Fractures (Healing, assessment of healing, complications of healing, general complications of fractures, soft tissue injuries associated with fractures)

Question 1

What is the definition of a fracture?

Answer 1

Breakage of a bone, either complete or incomplete

Question 2

What is a simple fracture?

Answer 2

Clean break with little damage to the surrounding tissues

Question 3

What is a compound fracture?

Answer 3

Direct communication between the broken bone and the skin surface

Question 4

What is a transverse fracture?

Answer 4

Fracture line is at 90^o to the longitudinal axis

Question 5

What is an oblique fracture?

Answer 5

Fracture line is usually angled by 30-45^o to the longitudinal axis

Question 6

What is a spiral fracture?

Answer 6

Fracture line is oblique and encircles portion of the shaft

Question 7

What is a comminuted fracture?

Answer 7

Multiple bone fragments - becomes more common with age as bones ossify

Question 8

What is a compression or crush fracture?

Answer 8

Often seen in vertebral bodies with compression of trabecular bone

Question 9

What is a greenstick or incomplete fracture?

Answer 9

Bone is incompletely fractured with a portion of cortex and periosteum remaining intact on the compression side

Question 10

What is a pathological/secondary fracture?

Answer 10

Fracture occuring in bones weakened generally or in a localised region by disease such as metabolic, infective, neoplastic or hereditary bone disease

Question 11

What are the clinical features of a possible fracture?

Answer 11

• Swelling or bruising
• Deformity
• Pain - gets worse when the area is moved or pressure is applied.
• Loss of function
• Bone protruding from the skin

Question 12

What imaging can be used to assess from fractures?

Answer 12

• X-ray
• CT
• MRI

Question 13

What are the 5 stages of bone healing?

Answer 13

1. Haematoma
2. Organization
3. Callus formation
4. Enchondral Ossification
5. Remodelling

Question 14

What occurs in the first stage of bone healing?

Answer 14

Haematoma Formation

• Lacerated medullary blood vessels leak ⇒Blood rapidly coagulates
• Osteocytes near fracture surface starve (due to vessel thrombosis) -> broken ends of bone become necrotic
• Acute inflammatory response to necrotic tissue -> production of granulation tissue by fibroblasts -> formation of reparative granuloma

Question 15

What occurs in the second stage of bone healing?

Answer 15

• Organization - Intramembranous Ossification
  
  • Mesenchymal cells differentiate into osteoblasts and migrate into granulation tissue
  • Angiogenesis also occurs

Question 16

What occurs in the Third stage of bone healing?

Answer 16

Callus Formation

• Primary Callus - Collagen is deposited along fibrin scaffold (new bon matrix synthesis) - osteoid from osteoblasts
• Secondary Callus - Bone formation in periosteum (woven bone) -> converts primary external callus into hard secondary callus - clinical union

Question 17

What occurs in the fourth stage of bone healing?

Answer 17

Modelling/Enchondral ossification

• Capillary ingrowth - osteoblasts follow capillary bed
• Mineralisation of osteoid - Occurs due to osteoclast and osteoblast activity
• Bridging of fracture gap - radiological union

Question 19

What occurs in the fifth stage of bone healing?

Answer 19

Remodelling/completion

• Woven bone is replaced by lamellar bone, according to wolffs law (form follows function)
• Under load, bone is gradually strengthened along the lines of stress

Question 20

What is the sequence of bone healing?

Answer 20

Question 21

How long does it take for haematoma and organisation to occur?

Answer 21

0-2 weeks

Question 22

How long does it take for callus formation and modelling to occur?

Answer 22

3-6 weeks

Question 23

How long does remodelling of bone take?

Answer 23

1-2 years

Question 24

What host factors can impair bone healing?

Answer 24

• Age
• Co-morbidities - osteoporosis, infection
• Nutritional status
• Hormonal status
• Medications - steroids, NSAIDs
• Smoking
• Recent trauma

Question 25

What local factors influence bone healing?

Answer 25

• Soft tissue injury
• Bone loss
• Radiation
• Tumour
• Distraction
• Infection
• Blood supply

Question 26

What is spontaneous fracture healing?

Answer 26

Most common mode of healing

Close together but not apposed, with intervening haematoma and variable displacement/angulation

Question 27

What is contact healing of a fracture?

Answer 27

• Occurs between adapted fragments - < 0.1mm between and neutralisation of interfragmentary strain
  
  • Osteoclasts forming cutting cones ⇒ traverse the fracture line
  • Accompanied by capillaries and osteoblasts - form lamellar bone ⇒ Haversian Remodelling
• NO FORMATION OF PERIOSTEAL CALLUS - if callus forms -> sign of instability (irritation callus)

Question 28

What is gap healing?

Answer 28

• Occurs if there is a gap after internal fixation
• Haversian remodelling does not start until gap has been filled with woven bone scaffolding
• Lamellar bone is deposited perpendicular to the long axis

Question 29

What problems can occur with fracture healing?

Answer 29

• Delayed union
• Non-union
• Malunion
• Avascular necrosis

Question 30

What is delayed union?

Answer 30

Fracture healing takes about twice as long as expected for a specific location

Question 31

What is non-union?

Answer 31

No further progress towards union within 6-9 months

Types include atrophic, hypertrophic, and infected non-union

Question 32

What is atrophic non-union?

Answer 32

• Gap at fracture site, bone loss - soft tissue interposition or pathological bone – infection, tumour, AVN, etc
• Bone resorption due to infection or impaired blood supply

Question 33

What is hypertrophic non-union?

Answer 33

Attempt at healing, but fracture site too mobile

• Rich in callus - elephant foot
• Poor in callus - horse hoof

Question 34

What is infected non-union?

Answer 34

Osteomyelitis - causes unstable fixation

Question 35

What is mal-union?

Answer 35

Fracture has healed, but not in an anatomically correct position

Question 36

What is Avascular Necrosis?

Answer 36

Loss of blood supply, resulting in bone necrosis

Question 37

What are the classic fractures that can result in avascular necrosis?

Answer 37

• Hip (intracapsular - #NOF)
• Scaphoid
• Talus

Question 38

How do bones heal by surgical ORIF and compression?

Answer 38

Primary bone healing

Question 39

What is an ORIF?

Answer 39

Open Reduction internal fixation

Open reduction” means surgery is needed to realign the bone fracture into the normal position. “Internal fixation” refers to the steel rods, screws, or plates used to keep the bone fracture stable in order to heal the right way and to help prevent infection.

Question 40

What can be seen in the following radiograph?

Answer 40

Transverse fracture of the tibia shaft

Question 41

What does the following radiograph show?

Answer 41

Oblique diaphyseal fracture of femur

Question 42

What is the following?

Answer 42

Displaced spiral fracture of the proximal femoral shaft

Question 43

What can be seen in the following radiograph?

Answer 43

Comminuted Humeral Shaft Fracture

Question 44

What can be seen in the following?

Answer 44

Comminuted olecranon fracture

Question 45

What can be seen on the following radiograph?

Answer 45

Greenstick fracture of distal radius

Question 46

What can be seen in the following radiograph?

Answer 46

Greenstick fracture of the 3rd metatarsal