Do Transtibial Amputations Outperform Amputations of the Hind- and Midfoot Following Severe Limb Trauma?: A Secondary Analysis of the OUTLET Study.

BACKGROUND: The purpose of this study was to compare 18-month clinical and patient-reported outcomes between patients with severe lower-limb injuries treated with a transtibial amputation or a hind- or midfoot amputation. Despite the theoretical benefits of hind- and midfoot-level amputation, we hypothesized that patients with transtibial amputations would report better function and have fewer complications. METHODS: The study included patients 18 to 60 years of age who were treated with a transtibial amputation (n = 77) or a distal amputation (n = 17) and who were enrolled in the prospective, multicenter Outcomes Following Severe Distal Tibial, Ankle, and/or Foot Trauma (OUTLET) study. The primary outcome was the difference in Short Musculoskeletal Function Assessment (SMFA) scores, and secondary outcomes included pain, complications, amputation revision, and amputation healing. RESULTS: There were no significant differences between patients with distal versus transtibial amputation in any of the domains of the SMFA: dysfunction index [distal versus transtibial], 31.2 versus 22.3 (p = 0.13); daily activities, 37.3 versus 26.0 (p = 0.17); emotional status, 41.4 versus 29.3 (p = 0.07); mobility, 36.5 versus 27.8 (p = 0.20); and bother index, 34.4 versus 23.6 (p = 0.14). Rates of complications requiring revision were higher for distal amputations but not significantly so (23.5% versus 13.3%; p = 0.28). One distal and no transtibial amputees required revision to a higher level (p = 0.18). A higher proportion of patients with distal compared with transtibial amputation required local surgical revision (17.7% versus 13.3%; p = 0.69). There was no significant difference between the distal and transtibial groups in scores on the Brief Pain Index at 18 months post-injury. CONCLUSIONS: Surgical complication rates did not differ significantly between patients who underwent transtibial versus hind- or midfoot amputation for severe lower-extremity injury. The average SMFA scores were higher (worse), although not significantly different, for patients undergoing distal compared with transtibial amputation, and more patients with distal amputation had a complication requiring surgical revision. Of note, more patients with distal amputation required closure with an atypical flap, which likely contributed to less favorable outcomes. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Definitive External Fixation for Anterior Stabilization of Combat-related Pelvic Ring Injuries, With or Without Sacroiliac Fixation.

BACKGROUND: Combat-related pelvic ring injuries frequently lead to placement of a temporizing external fixation device for early resuscitation and transport. These injuries are commonly complicated by concomitant polytrauma and extensive soft-tissue injuries, which may preclude early internal fixation and lead to prolonged use of external fixation. To date, few studies have reported on the outcomes of definitive external fixation for combat-related pelvic ring injuries. QUESTIONS/PURPOSES: (1) In patients treated with definitive external fixation after combat-related pelvic ring injuries, how often is the quality of reduction within radiographically acceptable parameters at the end of treatment? (2) What proportion of patients demonstrate local heterotopic ossification after these injuries? (3) What patient- and treatment-related factors are associated with increased complications and pain? METHODS: We retrospectively studied all patients with pelvic ring injuries treated at a tertiary military referral center from January 2003 to December 2012. In total, 114 patients were identified, 55 of whom maintained an external fixation frame throughout their treatment. During that time, the general indications for definitive external fixation were an open, contaminated pelvic ring injury with a high risk of infection or open urologic injury; confluent abdominal, perineal, and thigh wounds; or comminution of the pubic ramus that would necessitate plate fixation extending up the anterior column in patients with open abdomen or exposure-compromising abdominal wounds. Posterior fixation, either sacroiliac or lumbopelvic, was applied in patients with sacroiliac instability. Of the 55 patients with pelvic ring injuries treated with definitive external fixation (27 open and 28 closed), four underwent hemipelvectomy and construct removal for massive ascending infections and four were lost to follow-up, leaving 47 patients (85%) who were available at a minimum follow-up of 12 months (median 29 months, interquartile range 17-43 months). All 47 patients underwent serial imaging to assess their injury and reduction during treatment. External fixators were typically removed after 12 weeks, except in patients in whom pin-site irritation or infection prompted earlier removal, and all were confirmed to be grossly stable during an examination under anesthesia. Clinical union was defined as the absence of radiographically present fracture lines and stable examination findings under anesthesia when the external fixator was removed. Data on demographics, injury pattern, associated injuries, revision procedures, complications, and final functional outcomes including ambulation status, sexual function, and pain were collected. Pelvic radiographs were reviewed for the initial injury pattern, type of pelvic fixation construct, residual displacement after removal of the frame, and evidence of formation of heterotopic ossification in the pelvis or bilateral hips. Pelvic displacement and diastasis were determined by digital caliper measurement on plain images; malunion was defined as anterior diastasis of the pelvis or vertical incongruity of the hemipelvis greater than 10 mm. RESULTS: Radiographic malunion after construct removal occurred in eight of 24 patients with open injuries and in five of 23 patients with closed injuries. Heterotopic ossification developed in the pelvis or hips of all 24 patients with open injuries and in two of the 23 patients with closed injuries. In patients with open pelvic ring injuries, concomitant acetabular fractures were associated with pelvic pain at the final follow-up examination (risk ratio 1.9; 95% confidence interval, 1.0-3.5; p = 0.017). No treatment factor resulted in superior functional outcomes. In the closed-injury group, concomitant lower-extremity amputation was associated with improved radiographic final reduction (RR 0.4; 95% CI, 0.2-0.7; p = 0.02). There was no association between radiographic malunion and increased pain (RR 1.9; 95% CI, 0.5-7.0; p = 0.54 for the open group; RR 0.8; 95% CI, 0.7-1.0; p = 0.86 for the closed group). CONCLUSION: In this series of patients with severe combat-related pelvic ring injuries who were treated anteriorly with definitive external fixation because of a severe soft-tissue injury, high infection risk, or unacceptable physiologic cost of internal fixation, malunion and chronic pelvic pain were less common than previously observed. Prior studies primarily differ in their lack of sacroiliac or lumbopelvic stabilization for posteriorly unstable fracture patterns, likely accounting for much of these differences. There may have been important between-study differences such as extremely severe injuries, concomitant injuries, and study population. Our study also differs because we specifically analyzed a large cohort of patients who sustained open pelvic ring injuries. Future studies should prospectively investigate the ideal construct type and pin material, optimize the length of treatment and assessment of healing, and improve radiographic measures to predict long-term functional outcomes. LEVEL OF EVIDENCE: Level IV, therapeutic study.

Pelvic Fracture Care.

While combat-related pelvis fractures are more commonly open, higher energy, and complex in pattern than those seen in the civilian setting, the principles of management are similar. The primary differences are related to the austere setting in which the initial management takes place, and the lack of resources typically available. Initial management consists of cessation of hemorrhage, along with the multi-disciplinary prioritized management of associated injuries, and skeletal stabilization. This is most commonly achieved with a compressive sheet or pelvic binder, with pelvic external fixation when resources allow, and debridement of open wounds as necessary. Definitive, internal fixation is delayed until the patient arrives at a higher echelon of care.

Amputation: Evaluation and Treatment.

Combat extremity injury and amputation is a life threatening injury. Initial surgical care should focus on hemostasis followed by irrigation and debridement of contaminated and nonviable tissue. Preservation of limb length begins at the initial surgical procedure, to include retention of atypical soft tissue flaps for later reconstruction and treatment of proximal fractures. Serial irrigation and debridements are required throughout the MEDEVAC system as the evolving zone of injury becomes more mature, followed by the appropriate timing of closure outside the combat theater.

High Bilateral Amputations and Dismounted Complex Blast Injury (DCBI).

High, combat-related bilateral lower extremity amputations rarely occur in isolation. Dismounted complex blast injury is a devastating and life-threatening constellation of multisystem injuries most commonly due to dismounted contact with improvised explosive devices. Rapid damage control resuscitation and surgery are essential to improve patient survival and minimize both early complications and late sequelae. A coordinated team approach is essential to provide simultaneous airway management, volume resuscitation (ideally with whole blood or ratio transfusion), and immediate control of life-threatening hemorrhage. Temporary aortic or iliac vessel clamping during concurrent exploratory or vascular control laparotomy is frequently required. Stabilization of unstable pelvic fractures is then performed, followed by debridement and irrigation of all wounds, which should be left open, and subsequent provisional stabilization of long bone fractures. The goal of the initial surgical resuscitative endeavor is rapid concurrent control of all sources of hemorrhage to avoid the lethal triad of acidosis, hypothermia and coagulopathy. To this end, multiple surgeons or surgical teams should be utilized whenever feasible. Patients then require ongoing resuscitation followed by early and frequent return to the operating suite throughout the evacuation chain. Utilizing this approach, a high survival rate with reasonable functional outcomes is achievable despite the extreme severity of the DCBI pattern.

Treatment of Suspected Invasive Fungal Infection in War Wounds.

Invasive fungal wound infections (IFIs) were an unexpected complication associated with blast-related wounds during Operation Enduring Freedom. Between 2010 and 2012, IFI incidence rates were as high as 10-12% for patients injured during Operation Enduring Freedom and admitted to the intensive care unit at the Landstuhl Regional Medical Center. Independent risk factors for the development of IFIs include dismounted blast injuries, above knee amputations and massive (>20 units) packed red blood cell transfusions within 24 hours after injury. The Joint Trauma System developed a Clinical Practice Guideline on IFI prevention, identification and management. Aggressive and frequent surgical debridement remains the primary therapy accompanied by topical antifungal therapy (e.g., Dakins solution). Empiric systemic antifungal therapy with both liposomal amphotericin B and an intravenous broad-spectrum triazole (e.g., voriconazole or posaconazole) should be administered when there is strong suspicion of IFI based on the occurrence of recurrent wound necrosis following serial surgical debridements, since many cases involve multiple fungal species. Other recommendations include: (1) early tissue sampling for wound histopathology and fungal cultures, (2) early consultation with infectious disease specialists, and (3) coordination with surgical pathology and clinical microbiology.

Acute Extremity Compartment Syndrome and the Role of Fasciotomy in Extremity War Wounds.

Acute compartment syndrome (CS) is a frequent and potentially devastating complication of blunt and penetrating extremity injuries. Extremity war injuries are particularly susceptible to CS due to associated vascular injuries; high Injury Severity Score; extensive bone and soft tissue injury; and frequent transportation that may limit close monitoring of the injured extremity. Treatment consists of prompt fasciotomy of all compartments in the involved segment, over their full length. Delayed or incomplete fasciotomy is associated with worse outcomes, including muscle necrosis, infection, and amputation. Enhanced pre-deployment training of surgeons decreases the need for revision fasciotomy at higher echelons of care and should be continued in future conflicts. We recommend the liberal use of prophylactic fasciotomy prior to aeromedical evacuation and after limb reperfusion. For leg fasciotomy, we recommend a two-incision approach as it is more reproducible and allows easy vascular exposure when necessary.

Combat-related acetabular fractures: Outcomes of open versus closed injuries.

INTRODUCTION: Since the onset of the Global War on Terror close to 50,000 United States service members have been injured in combat, many of these injuries would have previously been fatal. Among these injuries, open acetabular fractures are at an increased number due to the high percentage of penetrating injuries such as high velocity gunshot wounds and blast injuries. These injuries lead to a greater degree of contamination, and more severe associated injuries. There is a significantly smaller proportion of the classic blunt trauma mechanism typically seen in civilian trauma. METHODS: We performed a retrospective review of the Department of Defense Trauma Registry into which all US combat-injured patients are enrolled, as well as reviewed local patient medical records, and radiologic studies from March 2003 to April 2012. Eighty seven (87) acetabular fractures were identified with 32 classified as open fractures. Information regarding mechanism of injury, fracture pattern, transfusion requirements, Injury Severity Score (ISS), and presence of lower extremity amputations was analyzed. RESULTS: The mechanism of injury was an explosive device in 59% (n=19) of patients with an open acetabular fracture; the remaining 40% (n=13) were secondary to ballistic injury. In contrast, in the closed acetabular fracture cohort 38% (21/55) of fractures were due to explosive devices, and all remaining (n=34) were secondary to blunt trauma such as falls, motor vehicle collisions, or aircraft crashes. Patients with open acetabular fractures required a median of 17units of PRBC within the first 24h after injury. The mean ISS was 32 in the open group compared with 22 in the closed group (p=0.003). In the open fracture group nine patients (28%) sustained bilateral lower extremity amputations, and 10 patients (31%) ultimately underwent a hip disarticulation or hemi-pelvectomy as their final amputation level. DISCUSSION: Open acetabular fractures represent a significant challenge in the management of combat-related injuries. High ISS and massive transfusion requirements are common in these injuries. This is one of the largest series reported of open acetabular fractures. Open acetabular fractures require immediate damage control surgery and resuscitation as well as prolonged rehabilitation due to their severity. The dramatic number of open acetabular fractures (37%) in this review highlights the challenge in treatment of combat related acetabular fractures.

Military and Civilian Collaboration: The Power of Numbers.

The purpose of this study was to compare the number and types of extremity injuries treated at civilian trauma centers (CIV CENs) versus military treatment facilities (MTFs) participating in the Major Extremity Trauma Research Consortium (METRC) and to investigate the potential benefits of a clinical research network that includes both civilian trauma centers and MTFs. Two analyses were performed. First, registry data collected on all surgically treated fractures at four core MTFs and 21 CIV CENs over one year were compared. Second, actual numbers and distribution of patients by type of injury enrolled in three METRC studies were compared. While MTFs demonstrated higher percentages of severe injuries including open fractures, traumatic amputations, vascular injuries, contamination, and injuries with bone, muscle, and skin loss when compared to CIV CENS, the CIV CENs treated a substantially higher number and, more importantly, enrolled patients in almost all categories. Comparison of service members to civilians was challenged by several differences between the two patient populations including mechanism of injury, the medical care environment, and confounding factors such as age, social setting and co-morbidities. Despite these limitations, in times without active military conflict, clinical trials will likely rely on civilian trauma centers for patient enrollment; only when numbers are pooled across a large number of centers can requisite sample sizes be met. These data demonstrate the benefits of maintaining a military-civilian partnership to address the major gaps in research defined by the Military.

A Prospective Randomized Trial to Assess Fixation Strategies for Severe Open Tibia Fractures: Modern Ring External Fixators Versus Internal Fixation (FIXIT Study).

The treatment of high-energy open tibia fractures is challenging in both the military and civilian environments. Treatment with modern ring external fixation may reduce complications common in these patients. However, no study has rigorously compared outcomes of modern ring external fixation with commonly used internal fixation approaches. The FIXIT study is a prospective, multicenter randomized trial comparing 1-year outcomes after treatment of severe open tibial shaft fractures with modern external ring fixation versus internal fixation among men and women of ages 18-64. The primary outcome is rehospitalization for major limb complications. Secondary outcomes include infection, fracture healing, limb function, and patient-reported outcomes including physical function and pain. One-year treatment costs and patient satisfaction will be compared between the 2 groups, and the percentage of Gustilo IIIB fractures that can be salvaged without soft tissue flap among patients receiving external fixation will be estimated.

Lower Extremity Limb Salvage: Lessons Learned From 14 Years at War.

American survivability during the current conflicts in Iraq and Afghanistan continues to improve, though the rate of extremity injury remains quite high. The decision to proceed with amputation versus limb salvage remains controversial. Exposure to combat wound with severe high-energy lower extremity trauma during the previous 14 years at war has incited important advances in limb salvage technique and rehabilitation.

Late Amputation Following Refracture After Removal of Multiplanar Circular External Fixator for Treatment of Severe Combat-Related Tibial Fracture: A Case Report.

CASE: The multiplanar circular external fixator is commonly used in the treatment of severe combat-related tibial fractures. We present the case of a patient who sustained a refracture after removal of such a fixator. This complication contributed to failure of the limb salvage and ultimately resulted in the patient undergoing transtibial amputation. CONCLUSION: The choice to pursue limb salvage or amputation must be a shared decision between the patient and provider. This discussion must now include the possibility of refracture if limb salvage is pursued using multiplanar circular external fixation. Further study is also required to define fracture stability after the removal of a multiplanar circular external fixator.

Combat-Related Hemipelvectomy: 14 Cases, a Review of the Literature and Lessons Learned.

OBJECTIVES: Trauma-related hemipelvectomy is a rare and often fatal injury that poses a number of challenges to the treating surgeon. Our objective was to identify patient and injury characteristics that have proven difficult to treat, and to describe management techniques. DESIGN: Retrospective review. SETTING: Level II trauma center. PATIENTS: Thirteen consecutive patients who underwent 14 combat-related hemipelvectomies between 2001 and 2013. INTERVENTION: We reviewed our prospective trauma registry, along with the patients' medical records, radiographs, and clinical photographs. MAIN OUTCOME MEASUREMENTS: Injury severity scores, required surgical procedures, ambulatory status, and bowel and bladder function. RESULTS: Hemipelvectomy was indicated for insufficient soft tissue coverage, complicated by life-threatening local infection and/or a dysvascular hemipelvis. Five patients underwent resection for angioinvasive fungal infections. All patients sustained a genitourinary injury, with 7 requiring suprapubic catheters and all undergoing diverting colostomy. After a median of 2 years of follow-up, 2 patients had normal urinary continence and 3 regained fecal continence. The surviving patients required a mean of 44 operations. One patient returned to community ambulation. CONCLUSIONS: This is the largest published series of trauma-related hemipelvectomies. Our lessons learned may benefit civilian surgeons who are confronted with high-energy open injuries to the pelvic girdle. Although the decision to perform hemipelvectomy should not be taken lightly, this procedure can be lifesaving and should be performed in a timely fashion when indicated. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Outcomes of war related femoral neck fractures.

INTRODUCTION: In the civilian trauma literature, femoral neck fractures in young adults are considered an orthopedic 'urgency'. To our knowledge, there have been no studies looking at the outcomes of these injuries in the combat setting. The purpose of this study is to determine the outcomes of war related femoral neck fractures; the rates avascular necrosis associated with these injuries as well as the effect time to fixation has on the development of avascular necrosis. METHODS: We performed a retrospective review of 21 patients who sustained combat related femoral neck fractures from October 2001 through October 2013. We collected demographic data, time to fixation, time to union, incidence of avascular necrosis, as well as complications and final recreational activity status. RESULTS: Our study included 21 males (100%). The average length of follow up was 19.0 (2.7-62.3) months, and the average length of radiographic follow up was 21.4 months. The average age was 25.2 (21-36) years. Displaced fractures were sustained in 71.4% of patients and 95.2% had a Pauwels' type 3 fracture. 56.9% had initial reduction and fixation within 24h of injury. Percutaneous screw fixation and dynamic hip screws were definitive fixation in 57.1% and 23.8% of patients, respectively, while the remainder had a cephalomedullary device or a salvage procedure. The average time to union was 5.5 months. There was 1 case of nonunion and 1 case of delayed union. Three of the patients (16.7%) developed avascular necrosis of the femoral head, 2 of which were initially reduced within 24h of injury. There were no statistically significant differences between time to fixation, type of reduction, or presence of displacement as a predictor of the development of avascular necrosis. DISCUSSION: We found a high rate of displaced and high Pauwels' angle fractures, consistent with the high-energy injury mechanisms. With nearly a two-year average radiographic follow-up, the incidence of avascular necrosis was 16.7%, despite only half of our patients receiving initial reduction within 24h of injury. Urgent reduction and fixation continues to be of utmost importance to decrease the risk of femoral head avascular necrosis.

Challenges in definitive fracture management of blast injuries.

The United States military remains engaged in the longest armed conflict in this nation's history. The majority of casualties in the global war on terror come from blast-related injuries. Multiple centers have published their experience and outcomes with these complex patients. Findings from the study of injured military personnel have implications for mass casualty events resulting from industrial accidents or terrorism in the civilian sector. This article will review the pathophysiology of blast-related injury. The authors will summarize treatment considerations, priorities, and techniques that have proven successful. Finally, the authors will discuss the incidence and management of common complications after blast-related injuries.

Risk factors for decreased range of motion and poor outcomes in open periarticular elbow fractures.

INTRODUCTION: The purpose of this study was to identify risk factors present at the time of injury that predict poor functional outcomes and heterotopic ossification (HO) in open periarticular elbow fractures. MATERIALS AND METHODS: We performed a retrospective review of 136 combat-related open elbow fractures from 2003 to 2010. Patient demographics, injury characteristics, treatment variables, and complications were recorded. Functional outcomes were analyzed to determine range of motion (ROM) and Mayo Elbow Performance Score (MEPS). Secondary outcome measures included the development of HO, return to duty, and revision operation. RESULTS: At a median 2.7 years from injury the median MEPS was 67.8 (range 30-100) with an average ulnohumeral arc motion of 89°. Bipolar fractures, with periarticular fractures on both sides of the elbow and at least one side containing intra-articular extension, were independently associated with decreased ulnohumeral motion (p=0.02) and decreased MEPS (p<0.004). Additional independent risk factors for decreased ROM included more severe osseous comminution (p=0.001), and increased time to definitive fixation (p=0.03) and HO (p=0.02). More severe soft tissue injury (Gustilo and Anderson fracture type, p=0.02), peripheral nerve injury (p=0.04), and HO (p=0.03) were independently associated with decreased MEPS. HO developed in 65% (89/136) of extremities and was associated with more severe Orthopaedic Trauma Association (OTA) fracture type (p=0.01) and escalating Gustilo and Anderson fracture classification (p=0.049). CONCLUSIONS: In the largest series of open elbow fractures, we identified risk factors that portend a poor clinical outcome and decreased ROM. Bipolar elbow fractures, which have not previously been associated with worse results, are particularly prone to decreased ROM and worse outcomes. LEVEL OF EVIDENCE: Prognostic level IV.

Retrograde intramedullary fixation of long bone fractures through ipsilateral traumatic amputation sites.

The technique of retrograde intramedullary fixation of fractures through open traumatic amputations has not been previously described. We performed a retrospective case series at a tertiary-care military hospital setting. Ten patients met inclusion criteria. All were male, and all were injured through improvised explosive device. Outcome measures included the incidence of fracture nonunion, osteomyelitis or acute infection, heterotopic ossification (HO), as well as successful prosthesis fitting and ambulation. Average time to fixation after injury and amputation closure was 11.7 and 12.2 days, respectively. Follow-up averaged 20.2 months. The radiographic union rate was 100%, and time to osseous union averaged 7.5 months. One patient had an amputation site infection requiring revision, but none of the nails was removed for infectious reasons. HO occurred in 7 patients, and 2 patients required revision for symptomatic HO. All patients were successfully fitted with prostheses and able to ambulate. To our knowledge, this is the only series in the literature to specifically describe retrograde intramedullary fixation of long bone fractures through the zone of traumatic amputation sites. The infectious risk is relatively low, whereas the union rate (100%) and successful prosthesis fitting are high. For patients with similar injuries, retrograde intramedullary fixation through the zone of amputation is a viable treatment option.

High seas to high explosives: the evolution of calcaneus fracture management in the military.

Calcaneus fractures typically occur as a consequence of axial load. In the civilian population, this is most often because of motor vehicle accidents or falls from height. Early management of these injuries in the military population largely mirrored that of civilian surgeons. However, calcaneus fractures secondary to underfoot blasts became a significant source of morbidity and mortality in World War II. First described in the aftermath of large-scale naval battles between metal-deck ships, this "deck-slap" phenomenon is associated with high rates of concomitant injuries, infection, and amputation. We review the historical and contemporary management of calcaneus fractures by military orthopedic surgeons, as well as detailing the unique challenges faced in managing the soft-tissue component and associated injuries commonly observed in this population. Combat-related calcaneus fractures are associated with very high rates of concomitant injuries and extensive soft-tissue wounds. Despite significant research and technological advances, functional outcomes following these devastating injuries have remained unsatisfying.

Open, combat-related loss, or disruption of the knee extensor mechanism: treatment strategies, classification, and outcomes.

OBJECTIVE: To report the outcomes of repair or reconstruction of high-energy, open knee extensor disruption or loss due to combat-related injuries. DESIGN: Retrospective review. SETTING: Tertiary (Level/Role V) Military Treatment Facility. PATIENTS: Fourteen consecutive patients who sustained 17 complex, open knee extensor mechanism injuries during combat operations between March 2003 and May 2012. INTERVENTION: Primary repair or staged allograft extensor reconstruction after serial debridement and closure or soft tissue coverage. MAIN OUTCOME MEASURES: Final knee range of motion, extensor lag, ambulatory ability and assist devices, and complications requiring reoperation or salvage procedure. RESULTS: The open knee extensor mechanism injuries required a mean of 11 procedures per injury. At a mean final follow-up of 39 months (range, 12-89 months), all patients achieved regular community ambulation, with 36% requiring assist devices due to concomitant or bilateral injuries. Average knee flexion was 92 degrees, and 35% of extremities had an extensor lag >10 degrees; however, 6 of 9 extremities with allograft reconstructions had extensor lags of <10 degrees, and 5 had no extensor lag. The presence of a major periarticular or patellar fracture was significantly associated with the knee requiring a subsequent extensor mechanism allograft reconstruction procedure. One extremity each underwent knee arthrodesis or transfemoral amputation due to severe infection. CONCLUSIONS: High-energy, open knee extensor mechanism injuries are severe and rarely occur in isolation, but limb salvage is generally successful after multiple procedures. Patients who required staged allograft reconstruction, despite high complication rates, generally had favorable results. LEVEL OF EVIDENCE: Therapeutic level IV. See instructions for authors for a complete description of levels of evidence.

A model to predict limb salvage in severe combat-related open calcaneus fractures.

BACKGROUND: Open calcaneus fractures can be limb threatening and almost universally result in some measure of long-term disability. A major goal of initial management in patients with these injuries is setting appropriate expectations and discussing the likelihood of limb salvage, yet there are few tools that assist in predicting the outcome of this difficult fracture pattern. QUESTIONS/PURPOSES: We developed two decision support tools, an artificial neural network and a logistic regression model, based on presenting data from severe combat-related open calcaneus fractures. We then determined which model more accurately estimated the likelihood of amputation and which was better suited for clinical use. METHODS: Injury-specific data were collected from wounded active-duty service members who sustained combat-related open calcaneus fractures between 2003 and 2012. One-hundred fifty-five open calcaneus fractures met inclusion criteria. Median followup was 3.5 years (interquartile range: 1.5, 5.1 years), and amputation rate was 44%. We developed an artificial neural network designed to estimate the likelihood of amputation, using information available on presentation. For comparison, a conventional logistic regression model was developed with variables identified on univariate analysis. We determined which model more accurately estimated the likelihood of amputation using receiver operating characteristic analysis. Decision curve analysis was then performed to determine each model's clinical utility. RESULTS: An artificial neural network that contained eight presenting features resulted in smaller error. The eight features that contributed to the most predictive model were American Society of Anesthesiologist grade, plantar sensation, fracture treatment before arrival, Gustilo-Anderson fracture type, Sanders fracture classification, vascular injury, male sex, and dismounted blast mechanism. The artificial neural network was 30% more accurate, with an area under the curve of 0.8 (compared to 0.65 for logistic regression). Decision curve analysis indicated the artificial neural network resulted in higher benefit across the broadest range of threshold probabilities compared to the logistic regression model and is perhaps better suited for clinical use. CONCLUSIONS: This report demonstrates an artificial neural network was capable of accurately estimating the likelihood of amputation. Furthermore, decision curve analysis suggested the artificial neural network is better suited for clinical use than logistic regression. Once properly validated, this may provide a tool for surgeons and patients faced with combat-related open calcaneus fractures in which decisions between limb salvage and amputation remain difficult.