MSK

Question 1

Which cells are involved in the formation of bone?

Answer 1

osteoblast

Question 2

Which cells are responsible for bone resorption?

Answer 2

osteoclasts

Question 3

Describe osteoblasts

Answer 3

;arge
mononuclear
found on surface on surface of bone

Question 4

When do osteoblasts become osteocytes?

Answer 4

whenever they become surrounded by osteoid

Question 5

Describe osteoclastss

Answer 5

large

multinnucleated

Question 6

How is bone resorption regulated?

Answer 6

complex milia of hormones and local cell mediators

Question 7

What happens in the immediate aftermath of a fracture?

Answer 7

haematoma formed

acute inflammatory response

Question 8

What happens within a few days of a fracture?

Answer 8

granulation tissue formed

Question 9

What is the primary callus response?

Answer 9

differentiation of osteoprogenitor cells into bone-forming cells

Question 10

What is the external bridging callus stage?

Answer 10

bone formation bridging the gap where the fracture is

Question 11

What is the remodelling stage in a fractre?

Answer 11

the obvious callus formation on the outside is reduced and streamlines to the shape of what it originally was

Question 12

Label the arrows

Answer 12

blue: osteoblast
red: osteoid

Question 13

What is vital in fracture healing?

Answer 13

complete immobilisation
good oxygen supply
good blood supply

Question 14

What can happen when oxygen supply is poor in distal fractures especially?

Answer 14

cartilage forms instead of bone

Question 15

What 2 areas do fractures complications fall into?

Answer 15

local

systemic

Question 16

What are 5 reasons for early local fracture complications?

Answer 16

infection
blood loss from haemhorrage
dislocation of joint
damage to nerves and vessels
skin loss and soft tissue injury

Question 17

What are the 5 reasons for delayed local fracture complications>

Answer 17

damage to epiphyseal plates
avascular necrosis of bone
secondary osetoarthritis
delayed union
non-union

Question 18

What are 8 reasons for systemic complications in fractures?

Answer 18

cardiac shock and circulatory failure
fat embolus
DVT and pulmonary embolus
respiratory distress syndrome
pneumonia
sepsis
bed sores
DIC (disseminated intravascular coagulation)

Question 19

How long after fracturing a major long bone can a fat embolus occur?

Answer 19

24-72 hrs

Question 20

How long after fracture can a DVT/PE form?

Answer 20

7-10 days if prolonged bed rest

Question 21

What 11 factors can impair healing?

Answer 21

age
malnutrition
diabetes
cancer
radiotherapy
soft tissue injury
compound fracture
large fracture gap
poor immobilisation
infection
ischaemia

Question 22

What is infection in bones called?

Answer 22

osteomyelitis

Question 23

What is an infection in a joint called?

Answer 23

septic arthritis

Question 24

How does acute osteomyelitis present?

Answer 24

septic process
high WCC
high CRP
high ESR
temperature
toxaemic
red/flushed
feeling sick
vomiting

Question 25

Who is affected most by acute osteomyelitis?

Answer 25

babies and young children

Question 26

How long does it take for X-ray changes in acute osteomyelitis?

Answer 26

10 days - too late to make diagnosis

Question 27

What is the most common organism in acute osteomyelitis?

Answer 27

Staph aureus

Question 28

In children younger than 4 what is the most common cause of acute osteomyelitis?

Answer 28

H influenzae

Question 29

What kind of reaction is seen in osteomyelitis?

Answer 29

periosteal reaction

Question 30

What is seen in this picture?

Answer 30

osteomyelitis red: neutrophil polymorphs blue: bone

Question 31

How do you prevent bone infection in fractures?

Answer 31

urgent and thorough debridement of open fractures in theatre on the same day strict aseptic technique appropriate prophylactic antibiotics esp. in metal prosthetic work

Question 32

Who is mostly affected by chronic osteomyelitis?

Answer 32

adults

Question 33

How does chronic osteomyelitis present?

Answer 33

smouldering infection causing bone necrosis and new bone formation this causes marked bone deformity

Question 34

What is seen in the picture?

Answer 34

chronic myelitis | fibrous tissue with some chronic inflammatory cells

Question 35

6 complications of osteomyelitis

Answer 35

``` septicaemia bone deformity secondary arthritis formation of skin sinus squamous carcinoma (Marjolin's ulcer) systemic amyloid ```

Question 36

What is bone/joint TB?

Answer 36

occurs secondary to pulmonary TB

Question 37

Where is bone TB found?

Answer 37

spine | sometimes hips and joints or small bones of hands and feet

Question 38

What is the name of spinal TB?

Answer 38

Pott's disease of the spine

Question 39

What is seen histologically in joint TB?

Answer 39

caseating granulomata caseous necrosis Langerhans multinuclear giant cells cells distributed in horse shoe fashion

Question 40

What spinal deformities can be caused by joint TB?

Answer 40

ankylosis of joints loss of joint movement systemic amyloid

Question 41

What spinal deformities can be caused by joint TB?

Answer 41

ankylosis of joints loss of joint movement systemic amyloid

Question 42

What is systemic amyloid?

Answer 42

misfolded protein becomes resistant to the body's catabolic processes and fibrils deposit extracellularly within tissues, leading to organ dysfunction and death

Question 43

What can be seen in the picture?

Answer 43

caseous necrosis | arrow: giant cells

Question 44

What are the 3 metabolic bone diseases?

Answer 44

osteoporosis osteomalacia Paget's disease

Question 45

What is osteoporosis?

Answer 45

reduction in amount of bone and loss of microarchitecture | leading to weakened bone and pathological fracture

Question 46

What is true about bone mineralisation and osteoblast and clast activity in osteoporosis?

Answer 46

all normal no increased activity just smaller amount of bone

Question 47

7 causes of osteoporosis

Answer 47

``` idiopathic/senility/post-menopausal Cushing's disease/steroids thyrotoxicosis hypogonadism hyperparathyroidism alcohol abuse scurvy ```

Question 48

Who are at risk of osteoporosis due to steroid therapy?

Answer 48

patients with long term asthma IBD transplant treatment

Question 49

How do steroids cause osteoporosis

Answer 49

increased output of glucocorticoids

Question 50

How can thyroxin cause osteoporosis?

Answer 50

stimulates osteoclasts

Question 51

How does hypogonadism cause osteoporosis?

Answer 51

lack of sex hormones results in reduced output of oestrogen and testosterone

Question 52

13 risk factors in osteoporosis

Answer 52

``` female caucasian/asian early menopause sedentary lifestyle slim body build nulliparity (woman who hasn't given birth) amennhorhoea positive family hx smoking alcohol steroids previous fractures low Ca intake ```

Question 53

What can help females in perimenopausal stages for osteoporosis?

Answer 53

HRT

Question 54

When does the critical zone typically occur in bone structure for females?

Answer 54

65-70

Question 55

What is osteomalacia?

Answer 55

reduced mineralisation of the bone

Question 56

What causes osteomalacia?

Answer 56

low serum calcium and phosphate

Question 57

What are the causes of osteomalacia?

Answer 57

``` deficient diet (calcium) lack of sun exposure malabsorption chronic liver disease chronic renal disease hypophosphataemia phenytoin therapy ```

Question 58

What are symptoms of osteomalacia?

Answer 58

``` abnormal blood chemistry - low serum calcium or phosphate osteopenia on X-ray pathological fracture bone pain proximal myopathy ```