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| Journal of the New Zealand Medical Association,
22-August-2008, Vol 121 No 1280
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Antibiotic prophylaxis and invasive dental treatment
in prosthetic joint patients
Darryl Tong, Jean-Claude Theis
The use of antibiotics to prevent infections of heart valves
and prosthetic joints following dental treatment remains controversial. Current
guidelines issued by the American Heart Association (AHA) in
20071 reflect a major change in attitude
resulting in fewer cardiac conditions requiring antibiotic prophylaxis in terms
of infective endocarditis. This change and subsequent modified recommendations
have not translated well to other areas and in particular to patients with
prosthetic joints.
When the AHA released the previous updated guidelines for
antibiotic prophylaxis against bacterial endocarditis in
1997,2 specialty groups subsequently reviewed
their own guidelines and protocols, reflecting the already changing attitudes
towards the use of antimicrobials and the growing problem of microbial
resistance in the community.
These specialty groups included infectious disease
specialists working in conjunction with various surgical specialties to produce
advisory statements on the perioperative use of antibiotics. A good example of
some of this work is the advisory statement from the National Surgical Infection
Prevention Project Group based in Oklahoma and Seattle, consisting of a
multidisciplinary team reviewing the current literature and developing
guidelines and protocols for various surgical specialties which included
cardiothoracic, vascular, colon, orthopaedic and gynaecological
surgery.3
The American Academy of Orthopaedic Surgeons (AAOS) has
published two advisory statements (with one update) regarding antibiotic
prophylaxis for patients with prosthetic joints: one with the American
Urological Association (AUA) and the other with the American Dental Association
(ADA).4–7
The 1997 ADA/AAOS advisory statement followed publication of
the 1997 updated AHA guidelines for antibiotic prophylaxis in bacterial
endocarditis.
The recommendation was that any invasive dental procedure
that causes bleeding in the oral cavity with a resultant significant but
transient bacteraemia should be covered with the appropriate antibiotics in
at-risk patients.4
Table 1 summarises a list of invasive dental procedures.
Table 1. Invasive dental procedures considered
for antibiotic prophylaxis in susceptible patients
*Adapted from Dajani et al,
19972
An updated advisory statement by the ADA/AAOS was issued in
2003 following further literature review. No changes or new recommendations were
issued however a single page statement was included by the AAOS for use as a
patient information leaflet.7
An independent advisory statement was issued by the AAOS/AUA
in 2002 discussing the need for antibiotic prophylaxis for prosthetic joint
patients undergoing urological procedures.5,6
The concluding recommendation was that antibiotic prophylaxis was not indicated
for patients with internal fixation devices nor for total joint replacement
patients in most cases. However, a small group of patients were identified as
being “at risk” as identified by the ADA and AAOS 4 (Table 2).
Table 2. Patients at potential increased risk
of haematogenous total joint infection from dental and urological
procedures
The two advisory statements by the ADA/AAOS clearly state
that routine antibiotic prophylaxis is not indicated for most dental patients
with total joint replacements and show a consistency with the AUA/AAOS
guidelines, especially in identifying the same small group of patients that have
been identified as having a greater risk of infection. Similar guidelines have
also been adopted by the New Zealand Dental Association and by the New Zealand
Orthopaedic Association. 8
Recommendations from orthopaedic surgeons and general
medical practitioners are often at variance from those stated in the guidelines
which lead to confusion resulting in patients receiving antibiotic coverage with
no clear indication. Given this difference in advice, we examined current
clinical practice in New Zealand with respect to antibiotic prophylaxis in
patients with prosthetic joints undergoing dental treatment and compared this
with findings from the literature.
MethodsA postal survey regarding antibiotic prophylaxis in
prosthetic joint patients was sent to all orthopaedic surgeons practicing in New
Zealand. Each questionnaire consisted mainly of questions requiring a simple
“yes” or “no” answer. A systematic review of the English
literature was performed in PubMed® using the key words: dental, antibiotic
prophylaxis and orthopaedic surgery. Data from the questionnaire was compared
with findings and recommendations from the literature.
Results152 questionnaires were posted in a single wave, with 114
respondents giving a response rate of 75%. Almost 94% of respondents recommended
antibiotic prophylaxis for prosthetic joint patients prior to invasive dental
treatment as a general principle and 90% of respondents considered that
antibiotic prophylaxis was necessary as long as there was a prosthetic joint
in situ.
The majority of clinicians follow the AHA guidelines, that
is, a single preoperative oral dose of 2g amoxicillin or 600mg clindamycin if
the patient was allergic to penicillin. Over half did not recommend a 6-hour
postoperative dose. Patients with medical conditions placing them
“at-risk” of prosthetic joint infection were correctly identified by
most orthopaedic surgeons especially those with diabetes and other forms of
immunosuppression. The setting in which dental surgery was performed was not
seen as being important.
The results of the questionnaire are summarised in Table
3.
Table 3. Summary of results.
The literature was evenly sourced from both medical and
dental peer reviewed English language journals.
No randomised controlled trials were identified and
currently no definite scientific evidence exists for the systematic use of
prophylactic antibiotics before dental procedures in patients with prosthetic
joints. In view of the high clinical cost of bacterial infection in cardiac and
prosthetic joint patients most guidelines currently favour the use of
prophylactic antibiotics before invasive dental procedures in all patients
within 2 years of the index surgery and high risk patients for the rest of their
life.
DiscussionThe conservative approach adopted by orthopaedic surgeons
towards antibiotic prophylaxis is understandable due to the potential
catastrophic morbidity associated with prosthetic joint infection (PJI). PJI
carries a significant clinical financial cost; in 1997 the estimated cost
associated with a single episode of PJI (excluding loss of wages or income) was
greater than $50,000 USD.9,10
As the number of joint replacements carried out in New
Zealand and worldwide is increasing steadily the absolute number of prosthetic
joint infections will increase particularly in the elderly with infection
generating comorbidities.
The incidence of PJI has been reported between
1.0–2.5% following primary arthroplasty with up to 60–70% of these
infections caused by staphylococci and 10% caused by streptococci and/or
enterococci. PJI associated mortality has been reported as high as
2.5%.10,11
La Porte et al12 reviewed
the records of 2973 patients who underwent total hip replacement arthroplasty
and found 52 patients with late PJI. Three of the 52 patients with late PJI were
identified as having undergone recent dental procedures lasting greater than 45
minutes with no antibiotic coverage given. These patients were described as
having an infection strongly associated with (but not stated as caused by) their
dental procedures. The overall incidence from this study was 0.1%, well below
the overall risk of haematogenous infection of joints from any source
(0.4–1.7%).13,14
Critics of antibiotic prophylaxis will often raise the issue
of cost, antibiotic resistance and complications in the form of adverse or even
fatal reactions to the antibiotics given. Using bacterial endocarditis as an
example, in 2003 the calculated cost to prevent a single non-fatal case of
endocarditis was $80,000 to $100,000
USD.15
This cost increases when antibiotic prophylaxis is used
inappropriately and given unnecessarily to patients where antibiotic coverage is
not indicated.
From an orthopaedic perspective however, the relative
advantages and disadvantages of antibiotic prophylaxis for prosthetic joint
infection were compared in a cost analysis study by Van Schaardenburg in
2002.16
According to this study, an infected joint prosthesis
carries a mortality of 10–15% with a loss of joint function in
25–50% of those patients surviving the infection. The main argument
therefore in favour of antibiotic coverage would be the prevention of serious
complications but on the other hand this would increase the risk of anaphylaxis,
adverse drug reaction, pharmaceutical costs and bacterial resistance in the
general population. The authors concluded that in a large group of patients with
joint disease including prosthetic joints, antibiotic treatment for skin
infections (Staphylococcus aureus) would be cost effective in
preventing infection, but prophylaxis given for medical and dental procedures
would not be cost effective, except in a small group of at-risk patients,
similar to those identified in the AAOS advisory statement.
The evidence for a late PJI caused by bacteraemia resulting
from a dental procedure is extremely poor and lacking in the current state of
our knowledge despite the fact that the older literature alludes to but does not
provide scientific evidence for a dental
aetiology.17,18 It would appear that the risk
of developing a deep periprosthetic joint infection is greatest at the time of
implantation of the prosthesis and that there is little consensus regarding the
causes of post operative or late PJI.19
Stinchfield et al in 1980 reported a case series of nine
patients with late PJI comparing organisms grown from the infected prosthetic
joint and those identified from blood cultures or distant focus of
infection.17 All nine patients grew the same
organisms from the joint and other sites. Two of the nine patients had a history
of dental treatment prior to the diagnosis of prosthetic joint infection: one
had a dental abscess and grew group G streptococcus and the other had dental
caries and grew S. aureus.
The assumption however cannot be made that these two
patients had PJI related to dental causes: S. aureus does not cause
dental caries and group G streptococci are nosocomial organisms not commonly
known to cause dental abscesses.20
In a review of 2693 patients, Jacobsen and Matthews found
only one instance of late PJI that was temporally related to a dental procedure,
giving an incidence of 0.04%.14
The overwhelming viewpoint of the most recent literature is
that there is no clear evidence for antibiotic prophylaxis in patients with
prosthetic joints undergoing routine dental procedures and that the risk of
adverse drug reaction and anaphylaxis is greater than the risk of PJI in the
majority of cases.21–24 Perhaps a more
common sense approach is to consider the health of the oral cavity from a
periodontal or other odontogenic infection risk standpoint, especially when
performing invasive and dental treatments causing bleeding such as dental
extraction and deep root scaling.25
Even when antibiotic prophylaxis is administered correctly
according to guidelines, patients may still be at risk of developing a PJI after
dental procedures.26
From the results of the survey, it would appear that over
90% of practicing orthopaedic surgeons in New Zealand do not follow the recent
guidelines on the use of antibiotic prophylaxis in patients with prosthetic
joints undergoing invasive dental treatment. This inconsistency leads to
confusion not only among dental practitioners but also general medical
practitioners whose advice is often sought prior to dental treatment.
It is unlikely that orthopaedic surgeons in New Zealand are
not aware of the guidelines (available at www.nzoa.org) but they probably feel that the
serious consequence of an artificial joint infection is a of a much greater
magnitude compared to the cost and possible adverse outcome of giving
prophylactic antibiotics.
A recent review of prosthetic joint infections by Theis et
al27 showed that staphylococci and streptococci
accounted for the majority of infections and that only 35% of patients retained
their original prosthesis. The other 65% required multiple operations requiring
prolonged periods of hospitalisation and long term antibiotic treatment which
failed in 30% of cases leaving the patient with no implants and significant
disability.
A similar finding was reported by Sandhu et al in 1997 who
conducted a postal survey on antibiotic prophylaxis in patients with prosthetic
joints requiring dental treatment between oral and maxillofacial surgeons and
orthopaedic surgeons to compare the advice and opinions between the two
groups.28 In this study almost 80% of
orthopaedic surgeons always recommended the use of antibiotic prophylaxis as
compared to only 30% of oral and maxillofacial surgeons. The authors concluded
that inconsistency was common and recommended that further discussion should
occur between the two speciality groups.
In the absence of level 1 evidence for or against the use of
prophylactic antibiotics in patients with prosthetic joints undergoing invasive
dental treatment the most recent ADA/AAOS guidelines provide the best available
advice for dental practitioners and their patients. These guidelines have been
endorsed by the New Zealand Orthopaedic Association which represents the
majority of orthopaedic surgeons in the country. The decision whether or not to
give prophylactic antibiotics, like for any other intervention, should be based
on a discussion between the patient and dental practitioner outlining treatment
options, risks and benefits and a chance to ask questions as part of the
informed consent process. Only when this has been achieved will it protect both
the patient and the practitioner.29
Further discussion between orthopaedic surgeons, general
medical practitioners and dental practitioners should be encouraged in order to
reach a consensus in New Zealand over this controversial issue.
Competing interests: None known.
Author information: Darryl C Tong,
Consultant Oral and Maxillofacial Surgeon and Senior Lecturer, Department of
Oral Diagnostic and Surgical Sciences, University of Otago, Dunedin; Jean-Claude
Theis, Consultant Orthopaedic Surgeon and Associate Professor, Department of
Orthopaedics, Dunedin Hospital, Dunedin
Correspondence: Mr Darryl Tong, Dept of
Oral Diagnostic and Surgical Sciences, University of Otago, PO Box 647, Dunedin,
New Zealand. Fax: +64 (0)3 4793937; email: darryl.tong@stonebow.otago.ac.nz
References:
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