Fracture Healing

Question 1

What is the implication of physeal blood supply damage?

Answer 1

Growth arrest (partial or complete)

Question 2

What is indirect fracture healing?

Answer 2

Healing which occurs through callus formation where formation of bone occurs via a process of differential tissue formation until skeletal continuity is restored

Question 3

Describe the first stage of indirect fracture healing

Answer 3

A fracture haemotoma forms - blood from the broken vessels form a clot. Inflammation and swelling also occurs where dead bone cells at the site of the fracture are phagocytosed. This occurs 6-8 hrs after injury

Question 4

What is the second stage of indirect fracture healing?

Answer 4

Soft fibrocartilage callus formation where new capillaries organise the fracture haemotoma into a procallus which is then invaded by fibroblasts and osteoprogenitor cells which secerete type III collagen to connect then ends of the fractured bine together. This occurs for 3 weeks

Question 5

What is the third stage of indirect fracture healing?

Answer 5

The bony hard callus forms and this is driven be osteoblasts which lay down new woven bone and then differentiate into osteocytes when they become trapped in their own secretions. This lasts for 3-4 weeks and starts around 3 weeks after fracture

Question 6

What is the final stage of indirect fracture healing?

Answer 6

Bone remodelling where osteoclasts remodel woven bine into both compact and trabecular bone. This lasts up to 6months

Question 7

What is direct fracture healing?

Answer 7

An artificial surgical solution where there is direct formation of bone without the process of callus formation to restore skeletal continuity

Question 8

What fractures are particularly prone to problems with union or necrosis due to blood supply?

Answer 8

Proximal pole of scaphoid
Talar neck fractures
Intracapsular hip fractures
Surgical neck of humerus

Question 9

What patient factors can affect fracture healing?

Answer 9

Increasing age
Diabetes
Anaemia
Malnutrition
Peripheral vascular disease
Hypothyroidism
Smoking
Alcohol

Question 10

How can NSAIDs affect fracture healing?

Answer 10

They reduce local vascularity at the fracture site and there is also additional reduction in healing independent of blood flow

Question 11

How can bisphosphonates affect fracture healing?

Answer 11

They inhibit osteoclastic activity which delays healing