Unstable Pelvic Fractures 

Updated: Nov 19, 2018
Author: Kenneth W Graf, Jr, MD; Chief Editor: William L Jaffe, MD 

Overview

Background

Most pelvic fractures are stable and occur with a low-energy mechanism of injury. The evaluation and treatment of these fractures are described in Pelvic Fractures. This article focuses on unstable pelvic fractures, which are usually caused by high-energy injuries.

The most common high-energy mechanism of injury is a motor vehicle accident (MVA). Patients who sustain these injuries not only have the osseous injury but also often have concomitant life-threatening injuries. Younger people are more likely to be involved in MVAs.[1] Early death after these injuries is usually due to hemorrhage, multiple organ system failure, or sepsis.[2] These unstable high-energy pelvic fractures require a multidisciplinary approach to treatment.

Before 1950, the treatment of pelvic fractures posed significant problems for orthopedic surgeons. Since 1950, however, significant progress has been made in understanding and treating these difficult fractures. The advent of clinically and anatomically significant classification systems has greatly increased the understanding of these injuries.

In 1948, Holdsworth reported on 27 patients with untreated sacroiliac (SI) dislocations and found that only half were able to return to work, with all 27 experiencing residual low back pain.[3]  In his 1966 report on 65 patients with double vertical fractures of the pelvis, Räf noted a worse outcome when SI dislocation was present.[4]  In the same report, Räf noted a high incidence of nerve injury with posterior fractures through the sacrum.

In 1972, Slatis and Huittinen reported on the late sequelae of unstable pelvic fractures, noting significant problems with pelvic obliquity, impaired gait, disabling low back pain, and signs of persistent lumbosacral plexus damage in 46% of their patients.[5]  They concluded that although conservative treatment of pelvic fractures of moderate severity afforded good results, conservative treatment of severe pelvic fractures had significant shortcomings.

In 1988, Tile reported on 248 patients with pelvic ring injuries.[6]  He noted that stable pelvic injuries resulted in few long-term problems. In contrast, vertically unstable injuries resulted in many problems, with 60% of patients having residual pain.

Over the past few decades, significant advances in the treatment of pelvic fractures have been made. In 1989, Matta published techniques for operative fixation of pelvic fractures.[7]  Routt popularized percutaneous methods of fixation.[8]

The improved techniques for open reduction and internal fixation (ORIF), as well as the percutaneous fixation techniques developed, have aided greatly in the treatment of these fractures. Because of the relatively recent use of these treatments, the reporting of more long-term results of treatment is essential. These studies will direct the future treatment of unstable pelvic fractures.

Continued improvements in the multidisciplinary treatment of patients with such injuries will be crucial to further decreasing the high morbidity and mortality associated with these severe injuries.

Anatomy

A firm knowledge of pelvic anatomy is critical for understanding fracture patterns and determining treatment goals.

The three bones that compose the pelvic ring are the sacrum and the two innominate bones. Each innominate bone is formed from the fusion of three ossification centers (ie, ilium, ischium, and pubis) that join at the triradiate cartilage of the acetabulum. The innominate bones join the sacrum posteriorly at the sacroiliac joints and anteriorly at the pubic symphysis.

The posterior SI ligaments run from the sacrum to the posterior iliac spines and are the strongest ligaments in the body. The sacrotuberous ligaments consist of a strong band that runs from the posterolateral sacrum and dorsal aspect of the posterior iliac spine to the ischial tuberosity. The sacrotuberous ligaments and the posterior SI ligaments maintain the vertical stability of the pelvis.

The sacrospinous ligaments run from the lateral edge of the sacrum and coccyx, separate the greater and lesser sciatic notches, and insert on the ischial spine. The iliolumbar ligaments run from the L4 and L5 transverse process to the posterior iliac crest to provide stability between the spine and the pelvis.

An understanding of the location of major nerves and vessels in relation to the bony anatomy is particularly important in view of the development of percutaneous techniques. The sciatic nerve is formed by the roots from the lumbosacral plexus (L4, L5, S1, S2, S3) and exits the pelvis deep to the piriformis. The lumbosacral trunk is formed by the anterior rami of L4 and L5 and crosses the anterior sacral ala and the SI joint.

Fractures of the sacral ala or dislocations of the SI joints are most likely to injure the lumbosacral trunk. The L5 nerve root exits below the L5 transverse process and crosses the sacral ala 2 cm medial to the SI joint and may be injured during the anterior approach to the SI joint.

Pelvic fractures are frequently associated with large amounts of blood loss. The internal iliac artery (hypogastric artery) is the most important vascular structure in pelvic trauma. The anterior division consists of the inferior gluteal artery, the internal pudendal artery, the obturator artery, the inferior vesicular artery, and the middle rectal artery. The posterior division consists of the superior gluteal artery, iliolumbar artery, and lateral sacral artery.

The superior gluteal artery is the largest branch of the internal iliac artery. It courses along the SI joint and exits through the greater sciatic notch superior to the piriformis. This artery supplies the gluteus medius, the gluteus minimus, and the tensor fasciae latae. The superior gluteal artery is the most commonly injured artery in pelvic fractures.

Most bleeding after pelvic fractures results from venous injury. The pelvic viscera lie on a large thin-walled venous plexus that drains into the internal iliac vein. Massive bleeding may result from disruption of this venous plexus. Other neurovascular structures that lie in close proximity to the bony pelvis may be damaged when a pelvic fracture occurs.

The close relation between the urogenital tract and the bony pelvis results in a high incidence of urinary tract injuries. Bladder rupture, diagnosed by means of cystography (see the image below), and posterior urethral injuries are the most common injuries.

Normal bladder. Normal bladder.

Signs of bladder injury include inability to void despite a full bladder, blood at the urethral meatus, a high-riding or abnormally mobile prostate, and an elevated bladder. Retrograde urethrography should be performed to exclude urethral injury before insertion of a Foley catheter if an anterior pelvic disruption is present or any sign of urethral injury exists (see the image below).

Urethral injury. Urethral injury.

Anatomic differences between males and females result in a higher incidence of urethral injuries in males. The male urethra may be divided into three sections: the prostatic portion, the membranous portion, and the bulbous portion. The bulbous urethra, located inferior to the urogenital diaphragm, is the most common site of injury. In contrast, the female urethra is short, not rigidly fixed to the pubis or pelvic floor, more mobile, and less susceptible to injury from shear forces.

If the urethra is ruptured, retrograde urethrography dye extravasates into the perineum. Impotence may occur in 25-47% of male patients with urethral rupture. Impotence is likely secondary to damage of parasympathetic nerves (S2-4). Note that the absence of meatal blood or a high-riding prostate does not exclude a urethral injury.

Bladder injuries may result from bony spicules caused by pubic rami fractures, from blunt force that causes rupture, or from shearing injuries. The superior and upper posterior portions of the bladder are covered by peritoneum. The remainder of the bladder is extraperitoneal and covered with loose areolar tissue.

Intraperitoneal ruptures usually require operative repair, whereas extraperitoneal ruptures are managed nonoperatively unless laparotomy is being performed. Extraperitoneal bladder ruptures are typically managed with suprapubic catheter drainage and broad-spectrum antibiotics. Cystography is performed before catheter removal to verify healing. About 87% of ruptures heal within 10 days, and virtually all ruptures heal within 3 weeks.

Pathophysiology

The two most commonly used classification systems are those of Tile[9, 10] and of Young and Burgess.[11, 12] These classifications help the orthopedic surgeon evaluate the stability of the pelvic injury and determine the appropriate treatment.

Tile classification

Tile proposed a classification into three types along a continuum of stability, as follows[9, 10]

  • Type A - These fractures, which include avulsion fractures, iliac wing fractures, and transverse fractures of the sacrum, are stable and do not fracture through the pelvic ring or soft tissues; the posterior ligamentous arch is intact
  • Type B - These fractures, which include open-book and lateral compression (LC) injuries, are rotationally unstable but vertically stable; an incomplete disruption of the posterior pelvic arch is present
  • Type C - These fractures are vertically and rotationally unstable, with complete disruption of the posterior arch and pelvic floor; the hemipelvis thus is completely unstable

Young-Burgess classification

Young and Burgess proposed a classification system based on Tile's classification. In their classification, however, they determined the injury pattern in relation to four different mechanisms of injury, as follows:

  • Anterior-posterior compression (APC)
  • LC
  • Vertical shear (VS)
  • Combined mechanisms (CM)

These four types of injury have been found to correlate with the resuscitation needs of the patient.[11, 12]

APC injury results from an anteriorly directed force applied directly to the pelvis or indirectly via the lower extremities (see the image below). The result is an external rotation force on the innominate bones and an open-book type injury.

Anterior-posterior compression (APC) pelvic fractu Anterior-posterior compression (APC) pelvic fracture.

APC injury may be further classified into the following three subtypes, which delineate the severity of the injury by quantifying the amount of ligamentous damage present with radiographs:

  • APC-I injury - These injuries result from low- to moderate-energy forces and result in slight (< 2 cm) widening of the pubic symphysis; the SI joint is ligamentously intact
  • APC-II injury - These are higher-energy injuries that result in tearing of the anterior SI ligaments, as well as tearing of the sacrotuberous and sacrospinous ligaments, with the posterior SI ligaments remaining intact; the pubic symphysis diastasis usually measures greater than 2 cm; these fractures are rotationally unstable and are more likely to be associated with neurovascular injuries, soft-tissue complications, and hemorrhage
  • APC-III injury - These injuries are a result of high-energy injuries; the hemipelvis continues to rotate externally until the posterior sacrospinous ligaments are also disrupted, and thus, these injuries result in complete ligamentous dissociation of the involved hemipelvis to the axial skeleton; these injuries are associated with the highest rate of neurovascular complications and blood loss

LC injuries result from lateral impact of innominate bone, with internal rotation of the pelvis toward the midline. The sacrotuberous, sacrospinous, and internal iliac vessels are shortened rather than stretched. The injury sustained to the anterior ring in these injuries is not critical to the weightbearing function of the pelvis. Because of this, LC injuries are further classified into three subtypes according to the nature of the injury to the posterior ring, as follows:

  • LC-I injury - The most common LC subtype, commonly observed in the elderly population, these injuries result in a transverse fracture of the anterior ring and a cancellous impaction fracture of the sacrum posteriorly; the impaction fracture often goes unidentified; generally, these injuries are low-energy and stable
  • LC-II injury - These injuries are usually the consequence of a greater laterally applied force and often result in posterior fracture dislocation of the SI joint (crescent fracture [13] ); they represent a combination of ligamentous disruption of the inferior portion of the SI joint and a vertical fracture of the posterior ilium that extends from the middle of the SI joint and exits the iliac crest; the posterior superior iliac spine remains firmly attached to the sacrum via the superior portion of the posterior ligamentous complex; the remaining anterior fragment is more mobile to internal rotation but remains relatively stable to external rotation and vertical forces
  • LC-III injury - These injuries usually occur when an individual receives a laterally directed force on one side of the pelvis and is trapped against an immobile object on the contralateral side, the result being a lateral compression injury pattern on the side of the laterally directed force and an external rotation injury on the contralateral side; the ligamentous injury pattern observed on the contralateral side is the same as that in the APC injuries, with disruption of the sacrospinous, sacrotuberous, and anterior SI ligaments; most hemorrhages observed in these fractures occur on the side contralateral to the injury force, where tensile forces are acting

A VS injury results in vertical translation of the hemipelvis (see the image below). The typical mechanism for this injury involves a fall from a height and landing on an extended limb. Anteriorly, the injury usually involves the pubic symphysis, but fractures through the pubic rami are not uncommon. Posteriorly, the force is directed through the SI joint, causing a complete disruption of this joint.

Vertical shear (VS) fracture pattern. Vertical shear (VS) fracture pattern.

CM injuries have features of at least two of the above-mentioned categories. The most common variety is the combination of LC and VS injuries.

A comparison of the Tile and Young-Burgess classifications systems carried out by Osterhoff et al did not identify any clinical relevant differences between the two with respect to their ability to predict mortality, transfusion or infusion requirement, or concomitant injuries.[14]

Denis zone-of-injury classification

Discussion of pelvic fractures is not complete without mentioning sacral fractures. Denis classified these fractures according to their zone of injury, as follows[15] :

  • Zone I injury - The sacral alar region is involved
  • Zone II injury - The sacral foramina are involved (see the image below)
  • Zone III injury - The central sacral canal is involved; transverse fractures of the sacrum may also occur
Denis zone II sacral fracture. Denis zone II sacral fracture.

Etiology

High-energy injuries that result in pelvic ring disruption are more likely to be accompanied by severe injuries to the central nervous system (CNS), abdomen, and chest. These are often the results of MVAs. The changes made in passenger restraints and an increased frequency of high-velocity motor vehicle trauma have led to a steady increase in the number of pelvic ring injuries observed and treated at trauma centers across the country.

With the institution of advanced trauma life support (ATLS) protocols, the treatment of patients with polytrauma has been associated with significant decreases in mortality. The reported range for mortality associated with pelvic ring fractures is 9-20%. The mortality among hemodynamically unstable patients has been reported to be 50%, whereas hemodynamically stable patients have a mortality of 10%.[16, 17, 18]

Young and Burgess[11] described different pelvic injury patterns observed with varying mechanisms of injury. With side-impact compression, lateral impaction injuries are observed in the pelvic ring. In head-on type collisions, an anteroposteriorly directed force results in opening of the pelvic ring and an external rotation force on the innominate bones. Combinations of these mechanisms may also occur.

Epidemiology

Pelvic fractures account for 1-3% of all skeletal fractures and 2% of orthopedic hospital admissions. The frequency of pelvic fractures occurs in a bimodal pattern, with peaks observed in persons aged 20-40 years and later in individuals older than 65 years.

Prognosis

Long-term functional outcome after pelvic ring injury has not been well reported. The natural history of unstable pelvic fractures treated nonoperatively has demonstrated a high incidence of residual disability, severe low back pain, and pelvic obliquity and gait disturbances.[19]

Henderson studied 26 patients with nonoperatively treated pelvic fractures at a minimum of 5 years' follow-up.[20]  Subjective symptoms included frequent or daily low-back discomfort (50%), localized dysesthesias (46%), and work disability (38%). Objective findings included neurologic deficits (42%), motor weakness or abnormal deep tendon reflexes, and persistent limp (32%). Long-term outcomes correlated well with the amount of residual vertical displacement and the stability of the fracture.

Semba et al also found a correlation between displacement on the initial film and residual symptoms.[21]  Patients with a combined anteroposterior and vertical displacement of less than 1 cm at initial injury were asymptomatic, whereas those with a displacement of more than 1 cm at initial injury had an increased frequency of late severe low-back pain.

Gruen et al studied the outcome of patients who had sustained multiple injuries that included unstable pelvic ring injuries and who were treated with ORIF.[22]  In this study, 62% of patients returned to full-time work, and most patients with pelvic fractures (77%) had mild disability at 1 year. Persons with open-book injuries tended to have higher individual and total Sickness Impact Profile scores than individuals with LC fracture despite similar Injury Severity Scores.

Tornetta et al reviewed 29 patients with rotationally unstable but vertically stable pelvic ring injuries treated by means of ORIF.[23]  The primary indication for surgery was symphyseal disruption. Follow-up evaluation after more than 3 years revealed that 96% had no pain or pain only with strenuous activity. Seventy-six percent ambulated without assistance or limitations, and 76% returned to their preinjury occupation.

Copeland et al found that women with pelvic fractures had higher rates of urinary symptoms, cesarean deliveries, and gynecologic pain (20%) than a matched group of female patients with multitrauma without pelvic fractures.[24]  In the pelvic fracture group, 21% had urinary tract symptoms despite a low incidence of frank genitourinary injuries.

Copeland et al postulated that the significant incidence of stress incontinence is due to disruption of the pelvic floor musculature or interruption of its innervations.[24]  Urinary tract symptoms were more common in patients with residual pelvic fracture displacement in a lateral or vertical direction as opposed to medial direction. The pelvic floor becomes redundant in individuals with LC injuries, whereas in persons with APC or VS injuries, the pelvic floor is placed under tension and can be disrupted.

McCarthy et al found that in comparison with age- and sex-standardized norms, women with pelvic fractures scored lower on all dimensions of the 36-Item Short Form Health Survey (SF-36), with the exception of mental health.[25]

A study by Kokubo et al found that in patients with unstable pelvic ring fractures, factors that negatively influenced short-term functional outcome included fractures of the lower extremity, conservative therapy, and nerve damage, whereas factors that negatively affected long-term outcome included nerve damage and pelvic ring displacement exceeding 20 mm.[26]

The outcome of unstable pelvic fractures appears to vary on the basis of the initial displacement, fracture classification, and associated injuries. Long-term outcome studies are required to better determine how operative intervention alters the natural history of these severe injuries.

 

Presentation

History

Upon admission to the emergency department (ED), treatment of a multiply injured patient with a pelvic ring injury requires a multidisciplinary approach, including the attention of specialists from general surgery and orthopedics and emergency care personnel. The initial evaluation should include the ABCs (airway, breathing, circulation) of trauma care, as described in the Advanced Trauma Life Support (ATLS) protocols.

Although the initial history is often lacking in such patients, it is vital to gather as much information as possible. Especially important to the orthopedic evaluation is the mechanism of injury. This information assists in determining the energy with which the injury has occurred, as well as in predicting the injury pattern.

Physical Examination

Several clinical signs may help with diagnosis before radiography is performed. The Destot sign, a superficial hematoma above the inguinal ligament, in the scrotum, or in the thigh, can indicate a pelvic fracture. The examiner should look for a rotational deformity of the pelvis or lower extremities. Leg-length discrepancies may also be present with pelvic fractures. The practice of compressing and distracting the iliac wings and applying manual traction to determine stability lacks specificity and should be avoided.

Neurologic injuries are commonly overlooked. The lower extremities must undergo a thorough neurovascular examination. The prevalence of neurologic injury in pelvic fractures has been reported to be in the range of 3.5-13%.

Sacral fractures and sacroiliac (SI) disruptions have a particularly high incidence of neurologic injury. According to the Denis classification of pelvic fractures,[15]  zone I sacral fractures are associated with a 5.9% incidence of neurologic injury. Zone II injuries have a 28% neurologic injury rate, usually involving L5, S1, and S2 nerve roots. Zone III injuries have a 56% incidence of neurologic injury. Such injuries frequently involve the bowel and bladder and may also cause sexual dysfunction.[27]

All patients with sacral fractures must undergo vaginal and rectal examinations in the ED. Open pelvic fractures can communicate directly with the rectum, vagina, or skin laceration and may carry a mortality as high as 50%. Many lacerations are missed if such examinations are not performed. A urethral disruption can also be revealed as a high-riding prostate on the rectal examination. The perineal area should be examined for blood at the meatus, which is a sign of a possible urethral tear.[28]

 

Workup

Laboratory Studies

Each patient observed in the emergency department (ED) with a pelvic fracture must receive a complete laboratory workup, which should include the following:

  • Complete blood count (CBC) with platelets, prothrombin time (PT), and activated partial thromboplastin time (aPTT)
  • Liver function panel, electrolytes, blood urea nitrogen (BUN), and creatinine
  • Blood type and screen
  • Toxicology panel
  • Pregnancy test [29]

It is particularly important to obtain and assess the results of these studies before proceeding to the operating room. They give the treating physician baseline laboratory values to help direct further treatment.

Plain Radiography

The most useful tool in the orthopedic evaluation of patients with pelvic fractures is an anteroposterior (AP) radiograph of the pelvis. This should be performed on every trauma patient observed in the ED and is part of the ED evaluation protocol. The standard AP pelvis radiograph demonstrates 90% of cases of posterior instability.

Stable fractures are characterized by one or more of the following: impacted vertical fractures of the sacrum, nondisplaced fractures of the posterior sacroiliac (SI) complex, and subtle fractures of the upper sacrum as evidenced by asymmetry of the sacral arcuate lines.

Unstable fractures are characterized by hemipelvic cephalad displacement that exceeds 0.5 cm and SI diastasis that exceeds 0.5 cm. Findings suggestive of pelvic instability include cephalad hemipelvic displacement less than 1 cm or a diastatic fracture of the sacrum or ilium less than 0.5 cm. These indeterminate cases may require further imaging to determine stability. Edeiken-Monroe et al[30]  found that standard radiographs accurately identified pelvic stability in 88% of cases.

A fracture of the fifth lumbar transverse process, previously described as a sign of an unstable pelvis, was found in both stable and unstable injuries and consequently was considered not to be a reliable sign of pelvic instability. However, a retrospective matched-pair analysis by Winkelmann et al identified a positive correlation between a transverse process fracture of L4, L5, or both and a biomechanically unstable pelvic ring injury.[31] They found such transverse process fractures to be indicative of increased severity of pelvic injury and thus potentially useful in the planning of emergency treatment.

If the patient is hemodynamically stable, additional radiographs can be obtained to improve the understanding of the fracture pattern. Treatment of an unstable fracture should never be delayed for additional radiographic studies.

The inlet pelvis radiograph is a 40-45° caudal tilt view that demonstrates AP displacement (see the image below). It also exhibits internal rotation associated with lateral compression injuries.

Inlet pelvis radiograph with displaced fracture of Inlet pelvis radiograph with displaced fracture of left sacroiliac joint.

An outlet pelvis radiograph is a 40-45° cephalad tilt view that demonstrates vertical displacement and fractures of the sacral foramina (see the image below).

Outlet pelvis radiograph. Outlet pelvis radiograph.

A lateral sacral view can help identify transverse sacral fractures.

All trauma patients in whom the spine cannot be clinically cleared must receive a full cervicothoracolumbosacral (CTLS) spine series. All fractures or areas not visualized on the plain films must be further evaluated with computed tomography (CT).

Initial evaluation also should include chest radiography to evaluate for pulmonary pathology (eg, pneumothorax, pulmonary contusion, or acute respiratory distress syndrome [ARDS]). Chest radiography should also be used to identify free air in the abdomen.

Computed Tomography

A multiply injured patient, if stable, often undergoes CT of the chest, abdomen, and pelvis.[32, 33]  A dedicated 3-mm thin-slice CT scan of the pelvis can help define the anatomy of the sacrum. The scan assists in the evaluation of crescent fractures (see the image below) and sacral fractures.

Crescent fracture on CT. Crescent fracture on CT.

The chest, abdomen, and pelvis CT scans assist in the evaluation of concomitant injuries to the abdomen and chest, which are often life-threatening. CT identifies intra-abdominal bleeding, as well as the specific organ that is injured. If a head injury is suspected, a head CT scan is obtained. A head CT scan assists in determining the severity of the injury and helps guide the surgical timing.

All spine fractures or areas not well visualized on plain radiographs should be visualized with a CT scan.

MRI and Ultrasonography

Magnetic resonance imaging (MRI) is seldom used in acute pelvic fractures.

Focused assessment with sonography for trauma (FAST) is often used as a first-line screen for intra-abdominal bleeding and fluid. It is inexpensive and can quickly provide valuable information. However, results are operator-dependent.

Procedures

Supraumbilical diagnostic peritoneal lavage can be performed to evaluate for an intra-abdominal hemorrhage and a ruptured viscus. It is reported to have a positive predictive value of 98% and a negative predictive value of 97%. The procedure should be performed through a supraumbilical incision to avoid a false-positive result secondary to pelvic hematoma. If the initial aspirate reveals more than 5 mL of gross blood or obvious enteric contents, an emergency laparotomy is indicated.

 

Treatment

Approach Considerations

The treatment goals for unstable pelvic fractures are the same as those for fractures of other bones—namely, a healed fracture with the prevention of nonunion, malunion, and other defined complications. The initial priority in a hemodynamically unstable patient is aggressive resuscitation and prevention of further hemorrhage. External fixation is indicated as the immediate treatment in a hemodynamically unstable patient with an unstable pelvic fracture.

Open reduction and internal fixation (ORIF) is preferred for definitive management and has been demonstrated to provide superior results. Operative indications include the following:

  • Diastases of pubic symphysis greater than 2.5 cm
  • Sacroiliac (SI) joint dislocations
  • Displaced sacral fractures
  • Crescent fractures
  • Posterior or vertical displacement of the hemipelvis greater than 1 cm
  • Rotationally unstable pelvic ring injuries
  • Sacral fractures in patients with unstable pelvic ring injuries that require mobilization
  • Displaced sacral fractures with neurologic injury

ORIF is contraindicated in patients who are unstable and critically ill or who have severe open fractures with inadequate wound debridement, crushing injuries, and placement of a suprapubic tube in the operative field. Additionally, a Morel-Lavalle lesion can be considered a contraindication to ORIF. This lesion is identified on the basis of a fluctuance under the skin of the involved area.

Contusions and abrasions are often associated with the Morel-Lavalle lesion. It represents a large area of hematoma and fat necrosis under degloved skin. The lesion results from shearing of the subcutaneous tissue from the underlying fascia. Although the Morel-Lavalle lesion is a closed injury, it is associated with high rates of bacterial contamination and, thus, must be treated with debridement and drainage before operative intervention is considered.

Specific contraindications for percutaneous fixation include a dysmorphic upper sacrum, obesity, skin compromise, and poor fluoroscopic images.

Medical Therapy

The initial evaluation and treatment of a patient with multiple trauma occur in the emergency department (ED). The Advanced Trauma Life Support (ATLS) recommendations for airway stabilization followed by breathing and circulation are followed. A multidisciplinary approach is employed that should include the following, as needed: emergency medicine, general surgery, neurosurgery, and orthopedic surgery.[34]

Patients with high-energy pelvic fractures often have abdominal, head, and thoracic injuries. Between 60% and 80% of patients have musculoskeletal injuries, 12% have urogenital injuries, and 8% have lumbosacral injuries.

Aggressive fluid resuscitation is critical in the patient who is hemodynamically unstable. The severity of blood loss can be determined by assessing the pulse, blood pressure, and capillary refill. These indicators can be used to evaluate a patient's response to the resuscitative effort. Two large-bore (16-gauge) intravenous catheters should be placed.

Replacement volume is estimated by using the formula of 3 mm of crystalloid for each 1 mm of blood loss. A minimum of 2 L of crystalloid solution is given over 2 minutes, or more rapidly if the patient is in shock. If an adequate blood pressure measurement is obtained, crystalloid is administered until type-specific blood of non-cross-matched universal donor (O-negative) is prepared.

Displaced pelvic fractures can be stabilized temporarily by simple means during the initial evaluation and transportation. These methods rely on immobilization and partial reduction of displacement. A sheet can be tied around the pelvis, or the legs can be tied together in an internally rotated position to approximate an anterior pelvic diastasis.

Military antishock trousers (MAST) have proved to be effective in the prehospital treatment of patients who are hypotensive and have pelvic fractures. Their use in the hospital is not common, because they limit access to injured areas of the body, decrease expansion of the lungs, and may contribute to the development of compartment syndrome in patients who are hypoperfused.

Most incidents of blood loss from a pelvic injury arise from cancellous bone at the fracture site or from a retroperitoneal lumbar plexus venous injury.[35] Only 20% of deaths from pelvic hemorrhage are attributed to a major arterial injury. Posterior arterial bleeding is more common in patients with unstable posterior pelvic fractures, and anterior arterial bleeding (pudendal or obturator) is more common in patients with lateral compression (LC) injuries.[36] The arterial vessel most frequently injured with a posterior fracture is the superior gluteal artery.

The Eastern Association for the Surgery of Trauma (EAST) has published guidelines for managing hemorrhage in pelvic fracture.[37]  Guidelines on management of hemodynamically unstable pelvic trauma have also been developed by the First Italian Consensus Conference on Pelvic Trauma.[38] (See Guidelines.)

Hemorrhage from a pelvic fracture is seldom the only source of bleeding. Poole described a large series of multiply injured patients with pelvic fractures in whom nonpelvic sites were the major source of bleeding.[39] The abdomen and bladder are frequently injured and should be evaluated as sources of hemorrhage. As mentioned, supraumbilical diagnostic peritoneal lavage (DPL) can be used as a quick and accurate diagnostic tool.

If DPL results are negative and the patient remains hemodynamically unstable, external fixation (see Surgical Therapy) may have a role in the patient's immediate treatment.[40] Riemer documented an overall decrease in mortality, from 26% to 6%, after initiating a protocol that included external fixation and early mobilization for pelvic fractures.[17] The mortality for hypotensive patients decreased from 41% to 21%.

Continued unexplained blood loss despite fracture stabilization and aggressive resuscitation mandates angiographic exploration to look for continued arterial bleeding.[41, 42] The techniques for arteriography and embolization were developed in the 1970s. Embolization provides the most direct and beneficial means of controlling arterial hemorrhage. It avoids the retroperitoneal contamination associated with operative ligation of bleeding vessels while preserving the tamponade effect in the retroperitoneal space.

The timing of arteriography and embolization is controversial. Most authors recommend arteriography after the initial stabilization, laparotomy, or both. A skilled radiologist is critically important. Aggressive fluid resuscitation must be continued during angiography. Hypothermia may develop during a prolonged radiographic procedure if the patient is not adequately warmed and resuscitated.

Extraperitoneal pelvic packing (EPP) appears to be a safe and quick means of enhancing hemodynamic stabilization and to reduce acute hemorrhage-related mortality in hemodynamically unstable pelvic fracture patients, in combination with optimal transfusion.[43] It may be useful as a bridge to angioembolization or other time-consuming procedures.

In a network meta-analysis of 13 clinical trials (N = 24,396), Tang et al attemtped to identify an optimal sequence of surgical procedures for hemodynamically unstable patients with pelvic fracture.[44] They concluded that the initial application of an external fixator was strongly supported and that for patients who remained hemodynamically unstable after application of an external fixator, EPP should be the next procedure to consider. They found angioembolization to be the complementary, but not alternative, subsequent method of choice.

Surgical Therapy

The goals of treatment are the same for pelvic fractures as for fractures of other bones—a healed fracture with the prevention of nonunion, malunion, or other complications.

External fixation also has been used in rotationally unstable pelvic fractures.[45, 46, 47] Benefits of external fixation include immobilization of fractures limiting the clot disruption that may occur during patient movement and transfer. Studies have shown that reduction of an open-book pelvis leads to an increase in retroperitoneal pressure, which may aid in the tamponade of venous bleeding.

The use of external fixation remains controversial. For example, Gruen et al reported that in 36 trauma patients who were hemodynamically unstable, pelvic fractures were not immediately stabilized by external fixation.[48] These patients received both volume resuscitation and treatment of associated injuries. About 39% of the fractures were rotationally unstable, and 61% were both rotationally and vertically unstable. Overall mortality was 11%. All of the deaths were attributed to associated injuries or comorbidities.

In most cases, ORIF is preferred for definitive management and has been demonstrated to give superior results. Operative indications include the following:

  • Diastasis of the pubic symphysis greater than 2.5 cm
  • Sacroiliac (SI) joint dislocations
  • Displaced sacral fractures
  • Crescent fractures
  • Posterior or vertical displacement of the hemipelvis greater than 1 cm
  • Rotationally unstable pelvic ring injuries
  • Sacral fractures in patients with unstable pelvic ring injuries that require mobilization
  • Displaced sacral fractures with neurologic injury

Minimally invasive approaches to fixation have been described that may yield results comparable to those of conventional fixation in patients with unstable pelvic fractures.[49, 50, 51]

Preparation for surgery

The mechanism of injury, soft-tissue condition, and patient positioning should be reviewed. Repeating a rectal and gynecologic examination before beginning the open procedure is also important to ensure that the fracture is not open.

Plain radiographs, including anteroposterior (AP) pelvis, inlet views, and outlet views, should be obtained and reviewed. Computed tomography (CT) is helpful in evaluating the sacrum and the SI joint for injury.[32]  It is also worthwhile to review a catalogue of injuries before proceeding to the operating room.

If percutaneous fixation is deemed acceptable for treatment, good fluoroscopic images should be obtained before the patient is prepared and draped. The need for skeletal traction must also be determined before definitive fixation. If a femoral traction pin is to be used, it should be placed before internal fixation.

Definitive internal fixation typically is not performed immediately after the injury. Instead, it is usually performed 2-3 days after stabilization of the patient. However, if a laparotomy is performed and an unstable anterior lesion is present, internal fixation of the symphysis may be performed.

Operative details

External fixation

External fixation is indicated for patients with pelvic fractures who are hemodynamically unstable. It should be avoided in patients who are hemodynamically stable except in those select cases where it will serve as definitive stabilization.[52] Infected or contaminated pin sites may compromise future approaches to the anterior SI joint and the iliac wing.

The surgeon must be familiar with the external fixation equipment so that it can be used quickly and effectively in patients who are hemodynamically unstable. Pins may be placed either along the iliac crest or in the supra-acetabular region.

Placement in the iliac crest is simple and direct; this location is most appropriate for rapid pin placement in a patient who is hemodynamically unstable (see the image below). The thickest bone for pin insertion is the anterior pillar of the iliac wing. Anatomically, the iliac crest overhangs laterally. A pin placed in the center of the crest will miss the iliac wing. The optimal starting point is in the medial one third of the anterior pillar.

External fixation of anterior-posterior compressio External fixation of anterior-posterior compression (APC) pelvic fracture.

Supra-acetabular pins are placed at the level of the anterior inferior iliac spine in a direction perpendicular to the floor. This pin is near the hip joint and must be inserted with great care. The skin incisions should be placed in line with the direction of the planned reduction. This avoids the need for additional relaxing incisions.

A spinal needle or Kirschner wire (K-wire) can be placed along the inner table of the pelvis to help determine the orientation of the hemipelvis. Frame constructs are varied. The frame should be far enough away from the abdomen to allow for distention, future surgical approaches, and upright positioning.

Iliosacral screws

Iliosacral screws can be used in the treatment of crescent fractures, sacral fractures, and SI dislocations. They can be placed through either open or percutaneous techniques.[8, 53]  If percutaneous techniques are chosen, an anatomic reduction is required because sacral displacement narrows the safe window for screw placement.

The procedure can be performed with the patient in either the supine or the prone position. The technique is technically demanding and requires good C-arm visualization. A thorough understanding of the radiographic anatomy is critical in performing this procedure. The pelvic inlet, outlet, and lateral sacral views must be obtained to define the safe corridor for screw placement. Three-dimensional (3D) CT (3D CT) of the pelvis has also been used to guide iliosacral screw placement.[54]

The ideal pelvic inlet view superimposes the upper sacral vertebral bodies as concentric circles. If the anterior cortex of S1 overlies the coccyx, the concavity of the sacrum may not be appreciated. This may result in a screw penetrating the S1 body. The ideal pelvic outlet view is obtained when the symphysis is superimposed on the second sacral vertebral body; this view allows visualization of the S2 foramina. A lateral sacral view is obtained by superimposing the greater sciatic notch images.

The iliac cortical density denotes the anterior extent for safe placement of the iliosacral screw insertion. The angle of screw placement may vary between SI dislocation and a sacral fracture. The screw placement for a sacral fracture must be in a transverse position to allow the screw to achieve fixation in the sacral body.

Sacral fractures are treated with fully threaded cancellous screws to avoid overcompression of the sacral foramina. SI dislocations are compressed with cancellous lag screws. If an open approach is necessary for reduction of the SI dislocation, either an anterior or a posterior approach may be taken.

For the posterior approach, a vertical incision is made 2 cm lateral to the posterior superior iliac spine. The gluteal muscle is elevated from the posterior iliac crest, and the gluteus maximus origin is reflected from the sacrum. The greater sciatic notch must be exposed for assessment of reduction.

For sacral fractures, the multifidus is elevated to provide visualization of the sacral foramina. A Matta angled jaw clamp can be used to obtain reduction by placing one tip on the sacrum through the sciatic notch and the other along the outer table of the ilium. Fixation is performed with iliosacral screws.

For an anterior approach, the incision is from the anterior superior iliac spine to the iliac tubercle. The iliacus is sharply dissected subperiosteally off the iliac wing. The L5 nerve root lies 2 cm medial to the SIJ and must be protected during dissection. Fixation is usually limited to a pair of two-hole plates placed at 90° to each other. In a study of 27 patients with SI dislocations treated with an anterior approach, three (11%) had incomplete L5 nerve injuries postoperatively, with full improvement occurring in two of them.[55]

Crescent fractures can be approached via an anterior or posterior approach.[13]  The posterior approach provides an easier dissection, without requiring special care for the L5 nerve root. The iliac wing fragment can be reduced to the intact posterior superior iliac spine and fixed in place with one or two cortical lag screws (3.5 mm) placed between the pelvic tables from posterior to anterior. A 3.5-mm reconstruction plate can be placed along the outer table to help neutralize the rotational and shear forces across the fracture site.

If the intact posterior superior iliac spine fragment is small, iliosacral screws may be required to stabilize the iliac wing.

Postoperative Care

Postoperative weightbearing status depends on the fracture pattern and associated injuries. Most unstable fractures require nonweightbearing restrictions for 3 months. Early weightbearing may be allowed in individuals with rotationally unstable but vertically stable fractures. All patients should be out of bed or upright in bed on postoperative day 1 to help pulmonary function.[56]

Complications

Complication rates for unstable pelvic injuries are high. An awareness of the complications and adequate preoperative planning can reduce these rates.

The Morel-Lavalle lesion is a significant soft-tissue injury associated with pelvic trauma. The subcutaneous tissue is torn away from the underlying fascia, creating a cavity filled with hematoma and liquefied fat. The diagnosis is based on physical examination findings, including a soft fluctuant area that commonly occurs over the greater trochanter but may also occur in the flank and lumbodorsal region. Management is important because the presence of necrotic tissue and hematoma in the subcutaneous tissue increases the risk of infection.

Open debridement is the preferred treatment. The incision should be placed close to the middle of the degloved area to decrease the risk of flap necrosis. The hematoma should be evacuated, and the necrotic fatty and connective tissue should be sharply debrided. The wounds should be packed with gauze, and dressings soaked with isotonic sodium chloride solution should be changed regularly. Prophylactic antibiotics should particularly cover gram-positive organisms.

If the overlying skin is intact, debridement can be performed at the time of fracture fixation. The deep fascia should be closed tightly, and the distal portion of the wound should be left open for dressing changes.

The incidence of deep venous thrombosis (DVT) in patients with pelvic trauma has been reported to be 35-60%. Geerts et al performed venography on 100 patients with pelvic fractures and found a 61% incidence of DVT and a 29% incidence of proximal DVT.[57] The incidence of symptomatic pulmonary embolism (PE) in pelvic trauma is 2-10%. Fatal PE occurs in 0.5-2% of patients with pelvic trauma.

The risk factors most consistently observed with a trauma population are increasing age, spinal cord injury, fractures of the lower extremity and pelvis, and duration of immobilization. The typical clinical findings of DVT include leg tenderness, swelling, and increased temperature. The sensitivity of detecting DVT in a patient with trauma is unreliable because lower-extremity fracture, edema, and soft tissue injury are often present. Duplex ultrasonography (US) is the most widely used screening test for the evaluation of DVT in trauma patients.

Given the high incidence of DVT in the pelvic trauma population, routine prophylaxis is recommended. Common forms of prophylaxis include low-dose heparin (LDH), low-molecular-weight heparin (LMWH), mechanical devices, and vena caval filters. Knudson et al performed a randomized trial of LDH with no prophylaxis in 154 trauma patients.[58, 59] Serial duplex Doppler US was performed every 3-5 days. Patients treated with LDH received no additional protection, as compared with controls.

Intermittent pneumatic compression has been demonstrated by itself to be ineffective prophylaxis for trauma patients. Fisher et al performed a randomized study of intermittent pneumatic compression in patients with pelvic fractures.[60] They found no significant difference in DVT rates. LMWH is more efficacious than LDH in preventing DVT (19% vs 12%). The use of LMWH has been associated with an increased risk of wound hematoma formation. The authors prefer warfarin prophylaxis for postoperative patients.

Treatment of DVT in persons with pelvic trauma depends on whether the patient requires surgical reconstruction. DVT can be identified both preoperatively and postoperatively. In patients who will be treated nonoperatively or with immediate reconstruction, LMWH or LDH and mechanical prophylaxis can be used. By 36 hours after injury, most patients are no longer actively bleeding, and it is usually safe to administer LMWH or LDH for prophylaxis. LMWH or LDH should be administered at midnight before surgical intervention is performed.

Postoperative prophylaxis is started with warfarin (international normalized ratio [INR] goal, 2.0-3.0). Because of the risk of intraoperative embolization, all patients with pelvic fractures receiving delayed surgical reconstruction (>4 days) should undergo bilateral lower-extremity venous US or venography.

If DVT is found, the patient should receive a vena caval filter. If no DVT is found, routine postoperative prophylaxis is performed. For patients with contraindications to anticoagulation, such as intracranial bleeding, prophylactic vena caval filter placement and screening US or magnetic resonance venography (MRV) should be considered.

The incidence of sciatic or lumbosacral nerve injury in pelvic trauma is reported to be 10-15%. A higher incidence has been noted in persons with fracture dislocations with posterior pelvic instability. Anatomically, this incidence can be explained by the close relationship of the lumbar and sacral nerve roots to the sacrum and the SI joint.

In 1966, Huittinen and Slatis reviewed the nonoperative treatment of 1476 patients with unstable pelvic fractures and found a 46% rate of persistent nerve injury.[61]

Helfet et al evaluated 28 patients with 30 vertically unstable fractures of the hemipelvis and found preoperative ipsilateral neurologic injury to the sciatic lumbosacral plexus in 50% of the patients.[62] Posterior approaches and reduction led to significant unilateral changes in the somatosensory-evoked potentials (SSEPs) concurrent with manipulation of the hemipelvis for reduction. Routine careful identification and retraction of the L5 nerve root intraoperatively did not result in SSEP monitoring changes during anterior approaches.

Nonunions and malunions occur as a result of inadequate initial treatment of displaced pelvic fractures. Pain is the most common subjective symptom and is usually related to the posterior pelvic injury. Deformity is also a common symptom. Cranial displacement of the hemipelvis results in shortening of the ipsilateral extremity, which can cause the sacrum and coccyx to become more prominent and thus can be troublesome with sitting or lying down.

Matta and Saucedo reported on operative correction of 37 nonunions and malunions.[7] The procedure is technically demanding, with a complication rate of 19%. Average operating time was 7 hours, and average blood loss was 2000 mL.

A three-stage reconstruction is often required. The first stage involves an anterior approach to mobilize structures and to perform osteotomies. The patient is then repositioned, and a posterior approach is used to complete the mobilization or osteotomy. ORIF of the posterior pelvis is performed. The third stage involves a repeat anterior approach for ORIF of the anterior pelvis.

Long-Term Monitoring

Patients should undergo radiographic evaluation at 2, 6, and 12 weeks after surgery. Wounds should be evaluated at these office visits. Sutures are generally removed at 2-3 weeks. Patients with significant mobility problems should receive anticoagulation treatment with warfarin for at least 2 weeks if such treatment is not contraindicated. This should continue until patients are able to maneuver with crutches or a walker.

 

Guidelines

First Italian Consensus Conference on Pelvic Trauma

In 2014, the First Italian Consensus Conference on Pelvic Trauma, which included members from Italian and international societies focusing on surgery, critical care, radiology, emergency medicine, and orthopedics, published the following cooperative guidelines for hemodynamically unstable pelvic trauma[38] :

  • Preperitoneal pelvic packing (PPP) is effective in controlling hemorrhage when used as part of a multidisciplinary clinical pathway that includes angiography and external fixation
  • PPP is effective in controlling hemorrhage when used as a salvage technique
  • Pelvic binders should be applied as soon as pelvic mechanic instability is assessed, better in the prehospital setting
  • Anterior or posterior external fixation must be accomplished in unstable fractures as soon as possible in substitution of pelvic binders
  • External fixation can be accomplished in the emergency department (ED) or in the operating room (OR) and appears to be a quick tool to reduce venous and bony bleeding
  • External fixation, whenever possible, can be the first maneuver to be done in patients with hemodynamic instability and a mechanically unstable pelvic fracture
  • After nonpelvic sources of blood loss have been ruled out, patients with pelvic fractures and hemodynamic instability or signs of ongoing bleeding should be considered for pelvic angiography/embolization
  • Patients in whom computed tomography (CT) demonstrates arterial intravenous contrast extravasation in the pelvis may require pelvic angiography and embolization regardless of hemodynamic status
  • After nonpelvic sources of blood loss have been ruled out, patients with pelvic fractures who have undergone pelvic angiography with or without embolization and who have persistent signs of ongoing bleeding should be considered for repeat pelvic angiography/embolization

Eastern Association for the Surgery of Trauma

In 2011, the Eastern Association for the Surgery of Trauma published the following guidelines for management of hemorrhage in pelvic fracture[37] :

  • The use of a pelvic orthotic device (POD) does not seem to limit blood loss in patients with pelvic hemorrhage (level III recommendation)
  • The use of a POD effectively reduces fracture displacement and decreases pelvic volume (level III recommendation)
  • Patients with pelvic fractures and hemodynamic instability or signs of ongoing bleeding after nonpelvic sources of blood loss have been ruled out should be considered for pelvic angiography/embolization (level I recommendation)
  • Patients with evidence of arterial intravenous contrast extravasation in the pelvis by CT may require pelvic angiography and embolization regardless of hemodynamic status (level I recommendation)
  • Patients with pelvic fractures who have undergone pelvic angiography with or without embolization, who have signs of ongoing bleeding after nonpelvic sources of blood loss have been ruled out, should be considered for repeat pelvic angiography and possible embolization (level II recommendation)
  • Patients older than 60 years with major pelvic fracture (open book, butterfly segment, or vertical shear) should be considered for pelvic angiography without regard for hemodynamic status (level II recommendation)
  • Although fracture pattern or type does not predict arterial injury or need for angiography, anterior fractures are more highly associated with anterior vascular injuries, whereas posterior fractures are more highly associated with posterior vascular injuries (level III recommendation)
  • Pelvic angiography with bilateral embolization seems to be safe with few major complications; gluteal muscle ischemia/necrosis has been reported in patients with hemodynamic instability and prolonged immobilization or primary trauma to the gluteal region as the possible cause, rather than a direct complication of angioembolization (level III recommendation)
  • Sexual function in males does not seem to be impaired after bilateral internal iliac arterial embolization (level III recommendation)
  • Focused assessment with sonography for trauma (FAST) is not sensitive enough to exclude intraperitoneal bleeding in the presence of pelvic fracture (level I recommendation)
  • FAST has adequate specificity in patients with unstable vital signs and pelvis fracture to recommend laparotomy to control hemorrhage (level I recommendation)
  • Diagnostic peritoneal tap/diagnostic peritoneal lavage (DPL) is the best test to exclude intra-abdominal bleeding in the hemodynamically unstable patient (level II recommendation)
  • In the hemodynamically stable patient with a pelvic fracture, CT of the abdomen and pelvis with intravenous contrast is recommended to evaluate for intra-abdominal bleeding regardless of FAST results (level II recommendation)
  • Fracture pattern on pelvic x-ray does not single-handedly predict mortality, hemorrhage, or the need for angiography (level II recommendation)
  • Presence or location of hematoma does not predict or exclude the need for angiography and possible embolization (level II recommendation)
  • CT of the pelvis is an excellent screening tool to exclude pelvic hemorrhage (level II recommendation)
  • Absence of contrast extravasation on CT does not always exclude active hemorrhage (level II recommendation)
  • Pelvic hematoma larger than 500 cm 3 has an increased incidence of arterial injury and need for angiography (level II recommendation)
  • Isolated acetabular fractures are as likely to require angiography as pelvic rim fractures (level III recommendation)
  • If a retrograde urethrocystogram is required, it should be performed after CT with intravenous contrast (level III recommendation)
  • Temporary pelvic binders (TPBs) effectively reduce unstable pelvic fractures as well as definitive stabilization and decrease pelvic volume. (level III recommendation)
  • TPBs may limit pelvic hemorrhage but do not seem to affect mortality (level  III recommendation)
  • TPBs work as well or better than emergency external pelvic fixation in controlling hemorrhage (level III recommendation)
  • Retroperitoneal pelvic packing is effective in controlling hemorrhage when used as a salvage technique after angiographic embolization (level III recommendation)
  • Retroperitoneal pelvic packing is effective in controlling hemorrhage when used as part of a multidisciplinary clinical pathway including a POD/C-clamp (level III recommendation)