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Practice NIHR Signals

Negative pressure dressings are no better than standard dressings for open fractures

BMJ 2019; 364 doi: (Published 13 March 2019) Cite this as: BMJ 2019;364:k4411


NIHR’s research signals in The BMJ

Wrong conclusions based on flawed assumptions

Dear Editors

I have concerns about how the authors of this NIHR Signals paper reached their conclusions

They wrote that the UK WOLLF randomised clinical trial (ref1) found

"There were no clinically important differences in disability, deep infections, or healing between the group that received negative pressure dressings and the group that received standard dressings."


"Quality of life was similar in both groups throughout."

However the authors of the NIHR Signals paper suggest the implications of the UK WOLLF Collaboration research are:

"The findings from this trial have been incorporated into an updated Cochrane review, plus two other small trials completed in 2016. This is the only randomised controlled trial to date that provides 12 month outcomes for disability and quality of life and indicates that the more expensive negative wound pressure dressings are no better. The pooled data show uncertainty about whether negative wound pressure reduces deep infections for open wounds following open fractures. These findings are likely to be important for orthopaedic practice.

Not offering this treatment would potentially save money for use on other therapies and would simplify the care pathway. Negative pressure dressings are used in other surgical contexts, and these might be suitable for a similar study."

While it may be true, based on the evidence of the Costa et al study, that there is no obvious difference in the measured outcome featured in the study, it is important to remember that the basis of the study is they recruited patients with an open fracture of the lower limb that could not be closed primarily at time of first operation to apply comparison dressings; the same patients had a second operation at 48 to72 hours, when a further wound assessment and debridement was performed and the wound closed either primarily with sutures or by soft-tissue reconstruction as necessary.

Hence these delayed primary closure or plastic reconstruction occurs within 48 to 72 hours. Not all hospitals can provide these reconstructive service, not all patients requires definitive wound closure within 48-72 hrs.

A key indication of negative pressure dressings had always been reduced need for wound dressing changes with ability to perform toileting and wound washing without time-consuming (and painful) removal and changing of dressings in the ward or operating theatre. The study design by the WOLLF Collaboration does not and cannot address these issues particularly when all patients are deemed to require definitive wound coverage within 72 hours. Nor did they look at the effects on length of stay.

Therefore in my view, the authors should not suggest that not offering negative pressure dressings can be money saving when the costs of more frequent dressing change of standard care involving materials and nursing expertise has not be seriously accounted for. The applicability of this study to centres without reconstructive service or easy access to operating time in order to achieve wound closure within 72 hours ultimately limits its relevance to many non-tertiary hospitals who account for a majority of care of patients with open fracture

1. Costa ML, Achten J, Bruce J, et al. Effect of negative pressure wound therapy vs standard wound management on 12-month disability among adults with severe open fracture of the lower limb: the WOLLF randomised clinical trial. JAMA. 2018 Jun 12;319(22):2280-2288. doi: 10.1001/jama.2018.6452.

Competing interests: No competing interests

14 March 2019
Shyan Goh
Orthopaedic Surgeon
Sydney, Australia