Bone regeneration and fracture healing

Question 1

Under the right conditions, bone has remarkable repair and regeneration potential

TRUE or FALSE

Answer 1

TRUE

Question 2

What does fracture regeneration provide the bone?

Answer 2

Provides the bone true functional restoration to initial tissue structure

Question 3

What 3 features is fracture regeneration dependent on?

Answer 3

Immobilisation

Fracture gap size

Soft tissue support - including vascularisation

Question 4

What is the approximate time a fracture takes to heal?

Answer 4

10 weeks

Question 5

What are the 3 types of facture healing?

Answer 5

Spontaneous (indirect/secondary) healing

Contact (angiogenic/primary) healing

Gap healing

Question 6

What is the most common healing process?

Answer 6

Spontaneous healing

Question 7

What type of fractures triggers spontaneous healing?

Answer 7

Fractures where:

Fracture ends are placed close to each to other

Intervening haematoma

Variable displacement and/or angulation

Question 8

What initiates sponatenous healing?

Answer 8

Pluriportent mesenchymal cells

Initiate the formation of healing tissues

Forms bridging callus that can be seen on radiographs

Question 9

What are sources of mesencymal stem cells?

Answer 9

Periosteum

Endosteum

Harvesian canals

Question 10

What type of fracture triggers contact healing?

Answer 10

Adapted fragments

Less than 0.1 mm distance

Neutralisation of interfragmentary strain

Stable internal fixation

Question 11

Describe the process of contact healing

Answer 11

Osteoclast form cutting cones

These traverse the fracture line at 50-100 um/day

Capillaries enter the bone

Osteoblast form lamellar bone oriented parallel to the bone length (Haversian remodelling)

Question 12

What is a way to distinguish spontaneous healing from contact healing?

Answer 12

Type of callus formed

Spontaneous healing - formation of bridging callus

Contact healing - formation of irritation callus

Question 13

What is Haversian remodeling?

Answer 13

Osteoblast form lamellar bone primarily oriented in the right direction

Question 14

Describe the process of gap healing

Answer 14

Internal fixation contains a gap

Lamellar bone is deposited perpendicular to the long axis

This process continues until the gap has been filled

Remodeling happens once this gap is filled

Haversian remodeling

Complete fracture healing occurs

Question 15

What are complications of fracture healing?

Answer 15

Delayed union

Non-union

Malunion

Refracturing

Osteomyelitis

Question 16

What is delayed union?

Answer 16

Fracture healing takes twice as long as expected for a location

Question 17

What is another name for nonunion?

Answer 17

Pseudoarthosis

Question 18

What is non-union

Answer 18

Fracture healing does not occur within 6-9 months

Question 19

In which bones is non-union common?

Answer 19

Scaphoid bone

Femoral neck

Tibial shaft

Question 20

What is malunion?

Answer 20

Healing of bones in the wrong position

Partly compensated for by remodeling (except for rotational malunion)

Question 21

What leads to a higher risk of refracturing?

Answer 21

Fixation material should be moved within 18 moths after consolidation fracture

Cortical atrophy leads to higher risk of refracturing

Question 22

What is osteomyelitis?

Answer 22

Infection of the bone

Question 23

What is an example of osteomyelitis?

Answer 23

Staphylococcus aureus

80-90% of all infections