. Granulation tissue forms from fibroblasts and new blood vessels
5. Chondroblasts form cartilage (soft callus)
6. Osteoblasts lay down bone matrix (collagen type 1)– Enchondral ossification
7. Calcium mineralisation produces immature woven bone (hard callus)
8. Remodelling occurs with organization along lines of stress into lamellar bone

Question 7

What may impeed fracture healing ?

Answer 7

Smoking, chronic ill health and malnutrition

Question 8

What are the 5 main different fracture patterns ?

Answer 8

• Transverse fractures
• Oblique fractures
• Spiral fractures
• Comminuted fractures
• A segmental fracture

Question 9

Describe the appearance of transverse fractures and the mechanism of how they usually occur

Answer 9

• Occur with pure bending force
• The broken piece of bone is at a right angle to the bone’s axis.

Question 10

Describe the appearance of oblique fractures and the mechanism at which the commonly occur

Answer 10

Occur with a shearing force (eg fall from height, deceleration).

The break has a curved or sloped pattern.

Question 11

Describe the appearance and the mechanism at which spiral fractures occur

Answer 11

• Occurs due to a rotatory force applied to the bone
• The fracture line spirals along the shaft of the bone

Question 12

Describe the appearance and mechanism of injury of comminuated fractures

Answer 12

They are fractures with 3 or more fragments

Generally a reflection of a higher energy injury (or poor bone quality)

Question 13

Describe the appearance of segmental fractures

Answer 13

The bone is fractured in two separate places.

Question 14

How can fractures be described ?

Answer 14

• According to the site of the bone involved in terms of the proximal, middle or distal third.
• Also type of bone involved - diaphyseal (shaft), metaphyseal or epiphyseal.
• A fracture at the end of a long bone (metaphyseal / epiphyseal) can be intra‐articular (extending into the joint) or extra‐articular.

Question 15

What does the position of a fracture depend on ?

Answer 15

Degree of displacement - i.e. the direction of translation of the distal fragment

Question 16

When talking about displacement of a fracture how can they be described ?

Answer 16

Anteriorly or posteriorly displaced and medially or laterally displaced.

Question 17

When a fracture is in the hand or forearm how does the way displacement is described changed ?

Answer 17

• Anterior and posterior displacement are typically substituted by volar (or palmar) and dorsal
• Whilst medial and lateral displacement are typically substituted by ulnar and radial

Question 18

How can displacement be estimated ?

Answer 18

With reference to the width of the bone (eg 25%, 50%, 75% displacement).

Question 19

When describing fractures what is meant by angulation?

Answer 19

Desribes the direction in which the distal fragment points towards and the degree of this deformity.

Question 20

How can angluation be described ? (hint similar to displacement)

Answer 20

• Angulation can be described as medial or lateral and anterior or posterior.
• In the upper limb however, radial or ulnar and dorsal or volar angulation are typically used.
• In the lower limb varus (distal fragment pointing towards the midline) and valgus (away from the midline) are used instead of medial or lateral.

Question 21

How can the degree of angulation be measured ?

Answer 21

In degrees from the longitudinal axis of the diaphysis of a long bone

Question 22

Why is it important to know the displacement and angulation of a fracture ?

Answer 22

Gives info of the direction of forces involved in the injury and gives info about the reversed direction of forces required to reduce a fracture.