· surgical antibiotic prophylaxis is the administration of antibiotics to patients undergoing surgery without clinical evidence of infection in the operative field
· prevent naturally occurring organisms in one site from proliferating in a normally sterile site
· prevent organisms contaminating a normally sterile site from producing disease
· prevent infection by exogenous organisms
· unacceptably high incidence of infection
· low incidence of infection where infection would be devastating or lethal
· prophylactic antibiotic use widespread
· 30-50% of antibiotics used in surgical services for prophylaxis
· esp. common in orthopaedics in implant surgery
· infection uncommon but devastating when it occurs
· expense
· drug-related side-effects
· masking of signs of unrelated infections
· unfavourable influence on local and hospital microflora
· choice influenced by
· type of surgery
· current hospital antibiotograms
· risk of adverse reactions
· expense
· should choose according to efficacy against most likely organisms
· 1st generation cephalosporins
· effective against gram-positive organisms (Staph. aureus and Staph. epidermidis)
· as effective as flucloxacillin
· some effect against gram-negative organisms
· not effective against Pseudomonas
· aminoglycosides
· more effective against gram-negatives (incl. effective against Pseudomonas)
· less effective against gram-positives
· 1st generation cephalosporins have high concentrations in synovial fluid and moderate concentration in bone
· gentamicin and clindamycin have better bone concentrations
· advantage to have high therapeutic index
· cephalosporins and penicillins have high therapeutic index and side-effects usually are hypersensitivity
· aminoglycosides have low therapeutic index and side-effects include nephrotoxicity and ototoxicity
· cephalosporins are drug of choice
· broad spectrum of activity against common pathogens
· low toxicity
· hight concentrations achieved in bone and soft tissue
· cephalosporins are drugs of choice
· inexpensive
· non-toxic
· effective against most of potential pathogens
· good bone antibiotic concentrations achieved
· comparative data among cephalosporins inadequate
· cefazolin theoretically advantageous because of
· longer half-life (allows 8-hour doses)
· higher bone concentrations
· should be given immediately preoperatively
· avoids problems with on call dosage
· if anaphylactic reaction occurs, is in controlled environment
· shown that peak levels reached 20-40 min after bolus IV dose
· must be given before tourniquet inflated
· should give another dose if surgery prolonged
· adequate levels maintained for 2 hrs for cephalothin and 4 hrs for cefazolin
· duration of administration varies
· probably sufficient to give for 24 hrs postoperatively only
· study showed 24 hrs effective
· Nelson showed no difference between 1 day and 7 days
· Wymenga showed no difference between 1 dose and 3 doses
· probably no need to wait for removal of drains
· 24 hrs of administration gives adequate antibiotic concentrations in joint for several days postoperatively
· shorter duration means
· less expensive
· lower incidence of side-effects
· less resistant organisms
· 2g preoperatively gives significantly higher bone and serum levels when important
· Williams et al (CORR 1983)
· bone and serum concentrations of 5 cephalosporins
· 1g postoperatively is probably sufficient
· incidence of infection in implant surgery reduced from 4% to <1%
· in form of local irrigation
· one study showed it to be effective
· Riska (Ann Chir Gyneacol 1980)
· more effective than systemic penicillin
· do not achieve tissue penetration or concentration
· may be useful against certain types of infection
· where toxic antibiotics are necessary
· eg. aminoglycosides for Pseudomonas
· antibiotics in powder form mixed with powdered polymer before mixing with liquid monomer
· gentamicin-impregnated cement available commercially (Palacos R)
· 0.5 g gentamicin in 40 g powdered polymer
· composition allows higher rate of elution over longer period
· mechanical properties altered
· breaking strength, modulus of elasticity and fatigue strength tested
· variable results
· probably insignificant cf. cementing techniques in Palacos R
· > 3 g gives more significant alteration
· antibiotic elution
· most rapid elution in first few days
· antibiotic continues to leach out for a prolonged period
· rates vary with type of cement
· local concentrations in first few days far in excess of that available from systemic administration
· no side-effects
· no hypersensitivities
· no resistant bacteria
· no toxic manifestation (include. ototoxicity or nephrotoxicity)
· no well constructed prospective trials
· appears to be at least as effective as systemic antibiotics
· Josefsson et al (CORR 1981)
· gentamicin cement in THR more effective than sinlge dose of systemic antibiotics (deep infection of 0.4% vs 1.2%)
· determined infection by ESR and x-ray changes
· appears to significantly reduces infection rate when used alone
· Bucholz et al (CORR 1984)
· infection rate in primary THR 1% with Palacos R as sole prophylaxis cf 5% with plain cement
· not a prospective randomised trial
· use best validated in prosthetic joints, as most of research done in this regard
· number of trials show reduction in infection from 4% with placebo to <1% with prophylactic antibiotics
· shown to be effective
· Boyd et al (JBJS, 1973)
· reduction in infection from 5% to 1% in hips treated by pinning
· should use prophylactic antibiotics as for prosthetic surgery
· no adequate trials
· resultant controversy
· often used in
· laminectomy
· surgery lasting > 2 hrs
· some use routinely
· probably not routinely justified
1. Mader, J & Cierny, G III, “The Principles of Use of Preventive Antibiotics”, CORR 190:Nov 1984, 75-82
2. Williams, N & Gustilo, R, “The Use of Preventive Antibiotics in Orthopaedic Surgery”, CORR 190:Nov 1984, 84-88
3. Bucholz, H et al “Antibiotic-loaded Acrylic Cement: Current Concepts”, CORR190:Nov 1984, 96-108