The postoperative dressing functions as an important barrier to prevent orthopaedic infections and reinfections. Preoperative assessment of patient factors and intraoperative evaluation of the soft tissue and wound serve as key elements to determining the right dressing for individual patients when treating orthopaedic infections. This chapter explores characteristics of the ideal dressing and fundamental features of different dressing options available to surgeons, including standard nonocclusive dressings, occlusive dressings with or without antimicrobial impregnated materials, negative pressure wound therapy, and closed incision negative pressure wound therapy. Advantages and disadvantages of each dressing type are discussed with literature evidence. Finally, this chapter provides surgeons with an algorithmic approach to dressing selection for patients undergoing treatment for orthopaedic infections.
4 Surgical Wound Dressings after Treating Orthopaedic Infections
When applying an occlusive dressing over a joint such as the knee or elbow with high anticipated excursion, place the dressing with the joint in flexion (20–30 degrees) to reduce tension on the dressing and thus reduce force on the surgical incision.
Apply dressings over joints with the dressing fibers oriented in the direction of joint movement to reduce blister formation (e.g., longitudinal on the knee or elbow).
If an incision is too long or its shape does not conform to one size of a particular prefabricated dressing, stacked dressings may be utilized by cutting the end of one or more dressings before applying a complete dressing over them to create an adequate seal.
When removal of a dressing is appropriate, begin by methodically lifting one corner of the dressing adhesive by gently pulling up and away to release the dressing and then gently work free the adhesive edge one small area at a time until the entire adhesive portion is free. This should allow the dressing to removed more easily.
The dressing should be carefully observed for drainage on the back side of the dressing. If just light spotting occurs, the dressing can be monitored. If there is a more saturated appearance or excessive strikethrough on the dressing, it should be removed and the incision carefully inspected.
Be prepared in the operative room with options for negative pressure wound therapy particularly for patients at risk for wound breakdown and incisions that may prove difficult to close.
Wound dressings are applied at the conclusion of a surgical case to cover the wound and potentially prevent reinfection when treating patients with orthopaedic infections. Many options are available, ranging from nonocclusive gauze and tape for routine closed incisions to negative pressure wound therapy (NPWT) for large wounds that may not be closed. The challenge is to choose the right dressing for each individual patient. Much of the literature to date addressing postsurgical dressings explores the use of dressings prior to development of an infection. Nevertheless, the principles behind successful dressings remain the same when addressing the surgical wound while treating an orthopaedic infection. This chapter will examine the characteristics of optimal dressings, explore different dressing types by increasing wound complexity, and give recommendations in the form of an algorithm to help select the right postoperative dressing for patients being treated for orthopaedic infections.
4.2 Characteristics of Optimal Surgical Dressings
As postsurgical dressings have evolved over the years with the advent of technological advances, multiple factors have been identified to describe the ideal surgical dressing. Collins described the following six characteristics: (1) permeable; (2) able to remain in situ while the patient is bathing; (3) transparent to observe fluid accumulation; (4) low adherence; (5) barrier to bacteria, but not moisture vapor; and (6) cost-effective. 1 In addition to these qualities, the ability of the dressing to accommodate the range of motion of nearby joints must be considered.
The ability of a dressing to provide a moist environment is crucial for surgical wound healing. Dressing permeability, as well as absorptive capacity, help establish this setting. 2 Previous research has shown that, compared to dry environments, moist environments result in a faster, better quality of wound healing that minimizes wound necrosis. 3 , 4 Despite the negative connotation of wound exudates, these are filled with growth factors that promote growth and the migration of fibroblasts, endothelial cells, and keratinocytes. However, excessive moisture can be detrimental to wound healing, leading to blistering, maceration, and wound breakdown. 5 Therefore, an ideal dressing should be able to address excessive wound exudate while maintaining an appropriately moist environment for wound healing.
Another important quality of an ideal dressing is its ability to create an occlusive barrier to the external environment. By creating a barrier for the surgical incision, a dressing can prevent bacterial ingress and introduction of infection. Occlusive barrier dressings can create a thermally insulated, relatively hypoxic environment that actually promotes angiogenesis at the wound surface and enhances wound healing. 6
Dressing characteristics that improve the experience of the patient and medical staff also make them ideal for use. This includes the ability of patients to retain the dressing while bathing, but also low adherence to allow for easy, atraumatic removal. Higher patient satisfaction has been seen with dressings that require less frequent changes. 7 Dressings must also demonstrate a degree of compliance to allow for movement of nearby joints to facilitate range of motion postoperatively. Transparency of dressings also allows the patient and medical staff to evaluate the saturation of the wound and determine if there is a need for replacement.
Lastly, cost-effectiveness of dressings should be considered. Standard postoperative dressings, such as gauze and tape, cost little to the patient and hospital. Alternatively, recently developed dressings with advanced technology are more expensive. However, one must weigh certain factors before choosing a dressing simply because of cost. Increased frequency of dressing changes increases cost and limits the ability to maintain the wound environment temperature more near to core body temperature, which facilitates mitotic cell division and leukocyte activity critical for wound healing. Each time a dressing is removed, 3 to 4 hours are required to return to the same level of cellular activity. 2 Clarke et al were able to show higher skin microbial colonization in patients who had earlier dressing changes after total joint arthroplasty. 8 Despite higher costs, dressings that require less changes can potentially protect a surgical wound from pathogen exposure, can reduce patient pain, and are less of a burden to staff and family members changing the dressings at home. The price of a dressing versus further operating and hospital care costs must be weighed when selecting a dressing.
4.3 Dressing Types
Multiple dressing types exist at a surgeon’s disposal. Over 3,000 types of dressings, biological materials, tissue-engineered substitutes, and mechanical devices exist to assist in surgical wound healing. 9 Each has at least some characteristics of the ideal dressing. The following paragraphs will discuss the use of nonocclusive and occlusive dressings, closed incision wound vacuum systems, and wound vacuum systems in the context of wound protection after treating orthopaedic infections. ▶ Table 4.1 highlights multiple dressings within these categories.
4.3.1 Nonocclusive and Occlusive Dressings
Nonocclusive dressings include supplies such as iodoform or regular gauze, abdominal pads (ABDs), Kerlix®, tape, or compression bandages (▶ Fig. 4.1). Following surgical debridement for infection, moist gauze dressings have traditionally been the most commonly used dressing for colonized wounds, providing a dressing option that is inexpensive and simple to use. 9 However, many surgeons are concerned about the effects of decreasing wound temperature, removal of healthy granulation tissue, vaso-constriction and subsequent wound ischemia, decrease of cellular migration and proliferation, higher costs from increased caregiver time or home nurse dressing changes, and increased frequency of dressing changes resulting in lower patient compliance associated with these dressings. 9 Despite these concerns, traditional nonocclusive dressings may represent the right option for a surgical wound under certain circumstances. Such settings may include surgical wounds requiring daily evaluation, with prolonged splint immobilization, and incisions requiring mechanical debridement of necrotic tissue that can be addressed with wet-to-dry dressings.
Early experiments by Winter demonstrated the importance of the moist environment created by occlusive dressings, which ignited a wave of research and development of multiple occlusive dressings. 3 Occlusive dressings were found to form excellent protective barriers to the external environment, which allow patients to participate in activities such as showering while improving epithelialization and granulation of wounds. 24 Further clinical studies have showed significant decreases in wound problems and lower infection rates associated with the use of occlusive dressings. 7 , 25 , 26 Occlusive dressings are either fully occlusive or semi-occlusive based on their permeability to water vapor. Both can be waterproof. There are currently multiple types of occlusive dressings available to address the surgical wound after treating orthopaedic infections, which can be generally categorized into regular occlusive dressings and those impregnated with antibacterial materials such as silver.
Regular Occlusive Dressings
Regular occlusive dressings employ a single layer of transparent film, such as Tegaderm™ (3M; Maplewood, MN) or Hydrofilm® (Hartmann; Heidenheim, Germany), to create a waterproof covering that can be used as a secondary dressing over another dressing layer, such as gauze or Xeroform® (multiple companies). Newer occlusive dressings possess an occlusive outer layer with the advent of advanced technology to address exudates and the wound surface, including Hydrofiber® (ConvaTecInc; Reading, UK) and hydrocolloid technology. Hydrofiber® technology allows for significant absorption of exudate, but does so via a process called vertical wicking. This process removes exudate directly from the wound, preventing lateral wicking that could result in maceration of wound edges. 5 Such maceration has the potential to cause wound breakdown and infection. Hydrofiber® dressings also facilitate the formation of a fibrin layer that prevents dressing ingrowth and damage to the wound during removal. It also serves as a barrier to the harmful effects of local granulocytes toward wound healing. 27
Like Hydrofiber® dressings, hydrocolloid technologies also have high absorptive capacity. However, these dressings absorb exudate differently by forming a gel, such as acrylate, that makes the dressing more permeable to water vapor. This allows the dressing to absorb more exudate while maintaining an appropriately moist environment. 28 Beyond this unique property, hydrocolloid dressings are relatively atraumatic to the skin. Some dressings, such as Aquacel® (ConvaTecInc), employ a combination of both Hydrofiber® and hydrocolloid technologies in attempts to provide an optimal wound healing environment (▶ Fig. 4.2).