Study designs of evaluations included in the review
Randomised controlled trials (RCTs) with an outcome follow-up of up to 1 year were eligible for inclusion. The duration of follow-up in the included studies ranged from no follow-up to 2 years.
Specific interventions included in the review
Studies that compared antibiotic prophylaxis with no antibiotics or placebo were eligible for inclusion. The included studies evaluated intravenous cefazolin (1 or 2 g), erythromycin (1 g where cefazolin allergy existed), ampicillin-sulbactam (1.5 g), amoxicillin plus clavulanic acid (2 g) and cefuroxime (1.5 g). Drugs were administered at anaesthetic induction or before surgical incision. Where reported, studies used a saline solution as the placebo control. Most hernias were repaired using polypropylene mesh and, where specified, the Lichtenstein technique was used.
Participants included in the review
Studies of adults undergoing elective mesh inguinal hernioplasty, including those without contraindications to antibiotics, were eligible for inclusion. Studies of patients who were immunosuppressed due to disease or medication were excluded. The participants in the included studies had inguinal or groin hernia; some studies excluded patients with bilateral hernias and other excluded recurrent hernias.
Outcomes assessed in the review
Studies that assessed surgical site infection (SSI) as defined by the Center for Disease Control were eligible for inclusion.
How were decisions on the relevance of primary studies made?
Two reviewers independently selected the studies and any disagreements were resolved by consensus.