Lecture 3: Injury and healing

Question 1

What are the 3 mechanisms of bone fracture?

Answer 1

• trauma (low energy, high energy)
• stress (abnormal stresses on normal bone)
• pathological (normal stresses on abnormal bone)

Question 2

What are the different types of fracture patterns?

Answer 2

SOFT TISSUE INTEGRITY - open or closed
BONY FRAGMENTS - greenstick, simple or comminuted
DISPLACEMENT - displaced or undisplaced

Question 3

What is an open fracture?

Answer 3

bone has broken through skin

Question 4

What is a closed fracture?

Answer 4

skin is not broken

Question 5

What is a displaced fracture?

Answer 5

bone breaks into 2 or more pieces and moves out of alignment

Question 6

What is a non-displaced/undisplaced fracture?

Answer 6

bone breaks but doesn’t move out of alignment

Question 7

What is a greenstick fracture?

Answer 7

an incomplete fracture in which the bone is bent, occurs most often in children

Question 8

What is a simple fracture?

Answer 8

a fracture of the bone only, without damage to the surrounding tissues or breaking of the skin.

Question 9

What is a comminuted fracture?

Answer 9

bone breaks into several pieces

Question 10

What is an example of high energy trauma?

Answer 10

car crash

Question 11

What is an example of low energy trauma?

Answer 11

falling down

Question 12

How can stress lead to stress fractures?

Answer 12

• stress exerted on bone is greater than bones capacity to remodel
• bone weakening
• stress fracture
• risk of complete fracture

Question 13

3 examples of weight-baring bones?

Answer 13

• tibia
• metatarsals
• navicular
  related to athletes, occupation, military, female athlete triad

Question 14

What are the 3 components of the female athlete triad?

Answer 14

• disordered eating
• amenorrhea
• osteoporosis

Question 15

What are some pathological disorders affecting bones?

Answer 15

• osteoporosis
• malignancy (cancer)
• vitamin D deficiency
• osteomyelitis
• osteogenesis imperfecta
• Paget’s disease

Question 16

What is osteopenia?

Answer 16

a medical condition in which the protein and mineral content of bone tissue is reduced, but less severely than in osteoporosis.

Question 17

What is osteoporosis?

Answer 17

a medical condition in which the bones become brittle and fragile from loss of tissue, typically as a result of hormonal changes, or deficiency of calcium or vitamin D.

Question 18

What causes a disrupted microarchitecture in bone?

Answer 18

if osteoclast activity > osteoblast activity

Question 19

Is osteoporosis more common in males or females?

Answer 19

females

Question 20

Who can get postmenopausal osteoporosis?

Answer 20

women aged 50 - 70

Question 21

Who can get senile osteoporosis?

Answer 21

people aged over 70

Question 22

What is secondary osteoporosis and who can get it?

Answer 22

osteoporosis that is a result of hypogonadism, glucocorticoid excess, alcoholism etc. (due to secondary factors)
can happen to anyone at any age, 60% males

Question 23

What is osteopenia and osteoporosis associated with?

Answer 23

fragility fractures - hip, spine, wrist (where low energy trauma can lead to fractures)

Question 24

What primary malignant tumour metastasize to bone?

Answer 24

• prostate (blastic - fill bone with extra cells)
• breast (blastic or lytic)
• kidney (lytic - destroy bone material)
• thyroid (lytic)
• lung (lytic)

Question 25

Name some primary bone cancers?

Answer 25

- osteosarcoma - chondrosarcoma - Ewing sarcoma - chordoma

Question 26

5 causes of vit D deficiency?

Answer 26

1. malabsorption or insufficient diet 2. inadequate sun exposure 3. liver disease 4. renal disease 5. receptor defects

Question 27

What does vit D deficiency cause in children?

Answer 27

Rickets (bowing of legs) - before physis closure

Question 28

What does vit D deficiency cause in adults?

Answer 28

osteomalacia - after physis closure, weaker bones

Question 29

What is osteogenesis imperfecta?

Answer 29

'brittle bone disease' hereditary - autosomal dominant or recessive - decreased type 1 collagen due to --> decreased secretion, production of abnormal collagen - results in insufficient osteoid production - effects: bones, hearing, heart, sight

Question 30

What is Paget's disease?

Answer 30

- aetiology: genetic + acquired factors - excessive bone break down and disorganised remodelling --> deformity, pain, fracture or arthritis - may transform into malignant disease - 4 stages: (1) osteoclastic activity, (2) mixed osteoclastic-osteoblastic activity, (3) osteoblastic activity, (4) malignant degeneration

Question 31

What is Wolff's law?

Answer 31

bone grows and remodels in response to forces that are placed on it

Question 32

What are the stages of fracture healing?

Answer 32

WEEK 1: haematoma formation, release of cytokines and granulation tissue WEEKS 2-4/1-4 MONTHS: soft callus formation (type II collagen - cartilage), converted to hard callus (type I collagen - bone) 4-12 MONTHS: callus responds to activity, external forces, functional demands and growth, excess bone is removed

Question 33

What is primary bone healing?

Answer 33

intermembranous healing, absolute stability (involves a direct attempt by the cortex to re-establish itself after interruption without the formation of a fracture callus) might involve plate and screws

Question 34

What is secondary bone healing?

Answer 34

- endochondral healing - involves responses in the periosteum and external soft tissues - relative stability (involves the classical stages of injury, haemorrhage inflammation, primary soft callus formation, callus mineralization, and callus remodelling)

Question 35

Outline fracture healing times?

Answer 35

``` 3-12 weeks depending on site Signs of healing visible on x-ray from 7-10 days - phalanges: 3 weeks - metacarpals: 4-6 weeks - distal radius: 4-6 weeks - forearm: 8-10 weeks - femur: 12 weeks - tibia: 10 weeks ```

Question 36

What are the 3 stages of fracture management?

Answer 36

- reduce - hold - rehabilitate

Question 37

What is reduction in fracture management?

Answer 37

realignment of the bone to prevent deformities OPEN: surgical incision made to expose fragments and put them back in proper position (can be mini or full exposure) CLOSED: displaced or fractured bone fragments are manipulated back into proper position or alignment w/o surgically exposing them (manipulation or traction which can be skin e.g. cast/bandaging or skeletal e.g. pins in bones)

Question 38

What is the hold phase of fracture management?

Answer 38

choosing how to hold the fracture - if it's closed then use plaster or traction (skin or skeletal - pins in bones) might need fixation

Question 39

What is fixation in fracture management?

Answer 39

stabilizing the fractured bone can be: - external: metal outside skin (can be monoplanar or multiplanar) - internal: metal underneath skin Internal can be: - intramedullary: into canal of bone (pins and nails) - extramedullary: into surface of bone (plates/screws and pins)

Question 40

What is the rehabilitate phase of fracture management?

Answer 40

- use (pain relief, retrain) - move - strengthen - weight-bear to reverse effects of muscular atrophy

Question 41

What needs to be considered in fracture management?

Answer 41

- is the fracture displaced? - is it stable? (soft tissues OK?, other illnesses?) or - is it at a joint surface? (what does the patient think)

Question 42

What is soft tissue injury?

Answer 42

INJURY TO: muscle - force and motion ligament - connect bone to bone tendon - connect muscle to bone

Question 43

What is tendinopathy?

Answer 43

pathologies of the tendon - tendinosis (abnormal thickening) - tendinitis (inflammation) - rupture

Question 44

Ligament injury classifications?

Answer 44

Grade I - slight incomplete tear - no notable joint instability Grade II - moderate/severe incomplete tear - some joint instability, one ligament may be completely torn Grade III - complete tearing of 1 or more ligaments, obvious instability, surgery usually required

Question 45

What are the phases of ligament healing?

Answer 45

- inflammatory phase, 1-7 days, fibrin clot formed in ligament tears - proliferation phase, 7-21 days, tendons and ligaments weakest, tensile strength builds - remodelling, >14 days, tendons and ligaments heal with scar tissue that reduces ultimate strength causes adhesions - maturation, weeks to years, max. strength reached within a year

Question 46

What factors affect tissue healing?

Answer 46

- mechanical environment - movement, forces | - biological environment - blood supply, immune function (autoimmune conditions), infection, nutrition

Question 47

What are the effects of immobilisation on injured ligamentous tissue?

Answer 47

GOOD - less ligament laxity (lengthening) BAD: - less overall strength of ligament repair scar - protein degradation exceeds protein synthesis (collagen quantity) - production of inferior tissue by blast cells - resorption of bone at site of ligament insertion - build tissue tensile strength (50% in 6-9 weeks)

Question 48

What are the benefits of mobilisation (movement) on injured ligamentous tissue?

Answer 48

- ligament scars are wider, stronger and more elastic | - better alignment/quality of collagen