Fractures

Question 1

What are the functions of bone

Answer 1

Functions of bone:

1. Biomechanical
2. Growth
3. Protection
4. Repair
5. Mineral homeostasis
6. Haemopoiesis

Question 2

What is a pathological fractures and a stress fracture?

Answer 2

A pathological fracture occurs when a bone fractures under non physiological circumstances. A stress fracture is one caused by repeated stress rather than one trauma.

Question 3

Describe the healing process for bone?

Answer 3

Large haematoma forms filling the fracture gap which provides a fibrin mesh which allow for the invasion of neutrophils, macrophages, endothelial cells, osteoblasts and fibroblasts. The necrotic tissue is removed and capillaries begin to develop. This large mixture of cell and clot forms a soft callus. Bone begins to be laid down in irregular patterns and the external callus provides a splint like support forming a hard callus. This is then slowly replaced by organised lamellar bone and the remodelling takes place in the direction of the mechanical stress for the bone.

Question 4

What factors affect the healing of a fracture?

Answer 4

Factors influencing bone healing:
• Fracture configuration and soft tissue injury - infection
• Type of bone i.e. cancellous vs cortical
• Blood supply/muscle cover
• Age
• Co morbidity
• Bone pathology
• Head injury – if head is injured bone healing is much faster

Question 5

How long do fractures take to heal in children and adults?

Answer 5

For a child a fracture in the upper limb will take about 3 weeks to heal and about 6 weeks for the lower whilst in an adult it will take 6 weeks in the upper limb and 12 weeks in the lower.

Question 6

What are the different types of fractures?

Answer 6

Types of fractures

1. Greenstick – partial fracture where part of the cortex remains intact – most common in children due to their flexible bones
2. Transverse – a fracture that is at right angles to the axis of the bone i.e. straight across
3. Oblique – a fracture that is curved or sloped i.e. at an angle to the axis of the bone
4. Spiral (torsion) – a fracture occurring when a rotating force is applied to the bone
5. Comminuted – a break or splinter of a bone into more than 2 pieces
6. Compression – when the bone is pressed together this is most common in vertebrae

Question 7

Where on the bone can fractures take place?

Answer 7

Location of fractures

1. Diaphyseal – a bone break along the shaft
2. Metaphyseal – fracture at the metaphysis i.e. before the growth plate
3. Epiphyseal – separation of the epiphysis
4. Condylar –any break in a condyle (a rounded projection at a joint)
5. Articular – fracture involving the joint surface of a bone
6. Avulsion – when a part of bone tears away as a result of physical trauma
7. Fracture dislocation – a fracture near a joint that also involves dislocation

Question 8

What are the early complications of bone fractures

Answer 8

Early complications
• Neurovascular injury
• Compartment syndrome
• Avascular necrosis
• Infection
• Hypovolemic shock
• Fat embolism
• Thromboembolism

Question 9

What are the late complications of bone fractures

Answer 9

• Delayed union – healing takes time
• Non-union – failure to heal
• Malunion – healing in the wrong place or orientation
• Myositis ossificans – bone begins to grow inside muscle
• Re-fracture