Effect of Negative Pressure Wound Therapy and External Fixation in the Treatment of Femur Fracture Complicated by Skin Avulsion: A Retrospective Case Series

Objective. The purpose of this study is to explore the clinical effects of negative pressure wound therapy (NPWT) and external fixation in the treatment of femur fracture complicated by skin avulsion. Materials and Methods. Seven cases of comminuted fracture of the femur caused by traffic accidents and complicated by skin avulsion were retrospectively analyzed. After stabilization and treatment of life-threatening injuries, these 7 patients underwent wound debridement, external fixation of the fracture, and coverage of the wound with NPWT. Secondarily, the wounds were covered by skin-grafting. Patients were followed for an average of 12 months. Results. After infection prophylaxis had been implemented and healthy granulation tissue had developed, each patient underwent secondary suture, free-skin grafting, or skin flap transfer. No wound had purulent drainage upon removal of the NPWT 4 to 7 days after placement. Secondary skin grafting was accomplished successfully in all 7 patients. Patients were followed for 6 to 15 months, and all wounds were well healed with no case of nonunion, osteomyelitis, or deformity at the site of union. Conclusion. External fixation with NPWT is effective treatment for femur fracture complicated by skin avulsion. The rate of infection is low and hospital stay is relatively short.

 Femoral shaft fractures complicated by skin avulsion are usually the result of high-energy trauma, and therefore tend to be seen in patients with multiple injuries. Such wounds represent serious injuries that are complicated and difficult to manage. Negative pressure wound therapy (NPWT) and external fixation can offer early wound protection and stabilization of the fracture. This treatment can assist in stabilizing vital signs, limiting further soft tissue damage, and decreasing the risk of bacterial infection.^1,2

  Here, the authors describe their experience of applying NPWT and external fixation in management of femoral shaft fractures complicated by skin avulsion in 7 individuals.

The study included 7 patients, 5 men and 2 women (mean age 44; age range 36–57 years), who were admitted to Renmin Hospital of Wuhan University (Hubei, China) from October 2008 to May 2011. Four patients previously had wound debridement and skin sutured in another hospital without fixation of fractures, and had been transferred to the authors’ hospital 2 days after the injury. The other 3 patients were transported to the hospital directly, within 6 hours of injury. Each patient underwent surgical treatment within 6 hours of arriving at the study hospital.

  All patients were injured by traffic accident. Figure 1 shows the soft-tissue progress necrosis and femur fracture of 1 female patient who had skin sutured in another hospital. Four patients had multiple injuries including 1 with head and facial injuries, 1 with blunt trauma to the abdomen, and 2 with blunt chest trauma. The femur fracture in 1 patient was classified as grade III A on the Gustilo open fracture classification system, and 2 were Gustilo grade II (Table 1). The study was approved by the hospital Institutional Review Board and all subjects provided written informed consent before being included in the study.

  Life-threatening injuries were first evaluated and treated. After initial resuscitation and bacterial wound cultures were given, broad-spectrum antibiotics were given before or during surgical treatment. Open fractures and soft tissue wounds were irrigated thoroughly with hydrogen peroxide, dilute povidone iodine, and sterile normal saline, and all devitalized tissues were excised. After initial debridement and irrigation, external fixation (Hoffmann II External Fixation System, Stryker, Kalamazoo, MI) was performed on the operating table with aid of an image intensifier (Figure 2). The length and alignment of the lower limb were restored by manual traction.

  Soft tissue defects were covered with NPWT equipment (vacuum sealing drainage system, BDE, Beijing, China), and negative pressures were set at 125 mmHg.^3,4 The NPWT devices were left in place for 2 to 5 days before removal or prior to repeat wound debridement and placement of a new NPWT dressing.

  Postoperative treatments. Prophylaxis for tetanus was given after surgery, and postoperative intravenous antibiotics were continued as warranted by the condition of the wound. Broad-spectrum antibiotic coverage was continued according to clinical assessment of the wound and according to culture and sensitivity.

  Failure to maintain a vacuum was the most common complication, and occurred in all the cases at least once in this report. Punctures in the occlusive dressing, power loss during use of the motorized suction unit, and clogging of the drainage system (sponge and tubing) can cause loss of effective suction. Therefore, adequate monitoring of suction is important postoperatively.

  Knee and hip mobilization and quadriceps exercises were started as soon as the patient was comfortable. Nonweight-bearing/partial weight-bearing walking was started with consideration of the type of fracture, progress of healing of the fracture, and presence of other injuries. Radiological assessment was accomplished with serial x-rays as needed. Bone union was assessed by the usual clinical and radiological criteria.

The 7 patients were followed for 6 to 15 months, with an average of 10 months. There was no case of deep vein thrombosis, fat embolism, or compartment syndrome. Two patients developed a rectal fistula because of a soft tissue defect involving the perineal region. The fistulas were closed 2 months after the injury.

 All patients in this report had positive bacterial wound culture results, with most having multiple pathogens. Infection was well prevented, and granulation tissue grew well after NWPT. All patients were treated by split-skin grafting for the management of soft tissue injuries (Figure 3a). Autologous bone grafting was performed in 4 femoral fractures with graft taken from the iliac crest. All femoral fractures achieved union within 36 weeks (Figure 4). One of the male patients had sustained serious injury to both nerves and muscles. Although his knee was stiff, the patient could walk unassisted. In the remaining 6 patients, at least 90 degree of flexion of the knee and hip was achieved.

Important objectives in the management of femoral shaft fractures with skin avulsion include prevention of infection, repair of soft tissue defects, and achievement of bony union. Negative pressure wound therapy is an effective dressing method to manage the soft tissue defects by preparing the wound bed when there are large defects in the skin and soft tissue,⁵ although it is important to remove devitalized or necrotic tissue and to control bacterial contamination and arterial bleeding before applying NPWT. Negative pressure wound therapy can be used to facilitate the formation of a healthy wound bed, promote faster growth of granulation tissue, and reduce the size and depth of a defect.⁶

 According to the authors’ clinical experience, thorough debridement is essential in the initial management of femur fracture with skin avulsion. In injuries caused by high-energy impact, wounds often are contaminated with foreign matter, and may develop extensive muscle necrosis. Thus, NPWT equipment may not effectively pump out all liquefied tissue. Wounds that are sealed without debridement often are complicated by severe local or systemic infection.

 External fixation is minimally invasive, and may be performed rapidly. It is often applied to treat open fractures and to treat fractures in patients with multiple injuries who are too critically ill to tolerate the surgical stress of internal fixation. External fixation is an expedient method of bone fracture stabilization but is associated with high rates of pin tract infection, malunion, reoperation, and loss of flexion.^7-11 Thus, many surgeons have removed external fixation and performed internal fixation after wounds were healed.^7,12 However, repair of the soft tissue defect took at least 4 weeks in all 7 patients in the current report. The authors did not convert external fixation to internal fixation because the fibrous bony callus often had formed between the fragments, and surgery in the field of a large scar would increase the risk of infection. Although external fixation cannot provide the same stabilization as internal fixation, all patients in this report had satisfactory fracture healing without delayed union or nonunion. The authors believe that external fixation helped to protect the periosteum during the surgical procedure, and that it allowed sufficient blood supply in the vicinity of fractures. Because of limited disturbance of soft tissue, no patient suffered deep infection in this study group.

  Negative pressure wound therapy has several advantages over traditional methods. Negative pressure wound therapy does not necessitate dressing changes during a prolonged period; it builds a protective screen to close the surface of the wound, thus guarding against contamination and keeping foreign matter out of the wound. In addition, the continued negative pressure can be a significant deterrent to the growth of bacteria, thus promoting the survival of grafted skin. With the application of normal saline, NPWT can provide unobstructed drainage, clear the tissue of necrotic material, and promote the growth of granulation tissue.¹³

  According to the author’s experience, there are 2 important problems in the management of patients in this NPWT study. First, the wounds are prone to infection, and are difficult to tend to because of their close proximity to the perineum. This also makes it difficult to maintain the negative pressure of NPWT during defecation. Second, pins and connecting rods often interfere with the seal around the wound. It is not difficult to observe an air leak at the point of contact with the pins. Such an air leak reduces the negative pressure, and thus, can affect the outcome of NPWT.

  In order to circumvent the problem of maintaining a seal when the wound involved the perineum in close proximity to the anus, the authors packed the anus with sufficient gauze to seal it, and then performed a sigmoid loop colostomy. If a sigmoid loop colostomy was not necessary, they changed the gauze and sealing membrane every day.

  Selecting appropriate pin fixation points is important for the success of NPWT. Ideally, the fixation points should be as far as possible from the wounds. In addition, in order to maintain sufficient space to accommodate the NPWT apparatus, the external fixation bar also should be as far from the wounds as is practical, although too great a distance risks compromising the stabilization of the fracture. The injury itself severely limits the level of activity for each patient, and thus, fixation of the fracture is more easily maintained.

  External fixation and NPWT in the management of open femoral fractures complicated by skin avulsion gives positive results with a good rate of fracture healing, short rehabilitation period, and acceptable infection rate. Patient compliance is good, access for secondary soft tissue and bony procedures is easy, and reoperation is infrequently necessary.

Affiliations: The authors are from the Department of Orthopaedics, Renmin Hospital of Wuhan University, Hubei, China.

Address correspondence to:
Bo Qiu, MD
Department of Orthopaedics
Renmin Hospital of Wuhan University
99 Zhangzhidong Road
Wuhan 430060, China
drqb123@163.com

Disclosure: The authors disclose no financial or other conflicts of interest.