Orthopaedic Infections

Question 1

What type of bone does osteomyelitis affect?

Answer 1

compact, spongy and bone marrow

Question 2

What is infection in osteomyelitis usually caused by?

Answer 2

bacteria, occasionally fungal

Question 3

How can organisms infect bone in osteomyelitis?

Answer 3

trauma, surgery or indirectly by haematogenous spread

Question 4

In osteomyelitis, what causes osteolysis?

Answer 4

enzymes from leukocytes

Question 5

What impairs local blood flow in osteomyelitis, making it hard to eradicate?

Answer 5

pus formation

Question 6

What is the name for a dead fragment of bone which can form in osteomyelitis which usually breaks off?

Answer 6

sequestrium

Question 7

At what point in osteomyelitis will antibiotics alone not cure the infection?

Answer 7

once an equestrium has formed

Question 8

What is the name for new bone which will form around the area of necrosis in osteomyelitis?

Answer 8

an involucrum

Question 9

In the absence of recent surgery, who is acute osteomyelitis likely to occur in?

Answer 9

children or immunocompromised

Question 10

In children, what to the metaphyses of long bones contain which can result in accumulation of bacteria and infection spreading towards the epiphysis?

Answer 10

abundant tortuous vessels with sluggish flow

Question 11

In neonates and infants, certain metaphyses are intra articular, including what? What does this mean can happen?

Answer 11

proximal femur, proximal humerus, radial head and ankle

infection can spread into joint causing septic arthritis to also occur

Question 12

What do infants have which may cause an abscess to extend widely along the subperiosteal space?

Answer 12

loosely applied periosteum

Question 13

What is Brodie’s abscess?

Answer 13

children develop subacute osteomyelitis with a more insidious onset, where bone reacts by walling off the abcess with a thin rim of sclerotic bone

Question 14

What does chronic osteomyelitis develop from?

Answer 14

untreated acute osteomyelitis

can be associated with a sequestrum/involucrum

Question 15

In adults, where does chronic osteomyelitis tend to be?

Answer 15

axial skeleton with haematogenous spread from pulmonary or urinary infections

Question 16

What may be a cause of peripheral chronic OM?

Answer 16

internal fixation or previous open fracture

Question 17

What can cause chronic OMG particularly in the spine through haematogenous spread from primary lung infection?

Answer 17

TB

Question 18

Name the causative organisms for osteomyelitis in newborns (younger than 4 months).

Answer 18

Staph aureus, enterobacter sp, and group A and B strep

Question 19

Name the causative organisms for osteomyelitis in children (4 months to 4 yrs).

Answer 19

staph aureus, enterobacter sp, group A strep, haemo influenza (reduced with vaccine),

Question 20

Name the causative organisms for osteomyelitis in children aged 4 to adults?

Answer 20

staph aureus

occasionally enterobacter or streptococcus

Question 21

Name the causative organisms for osteomyelitis in sickle cell anaemia patients.

Answer 21

Staph aureus most common, also Salmonella (unique to sickle cell patients)

Question 22

How can osteomyelitis be classed?

Answer 22

superficial (affects outer surface of bone) OR medullary
localized
diffuse (segment of bone is infected leading to skeletal instability)

Question 23

How is acute osteomyelitis treated?

Answer 23

best guess antibiotics firstly (Fluclox)

unless abscess formation - need surgical drainage

Question 24

What should be done if acute osteomyelitis fails to resolve after first line of antibiotics?

Answer 24

second line antiBs

or surgery to gain samples for culture

Question 25

How can chronic osteomyelitis be treated?

Answer 25

NOT by antibiotics alone ALso need surgery to gain deep bone tissue cultures, to remove sequestrum and excise any infected or non viable bone (DEBRIDEMENT)

Question 26

What is a problem with debridement?

Answer 26

may result in instability, bone must be stabilized by internal or external fixation

Question 27

What is the advantage of external fixation?

Answer 27

bone can be subsequently lengthened if it has been shortened as a result of the debridement

Question 28

What are continued for several weeks after surgery to treat chronic OM?

Answer 28

IV antibs

Question 29

Who are at particular risk of osteomyelitis of the spine?

Answer 29

poorly controlled diabetics, IV drug users, immunocomp

Question 30

What is the commonest location where in the spine which OM can present?

Answer 30

lumbar spine

Question 31

How does a patient present with OM of the spine?

Answer 31

insidious onset of back pain which is constant and unremitting

Question 32

What are signs of spinal OM?

Answer 32

muscle spasm spinal tenderness may have systemic upset

Question 33

Severe cases of spinal OM may have lower motor neurone/cauda equine syndrome below where and upper motor neurone and myelopathy above where?

Answer 33

L1

Question 34

What may vertebral collapse lead to in spinal OM?

Answer 34

kyphosis vertebra plana (flat vertebra) disc space may reduce

Question 35

What should also be considered in spinal OM?

Answer 35

endocarditis

Question 36

What treatment is given for spinal OM?

Answer 36

high dose IV antibiotics after CT guided biopsy to gain tissue culture may need for several months May need surgery - debridement, stabilization, fusion of vertebrae

Question 37

How does septic arthritis present?

Answer 37

severely painful, red, hot swollen and tender joint (similar to gout)

Question 38

How do pathogens spread to the joint in septic arthritis?

Answer 38

often via the blood or from adjacent tissues | Or from direct penetration e.g. rose thorn, tooth penetration

Question 39

What is the most common cause of septic arthritis?

Answer 39

staph aureus

Question 40

In whom is E.coli a cause of septic arthritis?

Answer 40

elderly, immunocomp, IV drug users

Question 41

Do bacterial infections cause irreversible or reversible damage to hyaline cartilage in joints?

Answer 41

can be irreversible within days

Question 42

What can metaphyseal osteomyelitis lead to?

Answer 42

septic arthritis

Question 43

What should be suspected if more than on joint or bone is affected by septic arthritis?

Answer 43

endocarditis

Question 44

What should be done for any joint suspected of being septic?

Answer 44

aspiration before antibiotics are given | a single dose of antibiotics can lead to a falsely negative gram stain and culture

Question 45

What is the normal treatment for septic arthritis?

Answer 45

surgical washout

Question 46

What can act as a very effective culture medium for bacteria to thrive on in soft tissues?

Answer 46

haematoma

Question 47

How do bacteria normally enter the operative site during surgery?

Answer 47

from patient's own skin

Question 48

What is there a risk of when a deep infection complicates a fracture fixation?

Answer 48

chronic osteomyelitis | non union of fracture

Question 49

Name a bacteria which causes a more low grade infection, most often diagnosed late?

Answer 49

staph epidermis and enterococcus

Question 50

What is the treatment for orthopaedic infection?

Answer 50

surgery (before antibs)