Crist 2014.

Methods	Study design: randomised controlled trial Study grouping: parallel Ethics and informed consent: ethics approved and consent obtained Follow‐up period: 12 months Sample size calculation: not stated ITT analysis: available‐case analysis Funding: non‐industry Pre‐registration: yes
Participants	Location: USA Intervention group: n = 55control group: n = 60 Mean age: intervention group = 47.2 years (SD 19.6)control group = 48.3 years (SD 20.1). Data extracted from results section of ClinicalTrials.gov (NCT00635479). Inclusion criteria: patients that had undergone an open surgical exposure for hip, pelvis, or acetabular fracture Exclusion criteria: none stated
Interventions	Aim/s: to determine the effectiveness of using NPWT over primarily closed surgical incisions used for open reduction and internal fixation of hip, pelvis, and acetabular fracture surgery Group 1 (NPWT) intervention: quote "negative pressure dressing applied over the primarily closed incision sterilely in the operating room. NPWT was left on for 2 days or longer if drainage continued" Group 2 (control) intervention: quote "standard gauze dressing"; description not provided Study date/s: not provided
Outcomes	infection LOS total serious adverse events Validity of measure/s: not provided Time points: followed for 12 months
Notes	Conference abstract. Additional information provided by the investigator and from a search of ClinicalTrials.gov (NCT00635479).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Evidence: quote "computer randomization" Comment: correspondence with author
Allocation concealment (selection bias)	Low risk	Evidence: quote "opaquesealed envelope opened in the OR" Comment: correspondence with author
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	Low risk	Evidence: quote "yes" Comment: correspondence with author
Incomplete outcome data (attrition bias) All outcomes	High risk	Evidence: quote "55 patients randomised to the NPWT group and 60 patients randomised to the standard dressing group. The NPWT group included 49 patients and the gauze group included 42 patients that completed the 12 month follow‐up" Comment: 10.9% participants in NPWT group and 30.0% of those in control group were lost to follow‐up.
Selective reporting (reporting bias)	Low risk	Comment: protocol registered on ClinicalTrials.gov with identifier (NCT00635479). Expected outcomes were reported in the abstract, but other outcomes specified in the protocol were not reported (such as total serious adverse events). These may be included when the full trial is published.
Other bias	Unclear risk	Comment: no other biases detected