Orthopaedic infections

Question 1

What is osteomyelitis?

Answer 1

Infection of bone including compact and spongy bone as well as the bone marrow

Question 2

What kind of infection is involved in osteomyelitis?

Answer 2

Mostly bacterial

Occasionally fungal

Question 3

What are the causes of the bone infection in osteomyelitis?

Answer 3

Trauma

Haematogenous spread

Question 4

What is the name given to a dead fragment of bone?

Answer 4

Sequestrum

Question 5

Which patients are most prone to development of osteomyelitis?

Answer 5

Young
Old
Immunocompromised patients
Those with chronic disease

Question 6

Why is the infection in osteomyelitis difficult to eradicate?

Answer 6

Leucocytes release enzymes which cause osteolysis, forming pus which impairs the blood supply

Question 7

What is an involucrum?

Answer 7

A growth of new bone that forms around a mass of dead or infected bone

Question 8

What in the bony anatomy of children can result in bacterial accumulation within the bones?

Answer 8

In children, the metaphyses of long bones contain abundant tortuous vessels with sluggish flow which can result in accumulation of bacteria and infection spreads towards the epiphysis

Question 9

In which patients might osteomyelitis co-exist with septic arthritis and why?

Answer 9

In neonates and infants, certain metaphyses are intra‐articular including the proximal femur, proximal humerus, radial head and ankle and infection can spread into the joint causing co‐ existent septic arthritis

Question 10

Why might an abscess form in the subperiosteal space in osteomyelitis in infants?

Answer 10

They have a loosely attached periosteum

Question 11

What is a Brodie’s abscess?

Answer 11

Subacute osteomyelitis in children which results in walling off of an abscess by a thin layer of sclerotic bone

Question 12

Where does chronic osteomyelitis tend to occur in adults?

Answer 12

Spine or pelvis, due to haematogenous spread from pulmonary or urinary infection, or from discitis

Question 13

Which causative bacteria is unique to developing osteomyelitis in sickle cell anaemia patients?

Answer 13

Salmonella

Question 14

What tends to be the causative organisms of osteomyelitis in adults?

Answer 14

Staph. aureus
Streptococcal infections
Enterobacter

Question 15

What tends to be the causative organisms of osteomyelitis in newborns (<4 months)?

Answer 15

Staph. aureus
Group A & B strep
Enterobacter

Question 16

What tends to be the causative organisms of osteomyelitis in children? (<4 years)

Answer 16

Staph. aureus
Group A strep
Enterobacter
Haemophilus influenzae

Question 17

How is acute osteomyelitis managed?

Answer 17

“Best guess” antibiotics
Surgical drainage of any abscess
C&S if infection fails to resolve

Question 18

How is chronic osteomyelitis managed?

Answer 18

Antibiotics for suppression of symptoms
Surgery for deep bone tissue biopsy
Debridement of any non-viable bone
Stabilisation of bone if necessary

Question 19

Which patients are at particular risk of osteomyelitis of the spine?

Answer 19

IV drug users
Immunocompromised patients
Patients with poorly controlled diabetes

Question 20

How might osteomyelitis of the spine present?

Answer 20

(Lumbar spine most commonly affected)
Insidious onset back pain - constant and unremitting
Paraspinal muscle spasm
Spinous tenderness
Fever/systemic upset

Question 21

How does septic arthritis present?

Answer 21

Painful, red, hot, swollen joint

Severe pain on movement

Question 22

How can a joint become infected?

Answer 22

Infection of adjacent tissues
Haematogenous spread
History of penetrating wound e.g. tooth or rose thorn injury
Following intra-articular surgery

Question 23

When should endocarditis be considered in a case where the main differential is septic arthritis?

Answer 23

Involvement of more than one joint

Involvement of bone (septic emboli)

Question 24

What is the most common causal bacteria in septic arthritis in adults?

Answer 24

Staphylococcus aureus

Streptococci

Question 25

In which patients is E. coli the most common cause of septic arthritis?

Answer 25

IV drug users
Elderly
Seriously ill

Question 26

What is the most common cause of septic arthritis in young adults?

Answer 26

Neisseria gonorrhoea

Question 27

What is the first course of action with any joint suspected of septic arthritis?

Answer 27

Aspiration of joint fluid

C&S before antibiotics are given

Question 28

What is the treatment for confirmed septic arthritis?

Answer 28

Surgical washout

Question 29

What complications are associated with deep infection of prosthetic joint replacement?

Answer 29

Pain
Poor function
Recurrent sepsis
Chronic discharging sinus formation
Implant loosening

Question 30

What complications are associated with deep infection of fracture fixings and stabilisations?

Answer 30

Chronic osteomyelitis

Non‐union of the fracture

Question 31

Which organisms tend to cause an early infection of a prosthetic replacement?

Answer 31

Staph. aureus

Gram negative bacilli including coliforms

Question 32

Which organisms tend to cause an indolent or “low grade” infection which isn’t usually picked up until much later in a prosthetic replacement?

Answer 32

Staph. epidermidis/coagulase negative staphylococci

Enterococcus

Question 33

Which organisms are associated with much later infection/infection from haematogenous spread of a prosthetic replacement?

Answer 33

Staph. aureus
Beta haemolytic streptococcus
Enterobacter