Yerdel 2001.

Methods	Study: prospective, randomised. Allocation: computer. Blinding: yes.
Participants	269 patients: 136 P / 133 C.
Interventions	Hernioplasty ATB: Ampicilln‐sulbactam 1,5 gr IV. MA: before the incision. Control: placebo.
Outcomes	IP= 1; IC= 12
Notes	Because of the high rate of wound infections, the code was broken after the discharge of patient 280 (140 patients in each group).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer‐generated code by a resident who also prepared the sealed antibiotic or placebo syringes. He was unaware of the research in progress and was never involved in surgery, data collection or patient follow‐up.
Allocation concealment (selection bias)	Low risk	Yes
Blinding (performance bias and detection bias) All outcomes	Low risk	Yes
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Yes
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Yes

P = prophylaxis group, C = control group, IP = infected with prophylaxis, IC = infected without prophylaxis, NM = not mentioned, ATB = antibiotic, MA = timing of prophylaxis administration