SLR - September 2015 - Pegah Samouhi(1)

Use of Negative Pressure Wound Therapy on Closed Surgical Incision After Total Ankle Arthroplasty

Reference: Matsumoto T, Parekh SG. Use of Negative Pressure Wound Therapy on Closed Surgical Incision After Total Ankle Arthroplasty. Foot Ankle Int. 2015 Jul; 36(7) 787-794.

Scientific Literature Review

Reviewed By: Pegah Samouhi, DPM
Residency: Cedars-Sinai Medical Center, Los Angeles

Podiatric Relevance: Total ankle arthroplasty has become increasingly popular over the years in the treatment of end-stage ankle arthritis due to good clinical outcomes. However, there have been relatively high incidences of wound complications with an anterior ankle incision. Negative pressure wound therapy (NPWT) has been used historically for open wounds for aiding in wound closure by advancing angiogenesis, increasing micro-vascular blood flow, stimulating granular tissue formation, and decreasing edema. The authors of this publication aimed to investigate the role of negative pressure wound therapy on the rate of wound healing problems after total ankle arthroplasty.

Methods: The study is a retrospective cohort study, with an experimental and control group, who underwent TAA by a single surgeon at a single institution from 2009-2013. Medical charts were reviewed and 37 patients were selected for the NPWT group and 37 patients in the control group for a total of 72 patients. All surgical incisions were approached by a standard anterior incision using the interval between the tibialis anterior and the extensor hallucis longus. Three different types of implants were used (Salto Talaris, STAR and Inbone). All closure techniques were held constant within both groups (the anterior capsule was closed with 0 Vicryl, the tendon sheath and extensor retinaculum were repaired with 2-0 Vicryl, the subcutaneous tissue with 2-0 Vicryl, and skin was closed with staples). The intervention group was treated with a NPWT device  (PICO, Smith & Nephew Medical) at 80 mmHg continuous pressure setting for 6-7 days. The control group was dressed with standard dressing (Telfa, gauze, and ABD pads). All patients were splinted and evaluated outpatient six-seven days post-operatively, at which point NPWT was removed from the intervention group and patients casted for three weeks. All post operative care was held constant for both groups with non weight bearing casts for three weeks then non-weight bearing in a CAM walker for three weeks, followed by full weight bearing as tolerated in CAM walker for four weeks.

Wound healing problems were defined as the presence of wound dehiscence, eschar, or drainage over three weeks after the surgery. Surgical site infections were defined according to the CDC criteria (Presence of: 1. Purulence; 2. Organisms isolated from cultures; 3. One of the following: pain or tenderness, erythema, localized swelling, rubor; or 4. Diagnosed by attending physician). Chi-square test and Fisher exact test were used to compare the two groups and p<0.05 was considered statistically significant.

Results: At one-week post operatively, a statistically significant favorable difference was found in regards to wound healing problems in intervention group. Incisional NPWT was found to reduce wound-healing problems with an odds ratio of 0.10 (95 percent CI 0.01-0.50; P=0.004).

Conclusions: Based on the authors’ findings there was a decrease in the incidence of wound healing problems following TAA with the use of NPWT dressing as an adjunct to standard post operative dressing. They suggest that the use of the PICO system, which is “skin friendly,” is superior in decreasing the incidence of deep and superficial infections and closure complications as opposed to standard dressings. This is the first study evaluating the efficacy of incisional NPWT as an adjunct treatment for wound healing after TAA.

This study failed to keep TAA devices standard within the groups and they feel this may be a contributing factor in the results. In addition, they failed to assess patient population to exclude patients with RA on long-term corticosteroids, which has been shown to effect wound healing. They also recognized that the sample size for this study is not sufficient as depicted by previous studies and power analysis, which requires 434 patients, would be necessary for each group to detect a significant effect of NPWT on infection after TAA. Although more studies are necessary to support this paper, the clinical value of this study is apparent, and practicing podiatric physicians can consider adding NPWT as an adjunct to wound care following TAA, which can also be cost effective. The equipment cost of NPWT is $220 and it has been shown that the cost of treatment of wounds for patients who develop wound complications could exceed five times as much as that of patients without complications. Podiatric physicians should use clinical judgment to assess the risks of wound complications based on each patient’s comorbidities and past medical history and use the aid of NPWT to decrease the probability of wound complications after TAA.

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