An Evaluation of the Efficacy of Negative Pressure Wound Therapy for the Treatment of Bone- or Tendon-Exposed Diabetic Foot Ulcers

Background: Negative pressure wound therapy (NPWT) is generally accepted as an important adjunctive therapy in deep wound treatment (1). However, clinicians may not be able to prescribe NPWT due to geographical or insurance constraints, which could delay healing. The availability of NPWT is a particular concern in public hospitals and developing nations (2,3). Delayed healing of bone- or tendon-exposed diabetic foot ulcers (DFUs) is especially problematic, as these ulcers are more vulnerable to infection and subsequent amputation (4).

Purpose: This study evaluated the efficacy of NPWT for healing extremely large and deep DFUs.
 
Methods: This sub-analysis evaluated 47 participants with a Wagner grade 3 or 4 DFU. Participants were part of a prospective trial that evaluated the efficacy of D-ADM* at two sites. NPWT was not prescribed at one study site because home health support was not available in this rural area. The effect of NPWT on granulation and healing was assessed. All statistical analyses were calculated using Stata (StataCorp, College Station, TX). Statistical significance was analyzed using Student’s t-test or Fisher’s exact test with a two-sided alpha of 0.05.

Results: The baseline ulcer areas were comparable, with 25.6 cm2 and 30.5 cm2 for the non-NPWT and NPWT sites, respectively (p=0.5425). Both sites exhibited 100% granulation and did not significantly differ in time to achieve granulation (p=0.4130). The non-NPWT site demonstrated a significantly greater healing rate over the site that used NPWT (70.0% vs. 21.6%; p=0.007). It should be cautioned that the sample size for the non-NPWT site had 10 participants versus 37 for the NPWT site.

Conclusion: While the disparity in sample size precludes generalization, these results provide evidence that satisfactory healing of complex diabetic foot ulcers can still occur in areas where access to NPWT may not be available.