Antibiotics in Orthopedic Surgery

Prophylactic Antibiotics in

Orthopedic SurgeryLaura Prokuski, MD

Associate ProfessorUniversity of Wisconsin

Department of Orthopedics and RehabilitationMadison, WI

Hospital Interventions Quality Improvement Organization Support

Surgical Site Infections

• 500,000 per year among an estimated 27 million procedures in the United States

• Most common nosocomial infection


• Patients with SSI are:

– 5 x more likely to be readmitted to hospital

– 60% more likely to reside in ICU

– Twice as likely to die


• Economic impact– Readmission to hospital– Surgical debridement– Prolonged antibiotics– Monitoring of antibiotic

toxicity– Delayed reconstruction

Staphylococcus epidermidis

Pathogenesis of Surgical Site Infections

• Bacteria contaminate every surgical wound

• The amount of bacteria required to cause infection in a wound is variable and depends on– Virulence of organism– Condition of wound– Presence of nonbiologic substances– Host immune competence


• Hematogenous Dissemination


• Bacteria have adaptive strategies to increase virulence– Antibiotic resistance– Surface compounds that inhibit

phagocytosis and facilitate adherence to implants, shielding them from immune defenses

Glycocalyx

Surgical Antibiotic Prophylaxis

• Can’t sterilize wound

• Minimize intraoperative contamination of the wound to a level that won’t overwhelm host defenses

Optimal Surgical Antibiotic Prophylaxis

• Antimicrobial active against most common pathogens in wound

• Safe• Inexpensive• Adequate concentrations present in the serum

and tissue during the entire time the wound is open

• Smallest impact possible nor the normal bacterial flora or the patient the biogram of the community

Antibiotic Prophylaxis in Orthopedic Surgery

• Choice of antimicrobial

• Timing of administration

• Duration of use

Penicillin

Choice of Antimicrobial Agent

• Organisms of concern: aerobic Gram + cocci

Penicillin


• Cephalosporins are first choice

– Cefazolin– Cefuroxime

Penicillin


• Beta-lactam allergy?– True allergy

• Urticaria, pruritis, bronchospasm, hypotension

– Adverse drug reaction• Drug fever, drug-induced hypersensitivity

Penicillin


• Beta-lactam allergy?– Incidence of adverse reactions to

cephalosporins among patients with reported penicillin allergy is rare

– Patients with a history of penicillin allergy and negative penicillin skin test results are not at increased risk of an adverse reaction to cephalosporins

Penicillin


• Beta-lactam allergy?– Targeted allergy consultation and penicillin

allergy skin testing can decrease prophylactic vancomycin use in patients undergoing elective orthopedic surgery

Penicillin


• True Beta-lactam allergy

– Clindamycin– Vancomycin

Penicillin

Vancomycin and MRSA

• Routine use of vancomycin is discouraged– Promotes vancomycin resistance

• Current or previous infection with MRSA, and known MRSA colonization, are indications to choose vancomycin for surgical prophylaxis

Penicillin

Vancomycin and MRSA

• MRSA colonization may be higher among patients who have spent more than 5 days in an institutional setting

• Preoperative nasal swabbing can detect 80-90% of MRSA carriers and may be a helpful screening test for elective surgery

Penicillin

Vancomycin and MRSA

• No evidence that routine use of vancomycin instead of cephalosporins for prophylaxis in institutions with perceived high rates of MRSA infection will result in fewer SSIs

• Cardiac surgery study: the choice of antimicrobial used for prophylaxis changed the infecting organism, but did not alter the infection rate

Penicillin

Recommendations for Choice of Antimicrobial

• Cephalosporins preferred

• True beta-lactam allergy: clindamycin or vancomycin

• Current or prior MRSA infection, MRSA colonization: vancomycin

Penicillin

Timing of Administration• Burke 1961 administering antibiotics before

or shortly after the inoculation of skin with S. aureus markedly reduced the inflammatory response

• With each delay of an hour in antibiotic administration the inflammatory lesion became larger

Penicillin

Timing of Administration

• Prospective analysis of patients undergoing a variety of clean and clean-contaminated procedures showed patients receiving antibiotics 2 hours before incision had lowest SSI rates

Penicillin


• Infusion of cephalosporins and clindamycin should begin within 60 minutes before incision, and be completed at the time of incision

• Infusion of vancomycin should begin 2 hours before incision and should be completed at the time of incision

Penicillin


• Administration of the antimicrobial at the time of anesthesia induction is safe and results in adequate tissue drug levels at the time of incisions

Penicillin

Timing of Administration with Use of Tourniquet

• Analysis of cefuroxime levels in soft tissue and bone demonstrated 10 minutes is needed between infusion and tourniquet inflation to achieve adequate tissue levels for prophylaxis

Penicillin

Intraoperative Redosing

• Duration of procedure exceeds 1-2 times the antimicrobial’s half-life

• Significant blood loss during the procedure

Penicillin

Every 6-12 hoursVancomycin

Every 3-6 hoursClindamycin

Every 3-4 hoursCefuroxime

Every 2-5 hoursCefazolin

FrequencyAntibiotic

Recommendations for Timing of Administration

• May be the single most important step in preventing SSI (given the right agent was chosen)

• Cephalosporins, clindamycin: Completion of infusion within 1 hour of incision

• Vancomycin: Completion of infusion within 1 hour of incision; start earlier to accommodate longer infusion time

• Redosing with length of procedure and/or blood loss

Penicillin

Duration of Antimicrobial Use

• The shortest effective duration of antimicrobial administration for preventing postoperative infection is not known

Penicillin


• The majority of published evidence demonstrates that antimicrobial prophylaxis after wound closure does not provide additional protection from SSI

Penicillin


• Continuing antibiotic prophylaxis longer than 24 hours after wound closure is not beneficial and may contribute to the development of antimicrobial resistance

Penicillin


• Continuing prophylactic antibiotics for the duration drains and catheters are in place has not been shown to reduce SSI rates

• Remove catheters and drains promptly

Penicillin

Recommendations for Duration of Antimicrobial Use

• Single-dose prophylaxis

• Multiple-dose prophylaxis not to exceed 24 hours

Penicillin

Antibiotic Prophylaxis in Orthopedic Surgery

Subspecialties• Spine• Arthroscopy• Pediatrics• Foot and Ankle• Hand• Trauma• Major Joint Arthroplasty

Penicillin

Spine Surgery• Early retrospective studies generally supported

• Later randomized trials did not overwhelmingly prove efficacy

• Meta-analysis provided statistically significant evidence that prophylactic antibiotic use reduces SSI in spinal surgery

Penicillin

Spine Surgery

• Spine surgery studies confirm importance of timing of administration and redosing after extended duration of procedure and/or blood loss

Penicillin

Recommendations

• Prophylactic antibiotics are recommended in spine surgery

Penicillin

Arthroscopy• Incidence of infection extremely low (0.2%)

• Two main studies do not demonstrate reduced SSI rate in arthroscopic procedures when prophylactic antibiotics are used

Penicillin

Concerns…• Many procedures are not exclusively

arthroscopic, and require incisions (ACL reconstruction)

• Some prolonged surgical times

• More complex arthroscopic procedures involve the use of implants

Penicillin

Arthroscopy Recommendations• No study has examined the effect of

prophylactic antibiotics along the spectrum of contemporary arthroscopic procedures

• The studies available are few, and may not be sufficiently designed or powered to provide meaningful recommendations about the use of prophylactic antibiotics in arthroscopic procedures

Penicillin

Pediatric Orthopedic Surgery

• Pediatric patients are subject to the same procedures as adults, but pediatric-specific data is sparse

• Pediatric tissue and physiology is markedly different from adults

Penicillin

Pediatric Orthopedic Surgery

• Case-control study to identify risk factors for SSIs after spinal fusion in children found that antibiotic prophylaxis was more frequently suboptimal in patients who developed an SSI

Penicillin

Pediatric Orthopedic Surgery Recommendations

• No definitive conclusions

• Extrapolate (justifiably?) recommendations from adult studies

Penicillin

Foot and Ankle

• Few studies available

• Retrospective study on non-traumatic, non-revision surgery showed no decrease in SSI rate when prophylactic antibiotics used

• Prospective analysis of outpatient ankle fractures demonstrated no benefit from prophylactic antibiotics

Penicillin

Foot and Ankle

• No data on diabetics undergoing foot surgery

Penicillin

Foot and Ankle

• No definitive conclusions can be drawn regarding the efficacy of antibiotic prophylaxis in patients undergoing foot and ankle surgery

Penicillin

Clean Elective Hand Surgery

• Prophylactic antibiotics have not been proven efficacious in clean, elective hand procedures

• Some recommendations exist to use prophylactic antibiotics in reconstructive procedures involving large flaps, procedures of prolonged duration, and arthroplasty

• Properly designed and powered studies do not exist to answer these questions definitively

Penicillin

Orthopedic Trauma

• Preoperative prophylactic antibiotics are beneficial in reducing SSIs after operative treatment of hip fractures

• Prophylactic antibiotics have also been shown effective in reducing SSI with internal fixation of other closed fractures

• Single dose prophylaxis equivalent effect to multi-dose prophylaxis

Orthopedic Trauma

• Antibiotics are critical in reducing the infection risk after open fractures

Penicillin

Orthopedic Trauma Recommendations

• Prophylactic antibiotics should be used in patients undergoing internal fixation of closed and open fractures

Penicillin

Hip and Knee Arthroplasty• Low infection rate• Consequences are

severe

Hip and Knee Arthroplasty

• Prophylactic antibiotics have been shown to reduce the incidence of infection after primary hip and knee arthroplasty

Penicillin


• Cephalosporins preferred agent

• Vancomycin has been proven to be a successful prophylactic agent

Penicillin


• Optimal duration of antimicrobial prophylaxis is not known

• No benefit established by extending prophylaxis beyond 24 hours

• No benefit established by continuing prophylaxis until all drains and catheters have been removed

Penicillin

Hip and Knee Arthroplasty Recommendations

• Prophylactic antibiotics should be used

• Duration should not exceed 24 hours

Penicillin

Antibiotic Irrigation• Not proven to reduce surgical site infection in:

– Spine surgery– Hand surgery– Arthroplasty– Open lower extremity fractures

Penicillin

Antibiotic Irrigation Concerns• Adverse reactions to topically applied

antibiotics occur– Anaphylaxis with bacitracin– Neomycin neuromuscular blocking agent– Renal failure neomycin-polymyxin-bacitracin– Hypersensitivity reactions

Penicillin

Antibiotic Irrigation Concerns• Cost of acquiring, storing, mixing, dispensing

Penicillin

Antibiotic Irrigation Concerns• May contribute to antibiotic resistance

Penicillin

Resistant StrainsRare

xx

Resistant Strains Dominant

Antimicrobial Exposure

xxxx

xx

xx

xx

Antibiotic Irrigation is not Recommended

Penicillin

Prophylactic Antibiotics in Orthopedic Surgery

• Proven effective in reducing SSIs in– Spine surgery– Fracture fixation– Major joint arthroplasty


• Data inadequate on the effect of prophylactic antibiotics in– Foot and ankle surgery– Pediatric orthopedic surgery– Hand/upper extremity procedures not

considered clean, elective, and short duration

– Contemporary complex arthroscopic procedures


• Efficacy of prophylactic antibiotics unproven in– Clean, elective hand procedures lasting less

than 2 hours– Simple arthroscopic procedures


• Cephalosporins agents of choice– True beta-lactam allergy– MRSA colonization/infection

• Timing of administration 1-2 hours before incision

• Redose• Duration not longer than 24 hours

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Antibiotics in Orthopedic Surgery