Abstract: Orthopedic trauma wounds with extensive soft tissue damage can be costly and time consuming to heal. This case report illustrates a positive outcome using negative pressure wound therapy in tandem with a silicone gel liner to treat a nonhealing, dehisced incision following a below-the-knee amputation. The primary goal of using the 2 therapies together was to close the wound while actively reshaping and shrinking the residual limb for a prosthesis. The simultaneous use of these therapies resulted in quicker limb maturation and a reduction in the time for prosthetic fitting compared to the previous standard of care at the authors’ institution.

A

54-year-old man was involved in a motor vehicle crash as the driver of a motorcycle. No significant medical history was noted prior to the accident. He sustained no damage to his vital organs, spine, or head. He sustained an open right ankle crush fracture, which transected his right posterior tibial artery. Six days after admission to a tertiary hospital, after 2 surgical attempts at limb salvage and 17 units of packed cells, a below-the-knee amputation (BKA) was performed.
       Five days postamputation, the patient was transferred to a local transitional care unit for reconditioning and management by the hospital’s wound center. At the initial wound care assessment, a moderate amount of edema was noted throughout the entire extremity. The anterior flap had small areas of blistering and discoloration. At the tertiary care center, the wound cultured positive for methicillin-resistant Staphylococcus aureus (MRSA), and the incision was treated with silver sulfadiazine cream on first inspection (Figure 1). Twenty days later at a follow-up visit, an orthopedic surgeon removed the sutures over the BKA, and the incision line dehisced with eventual formation of brown, necrotic tissue and yellow slough (Figure 2).

Methods

       All wound care was performed in an outpatient clinic. To remove the nonviable tissue and reduce bacterial colonization, an enzymatic debriding agent (ACCUZYME®, Healthpoint, Ltd., Fort Worth, Tex) and cadexomer iodine (IODOFLEX®, Healthpoint, Ltd.) were applied in an alternating fashion (Figure 3). The wound was believed to be colonized rather than clinically infected, so systemic antibiotics were not administered. This debriding and treatment regimen was continued until the insurance authorization for negative pressure wound therapy (NPWT, V.A.C.® Therapy™ System, KCI, San Antonio, Tex) was obtained. Negative pressure wound therapy is not a substitute for debridement; the angiogenic stimulation of the therapy has maximal benefit on a clean wound bed.^1,2 On Day 71 postwound dehiscence, NPWT was initiated with the silicon gel liner (Table 1).

Figures 1-4

       The periwound area was protected with a skin preparation solution and covered with a transparent drape. A medical grade reticulated polyurethane ether sterile foam dressing (V.A.C.® GranuFoam®, KCI) was placed in the wound cavity and covered with a semi-occlusive adherent drape to create an airtight seal. Tubing was then applied to the foam dressing in the wound (Figure 4).

Table 1

       A silicone postoperative gel liner (Iceross Original, Ossur, Reykjavik, Iceland) was modified to be placed over the NPWT dressing. The distal locking piece was removed from the bottom of the white, 2-mm thick liner, which created a hole from which the tubing could exit. The liner was turned inside out, and the outside was sprayed with 70% isopropyl alcohol for smoother application. The liner was then rolled over the NPWT dressing and stump (Figure 5A and B). An optional cotton sleeve was placed over the gel liner for added protection (Figure 6). The tubing exiting the liner was then connected to a collection canister, which was contained within a computer-controlled portable NPWT unit (V.A.C. Freedom®, KCI) used to deliver controlled negative pressure.

Figure 6

Figure 5

       The NPWT unit was set to deliver 125 mmHg continuous subatmospheric pressure with dressing changes every other day, based on previously published and recommended parameters.^3–5 At each dressing change, the silicone gel liner was removed, cleansed with soap and water, and dried with a towel. The NPWT dressing was replaced, and the gel liner was reapplied over the dressing. This combination therapy was applied for 26 days until the wound was granulated to the surface, at which time NPWT was discontinued (Figure 7).

Figure 7

       To stimulate final reepithelization, the wound was then covered with 2 layers of small intestinal submucosa (SIS) wound matrix graft material (OASIS®, Healthpoint, Ltd.), which was covered with a nonadhering dressing (Adaptic, Johnson & Johnson Wound Management, Somerville, NJ). A collagen wound matrix dressing (Promogran, Johnson & Johnson Wound Management) was then applied, over which a silver antimicrobial barrier (Acticoat 7, Smith & Nephew Inc., Largo, Fla) was placed. All of this was secured by a semipermeable dressing (ThinSite®, Swiss-American Products, Inc., Dallas, Tex). The silicone gel liner was then reapplied. The first dressing change was at 3 days, and the next dressing change was at 7 days. After 2 treatments of SIS wound matrix grafting, the wound was treated with a cadexomer iodine paste (IODOFLEX®, Healthpoint, Ltd.) until the wound was fully epithelized.

Results

       After 26 days of combination therapy with NPWT and the silicone gel liner, the wound length and width measurements had decreased by 50%, and the depth and tunneling were reduced to 0.0 cm. The wound was 100% granulated to the surface. The diameter of the residual limb was reduced from 38.5 cm to 36.0 cm, and the limb contour was reshaped from oval to cylindrical. Three days after the discontinuation of NPWT, the patient was fitted with a prosthetic leg (Figure 8). Because reshaping and shrinkage of the limb were significant at this time, the initial prosthesis fit more comfortably and for a longer period of time. The patient was able to wear his prosthesis over the dressed epithelizing wound, which closed completely 27 days later (Table 1). Throughout the duration of his treatment, the patient continued to work full time as a hospital departmental medical director, while maintaining an extensive travel schedule.

Figure 9

Figure 8

Discussion

       Negative pressure wound therapy was introduced by Argenta and Morykwas in 1995 based on the principle of applying topical subatmospheric pressure to the wound cavity.^6,7 This mechanically-induced subatmospheric pressure removes excess fluid from the extracellular space, delivers mechanical stress to the wound, and has been shown to enhance blood flow, reduce edema, and increase the proliferation of reparative granulation tissue.^8–12 Negative pressure wound therapy is a closed system that helps protect the wound from bacterial invasion and maintains a moist wound healing environment.^1,13
       Webb et al.¹ published orthopedic indications for NPWT to include traumatic wounds after debridement, infection after debridement, and fasciotomy wounds for compartment syndrome. Negative pressure wound therapy can also be used as a dressing for anchoring or bolstering a split-thickness skin graft.¹ The technique is contraindicated in patients with thin, easily bruised, or abraded skin; those with neoplasm as part of the wound floor; and those with allergic reactions to any of the components that contact the skin.¹ Negative pressure wound therapy is also contraindicated in cases of untreated osteomyelitis, malignancy in the wound, nonenteric and unexplored fistulas, necrotic tissue with eschar present, and over exposed blood vessels or organs.
       Recent studies^1,14–19 have documented successful outcomes of NPWT on a variety of orthopedic wounds. Wongworawat et al.¹⁷ published a study showing that when NPWT was applied to a series of 14 infected orthopedic wounds, wound size decreased an average of 43% during a mean duration of 10 days. Page et al.¹⁸ published controlled results of applying NPWT to wounds with large soft tissue defects, resulting in a statistically significant reduction in risk for additional complications, additional surgeries, and hospital readmission compared to wounds treated with wet-to-moist dressings.
       The modified silicone gel liner allowed for total contact with the skin and applied uniform compression to the entire stump. It also allowed for gentle splinting of the residual limb in extension, which prevented contraction.^20,21 The liner was easy to apply, clean, and re-use. Contraindications for silicone liner treatment are purulent infection and senile dementia.²² Maintaining a NPWT seal around extremities of orthopedic trauma patients can be challenging, and placing the liner over the dressing provided additional stability to the dressing.¹⁹ No leaks occurred for the duration of NPWT.
       This surgical wound had been open for 3 months prior to the application of NPWT. The majority of this time (71 days) was spent waiting for insurance authorization for NPWT, during which time a variety of wound care therapies were tried to facilitate closure. Basic wound care principles were followed. The wound was adequately debrided of all devitalized tissue. After repeated debridement and the use of different wound care products, neither the wound depth nor the tunnel measurements had decreased during the 3 months. Since the patient care was outpatient at this time, no additional hospital days were incurred, but the wound therapy material costs and nursing time expended were significant.
       Negative pressure wound therapy was initiated with the goal of stimulating granulation tissue formation to fill in the depth and tunneling.^11–17 Once the therapy was initiated, the active removal of third space edema, increased perfusion, and resulting stimulation in granulation tissue formation were apparent. Within 1 week, the wound depth had decreased by over 50%. Within 26 days of the application of dual therapies, the wound had completely granulated to the surface, and a prosthesis could be fitted.
       Prior to incorporating these dual therapies concurrently, the standard of care at the authors’ facility for a surgical wound would have been to apply NPWT until the wound granulated to the surface, then wrap the stump with an elastic bandage to facilitate shrinkage and reshaping of the limb residuum. In the authors’ experience, this 2-step approach could take approximately 30–60 days longer to reach the point of limb fitting (26 days of NPWT, plus a subsequent 30–60 days of stump shrinkage with either an elastic bandage or liner) compared to the 26 days of dual therapy that resulted in this case report. In addition to time savings, the major advantage of the liner is that the same level of compression is achieved regardless of who applies the liner. In the case of elastic bands, both the level of compression and quality of the dressing can vary, depending on the clinician applying them.²²
       In fact, the manufacturer of the NPWT system generally recommends against placing compression therapies over NPWT dressings in cases of venous stasis ulcers because of the possibilities of unequal pressure distribution causing additional circulatory deficits. Because of the even stretch of the silicone material, the liner affected uniform compression every time it was applied, eliminating potential restriction of blood flow caused by user application.
       After NPWT was discontinued and the prosthesis was fitted, the authors chose a combination wound care therapy regimen to address final epithelization of the wound. The aim was to reduce the remaining wound’s relatively large surface area, cushion against pressure created by the prosthesis, and protect against recurrent bacterial colonization. The 2 layers of SIS wound matrix graft material were applied to stimulate granulation tissue deposition, growth factor activity, and reepithelization.²³ One layer of nonadhering dressing was then placed to protect the graft material and allow subsequently applied materials to penetrate through to the wound bed. The collagen wound matrix dressing was applied as a protease modulating matrix to further stimulate wound repair,²⁴ and the silver antimicrobial barrier was placed to protect against recurrence of MRSA colonization.²⁵ After 2 treatments of SIS wound matrix grafting, the surface area of the wound was significantly reduced. Therapy was then switched to a cadexomer iodine paste until closure. The silicone liner remained applied over the dressing throughout the entire reepithelization process to help evenly distribute the pressure from the prosthesis.

Conclusion

       The most common wound that practitioners face in orthopedics is the surgical wound. Often, these wounds are left to heal by secondary intention,¹⁹ but the time to heal is generally considered “lost” by the patient. In the case of a relatively young, active patient who receives a BKA following traumatic injury, an important consideration in the treatment regimen is the patient’s psychological well being in response to the physical changes that accompany limb loss. Attentive care of the limb residuum is imperative in promoting the patient’s present health and future function.^22,26 Applying NPWT with the silicone liner accelerated the rehabilitation process, which in turn reduced the need for physical therapy, decreased the overall number of prosthetic refittings needed, and reduced the risk of thromboembolism.
       In this case and many other postamputation cases, the speed in which the wound was closed and the prosthesis fitted impacted the patient’s mental health and lifestyle. Because the wound closure progressed quickly while the stump was being reshaped and shrunk, little time was lost in the wound healing process. The patient felt a higher sense of control of the situation, as he maintained considerable mobility throughout the healing process. He could continue working throughout treatment, which in turn contributed to a higher sense of self worth. All of these factors resulted in the patient’s response of “acceptance with resilience,” meaning that the patient was able to move past his injury and make extraordinary achievements despite a drastic physical change.²⁷ One year after the amputation, the patient took a ski holiday and was skiing so naturally, his prosthesis went completely unnoticed.