the bone and joint journal - Aug 2016

1. Antibiotic prophylaxis in
orthopaedic surgery
PRESENTER : Dr CHINTAN N PATEL
CHAIR PERSON : Dr KIRAN S PATIL
Dept of Orthopaedics , J.N. Medical College and
Dr. Prabhakar Kore Hospital and MRC, Belgaum
THE BONE & JOINT JOURNAL
| AUGUST 2016 |

2. ABSTRACT
• Prophylactic antibiotics can decrease the risk of
wound infection and have been routinely
employed in orthopaedic surgery for decades.
• Selection of antibiotics for prophylaxis, timing
and duration of administration is important.
• The health economic costs associated with
wound infections are significant, but appropriate
use of antibiotics can reduce this risk.

3. HISTORY
• Since Alexander
Fleming’s discovery
of penicillin in 1928,
over 100 derivative
compounds have been
discovered.
• Their use has become
integral to orthopaedic
practice for the
prophylaxis and
treatment of
infections.

4. Surgical site infection
• Most SSIs are acquired at the time of surgery,
with airborne organisms and those present on
the patient’s skin being the cause in most cases.
• Humans shed 10 000 bacteria every minute.
• Staphylococcus aureus and coagulase negative
staphylococci such as Staphylococcus
epidermidis, are the most common causative
infective organisms.

5. Surgical site infection
• The overall risk of SSI following surgery for
fractures of the hip has been reported to
be 4.97%, with about a third of these cases
representing deep infection.
• About half of all patients who develop an SSI
following surgery for fracture of the hip will die
within a year.

6. Surgical site infection
• In elective surgery, infection accounts
for about 23% of revisions following
total knee arthroplasty (TKA), and
between 7% and 13% of revisions
following total hip arthroplasty (THA).
• The mortality associated with prosthetic
joint infection (PJI) has been reported to
range between 2% and 18%.

7. TRIALS
• Effectiveness of prophylactic antibiotics in orthopaedic
surgery was confirmed by the 1984 study of Lidwell et al,
funded by the Medical Research Council, which
demonstrated a three-fold reduction in PJI using antibiotic
prophylaxis following THA and TKA.
• Later, in Dutch Trauma Trial, patients with closed
fractures were given a single dose of either a third
generation cephalosporin or a placebo, demonstrated a >
50% reduction in the incidence of superficial and deep
infections from 8.3% in the placebo to 3.6% with
antibiotics.

8. The timing of Prophylaxis
• The first 2 hours following either incision or
contamination is the most important period for the
concentration of antibiotics to be maintained.
• It is best practice to administer antibiotics within an
hour of the incision, although administration within
2 hours is acceptable.
• Failure to administer antibiotics within this two-
hour window is associated with a 2 to 6 fold
increase in the rate of SSI.
• When a tourniquet is used, a 10 minute interval
between administration of the antibiotic and
inflation of the tourniquet is the minimum required.

9. Prophylaxis: which antibiotic?
• Cephalosporins offer cover against most
Staphylococcus aureus and some Gram negative
organisms but do not cover 90% of coagulase-
negative staphylococci (CoNS).
• As with all β-lactam antibiotics, cephalosporins
are ineffective against MRSA.
• Cephalosporins have a good safety profile, a
long half-life and good penetration in bone,
synovium and muscle.
• In 2008, the AAOS recommended cefazolin or
cefuroxime for patients undergoing arthroplasty.

10. Other Penicillins
• Flucloxacillin is a penicillinase-resistant
penicillin offering good cover against
Staphylococcus aureus (again, it is ineffective
against MRSA and 90% of CoNS), and is
routinely used as first-line treatment for
Staphylococcus aureus infection
• Co-amoxiclav, a mixture of amoxicillin and
clavulanic acid, a beta-lactamase inhibitor, is the
recommended first-line antibiotic for open
fractures according to the guidelines of the
British Orthopaedic Association (BOA).

11. • The addition of a beta-lactamase inhibitor
renders amoxicillin effective against
resistant strains of Staphylococcus aureus,
Escherichia coli, Haemophilus influenzae,
Bacteroides and Klebsiella spp.
• Clindamycin provides Gram-positive and
anaerobic cover but has no activity against
aerobic Gram-negative bacteria. It is
recommended by the AAOS for patients
with β-lactam allergy.

12. • Quinolones offer excellent oral bioavailability
and provide broad spectrum cover against Gram-
positive and Gram-negative bacteria.
• Experiments in rats suggest that ciprofloxacin
may predispose to delayed or nonunion.
• Teicoplanin is a glycopeptide antibiotic that has
excellent penetration into bone, covers Gram-
positive bacteria including methicillin sensitive
(MSSA) and resistant Staphylococcus aureus,
has a long half-life.

13. Vancomycin
• Vancomycin is another glycopeptide antibiotic
that offers cover against Gram-positive
bacteria including MRSA and MSSA.
• Vancomycin may also be added to
polymethylmethacrylate (PMMA) bone cement
for prophylaxis in arthroplasty,or in antibiotic
spacers or beads for the prevention of infection
in contaminated open fractures.

14. Gentamycin
• Gentamicin is an aminoglycoside antibiotic,
effective against Gram-negative and Gram-
positive bacteria including Staphylococcus aureus.
It is routinely used in combination with
flucloxacillin as prophylaxis in both elective and
trauma surgery.
• Gentamicin is the most common antibiotic additive
to PMMA bone cement and provides local elution
at highly effective antibacterial concentrations.
• Gentamicin-eluting PMMA beads and sponges
may be used in the treatment of contaminated open
fractures.

15. Antibiotics and urinary catheters
• Asymptomatic urinary tract colonisation or bacteriuria is
significantly associated with, superficial and deep joint
infections.
• Sousa et al established in a series of 2479 patients that
asymptomatic bacteriuria (ASB) was an independent risk
factor for PJI.
• Urinary catheterisation has been linked to deep wound
infections in patients with a fracture of the hip, with a
higher incidence of deep sepsis in those who have a
urinary catheter inserted peri-operatively or within five
days of surgery, those who undergo more than two
catheterisations or have a long-term catheter (≥ 21 days).

16. Conclusion
• Antibiotics are an integral component of
orthopaedic practice as prophylactic agents.
• The threat of antibiotic resistance is real.
• Greater awareness and the judicious use of
antibiotics are required if we are to continue to
derive benefit from antibiotics for the prevention
of SSIs and the treatment of bone, joint and soft-
tissue infections.

17. Take home message
• Orthopaedic surgeons must
have an awareness of the
efficacy and indications for
commonly used antibiotics
to ensure good clinical
care in an era of evolving
antibiotic resistance.

18. THANK YOU !