Langlois 2015.

Methods	2‐arm RCT undertaken in France
Participants	80 participants undergoing primary THA or TKA Inclusion criteria: aged 18‐95 years; able to understand information; undergoing primary THA or TKA Exclusion criteria: prior operative local procedure around the joint; past local infection; or advanced cancer
Interventions	Group A (n = 40): sterile gauze held in place with a crepe bandage Group B (n = 40): hydrofibre dressing (Aquacel, ConvaTec) In the sterile gauze group, the dressing change was scheduled between days 1and 3 postoperatively, with a second change on the day of discharge. Gauzes were then replaced by a conventional adhesive pad (Mepore, Mölnlycke Health Care, Göteborg, Sweden). In the hydrofibre dressing group, the only change was scheduled for the day of discharge. In both groups, an extra change of dressing was performed in case of saturation with leakage, major loss of adherence, bleeding, or suspected infection. The postoperative regimen included administration of systemic antibiotics for 48 hours, thromboprophylaxis with low molecular weight heparin for six weeks, and anti‐inflammatory medication (ketoprofen, 100 mg/day for 5 days).
Outcomes	Primary review outcome: SSI (not defined further) Secondary review outcome: scar cosmetic appearance; pain
Notes	Trial outcome data: see Table 12 Follow‐up: 6 weeks
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "The patients were randomised using a computer‐generated block randomization scheme to have either conventional or hydrofibre dressing." Comment: adequate
Allocation concealment (selection bias)	Unclear risk	Quote: "The randomization was based on the order of patient presentation, so each patient was randomised individually regardless of severity of osteoarthritis and co‐morbid situation." Comment: unclear if allocation was concealed.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Quote: "scar cosmetic appearance evaluated six weeks after surgery by a plastic surgeon that was blinded to the dressing used and not involved in the surgical procedures." Comment: low risk for surgeon scar assessment unclear for other outcomes.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Flow chart suggests all participants analysed.
Selective reporting (reporting bias)	Low risk	None noted. Protocol not obtained.
Other bias	Low risk	None noted based on reported information.