Fractures and Dislocations Flashcards Preview

Muscluloskeletal Systems > Fractures and Dislocations > Flashcards

Flashcards in Fractures and Dislocations Deck (35):
1

What is a fracture?

Break in structural continuity of bone

May be a crack, break, split, crumpling or buckle

2

Give 3 broad reasons why bones fail

High energy transfer in normal bones:
-Takes a lot

Repetitive stress in normal bones:
-Stress fracture

Low energy transfer in abnormal bones:
-Osteoporosis
-Osteomalacia, metastatic tumour
-Other bone disorders

3

What is Wolff's law in relation to bone shape?

Bone is laid down where it is needed and removed where it is not needed

("form follows function")

4

What 7 criteria should you cover when you are describing a fracture?

-Mechanism and energy of injury
-Skin and soft tissues
-Site
-Shape
-Comminution
-Deformity
-Associated injuries

5

What are the 3 aims in treating fractures?

Relieving Pain
Restoring Function
(Saving Life)

6

What is the key to understanding fractures?

SOFT TISSUE DAMAGE

(fractures are a form of soft tissue damage with a broken bone)

7

How will a severe soft-tissue injury effect fracture healing?

Delay healing

8

All severe soft tissue injuries require urgent treatment.

Give some examples

Open fractures
Vascular injuries
Nerve injuries
Compartment syndromes
Fracture/ dislocations

9

There are many different treatments for fractures

What does your choice depend on?

(6 possible)

Fracture
Bone
Soft tissue
Patient
Facilities (!)
Abilities of surgeon (!)

10

What percentage of fractures have delayed or impaired healing?

5-10%

11

How does fracture healing differ from soft injury repair?

(Think about how bone and soft tissue heal)

Soft tissues heal by replacing injured tissue with a fibrous scar

Bone heals by regeneration of normal bony anatomy

12

Bone heals by the formation of callus

What is callus?

An intermediary stabilising structure fromed after a fracture, which has cartilaginous grwoth plate characteristics and results in eventual

13

Descrube the 3 phases of bone healing

Inflammatory:
-24-72h
-Mesenchymal
-10% of healing time

Reparative
-From 2 days
-Chondral and osseous
-40% of healing time

Remodelling
-From middle of repair phase
-Osseous
-70% of healing time

(NOTE: phases overlap so percentage healing time wont add up to 100)

14

Describe the 7 cellular events in fracture repair

(Immediate response to injury)

Haematoma formation

Release of vasoactive mediators (e.g. nitric oxide), cytokines

Proliferation of undifferentiated cells - migration, recruitment, proliferation, differentiation

Invasion by inflammatory cells (macrophages, PMNs)

Organisation of clot into fibrous tissue by fibroblasts

Formation of reparative granuloma

Vessel thrombosis and osteocyte death

15

Describe the 4 cellular events in intra-membranous ossification

Differentiation of osteo-progenitor precursor cells into osteoblasts

Angiogenesis

Collagen deposited along fibrin scaffold - new bone matrix synthesis (osteoid from osteoblasts - uncalcified mass = primary callus)

Bone formation in periosteum (woven bone) - converts primary external callus into hard secondary callus - clinical union)

16

Describe the 5 cellular events in endochondral ossification

Bone formation in callus similar to bone formation in growth plate

Osteoblasts follow capillary ingrowth

Synthesis of osteoid (un-calcified mass) - becomes mineralised to give speckled calcification

Formation of "mixed spiculae" (immature bone and cartilage)

Bridging of fracture gap - radiological union

17

Describe the 8 cellular events in remodelling

Osteoblastic and osteoclastic activity

Osteoclastic cutting cones

Consolidation

Remodelling of woven bone, according to Wolff's law

Lamellar bone more efficient, so volume decreases

Cancellous bone remodels at trabecular level

Longest stage

Remodelling of some deformities but not others

18

Measurement of fracture healing can be done by 4 different methods.

One of which is clinical examination. When should this be done for adults and children in lower and upper limbs?

Upper limb:
-Adult -> 6-8 weeks
-Child -> 3-4 weeks

Lower limb:
-Adult -> 12-16 weeks
-Child -> 6-8 weeks

19

How can radiological measurement determine fracture healing?

(2 marks)

Bridging callus formation

Remodelling

20

How can you biomechanically measure fracture healing?

Stiffness

21

When is a frcature healed?

(3 marks)

When patient can bear weight

When X-ray says so

When remodelling complete

22

What host factors can influence fracture repair?

(3 marks)

Nutritional and hormonal status

Drugs

CNS injury

23

What local factors influence fracture repair?

(10 marks)

Soft tissue injury
Bone loss
Radiation
Tumour
Distraction
Tissue interposition
Blood supply
Infection
Type of bone
Synovial fluid

24

Give 4 bony problems of fracture healing

Delayed union

Non-union
-Atrophic
-Hypertrophic
-Infected

Mal-union

Avascular necrosis

25

What is mal-union?

Fracture has healed, but not in an anatomically-correct position

26

What is delayed union?

Healing takes longer than average for that fracture in that individual

27

What is nonunion?

No further progress towards union

28

What problems with treatment may lead to delayed or non-union?

Inadequate immobilisation

Distraction of fracture by fixation device or traction

Repeated manipulations

Periosteal stripping and soft tissue damage at operation

Anatomical vascular suspectibility
-e.g. femoral neck, scaphoid, talus (distal tibia)

29

What is the difference between the 3 types of non-union?

Atrophic:
-Gap at # site, bone loss- soft tissue interposition or pathological bone- infection, tumour, AVN etc

Hypertrophic
-Attempt at healing, but # site too mobile
-horses hoof, elephant's foot

30

How do you manage infeted non-union?

Suspect

Diagnose

Remove dead, devitalised and infected tissue

Obtain organism (if possible)

Treat infection and stabilise fracture

31

What is avascular necrosis?

What classical fractures does it occur?

Loss of blood supply

Any bone fragment stripped of soft tissue attachments

"Classical fractures"
-Hip (intracapsular - NoF)
-Scaphoid
-Talus

32

What is the aim of fracture management?

Preserve life
Preserve limb
Preserve function

33

What are the aims of treating fractures?

Relieving pain
Restoring function
(Saving life?)

34

What score can you use to determine when it may be best to perform an amputation?

Mangled Extremity Severity Score (MESS)

35

What 2 factors give a very poor prognosis regardless of MESS score?

Warm ischeamic time >6hrs
Tibial nerve divided