Acute pelvic fractures are potentially lethal, even with modern techniques of poly-trauma care. The appropriate treatment of such fractures is dependent on a thorough understanding of the anatomic features of the pelvic region and the biomechanical basis of the various types of lesions. Although the anterior structures, the symphysis pubis and the pubic rami, contribute approximately 40% to the stiffness of the pelvis, clinical and biomechanical studies have shown that the posterior sacroiliac complex is more important to pelvic-ring stability. Therefore, the classification of pelvic fractures is based on the stability of the posterior lesion. In type A fractures, the pelvic ring is stable. The partially stable type B lesions, such as "open-book" and "bucket-handle" fractures, are caused by external- and internal-rotation forces, respectively. In type C injuries, there is complete disruption of the posterior sacroiliac complex. These unstable fractures are almost always caused by high-energy severe trauma associated with motor vehicle accidents, falls from a height, or crushing injuries. Type A and type B fractures make up 70% to 80% of all pelvic injuries. Because of the complexity of injuries that most often result in acute pelvic fractures, they should be considered in the context of polytrauma management, rather than in isolation. Any classification system must therefore be seen only as a general guide to treatment. The management of each patient requires careful, individualized decision making.

Acute Pelvic Fractures: I. Causation and Classification

Due to the increasing life expectancy, orthopaedic surgeons are more and more often confronted with fragility fractures of the pelvis (FFPs). These kinds of fractures are the result of a low-energy impact or they may even occur spontaneously in patients with severe osteoporosis. Due to some distinct differences, the established classifications for pelvic ring lesions in younger adults do not fully reflect the clinical and morphological criteria of FFPs. Most FFPs are minimally displaced and do not require surgical therapy. However, in some patients, an insidious progress of bone damage leads to increasing displacement, nonunion and persisting instability. Therefore, new concepts for surgical treatment have to be developed to address the functional needs of the elderly patients. Based on an analysis of 245 consecutive patients with FFPs, we propose a novel classification system for this condition. This classification is based on morphological criteria and it corresponds with the degree of instability. Also in the elderly, these criteria are the most important for the decision on the type of treatment as well as type and extent of surgery. The estimation of the degree of instability is based on radiological and clinical findings. The classification gives also hints for treatment strategies, which may vary between minimally invasive techniques and complex surgical reconstructions.

Comprehensive classification of fragility fractures of the pelvic ring: Recommendations for surgical treatment.

Background: Pelvic fractures may be associated with significant hemorrhage. Although this hemorrhage may emanate from the pelvic vasculature, it may also be secondary to abdominal visceral injury. The purpose of this study was to determine factors associated with pelvic and/or abdominal visceral bleeding in hypotensive patients with pelvic fractures to guide the appropriate therapeutic intervention sequence for these difficult-to-manage patients. Methods: Medical records of all hypotensive (systolic blood pressure ≤ 90 mm Hg) patients with pelvic fractures seen at a Level I trauma center from January 1995 to December 1999 were evaluated. Records were abstracted for age, base deficit, 24-hour blood requirement, hemoperitoneum (positive ultrasound, diagnostic peritoneal lavage, or computed tomographic scan), abdominal hemorrhage discovered at celiotomy, pelvic hemorrhage discovered at angiography, emergency department disposition, Injury Severity Score, and mortality. Pelvic fracture categories were derived by adapting the Young-Burgess pelvic fracture classification scheme. Lateral compression (LC) I and anteroposterior compression (APC) I fractures were characterized as stable fracture patterns (SFPs), and APC II, APC III, LC II, LC III, and vertical shear were characterized as unstable fracture patterns (UFPs). Results: Of 231 hypotensive patients, 38 patients died in the emergency department, leaving 193 surviving initial resuscitation. One hundred seven patients stabilized (group I) and were transferred to the intensive care unit. Eighty-six patients (group II) required ongoing resuscitation and underwent celiotomy and/or angiography in an attempt to manage their hemorrhage. Within group II, in the SFP population, abdominal hemorrhage was responsible for hypotension in 34 of 40 (85%), and 10 patients died (25%). In patients with UFP injury, hemorrhage was predominantly from a pelvic source, as shown by 27 positive angiograms in the 46 patients (59%). Twenty-four of 46 (52%) UFP patients died. In patients with a UFP, 14 had both angiography and celiotomy. Four patients underwent angiography before celiotomy and one of four (mortality, 25%) died. In contrast, 10 patients underwent celiotomy before angiography and 6 of 10 died (mortality, 60%). Conclusion: Patients with signs of ongoing shock with SFP pelvic injury and hemoperitoneum require celiotomy as the initial intervention, as the hemorrhagic focus is predominantly intraperitoneal. In patients with UFP, even in the presence of hemoperitoneum, consideration should be given to angiography before celiotomy.

The importance of fracture pattern in guiding therapeutic decision-making in patients with hemorrhagic shock and pelvic ring disruptions.

Acid–base abnormalities are common in the intensive care unit (ICU). Differences in outcome exist between respiratory and metabolic acidosis in similar pH ranges. Some forms of metabolic acidosis (for example, lactate) seem to have worse outcomes than others (for example, chloride). The relative incidence of each type of disorder is unknown. We therefore designed this study to determine the nature and clinical significance of metabolic acidosis in critically ill patients. An observational, cohort study of critically ill patients was performed in a tertiary care hospital. Critically ill patients were selected on the clinical suspicion of the presence of lactic acidosis. The inpatient mortality of the entire group was 14%, with a length of stay in hospital of 12 days and a length of stay in the ICU of 5.8 days. We reviewed records of 9,799 patients admitted to the ICUs at our institution between 1 January 2001 and 30 June 2002. We selected a cohort in which clinicians caring for patients ordered a measurement of arterial lactate level. We excluded patients in which any necessary variable required to characterize an acid–base disorder was absent. A total of 851 patients (9% of ICU admissions) met our criteria. Of these, 548 patients (64%) had a metabolic acidosis (standard base excess < -2 mEq/l) and these patients had a 45% mortality, compared with 25% for those with no metabolic acidosis (p < 0.001). We then subclassified metabolic acidosis cases on the basis of the predominant anion present (lactate, chloride, or all other anions). The mortality rate was highest for lactic acidosis (56%); for strong ion gap (SIG) acidosis it was 39% and for hyperchloremic acidosis 29% (p < 0.001). A stepwise logistic regression model identified serum lactate, SIG, phosphate, and age as independent predictors of mortality. In critically ill patients in which a measurement of lactate level was ordered, lactate and SIG were strong independent predictors of mortality when they were the major source of metabolic acidosis. Overall, patients with metabolic acidosis were nearly twice as likely to die as patients without metabolic acidosis.

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Lactate versus non-lactate metabolic acidosis: a retrospective outcome evaluation of critically ill patients

3260 patients with pelvic and acetabular fractures were assessed using a standardized documentation form by collating the data on 1905 patients treated at the Department of Traumatology of the Hannover Medical School together with those patients treated between 1991 and 1993 in the German Multicentre Study Group (Pelvis) of the German Trauma Society and the German Section of the AO International. 2551 patients had pelvic ring injuries. 61.7% of the patients were multiply injured. 12.2% were suffering a complex pelvic trauma defined as a pelvic injury with concomitant soft tissue injury. The pelvic ring fracture was classified as stable in 54.8% (type A injury), as rotationally unstable in 24.7% (type B injury), and as unstable in translation in 20.5% (type C injury). There were concomitant acetabular fractures in 15.7%. The most frequent single lesions affecting the pelvic girdle were fractures of the ischiopubic bones (transpubic instability), injuries involving the sacroiliac joint (transiliosacral instability), and sacral fractures (transsacral instability). The overall rate of operative stabilizations was 21.6%. Type B injuries were stabilized in 28.9% and type C injuries in 46.7%. The overall mortality rate was 13.4%, depending significantly on the associated extrapelvic trauma. In complex pelvic injuries, the mortality rate was 31.1% whereas for pelvic fractures without concomitant soft tissue injury the rate was only 10.8%.

Epidemiology of pelvic ring injuries

Three hundred forty-three multiple trauma patients with major pelvic ring disruption were studied and subdivided into four major groups by mechanism of injury: antero-posterior compression (APC), lateral compression (LC), vertical shear (VS), and combined mechanical injury (CMI). Acetabular fractures which did not disrupt the pelvic ring were excluded. The mode of injury was: MVA, 57.4%; motorcycle, 9.3%; fall, 9.3%; pedestrian, 17.8%; crush, 3.8%. The LC and APC groups were divided into Grades 1-3 of increasing severity. The pattern of organ injury: including brain, lung, liver, spleen, bowel, bladder, pelvic vascular injury (PVASI), retroperitoneal hematoma (RPH) and complications: circulatory shock, sepsis, ARDS, abnormal physiology, and 24-hr total fluid volume administration were all evaluated as a function of mortality (M). As LC grade increased from 1 to 3 there was increased % incidence of PVASI, RPH, shock, and 24-hr volume needs. However, the large incidence of brain, lung, and upper abdominal visceral injuries as causes of death in Grade 1 and 2 fell in LC3, with limitation of the LC3 injury pattern to the pelvis. As APC grade increased from 1 to 3 there was increased % injury to spleen, liver, bowel, PVASI with RPH, shock, sepsis, and ARDS, and large increases in volume needs, with important incidence of brain and lung injuries in all grades. Organ injury patterns and % M associated with vertical shear were similar to those with severe grades of APC, but CMI had an associated organ injury pattern similar to lower grades of APC and LC fractures. The pattern of injury in APC3 was correlated with the greatest 24-hour fluid requirements and with a rise in mortality as the APC grade rose. However, there were major differences in the causes of death in LC vs. APC injuries, with brain injury compounded by shock being significant contributors in LC. In contrast, in APC there were significant influences of shock, sepsis, and ARDS related to the massive torso forces delivered in APC, with large volume losses from visceral organs and pelvis of greater influence in APC, but brain injury was not a significant cause of death. These data indicate that the mechanical force type and severity of the pelvic fracture are the keys to the expected organ injury pattern, resuscitation needs, and mortality.

Pelvic fracture in multiple trauma: classification by mechanism is key to pattern of organ injury, resuscitative requirements, and outcome

Background and MethodsAn experimental canine model of hemorrhagic, hypovolemic shock is described that uses oxygen debt and its metabolic consequences of lactic acidemia and metabolic base deficit as independent variables for the prediction of probability of death.ResultsLactic acidemia and metaboli

C. Dunham

Papers

Pelvic fracture in multiple trauma: classification by mechanism is key to pattern of organ injury, resuscitative requirements, and outcome

Oxygen debt and metabolic acidemia as quantitative predictors of mortality and the severity of the ischemic insult in hemorrhagic shock.