Elective surgery

Question 1

What are the complications of joint replacement?

Answer 1

Early local complications: Infection, dislocation, instability, fracture, leg length discrepancy, nerve injury, bleeding, arterial injury / ischaemia, bleeding, DVT.

Early general complications: Hypovolaemia, shock, acute renal failure, MI, ARDS, PE, chest infection, urine infection. There is approximately a 0.2% chance of dying as a result of a hip or knee replacement.

Late local complications: Infection (from haematogenous spread), loosening, fracture, implant breakage, pseudotumour formation.

Question 2

what is the treatment of deep infection diagnosed within the first 2-3weeks?

Answer 2

surgical washout & debridement and prolonged parenteral antibiotic therapy (around 6 weeks) can be attempted to salvage the artificial joint. This strategy is around 50% successful.

Question 3

What is the treatment for deep infections that present for longer than 3 weeks?

Answer 3

Deep infections present for longer than 3 weeks or so tend not to be salvageable by washout as the infecting bacteria adhere to the foreign surfaces and form a Biofilm which prevents the patient’s immune system attacking. In this situation, removal of the infected implants and all foreign material (including cement) which requires extensive surgery is usually required. The patient is usually left without a joint for around 6 weeks and given parenteral antibiotics. Once the infection is under control (wound healed, clean and dry, CRP reduced) a revision (re‐do) joint replacement is performed with more complex joint replacement components. This strategy is around 80‐90% successful in eradicating infection however throughout this process the soft tissues scar and lose elasticity. The joint inevitably stiffens and the overall functional outcome is usually compromised.

Question 4

what is a brodies abscess?

Answer 4

Children can also develop a subacute osteomyelitis with a more insidious onset and where the bone reacts by walling off the abscess with a thin rim of sclerotic bone. This is known as a Brodie’s abscess.

Question 5

What organisms cause osteomyelitis in <4mths?

Answer 5

s.aureus
enterobacter sp
group A and B strep

Question 6

What organisms cause osteomyelitis in 4mth-4yrs

Answer 6

s. aurea, group a strep, haemophilus influenza and enterobacter

Question 7

what organisms cause osteomyelitis in adults?

Answer 7

s. aureus and occasionally enterobacter or strep.

Question 8

What organisms cause osteomyelitis in sickle cell anaemia pts?

Answer 8

s. aureus but salmonella spp quite common and unique to sickle cell

Question 9

What are predisposing factors to osteomyelitis?

Answer 9

Predisposing conditions

    diabetes mellitus
    sickle cell anaemia
    intravenous drug user
    immunosuppression due to either medication or HIV
    alcohol excess

Question 10

What is the investigation for osteomyelitis?

Answer 10

MRI is the imaging modality of choice, with a sensitivity of 90-100%

Question 11

What is the treatment of osteomyelitis?

Answer 11

Flucloxacillin for 6 weeks
clindamycin if penicillin-allergic

Surgery is usually recommended to gain deep bone tissue cultures, to remove any sequestrum and to excise any infected or non‐ viable bone (known as debridement).

Question 12

Who are at particular risk of osteomyelitis of the spine?

Answer 12

Poorly controlled diabetics, intravenous drug abusers and other immunocompromised patients

Question 13

What are common organisms that produce an early prosthetic infection?

Answer 13

Staph. aureus and gram negative bacilli including coliforms.

Question 14

Which organisms cause a more indolent or low grade infection in a prosthesis?

Answer 14

Staph. epidermidis (also known as coagulase negative staphylococci) and enterococcus.

-inevitably diagnosed late (up to a year after surgery) and often requires surgical intervention.

Question 15

Which organisms are assoc. with late onset haemotogenous infection?

Answer 15

Staph. aureus, beta haemolytic Streptococcus and Enterobacter.