Changing strategies results in “damage-control orthopaedics”

Hans-Christoph Pape, MD, has won the 2008 Orthopaedic Research and Education Foundation (OREF) Clinical Research Award, for his study on “Effects of Changing Strategies of Fracture Fixation on Immunologic Changes and Systemic Complications after Multiple Trauma: Damage Control Orthopaedic Surgery.”

Dr. Pape and his research team have conducted multiple studies during the past decade—closely examining how the management of major fractures in polytrauma patients has shifted from the 1980s, when definitive surgical stabilization was done within the first

24 hours of the trauma, to a more selective treatment strategy referred to as “damage-control orthopaedics” (DCO).

“In the treatment of multiple-trauma patients, the timing and type of the initial surgery of long bone fractures, duration of the surgical procedures, and immune inflammatory changes all play a role in the incidence of systemic complications,” said Dr. Pape.

Early surgery isn’t always best
Two decades ago, early fracture stabilization for polytrauma patients—particularly those with the highest degrees of injury—was thought to reduce the incidence of acute respiratory distress syndrome (ARDS).

But when early fracture stabilization was used on a routine, less selective basis, Dr. Pape and others found that systemic complications such as ARDS and multiple organ failure (MOF) occurred.

Dr. Pape and his team conducted a 10-year retrospective study of 766 polytrauma patients, focusing on patients with high injury severity scores (ISS) to determine which factors were contributing to the unexpected complications of ARDS and MOF. They found that patients with severe chest injuries had a higher rate of pulmonary complications, including pneumonia and ARDS. They also found a higher rate of ARDS among patients with chest trauma who were treated with intramedullary (IM) nailing for femoral shaft fractures.

Perhaps most significantly, some patients who had been in satisfactory clinical condition and undergone definitive fixation unexpectedly deteriorated after the procedure. Based on their clinical findings, Dr. Pape added a new classification of “borderline” to the existing criteria of stable, unstable, and extremis polytrauma patients (Table 1).

“Some of the criteria were derived from clinical experience only, whereas others were the result of clinical studies undertaken to evaluate the impact of initial surgery on the outcome,” Dr. Pape explained. For example, he pointed to a study of patients from the German Trauma Registry that indicated a prolonged surgical time (more than 6 hours) was associated with an adverse outcome.

Surgical technique plays major role
Dr. Pape also found that the technique used in femoral fracture fixation played a major role in increasing the risk of posttraumatic complications. A comparison of reamed nailing with unreamed nailing found that reamed nailing was associated with an increase in pulmonary arterial pressure, worsening of lung function, and pathologic inflammatory changes.

According to Dr. Pape, the shape of the reamer head “was found to play a significant role in the development of pulmonary fat embolization.” Larger reamer tips with broader flutes “appeared to transport fat proximally and decompress the femoral canal distal to the fracture site,” and an animal model study demonstrated that the discharge of bone marrow fat was related to an inflammatory process.

Other issues also were found related to reamer use. Of particular concern, coagulopathy inside the medullary canal was associated with blockage by cancellous bone near the fracture site.

As a result of these studies, a number of new reaming systems have been developed to reduce fat embolization and address medullary canal blockage.

Surgery as a “second hit”
Ample evidence exists that the incidence of ARDS and MOF is influenced by inflammatory changes following trauma, which Dr. Pape describes as the “first hit.” His team found that macrophages do become a part of the inflammatory process, but not until days after the trauma, as the intestinal barrier deteriorates.

Dr. Pape and his team also investigated the issue of genetic predisposition to ARDS and MOF by examining the genetic polymorphisms for interleukins-6 (Il-6) and 8 in patients who had sustained severe trauma. They found that complication rates differed depending on the expressions of these cytokines.

Not only did trauma cause inflammatory changes, but surgical procedures were found to have effects comparable with those of the initial trauma—the “second hit.” Based on these findings, Dr. Pape and his team decided to limit the initial procedure to less than 6 hours, control the blood loss, and avoid additional soft-tissue damage by overmanipulation of fracture fragments. They found that this led to fewer unexpected complications following the first surgical procedure.

When comparing several inflammatory mediators, Dr. Pape found that Il-6 served as the most specific marker for trauma patients. In patients with high ISS, levels of Il-6 remained elevated for more than 5 days following the initial trauma and, the team found, these levels could be used to determine which patients would experience organ failure at a later date.

Optimal timing for surgery
As the result of a prospective, randomized study, Dr. Pape showed that the timing of surgery has an impact on the inflammatory response. Trauma patients who received early definitive fracture stabilization experienced an increase in systemic inflammation; those who were treated with temporary stabilization (external fixation) and later converted to definitive fixation within 2 to 4 days following trauma did not have a similar sustained inflammatory response.

Dr. Pape’s studies also found that secondary surgeries that were longer than 3 hours in duration may be related to organ dysfunction. As a result, a “waiting period of several days may be required before secondary definitive fixation can be performed.”

General surgeons have practiced “damage control surgery” for patients in critical condition for more than a decade, and the orthopaedic community has begun to migrate to this model—postponing longer definitive fixation stabilization for several days in favor of external fixation for patients deemed to be in critical condition. These patients can be defined by the degree of shock, hypothermia, and coagulopathy—“the triad of death.” By adding soft-tissue injuries as a fourth parameter, and by defining “borderline” patients, Dr. Pape was able to develop a treatment algorithm for tailoring clinical treatment (Fig. 1).

According to Dr. Pape, a preoperative assessment of every polytrauma patient should be done. Based on the studies he has conducted, he recommends that stable patients should “undergo IM nailing of the femur while unstable patients should undergo a temporizing approach using external fixation.”

Conclusion
In terms of clinical treatment, DCO is the treatment of choice for patients with “severe polytrauma and at high risk for developing systemic complications.” Clinical studies conducted by Dr. Pape have shown that the appropriate type and timing of the orthopaedic surgical procedure based on a careful assessment of the patient’s clinical condition can result in a less sustained inflammatory response and a reduction in ARDS, MOF, and other serious complications.

Dr. Pape uses an analogy to summarize his work, “Surgery is like administering medications. You don’t want to give your patient an overdose.”

Dr. Pape reports no conflicting commercial or consulting relationships with any medical, orthopaedic, or device manufacturer.

Annie Hayashi is the senior science writer for AAOS Now. She can be reached at hayashi@aaos.org