Antibiotic prophylaxis for total joint replacement surgery: results of a survey of Canadian orthopedic surgeons

Discussion

The use of prophylactic antibiotics in primary joint replacement surgery is considered the standard of practice according to the 2003 National Institutes of Health (NIH) Consensus Statement.3 Despite this statement and available supporting data, 3 surgeons in our survey indicated that they do not routinely use prophylactic antibiotics. Quenon and colleagues4 showed that the relative risk for deep infection was increased in those patients who did not receive perioperative antibiotics. Large observational joint registries have also shown reduced revision rates with systemic antibiotic prophylaxis.5

This study describes Canadian orthopedic surgeons’ preferences for antibiotic prophylaxis for TJR surgery. Although no national Canadian guidelines for prophylaxis have been promulgated, it would appear that antibiotic prophylaxis practice for TJRs is relatively uniform with regard to the antibiotic of choice and dose administered. Our survey showed that most Canadian surgeons favour a first-generation cephalosporin; however, the dose most frequently used was 1 g, whereas the literature seems to support the use of a larger dose of 2 g intravenously.6^,7 Further, Bratzler and Houck, writing for the Surgical Infection Prevention Guidelines Writers Workgroup,2 have advised that the initial antimicrobial dose should be adequate based on the patient’s body weight, adjusted dosing weight or body mass index.

In the current study, surgeon volume did not seem to be a factor influencing decisions regarding prophylaxis. Most studies in the literature do support the fact that clinical outcomes are improved by high-volume arthroplasty surgeons.8^–12 However, only 1 study reported fewer deep infections with high-volume surgeons, and no clear data were provided to suggest that this was related to a difference in antibiotic prophylaxis.13 Our survey suggests that management decisions regarding infection prophylaxis do not differ between low- and high-volume arthroplasty surgeons in Canada. We did not survey for any difference in outcomes between these groups.

There are ample data in the literature to support the opinion that orthopedic surgeons do not consistently implement ideal antibiotic prophylactic measures. For the most part, this seems to focus around inappropriate timing of antibiotic delivery as well as duration of administration.4^,14^–17 Recent studies suggest that the optimum timing for the pre-operative antibiotic dose should be within less than 1 hour of skin incision and extended postoperatively for a duration of 24 hours.18 In our survey, 90% of surgeons stated that antibiotic prophylaxis was given within 1 hour of skin incision. Whereas this response reflects opinion and may be subject to bias, it should be noted that 48% reported administering antibiotics in the operating room, which has indeed been shown to dramatically improve the likelihood of this occurring within less than 1 hour before incision.19

Our survey showed no consensus among responding surgeons regarding duration of administration for prophylactic antibiotics. Only 42% choose a 24-hour regimen of intravenous antibiotic prophylaxis, despite numerous reported studies that support this practice with no additional value to more prolonged therapy.2^,20^–23

Antibiotic-loaded cement has been advocated in prophylactic doses when a cemented implant fixation is used in routine TJR to reduce the risk of infection, and has also been shown to reduce the rate of revision surgery in large national registries.5^,9^,24 Others have expressed concerns about the emergence of resistant organisms, allergic reactions and cost as reasons to avoid the use of ABLC for routine TJR.25 Some have suggested its use be reserved for high-risk cases, which includes revision TJR surgery.25^,26 There are differing opinions about the routine use of ABLC in the literature, and this is also evident from our survey, with a fairly even mix of surgeons supporting the 3 possible approaches. Premixed commercial antibiotic cement preparations have superior mechanical and elution properties relative to hand-mixed ABLC, and most Canadian surgeons using ABLC support this practice.26

There was no consensus as to which antibiotic is best in ABLC, and this is again reflected by a lack of consensus in the literature, although gentamicin seems to be the most widely used.26 Tobramycin is the most widely used in the United States, since it is more readily available in a powdered form and perhaps may be less detrimental to the mechanical properties of polymethylmethacrylate, as opposed to a gentamicin liquid preparation.25^,27 Cefuroxime has also been used in bone cement effectively to reduce arthroplasty-related infections in a randomized controlled trial.28

Several authors have shown a link between prolonged serous wound drainage and subsequent deep and superficial wound infections.29^–31 There is a paucity of data in the literature concerning the management of asymptomatic wound drainage following TJR. This issue is separate from that of antibiotic prophylaxis, but given the lack of any firm guidelines on this problem, we hoped our survey would help inform further regarding current practice. Some studies have suggested that swabbing of a serous draining wound may cloud and delay the diagnosis.32 Only about one-third of responding surgeons reported that they would swab a persistent draining wound without fever or local redness/erythema. The use of an antibiotic for asymptomatic serous wound drainage and duration is disputed.30^,32^–34

In our survey, the majority of surgeons (60%) would discharge patients home with a serous draining wound if asymptomatic, and two-thirds of surgeons would prescribe antibiotics for draining wounds at least some of the time. All wounds have some degree of hematoma postoperatively, and it is unclear in the literature what size of hematoma predisposes patients to an increased risk for infection. Saleh and colleagues30 diagnosed “hematoma” as opposed to “hemarthrosis” based on clinical palpation of fluid and local tenderness to touch, both of which are purely subjective measures. Some authors advocate returning the patient to the operating suite for irrigation, débridement and closure of the wound if drainage persists beyond 5–7 days postoperatively.30^,33^,34 If and when operative evacuation of a hematoma should be entertained is unclear, as reflected by the small number of Canadian surgeons (16%) who return patients to the operating suite for an otherwise asymptomatic draining wound beyond 4 days.

There are few data in the literature to guide antibiotic prophylaxis in the revision setting. In general, if the diagnosis of infection is in question at the time of surgery, the practice of withholding preoperative antibiotics to improve the yield of intraoperative soft tissue and bone cultures remains controversial. Recently, Ghanem and colleagues35 concluded that the administration of preoperative antibiotics to patients with a positive preoperative joint aspirate did not interfere with the isolation of the infecting organism.

Similarly, if the erythrocyte sedimentation rate and C-reactive protein levels are normal preoperatively, then the chance of infection is very low,36^,37 and antibiotic prophylaxis may be administered. Also, if the diagnosis of infection has already been made and the organism isolated, it seems reasonable and appropriate to administer preoperative antibiotics. With this in mind, most surgeons in our survey withhold preoperative antibiotics if there is any suspicion of infection, and most give preoperative antibiotics if the probability of infection is felt to be low. Most surgeons opt to use the same antibiotics for revision procedures as used in the primary setting, and this seems reasonable given the lack of available data that would suggest changing the antibiotic prophylaxis.