Breiting 1981.

Study characteristics
Methods	QRCT
Participants	104 adult men having elective surgery on lower legs in Denmark (dates not given, though study published in 1981). Procedures included knee arthrotomy, plastic surgery to knee ligaments, foot joints and tibial osteotomy.
Interventions	Group 1: preoperative hair removal with a razor (n = 52) Group 2: preoperative hair removal with depilatory cream (n = 52) Product details: the razor was disposable, the cream was Prelprep. Timing of hair removal: not reported. Hair removed by: razors ‐ nurses, cream ‐ study authors. Venue for hair removal: razors on the ward, cream not reported.
Outcomes	Primary outcome: effectiveness of hair removal and patient preference, both assessed by participants Secondary outcome: clinical evidence of superficial and deep infections assessed at discharge and outpatient visit by surgical staff. Definition of infection was not given.
Notes	Paper published in Danish. No funding sources mentioned. No details of conflict of interest.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Quote: "Allocated on the date of admission to hospital" Comment: inadequate randomisation technique.
Allocation concealment (selection bias)	High risk	Quote: "Allocated on the date of admission to hospital" Comment: care‐provider could predict allocation by reference to date of admission to hospital.
Blinding (performance bias and detection bias) Care providers blinded	Unclear risk	Not reported. Comment: unclear whether care providers were blinded to intervention allocation.
Blinding (performance bias and detection bias) Participants blinded	High risk	Not reported. Comment: participants would have been aware of hair removal method.
Blinding of outcome assessment (detection bias) All outcomes	High risk	Interventions and assessments were carried out by study authors. Comment: outcome assessors were not blinded, and it is likely that knowledge of the group the participant was in could have influenced their judgement.
Incomplete outcome data (attrition bias) ITT analysis undertaken	Unclear risk	Not reported. Comment: no information provided regarding whether participants were analysed in the groups to which they had been allocated.
Incomplete outcome data (attrition bias) Drop out rate acceptable	Low risk	No participants appeared to have dropped out from the study. Comment: data presented for 104 participants.
Selective reporting (reporting bias)	Low risk	Main outcomes reported. Comment: unlikely to be affected by reporting bias.
Other bias	Low risk	Comment: participant groups were equal or similar.