Negative Pressure Dressings on Surgical Incisions: What One Large Trial Showed

Quick answer: Single use negative pressure dressings are sometimes placed over a closed surgical incision to try to reduce healing problems. In a completed 526 patient trial after hip and knee replacement, incision appearance scores were almost identical to ordinary dressings. Choose a dressing with your surgical team, and watch the incision rather than the device.

What is negative pressure wound therapy on a closed incision?

Negative pressure wound therapy, often shortened to NPWT, uses a sealed dressing connected to a small pump that applies gentle suction. Most people picture it on an open wound. A newer use is different: a small single use unit is placed over a surgical cut that has already been stitched or stapled, in the hope of managing fluid and protecting the closure during the first days of healing.

It is a preventive idea rather than a treatment for an infected wound. That distinction matters, because the evidence for prevention in a general surgical population is not the same as the evidence for using suction on a large open wound.

What did the completed trial actually find?

The completed ClinicalTrials.gov study NCT02064270, sponsored by the University of Missouri-Columbia, randomised 526 adults having total knee or total hip replacement to either a single use incisional NPWT dressing or standard post surgical dressings. It was an open label study, so patients and staff knew which dressing was used.

Results are posted on the registry. The primary outcome was incision appearance rated on a 0 to 100 visual analogue scale at about 35 days. The mean score was 83.4 (standard deviation 13.3) in 201 assessed NPWT participants and 83.5 (standard deviation 12.2) in 231 assessed standard dressing participants. In other words, the two groups looked essentially the same.

For drainage, 178 NPWT participants and 211 standard dressing participants were recorded as having none, with small numbers in the moderate and extensive categories in both groups. Two honest caveats apply: more people dropped out of the NPWT arm (62) than the standard arm (32), and no statistical comparison is posted for the primary outcome. This single study does not show that incisional NPWT improved healing after joint replacement, and it also cannot rule out benefit in higher risk groups it did not study.

Who might still be considered for it?

Surgical teams tend to think about incisional NPWT for people they judge to be at higher risk of wound problems, for example after certain abdominal, vascular, cardiac or trauma surgery, or where obesity, diabetes, steroid use, poor nutrition or previous wound breakdown are in the picture. That decision belongs to the operating team, who know the incision, the tissue quality and the local protocol. It is not a product you should add on your own.

What actually helps a surgical incision heal at home?

• Follow the discharge instructions on when the dressing may be changed or removed, and who should do it.
• Wash your hands before and after touching the dressing area.
• Keep the incision dry as advised, and check what your team says about showering.
• Do not pick at scabs, staples, clips or the ends of dissolvable sutures.
• Support blood sugar control, nutrition, protein intake and hydration, because healing has metabolic demands.
• Take a photo in good light every day or two so gradual change is easier to notice.

When should you call for help?

Contact your surgical team or doctor promptly if you notice spreading redness or warmth, increasing pain after the first few days, swelling, new or heavier fluid leaking from the incision, cloudy or foul smelling discharge, edges that separate, or fever and chills. Seek urgent care for heavy bleeding, a rapidly spreading rash, severe pain, confusion or feeling very unwell. Early review of a wound is almost always easier than late review.

The practical takeaway

Incisional NPWT is a plausible idea with mixed and setting specific evidence, and in this joint replacement trial it did not visibly outperform an ordinary dressing. The everyday basics of clean hands, an undisturbed closure, good nutrition and early reporting of change remain the part you control.

This article is general information, not medical advice. Please consult your doctor, surgeon or wound care nurse about your own wound and dressing plan.

EMIS+ supplies wound care, ostomy and continence products to homes, clinics and care facilities in Singapore. You can browse our range at www.emis.asia.

Related reading

Exudate management sits underneath every dressing decision. For the underlying principle and how to match a dressing to a wound, see moist wound healing and choosing a dressing. For an evidence breakdown of one commonly misunderstood option, see medical grade honey and where the evidence supports it.