Goyal 2011.

Study characteristics
Methods	RCT Enrolment period: 1 year (not specified) Country: India Single centre
Participants	N: 200 participants Age (years): range 11 to 90 yrs, with 70.5% of the patients in the 31 to 70 years age group (overall population) % Men: not reported; both male and female were included Inclusion criteria: any type of primary inguinal hernia. Exclusion criteria: patients with complicated, strangulated hernia, those having local skin infection, systemic infection, diabetes or history of antibiotic use within previous week BMI: not reported Skin antiseptic: 10% povidone iodine Operative time: not reported Method of repair: Lichtenstein technique (hernioplasty) Drain use: not reported ASA class: not reported Anaesthesia method: not reported Hospitalisation: inpatient Length of hospital stay: 1 day Surgeon: not reported
Interventions	Prophylactic group (PG): N: 100 antibiotic: amoxicillin‐clavulanate dose: 1.2 g number of doses: 1 route of administration: intravenous timing of administration: induction Control group (CG): N: 100 substance: equal volume of sterile saline
Outcomes	Wound infection definition: serous discharge, seroma formation, erythema and stitch abscess. Follow‐up: 8 days SSSI N infected/N patients (%) PG: 1/100 (1%); CG: 3/100 (3%) (SSSI cases had erythema or stitch abscess, cases with serous discharge were considered not having wound infection) DSSI: not reported (reported: "not necessary to remove any mesh") Adverse effects: not reported
Notes	Patients aged < 18 years included Funding was not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “Patients were randomized in two groups by random number table method, Group 1 as cases, Group 2 as controls”
Allocation concealment (selection bias)	Unclear risk	Insufficient information available.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Insufficient information available, but performance bias is unlikely in this setting Quote: "Group 1 was given IV injection of 1,2 gr amoxicillin‐clavulanate in 20 ml saline at the time of induction, while the other group was given 20 ml of sterile saline as placebo”
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information available
Incomplete outcome data (attrition bias) All outcomes	Low risk	No missing outcome data
Selective reporting (reporting bias)	Low risk	The study protocol was not registered, but report includes all expected outcomes, including specification of SSSI
Other bias	Low risk	The study appears to be free of other sources of bias.