Ilankovan 1992.

Study characteristics
Methods	RCT
Participants	50 people (age 15 to 60) requiring zygomatic arch repair in England. Dates of study not given.
Interventions	Group 1: hair removal with a razor (n = 25) Group 2: no hair removal (n = 25) Product details: no details are given for the razor. Timing of hair removal: after anaesthesia had started. Hair removal carried out by: not specified. Venue for hair removal: the operating table.
Outcomes	Primary outcome: participant and surgeon preferences. Participants were asked to assess their appearance (scalp hair removal) immediately after surgery. Surgeons were asked to assess surgical difficulty. Secondary outcome: signs of local infection, including pus in conjunction with erythema associated with tenderness and wound breakdown. Assessed 1 week after surgery, no details as to who conducted the assessment.
Notes	Numbers of infections were not reported, though "there was no difference in the incidence of infection between the two groups". No funding sources mentioned. No details on conflict of interest.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "Patients were randomised by a random number sequence into two groups" Comment: adequate approach.
Allocation concealment (selection bias)	Unclear risk	Not reported. Comment: not clear whether the person responsible for allocation to groups would have been able to predict to which group a potential participant would be allocated.
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	Quote: "Group 1 underwent conventional temporal shaving, while group 2 had no preoperative hair removal" Comment: participants would have been aware of hair removal method.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported. Comment: unclear whether assessors were blinded to intervention allocation.
Incomplete outcome data (attrition bias) ITT analysis undertaken	Unclear risk	Not reported. Comment: no discussion of whether participants were analysed in groups to which they had been allocated.
Incomplete outcome data (attrition bias) Drop out rate acceptable	Unclear risk	Dropouts were not reported. Comment: insufficient details to permit a judgement.
Selective reporting (reporting bias)	Low risk	Main outcomes reported. Comment: raw data for study secondary outcome (SSI) are not presented. The author states no difference between groups in SSIs. Unlikely to be affected by reporting bias.
Other bias	Low risk	Comment: participant groups were equal or similar.