Fractures and Bone Healing

Question 1

What is the most common fracture under the age of 75?

Answer 1

Colles fracture

Question 2

What is the most common fracture over the age of 75?

Answer 2

Hip fracture

Question 3

When are fractures most common in men and women?

Answer 3

In men = under 45

In women = over 45

Question 4

What is a closed fracture?

Answer 4

Where the bone fragments don’t pierce the skin

Question 5

What is an open fracture?

Answer 5

The bone fragments from fracture pierce the skin

Question 6

What is a displaced fracture?

Answer 6

Where the fracture has moved the bone out of it’s anatomical position

Question 7

What is a transverse fracture?

Answer 7

Usually caused by direct force to the fracture site, and is a horizontal fracture

Question 8

What is a spiral/oblique fracture?

Answer 8

Caused by violence transmitted through the limb from a distance, often due to twisting movements. The fracture is a diagonal line.

Question 9

What is a crush/compression fracture?

Answer 9

Where there is a fracture in the cancellous bone (trabecular) and is a result of compression, and is often seen in osteoporosis, especially in the vertebrae.

Question 10

What is a burst fracture?

Answer 10

This is where strong direct pressure leads to impaction (of a vertebral disc) which leads to a burst appearance. This only occurs in the short bones such as the vertebrae.

Question 11

Where are burst fractures most likely to occur?

Answer 11

Thoraco-lumbar vertebral junction.

Question 12

What is an avulsion fracture?

Answer 12

Where the bone fragment is torn off by a tendon or ligament

Question 13

What is a dislocation/subluxation fracture?

Answer 13

Where a fracture involves a joint and results in mal-alignment of the joint surfaces

Question 14

What is an impacted fracture?

Answer 14

Where the bone fragments are forced into each other

Question 15

What is a comminuted fracture?

Answer 15

Where there are two or more bony pieces affected; usually the result of high-energy trauma

Question 16

What are the two types of stress fracture?

Answer 16

Fatigue and insufficiency

Question 17

What is a fatigue fracture?

Answer 17

Where there is abnormal stress on a normal bone leading to fracture

Question 18

What is an insufficiency fracture?

Answer 18

When there is normal stress on an abnormal bone leading to a fracture

Question 19

What is a greenstick fracture?

Answer 19

Where there is a bend in the bone without a complete fracture; tend to occur in children where the bones are softer.

Question 20

What are the four stages of fracture healing?

Answer 20

Haematoma formation, fibrocartilaginous callus formation, bony callus formation and bone remodelling

Question 21

Describe haematoma formation in fracture healing

Answer 21

The blood released from the broken vessels clots within 6-8 hours after the injury followed by swelling and inflammation to remove the dead bone cells (osteocytes) at the fracture site

Question 22

Describe fibrocartilaginous callous formation in fracture healing

Answer 22

New capillaries organise the fracture haematoma into a granulation tissue known as a ‘pro-callus’. Fibroblasts and osteogenic cells then invade the pro-callus and make collagen fibres to connect the ends together followed by the production of fibrocartilage by chondroblasts. Inflammatory cells then appear and organise and resorb the clots as new capillaries form. The fibroblasts then enter and differentiate as chondrocytes which then produce collagen which bridges the fracture site cartilage and the trabecular bone that has been laid down.

Question 23

Describe bony callus formation in fracture healing

Answer 23

Osteoblasts make woven bone, and this lasts 3-4 months.

Question 24

Describe bone remodelling in fracture healing

Answer 24

Osteoclasts remodel the woven bone into compact and trabecular bone, and thereafter there is often no trace of the fracture line on x-rays.

Question 25

Outline the process of fracture healing

Answer 25

Blood capillaries are damaged and the leaked blood forms clots followed by inflammation to remove the dead osteocytes. New capillaries then reorganise the haematoma and collagen is produced from invading fibroblasts which connects the two ends. Osteoblasts then make woven bone and thereafter bone remodelling takes place (woven into compact and trabecular bone)