Pauser 2016.

Methods	Study design: randomised controlled trial Study grouping: parallel Ethics and informed consent: yes Sample size estimate: no Follow‐up period: 10 days ITT analysis: yes number randomised: 21 number analysed: 21 Funding: "Prevena wound treatment system was provided by KCI free of charge" Pre‐registration: no
Participants	Location: Nuremberg, Germany Intervention group: n = 11control group: n = 10 Mean age: intervention group = 81.6 ± 5.2 yearscontrol group = 82.6 ± 8.6 years Inclusion criteria: patients with femoral neck fracture who were scheduled for hip hemiarthroplasty Exclusion criteria: not stated
Interventions	Aim/s: "to evaluate different aspects of wound healing after fractures of the femoral neck treated by hemiarthroplasty" Group 1 (NPWT) intervention: the iNPWT group was treated with a PREVENA system (KCI, San Antonio, Texas). The PREVENA system was left on the wound for 5 days including the day of surgery. Group 2 control: control group received the standard wound dressing of our department, consisting of a dry wound coverage (compresses attached to the skin). Study date/s: not reported
Outcomes	seroma Validity of measure/s: ultrasound was used as a standardised imaging modality to detect seromas in the wound area. Time points: day 5 and day 10 after surgery
Notes	Investigator contacted for additional details.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Insufficient information given.
Allocation concealment (selection bias)	Unclear risk	Insufficient information given.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Evidence for participants: not possible Comment: unlikely to affect outcomes Evidence for personnel: not possible Comment: unlikely to affect outcomes
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Insufficient information given.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All those recruited appear to have been included in the analysis.
Selective reporting (reporting bias)	High risk	Only seroma was reported, not SSI.
Other bias	Unclear risk	Data for the NPWT group reported at day 5 and day 10, but data for the control group only reported overall.