Journal of the New Zealand Medical Association, 22-August-2008, Vol 121 No 1280
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.
A 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.
152 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.
The 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: email@example.com
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