Bone and Joint Infections

Question 1

What is arthroplasty?

Answer 1

Putting in an artificial joint

Question 2

What is resection arthroplasty?

Answer 2

Taking a disease joint out and replacing this with an artificial joint

Question 3

What is a revision arthroplasty?

Answer 3

Re-operating on an artificial joint

Question 4

What is arthrodesis?

Answer 4

Fusing two bones together

Question 5

What is pseudo-arthrosis?

Answer 5

Allowing two bones to articulate against one another but without a joint

Question 6

Septic arthritis is a medical emergency. T/F?

Answer 6

True

Question 7

Why should septic arthritis be treated as a medical emergency?

Answer 7

Untreated joint infection can result in loss of cartilage leading to OA in later life and can cause severe sepsis

Question 8

How does septic arthritis present?

Answer 8

Fever, single hot joint (commonly knee or hip), loss of movement, pain

Question 9

What investigations should be done in septic arthritis?

Answer 9

Blood cultures, joint aspirate, FBC, CRP, imaging

Question 10

What pathogens commonly cause septic arthritis?

Answer 10

S.aureus (MSSA, MRSA)

Streptococci (S.pyogenes)

Question 11

What pathogens are less common causes of septic arthritis?

Answer 11

H.influenzzae
Kingella
N.meningitidis
N.gonorrhoeae
E.coli
P.auruginosa
Salmonella species

Question 12

What is the minimum length of time that septic arthritis should be treated with IV antibiotics?

Answer 12

2 weeks

Question 13

What are the risk factors for the development of prosthetic joint infections in primary arthroplasty?

Answer 13

RA
Diabetes
Obesity
Poor nutritional status
Concurrent UTI
Steroids
Malignancy

Question 14

What are the risk factors for the development of prosthetic joint infections in revision arthroplasty?

Answer 14

Prolonged operating room time

Pre-op infection (teeth, skin, UTI)

Question 15

Local spread is more common than haematogenous spread for prosthetic joint infections. T/F?

Answer 15

True

Question 16

Which organisms causing prosthetic joint infections commonly spread locally?

Answer 16

Organisms from the skin surface

Question 17

When does prosthetic joint infection which has local spread usually manifest?

Answer 17

Immediate post-op period

Question 18

Why does a prosthesis require fewer bacteria to establish sepsis than in soft tissue?

Answer 18

Avascular surface allows survival of bacteria as it protects bacteria from circulating and immunological defences and most antibiotics
Cement can inhibit phagocytosis and lymphocyte/complement function

Question 19

What is the presentation of a prosthetic joint infection?

Answer 19

Pain
Effusion
Warm joint
Fever
Systemic symptoms
Loosening of joint on X-Ray
Discharging sinus
Mechanical dysfunction

Question 20

Which antibiotic is given as prophylaxis to prevent prosthetic joint infection?

Answer 20

Cephalosporin

Question 21

How long before skin incision should cephalosporin be given to prevent prosthetic joint infection?

Answer 21

30-60 minutes

Question 22

Explain the DAIR method of treating prosthesis infection?

Answer 22

Debride, antibiotics, implant retained
Can be used if prosthesis infection is acute <30 days since insertion, is still mechanical function
Joint washed out to reduce burden of infection, then IV antibiotics started for 4-6 weeks

Question 23

When would an infected prosthetic joint need to be removed?

Answer 23

If infection occurs >30 days after surgery

Question 24

What procedures can be used to remove/replace an infected prosthetic joint?

Answer 24

Girdlestone procedure
One stage revision
Two stage revision

Question 25

Why do the chances of success and cure of infection reduce with each revision surgery to replace am infected prosthetic joint?

Answer 25

Anatomical distortion

Infection becomes harder to suppress

Question 26

What samples are preferred over a surface swab when trying to culture the causative organism of a prosthetic joint infection?

Answer 26

Tissue
Pus
Fluid

Question 27

Combination therapies including which antibiotic have the greatest success of treating prosthetic joint infection?

Answer 27

Rifampicin

Question 28

Antibiotics should be started pre-operatively when treating a patient with prosthetic joint infection. T/F?

Answer 28

False - unless the patient has life-threatening infection

Question 29

What is osteomyelitis?

Answer 29

Progressive infection of the bone characterised by the death of the bone and the formation fo sequestra

Question 30

Osteomyelitis can spread via contiguous spread due to…?

Answer 30

Overlyign infection e.g. cellulitis ulcer
Trauma
Surgical inoculation

Question 31

Acute osteomyelitis is more common in which age group?

Answer 31

Children

Question 32

Anaerobes can cause osteomyelitis. T/F?

Answer 32

True

Question 33

How is osteomyelitis treated?

Answer 33

Surgery to debulk the infection back to health bone and manage the dead space that remains with muscle flaps
Infected fractures stabilised
Sinuses derided
IV antibiotics 4-6 weeks

Question 34

What tissue does diabetic foot infection normally affect?

Answer 34

Bone but can also involve the joints

Question 35

What is vertebral discitis?

Answer 35

Infected of a disc space and the adjacent vertebral end plates

Question 36

What are the possible complications of vertebral discitis?

Answer 36

Cord compression
Paraplegia
Disability

Question 37

What are the possible causes of vertebral discitis?

Answer 37

Septic arthritis
Osteomyelitis
Tuberculosis infection