Chapter 17: Pelvis

Pelvic fractures represent 3% of all skeletal fractures and are exceeded only by skull fractures in their associated complications and mortality.¹ Pelvic fractures range from low-energy stable fractures to high-energy unstable injuries, associated with abdominal injuries, need for major blood transfusion, and even death.² The mortality rate for high-energy pelvic fractures ranges from 10% to 20%, but in hemodynamically unstable patients or after open fractures, it increases to 50%.^3,4 Motor vehicle collisions account for approximately two-thirds of all pelvic fractures. Pedestrians struck by automobiles are responsible for 15% of cases. Crush injuries, motorcycle crashes, and falls each account for an additional 5%.⁵

Pubic rami fractures are the most common pelvic fractures with the superior ramus more frequently involved than the inferior ramus. Pubic rami fractures account for over 70% of all pelvic fractures.⁶ The incidence of fractures of the remaining pelvic bones in descending order is the ilium, ischium, and acetabulum. Sacroiliac (SI) fractures are associated with the most significant bleeding. Both the mechanism of injury and the fracture pattern identified on imaging studies are important in predicting associated injuries.

Essential Anatomy

In humans, the pelvic ring serves two important functions: weight support (stability) and protection of the viscera. There are essentially three bones that combine to form the pelvic ring: two innominate bones (composed of the ischium, ilium, and pubis) and the sacrum (Fig. 17–1). The coccyx is a fourth bone, but it is not incorporated into the pelvic ring. The two innominate bones and the sacrum are united by the formation of three joints (the symphysis pubis and the two SI joints). The ligaments that form the pelvic ring are the strongest in the body.

Weight bearing is transmitted through the bony pelvis along two pathways (Fig. 17–2). When standing, weight is transmitted through the spine to the sacrum, SI joints, and along the arcuate line to the superior dome of the acetabulum and down the femur. In the sitting position, the force is transmitted down the spine to the sacrum and the SI joints and to the ischium by way of the inferior ramus. The bone is very strong in these areas and the anteroposterior (AP) radiograph of the pelvis clearly demonstrates the thick trabecular pattern along these lines of stress. As a result, pelvic fractures more commonly interrupt the ring in areas not involved in weight transmission. A greater force is required to fracture a “weight-bearing” area of the pelvis. In addition, fractures involving the weight-bearing arches are associated with much more pain when stressed than those fractures that do not involve these arches. A good example is the superior ramus fracture. Because this structure is a nonweight-supporting area, it is generally less painful and mechanically stable compared to fractures in weight-supporting portions of the pelvis. A patient with a fracture of the superior pubic ramus may walk into the emergency department (ED), whereas a patient with a fracture through the sacrum will not be able to bear weight without significant pain.

The concept of the pelvis as an anatomic ring also has important implications for fracture detection. The presence of at least two fractures or one fracture and a dislocation is required to cause a displaced fracture in the ring. Therefore, if a displaced pelvic ring fracture is diagnosed, the clinician should search for a second fracture or joint injury. Single breaks in the pelvic ring are unusual and are usually nondisplaced and occur near or at a joint (SI joint or symphysis pubis).

Pelvic stability during ambulation is a combined function of ligaments and bones. Anteriorly, the interpubic ligaments join the two pubic bones forming the symphysis pubis. The anterior pelvic structures (symphysis and rami) are responsible for 40% of pelvic ring stability.³ Posteriorly, the SI joint is supported by a series of strong ligaments that are the major stabilizers of the pelvic ring (Fig. 17–3). Disruption of the SI ligaments will alter the normal weight-bearing function of the pelvic ring.

Disruption of the interpubic ligaments may result in diastasis of the pubic symphysis of up to 2.5 cm. The intact ligaments of the SI joint—specifically the sacrospinous, sacrotuberous, and anterior SI ligaments—limit further opening. If these ligaments are sectioned, the pelvis becomes rotationally unstable and the pelvis will “open like a book.” As long as the posterior ligaments of the SI joint (interosseous SI ligament and posterior SI ligament) remain intact, the hemipelvis will remain vertically stable. Additional injury to the posterior SI ligaments results in a pelvis that is unstable both rotationally and vertically.

The muscles attached to the pelvis serve to support the body in the erect position and to provide mobility to the lower limbs. For the purpose of this text, the essential muscular anatomy concerns only those muscles responsible for avulsion fractures.

1. The sartorius inserts on the anterior superior iliac spine.

2. The rectus femoris inserts on the anterior inferior iliac spine.

3. The hamstrings insert on the ischial tuberosity.

The spinal nerves leave the protection of the vertebral column by way of the lumbar intervertebral foramina or the sacral foramina and course along the posterior aspect of the pelvis. Pelvic fractures, particularly those involving the sacrum, may be associated with nerve injury. A thorough neurologic examination of the lower extremities and the sphincters is essential in the assessment of pelvic fractures.

The abdominal aorta descends to the left of the midline and divides at L4 into the two common iliac vessels. At the level of the SI joints the common iliacs branch, forming the external and internal iliacs. The internal iliac artery further divides into anterior and posterior branches. The posterior branch gives rise to the superior gluteal artery, which has an acutely angled base and is exposed to shearing forces with fractures in the area. The anterior branch supplies the viscera of the pelvic cavity. Posterior pelvic (ilium and SI) fractures are associated with more extensive hemorrhage than are anterior pelvic fractures.

The rectum, anus, sigmoid, and descending colon are contained within the bony pelvis. These structures may be damaged with any pelvic fracture, but are most commonly injured with fractures associated with penetrating injuries. The genitourinary system is frequently damaged in association with pelvic fractures due to blunt or penetrating trauma. The bladder, lying directly behind the symphysis pubis, is frequently injured following pelvic fractures involving the pubis. Anterior pelvic fractures are also associated with urethral injuries. If the urethra ruptures below the level of the urogenital diaphragm, the extravasation of urine will involve the scrotum, the superficial perineal compartment, and the abdominal wall.⁷

In addition to associated injuries of the pelvic viscera, there is significant risk of injury to the other intra-abdominal organs due primarily to the mechanism of injury. The incidence of abdominal injuries in patients with blunt pelvic fracture in one study was 16.5%. The most commonly injured organs were the liver (6.1%) and the bladder and urethra (5.8%). In severe pelvic fractures the incidence of associated abdominal injuries was 30.7% and the most commonly injured organs were the bladder and urethra (14.6%).²

Examination

Patients who present with pelvic pain after a minor trauma and a possible fracture should have a simple six-point examination.

1. External rotation of the pelvis (Fig. 17–4)

2. Internal rotation of the pelvis (Fig. 17–5)

3. Compression of the pubic symphysis

4. Palpation of the anterior superior iliac spine

5. Palpation of the sacrum and coccyx

6. Palpation of the trochanters and ischial tuberosities

The evaluation of a patient with major trauma should begin with a thorough primary survey searching for and treating any immediate life threats. Pelvic fractures may result in exsanguination and therefore two large bore intravenous lines must be started, and cross-matched blood made available should the need arise. During the secondary survey, an assessment of pelvic injury and stability should take place. All patients with multiple injuries must be suspected of having a pelvic fracture until proven otherwise.

Following exposure, the examiner should perform a careful inspection of the soft tissues of the pelvis looking specifically for deformity of the pelvis or lower extremities that suggest a pelvic fracture. Examination should continue with a search for lacerations that might indicate an open fracture. This includes visual inspection of the gluteal folds and perineal area where an injury might be missed otherwise. Gross blood on rectal or bimanual examination suggests an open pelvic fracture. The examination of suspected pelvic fractures must include direct palpation of the entire ring, with special emphasis on the pubic symphysis, the SI joints, and the sacrum. Examination of each hip and its range of motion will help exclude an acetabular injury.

Pelvic instability can be detected on physical examination. Rotational instability is present when gentle manual pressure over the anterosuperior iliac spines in both external and internal rotation causes significant movement of the pelvis. Bony crepitus may also be noted. Vertical instability can be assessed by noting vertical movement of the pelvis with the examiner’s palms palpating the anterosuperior iliac spines while a second examiner provides traction and then a vertical load to the lower extremity. Testing for vertical instability is not recommended because if it is present, the examination will only increase the amount of hemorrhage.

It is of utmost importance to note that only one examination for instability should be permitted as repeated examinations can disrupt hematoma formation and exacerbate or create hemodynamic instability. These patients should be moved or manipulated as little as possible so as not to aggravate hemorrhage or induce further complications.

The genitourinary system is frequently injured with pelvic fractures, and questions relating to hematuria, inability to void, last menses, and vaginal bleeding should be noted on history. During the digital rectal examination, the position of the prostate gland is assessed. Prostate displacement, scrotal ecchymosis, or blood at the urethral meatus indicates possible disruption in the membranous urethra. Unfortunately, physical signs of urethral injury are absent in over half of patients with these injuries.⁸

A thorough neurologic examination of the lower extremities is important. Particular areas of concern include the L5 and S1 nerve roots. Both motor and sensory functions should be documented. Sacral fractures can injure sacral roots, the obturator nerve, and the L5 nerve roots. The sciatic nerve is commonly injured following acetabular fractures.

Secondary signs of a potential pelvic fracture include the following:

• Destot’s sign—a superficial hematoma above the inguinal ligament or in the scrotum.

• Roux’s sign—occurs when the distance measured from the greater trochanter to the pubic spine is diminished on one side, as compared with the other, as might result from an overlapping anterior ring fracture.

• Earle’s sign—occurs when a large hematoma, an abnormal palpable bony prominence, or a tender fracture line is detected on a rectal examination.

Imaging

An AP radiograph of the pelvis is indicated in the alert trauma patient in the setting of pain or tenderness (Fig. 17–6).⁹ This view detects most injuries to the sacral wings, iliac bones, ischium, and pubis. Obvious fracture lines are diagnosed on this film and suspected fracture areas are the cause for further imaging studies. The initial AP pelvic film allows for classification of the pelvic fracture and guides resuscitation and the need for acute pelvic stabilization in 90% of cases.¹⁰ If the AP radiograph reveals significant pelvic ring instability, treatment of a hemodynamically unstable patient should be instituted on the basis of this film alone.¹¹ Although Advanced Trauma Life Support (ATLS) still recommends performing pelvic radiography in all major blunt trauma patients, more recent evidence suggests that it can be limited to blunt trauma patients who are hemodynamically unstable or have positive pelvic physical examination findings.¹²

Inlet (AP with x-ray beam angled caudad 45 degrees) and outlet (AP with 45 degrees of cephalic tilt) views may aid in the diagnosis of pelvic ring fractures in hemodynamically stable patients (Fig. 17–7). The inlet view demonstrates the true pelvic inlet. Injuries to the anterior ring are easily identified on this view, whereas posterior injuries may remain subtle. The outlet view is oriented 90 degrees to the anterior sacrum and therefore more readily detects fractures of this bone. This projection also detects any bony displacement in the sagittal plane. Both the inlet and outlet views have largely been replaced by computed tomography (CT). Oblique (Judet) views may be useful for diagnosing acetabular fractures, although CT is more sensitive in diagnosing fractures of the acetabulum and sacrum and is therefore the imaging test of choice.^13,14

The CT scan of the pelvis has other advantages. It aids in the evaluation of the integrity of the posterior pelvic structures, which facilitates a more accurate assessment of pelvic injury and stability. CT is very helpful in the evaluation of hematoma size and location, as well as in the diagnosis of visceral injuries in patients sustaining pelvic fractures. Visualization of a blush of contrast or a hematoma greater than 10 cm² suggests an arterial hemorrhage.^15–17 Three-dimensional CT imaging is being used more frequently and may aid in defining the overall pelvic ring injury.

Elderly osteopenic patients with pelvic pain after a low-energy mechanism of injury who have negative plain films may benefit from a radionuclide scan. A delay of 3 days from the trauma is recommended before scanning.^13,17

In the setting of high-energy pelvic trauma, additional radiographic studies are often required. In hemodynamically unstable patients, pelvic angiography may be lifesaving if it can occlude arterial bleeding. If a urethral tear is suspected in a male patient, based on the findings of blood at the urethral meatus, hematuria, or a high-riding prostate, a retrograde urethrogram is obtained before placement of a Foley catheter. If this study is normal, a retrograde cystogram is obtained to evaluate the integrity of the bladder. A postvoid film is imperative to exclude extravasation of dye. A retrograde cystogram should be deferred in a patient who may undergo pelvic angiography, as this test will interfere with proper angiographic diagnosis.

There are multiple classification systems for pelvic ring fractures. Pennal and Sutherland were the first to develop a mechanistic classification of pelvic ring injuries.¹⁸ They divided pelvic ring injuries into categories based on the force that caused them—lateral compression (LC), anteroposterior compression (APC), and vertical shear (VS).

Burgess and Young further refined Pennal and Sutherland’s system by subdividing the first two categories (LC and APC) into three subcategories (I, II, and III) based on the extent of injury (Table 17–1). With this system, the clinician classifies pelvic fractures by observing both the anterior and posterior injury patterns. The anterior injuries within each category (LC and APC) are the same. The degree of posterior injury defines the three sub-categories (I, II, and III) in LC and APC mechanisms. These authors also added another category—combined mechanism (CM)—when the fractures noted were a result of a combination of forces (i.e., APC and LC or more frequently, LC and VS).¹⁹ This system is beneficial to the emergency physician during the initial resuscitation as it helps predict fluid resuscitation requirements, associated skeletal and solid organ injury, the need for acute stabilization of the pelvis, and ultimately patient survival.^19–21 APC III, LC III, and VS injuries are all associated with high-energy mechanisms. APC III injuries are associated with the highest transfusion requirement, highest mortality, and the highest rate of neurologic injury.

Tile introduced a modification of the Pennal classification system in 1988, highlighting the importance of the posterior SI complex in maintaining the ability of the pelvis to withstand physiologic force and therefore maintain mechanical stability (Table 17–2).^3,22 This system combines the mechanism of injury with the potential instability present. In hemodynamically stable patients, Tile’s classification aids the orthopedic surgeon and the emergency physician in determining the requirement for surgical stabilization as well as the prognosis.²⁰

In this chapter, pelvic fractures will be divided into those that do not involve the pelvic ring and those that do (Table 17–3). Fractures that do not disrupt the pelvic ring are mechanically stable fractures and have a low rate of associated injuries.

Pelvic fractures that disrupt the pelvic ring are then further subdivided into nondisplaced mechanically stable fractures and displaced high-energy fractures based on the classification of Burgess and Young.¹⁹

Mechanically stable fractures generally occur when only one nondisplaced fracture in the pelvic ring is present and the SI joint and symphysis pubis remain intact. Stable, nondisplaced fractures tend to occur near the symphysis pubis or SI joint as the relative mobility of the pelvis in these areas allows a ring transection without additional injury. As mentioned earlier, displaced pelvic fractures are usually mechanically unstable and suggest that there are two fractures transecting the ring or one fracture and a joint dislocation.

Unstable fractures involve a transection of the pelvic ring in two places with displacement. These fractures represent 15% of patients with pelvic fractures.¹⁰ The mortality rate for displaced pelvic fractures is high, and life-threatening–associated injuries, including hemorrhage and visceral organ damage, frequently accompany these injuries. These fractures usually are secondary to severe direct forces such as those that occur in a high-speed car collision or after a fall from a significant height.

Avulsion Fractures

These fractures generally occur in young athletes and are due to a forceful muscular contraction in an area where the apophyseal centers are not yet fused (Fig. 17–8). They typically fuse at the following ages:

• Anterior superior iliac spine (sartorius insertion) fuses at 16 to 20 years.

• Anterior inferior iliac spine (rectus femoris insertion) fuses at 16 to 20 years.

• Ischial tuberosity (hamstrings insertion) fuses at age 25.

In addition to the above, an avulsion at the symphysis pubis by the adductor longus muscle may be seen in young athletes. After the fracture, callus formation is extensive and at times can be mistaken for a neoplasm.

Mechanism of Injury

Each type of avulsion fracture is associated with a different mechanism of injury.

Avulsion of the anterosuperior iliac spine is typically seen in young sprinters and is secondary to a forceful contraction of the sartorius. Displacement is usually mild and inhibited by the attachment of the inguinal ligament and fascia lata to this bone. Avulsion of the anterior inferior iliac spine is less frequent and is due to a forceful contraction of the rectus femoris, as can occur during a soccer kick. Avulsion of the ischial tuberosity is typically seen in athletes, such as hurdlers, cheerleaders, and pole-vaulters after a forceful contraction of their hamstrings.

Examination

Patients with an avulsion of the anterosuperior iliac spine will have pain and tenderness over the area that is exacerbated with use of the sartorius (flexion or abduction of the thigh). Avulsion of the anterior inferior iliac spine will result in complaints of pain and tenderness in the groin. Active hip flexion using the rectus femoris, as during walking, will be painful. Avulsion of the ischial tuberosity may present with acute or chronic symptoms of pain that worsen with sitting. Tenderness will be elicited with percutaneous and rectal palpation of the ischial tuberosity. Palpation over the sacrotuberous ligament on rectal examination will also greatly exacerbate the pain. In addition, flexion of the thigh with the knee extended is painful, although it is painless with the knee flexed.

Imaging

An AP view is generally adequate in defining the fracture fragment (Fig. 17–9). Nonossified apophyseal centers may confuse the interpretation of these radiographs and therefore comparison to the uninjured side is warranted.

Associated Injuries

Avulsion fractures are usually not associated with any other significant injuries.

Treatment

The treatment of avulsion pelvic fractures is symptomatic. Crutches are required in all patients. Referral is indicated if the avulsed fragment is markedly displaced. In general, patients with avulsions of the anterosuperior iliac spine should rest in bed for 3 to 4 weeks with the hip in flexion and abduction. The patient may sit as tolerated, although ambulation and vigorous activity should be restricted. Complete recovery takes as long as 8 weeks or more. The treatment of avulsions of the anterior inferior iliac spine is treated in a similar manner, except the hip should be in flexion with no abduction. Patients with avulsions of the ischial tuberosity should be placed on bed rest with the thigh in extension with external rotation and slight abduction. An inflatable ring cushion for sitting is advised.

Complications

Avulsion fractures may be followed by the persistence of chronic pain due to the overzealous growth of callus. Surgical excision is occasionally required.

Single Pubic Ramus or Ischial Ramus Fracture

These fractures do not result in complete transection of the pelvic ring (Fig. 17–10). Earlier studies suggested that these fractures represented one-third of all pelvic fractures, but recent advances in radiographic techniques have led many clinicians to conclude that they are a rare occurrence and are usually associated with injury to an additional ipsilateral ramus or subtle posterior injury.

Some authors elect to classify these injuries as stress fractures because they are seen in women during the third trimester of pregnancy, in military recruits after a strenuous activity, or in long-distance runners. These fractures are also seen in elderly patients. Most patients with these injuries experience persistent groin discomfort during any activity. All patients recover with an 8- to 12-week rest period and particularly with the avoidance of running.

Mechanism of Injury

In the elderly, the mechanism is generally secondary to a fall. In the young, persistent tension on the adductors and the hamstrings may result in a stress fracture of the inferior ramus.

Examination

The patient will complain of a “deep pain” that is exacerbated with deep palpation or walking. Hamstring stressing will elicit or worsen the pain.

Imaging

An AP pelvic view is obtained first as a general overview of the area. If clinical or radiographic suspicion is high, an outlet view should be obtained. Bone scan may be the only way to demonstrate a stress fracture.

Associated Injuries

These fractures may be accompanied by a hip fracture in elderly patients.

Treatment

Symptomatic treatment is recommended including analgesics and bed rest progressing to crutch walking as tolerated.

Complications

Complications are not commonly seen after these fractures.

Ischial Body Fractures

Ischial body fractures (Fig. 17–11) are frequently comminuted and are the least frequent of all pelvic fractures.

Mechanism of Injury

These fractures result from a significant fall landing on the buttocks in the seated position.

Examination

There will be pain and tenderness to deep palpation that is exacerbated with tension on the hamstrings.

Imaging

An AP view of the pelvis is generally adequate in demonstrating this fracture.

Associated Injuries

These fractures usually follow a significant fall, and associated fractures of the lumbar and thoracic spine may accompany these injuries.

Treatment

Symptomatic treatment with 4 to 6 weeks of bed rest is usually adequate. Elderly patients typically require active and passive motion exercises along with earlier mobilization. A pneumatic cushion for sitting is helpful during the later stages of healing.

Complications

Ischial body fractures may be complicated by malunion or excessive callus formation resulting in the development of chronic pain exacerbated by sitting or hamstring stress.

Iliac Wing (Duverney) Fracture

Mechanism of Injury

These fractures are usually the result of a medially directed force. A Duverney fracture may be due to a high-energy force and, therefore, may serve to alert the clinician to other injuries. The iliac wing may at times demonstrate medial displacement (Fig. 17–12).

Examination

The patient will complain of tenderness and swelling over the iliac wing. The abductors of the hip insert on the iliac wing and therefore pain will be exacerbated with walking or stressing of the hip abductors.

Imaging

An AP pelvic view is generally adequate in demonstrating this fracture. Oblique views may be indicated if the fracture is not clearly identified or if displacement is suspected. A CT scan can be obtained in equivocal cases (Fig. 17–13).

Associated Injuries

Although these fractures do not involve the pelvic ring, iliac wing fractures typically follow severe forces and may be accompanied by associated injuries including:

1. Acetabular fractures.

2. Gastrointestinal injuries. These are uncommon but may be delayed in their presentation.

3. Solid organ abdominal and thoracic injuries.

Treatment

Symptomatic treatment, including bed rest and nonweight bearing until the hip abductors are pain-free, is appropriate. Displaced fractures typically do not require reduction.

Complications

Iliac wing fractures are generally free of long-term complications.

Horizontal Sacral Fractures

Sacral fractures may be either horizontal or vertical. Vertical fractures are secondary to an indirect mechanism, transect the pelvic ring, and are commonly associated with an additional, sometimes occult, pelvic ring fracture. Vertical sacral fractures will be discussed elsewhere. The following discussion is limited to horizontal sacral fractures. Isolated horizontal (transverse) sacral fractures account for 2% to 3% of pelvis fractures (Fig. 17–14). Fractures above the level of S2 are less common than fractures below S2.

Mechanism of Injury

A direct blow over the posterior sacrum in an anterior direction is the usual mechanism. These fractures also occur following a fall with landing in the sitting position or a massive crush injury to the pelvis.

Examination

The patient will complain of tenderness, swelling, and ecchymosis over the sacral prominence. Rectal examination will elicit pain in the sacrum and displacement can be assessed with a bimanual rectal examination. Blood on the examiner’s glove following the digital rectal examination suggests an open fracture. Open fractures require emergent broad-spectrum antibiotics and surgical intervention. Neurologic function of the lower sacral nerves is assessed by noting anal sphincter tone, perineal sensation, and the bladder sphincter.

Imaging

Horizontal sacral fractures may be difficult to detect on routine pelvic radiographs. Horizontal fractures tend to occur distally to the SI joints. A malalignment or buckling of the sacral foramina may be indicative of a displaced sacral fracture. The outlet (AP cephalic) view is better for demonstrating displaced sacral fractures.²³ A CT scan is very helpful in delineating these fractures when plain films are not definitive.²⁴

Associated Injuries

Various series report a 4% to 14% incidence of associated pelvic fractures with horizontal sacral fractures. Fractures above S2 are associated with a greater incidence of neurologic dysfunction than fractures below S2.

Treatment

Nondisplaced horizontal sacral fractures are treated with bed rest for 4 to 5 weeks. An inflated cushion may be used later for sitting. Displaced horizontal fractures require emergent orthopedic referral because of the potential for neurologic injury. It is imperative that the initial examining physician performs a thorough neurologic examination of the patient.

Complications

Horizontal sacral fractures may be complicated by the development of chronic pain or nerve dysfunction secondary to callus formation.

Coccyx Fractures

Coccyx fractures tend to be transverse and, because numerous muscle fibers insert here, they are impossible to immobilize (Fig. 17–15). Coccyx fractures are among the easiest fractures to treat and yet the most difficult to cure.

Mechanism of Injury

A fall landing in the sitting position is the most common mechanism of injury. In addition, surgical procedures performed in this area may be complicated by the development of a coccyx fracture.

Examination

The patient will complain of tenderness localized to “one spot.” Use of the tensor levator ani or spasm of the anococcygeal muscle, as during sitting or defecation, will exacerbate the pain. Palpation rectally or externally over the coccyx is usually diagnostic. Similar to sacral fractures, rectal examination will elicit pain over the coccyx. Blood on the examiner’s glove following the digital rectal examination suggests an open fracture. Open fractures require emergent broad-spectrum antibiotics and surgical intervention.

Imaging

An AP pelvic view along with a lateral projection with the thighs in flexion is best for demonstrating these fractures. Coccygeal fractures are often not visualized radiographically.

Associated Injuries

Coccygeal fractures are not commonly associated with any other significant injuries.

Treatment

The treatment is symptomatic with bed rest, inflated cushions, sitz baths, and laxatives to avoid straining. Patients may suffer from debilitating pain that requires narcotic pain medications, nonsteroidal anti-inflammatory drugs (NSAIDs), and laxatives. The patient should be told to expect that the pain may persist for months before recovery. Coccygectomy may be indicated if chronic pain persists despite adequate conservative therapy.

Complications

Chronic pain may persist for several years after coccygeal fractures.

Pubic Rami Fractures (Nondisplaced)

This injury is the first of four stable (nondisplaced) fractures of the pelvic ring to be presented. Nondisplaced fractures of the superior and inferior pubic rami are very commonly seen and are very stable from an orthopedic standpoint (Fig. 17–16). A common mistake, however, is for the clinician to miss an occult injury to the SI joint in a patient with minimally displaced fractures of the pubic rami.

Mechanism of Injury

This fracture usually results from direct trauma to the area. If the fracture lines run horizontally, a lateral compressive force may be the mechanism of injury. Ipsilateral sacral compression may be present and would classify this fracture as an LC I injury based on the work of Burgess and Young (Table 17–1).¹⁹

Examination

The patient will present with tenderness, swelling, and ecchymosis over the fracture site. LC of the ring (Patrick’s test) will exacerbate the patient’s pain.

Imaging

A routine AP pelvic view is usually adequate in demonstrating the fracture. The ipsilateral SI joint must be inspected carefully for any evidence of disruption. CT scanning is recommended if an SI joint disruption is suspected.

Associated Injuries

Although these fractures are considered mechanically stable, they may still be associated with significant associated injuries. CT scanning is useful in evaluating patients with suspected visceral and/or vascular injuries.

Treatment

Early orthopedic consultation is recommended. These fractures are typically stable and treated symptomatically with bed rest for 3 weeks. Internal fixation of pubic rami fractures is necessary only when a posterior pelvis injury has occurred in combination.²⁵

Complications

These fractures may be complicated by the persistence of pain secondary to posttraumatic arthritis.

Pubic Bone Fracture (Nondisplaced)

This is rare as an isolated injury (Fig. 17–17).

Mechanism of Injury

A direct AP force is the usual mechanism, although indirect forces may add to the displacement.

Examination

The patient will present with tenderness, swelling, or even deformity over the involved area. Pain will be localized and exacerbated with anterior or LC of the pelvis.

Imaging

A routine pelvic view is usually adequate in demonstrating the fracture. Urologic imaging studies are indicated for patients with suspected urinary tract disruption.

Associated Injuries

Damage to the urologic system frequently accompanies these injuries.

Treatment

Although these are typically stable injuries, early orthopedic consultation is recommended. The treatment is symptomatic with bed rest in the lateral position and crutches for ambulation.

Complications

These injuries may be complicated by the development of persistent pain over the involved area.

Ilium Body Fracture (Nondisplaced)

Pelvic fractures in this category are isolated, nondisplaced ilium body fractures near the SI joint (Fig. 17–18). These fractures are rare. Typically, posterior pelvic fractures are associated with anterior ring fractures.

Mechanism of Injury

Ilium body fractures near the SI joint are usually the result of a direct force pushing the ilium posteriorly and medially.

Examination

The patient will present with tenderness over the posterior pelvis that is exacerbated with anterior or LC. Straight-leg raise is painful with this type of fracture.

Imaging

An AP pelvic view is usually adequate for visualizing these injuries. A CT or bone scan is often helpful in delineating these fractures where plain films are not conclusive.²⁴

Associated Injuries

These fractures are frequently associated with anterior pelvic fractures.

Treatment

Although these are typically stable fractures and treated symptomatically, early orthopedic consultation is recommended. Bed rest with a pelvic sling or belt is recommended. Ambulation, with crutches initially, should progress as tolerated with an expected return to normal function within 3 to 4 months.

Complications

These fractures may be complicated by the development of chronic back pain or neurologic compromise.

Vertical Sacral Fractures

Vertical sacral fractures usually begin at the weakest point of the bone that is adjacent to the first and second neural foramina (Fig. 17–19).

Mechanism of Injury

Vertical sacral fractures are the result of indirect trauma, as when an anterior force drives the pelvic ring posteriorly.

Examination

The patient will present with tenderness over the posterior pelvis that is exacerbated with anterior or LC. Straight-leg raise is painful with this type of fracture. Patients with this fracture should have a digital rectal examination. Blood on the examiner’s glove following the digital rectal examination suggests an open fracture.

Imaging

An AP pelvic view is usually adequate for both of these injuries. Sacral fractures may be better demonstrated on an AP cephalic tilt (outlet) view. A CT scan is helpful in delineating these fractures where plain films are not conclusive (Fig. 17–20).²⁴

Associated Injuries

These fractures are frequently associated with anterior pelvic fractures. Vertical sacral fractures have a high incidence of associated neurologic injury.

Denis et al.²⁶ classified sacral fractures by the location of injury. See “Associated Injuries” of pelvis fractures later in this chapter.

Treatment

Although these are typically stable fractures and treated symptomatically, early orthopedic consultation is recommended. Bed rest with a pelvic sling or belt is advised. These devices are commercially available at orthopedic supply companies. Ambulation with crutches for assistance should progress as tolerated with an expected return to normal function within 3 to 4 months. Open fractures require emergent broad-spectrum antibiotics and surgical intervention.

Complications

These fractures may be complicated by the development of chronic back pain or neurologic compromise.

Straddle Injury

Straddle fractures are the most common type of displaced pelvic fractures seen (Fig. 17–21). Nearly one-third of these fractures have an associated lower urinary tract injury.

Mechanism of Injury

The most common mechanism is a fall resulting in the straddling of a hard object. LC of the pelvis may result in a similar appearing fracture, but without the same incidence of associated GU injuries.

Examination

The patient will present with anterior tenderness, swelling, and ecchymosis. It is important to examine and palpate the perineum, rectum, scrotum, testes, and vagina for lacerations, bony deformities, and hematomas.

Imaging

An AP pelvic view is usually adequate in demonstrating the fracture (Fig. 17–22). CT scanning is valuable in determining the extent of the damage to the underlying tissues and organs as well as the SI joint. Radiographic imaging of the lower urinary tract is also recommended. Ultrasound may be needed to evaluate for testicular injury associated with straddle injuries.

Associated Injuries

As mentioned earlier, these injuries are associated with a high incidence of vascular and visceral injuries. Up to 33% have an associated lower urinary tract injury, the most common being a urethral rupture. It is therefore imperative that patients with these fractures undergo a radiographic examination of the lower urinary tract, particularly if there is blood at the urethral meatus.

Treatment

Emergent orthopedic consultation is recommended. The emergency management of these fractures includes immobilization and stabilization, including fluid therapy and the exclusion of serious associated injuries. The physician’s priority must be directed at the identification and stabilization of life-threatening–associated injuries. Operative fixation of the anterior pelvis is necessary after straddle injuries.

Complications

1. Posttraumatic arthritis.

2. Malunion or nonunion.

3. Pulmonary or fat emboli (early).

Burgess and Young

Unstable pelvic ring disruptions are classified on the basis of the system developed by Burgess and Young, because the acute management of the patient is best guided by this classification system. As stated earlier, this system helps predict fluid resuscitation requirements, associated skeletal and solid organ injury, the need for acute stabilization of the pelvis, and ultimately patient survival.^19–21 These fractures are therefore divided by the mechanism of injury into four subtypes: (1) lateral compression (LC), (2) anteroposterior compression (APC; open-book injury), (3) vertical shear (VS; Malgaigne fracture), and (4) a combined mechanism (CM) (Table 17–1).¹⁹

Lateral Compression Mechanism

These injuries are due to an LC force that results in an implosion of the pelvis. The anterior pelvic ligaments (anterior SI, sacrotuberous, and sacrospinous) are shortened in this mechanism rather than stretched. Because these ligaments remain intact, a tamponade effect is created if there is pelvic hemorrhage. Anterior injury is similar in all three subtypes and consists of transverse pubic rami fractures. Pubic rami fractures may occur ipsilaterally (most common), contralaterally, or bilaterally to the applied lateral force. The injury to the posterior structures of the pelvis distinguishes the three subtypes of the LC mechanism (Fig. 17–23).

Lateral Compression I (LC I)

The posterior component of an LC I injury is a sacral impaction fracture (Fig. 17–23A). This fracture is often misdiagnosed as isolated pubic rami fracture unless the posterior components are closely scrutinized (Fig. 17–24A). The posterior elements are demonstrated on an outlet view of the pelvis with close examination of the sacral foramina. CT scan is the most sensitive for detecting an LC I injury (Figs. 17–24B and 17–25). These fractures are generally stable to physical examination and are considered mechanically stable fractures with a low incidence of associated injuries.

Definitive treatment consists of protected weight bearing on the side of injury (crutches for support) and repeat radiographs in 2 to 5 days to ensure that no additional displacement has occurred. External fixation (in the nonacute setting) is required only in patients with debilitating pain due to fracture instability.

Lateral Compression II (LC II)

In the LC II injury, there are transverse pubic rami fractures with either an ipsilateral iliac wing fracture (crescent fracture) adjacent to the SI joint or ipsilateral SI joint disruption (Figs. 17–23B and 17–26). An LC II injury can be treated with bed rest and delayed open reduction and internal fixation unless hemodynamic instability necessitates the acute application of external fixation. The reader is referred to the “Associated Injuries” section of this chapter for further discussion.

Definitive treatment consists of both anterior and posterior stabilization. Either an external fixator or open reduction is used anteriorly, whereas open reduction with a plate or screw is required to stabilize the posterior injury.

Lateral Compression III (LC III)

In the LC III injury pattern, LC causes the contralateral hemipelvis to rotate externally (i.e., “open”) while the hemipelvis on the side of the impact rotates internally (Fig. 17–23C). Pubic rami fractures occur on the side of impact with or without an associated ipsilateral ilium fracture or SI joint disruption. An example of an LC III–type mechanism is a pelvis that is rolled over by an automobile. The initial LC that occurs results in an LC II injury, and, as the car wheel hits the contralateral pelvis, it applies an externally rotated force. An LC III injury is mechanically unstable and often necessitates acute application of an external fixator in hemodynamically unstable patients.¹⁹ The reader is referred to the “Associated Injuries” section later in the chapter for further discussion.

Definitive treatment consists of both anterior and posterior stabilization. Anterior stabilization is similar to LC II injuries. For the posterior injury, the contralateral open-book injury is reduced with percutaneous iliosacral screws. The ipsilateral posterior injury is treated on the basis of the injury present. LC I injury requires no treatment. LC II injury requires plate fixation for ilium fractures and percutaneous iliac screws for displaced sacral fractures.

Anteroposterior Compression Mechanism

These fractures are due to anterior compression of the pelvis. The anterior injury to the pelvis consists of a symphysis pubis diastasis or vertical pubic rami fractures. Anterior force may be due to a directly applied force, as in a crush injury, or indirectly via the lower extremities. The injury to the posterior pelvis defines the subtype (I, II, and III) (Fig. 17–27). APC II and III injuries are also known as open-book injuries or a sprung pelvis.

Anteroposterior Compression I (APC I)

This stable injury occurs following an AP force that results in symphysis pubis diastasis or vertical pubic rami fractures without posterior injury (Fig. 17–27A). This is a rare injury and results from low- to moderate-energy trauma. The anterior ligaments of the SI joint are stretched but not torn. The ligaments of the symphysis pubis normally allow for 0.5 to 1 cm of movement. Any separation beyond 1 cm is considered abnormal (Fig. 17–28A). Subluxation beyond 2.5 cm is associated with posterior ligamentous injury and should be considered unstable (APC II, III). Examination of APC I patients will result in little movement to external rotation forces. Third trimester and postpartum patients are susceptible to this injury because the hormonally induced ligamentous laxity allows for more mobility. Patients with APC I injuries suffer from a low incidence of associated injuries.

Definitive treatment is symptomatic with bed rest in the lateral position. Early orthopedic consultation is recommended. These injuries may be complicated by the development of persistent pain over the involved area.

Anteroposterior Compression II (APC II)

In the APC II injury, symphyseal diastasis is accompanied by disruption of the anterior SI ligamentous structures and the ligaments of the pelvic floor (sacrotuberous and sacrospinous) (Fig. 17–27B). The symphysis pubis diastasis is >2.5 cm and these injuries are considered open-book injuries (sprung pelvis) (Fig. 17–28B). APC II injuries are mechanically unstable to external and internal rotation, but do not demonstrate instability to vertical forces due to the intact posterior SI ligaments. APC II injuries are associated with a high rate of hemorrhage and neurologic injury and often require external fixation and arterial embolization in the acute setting. The reader is referred to the “Associated Injuries” section later in the chapter for further discussion.

Definitive treatment consists of plate fixation of symphysis pubis disruptions and external fixation or open reduction for pubic rami fractures. If external fixation is used, it is left in place for 8 weeks.

Anteroposterior Compression III (APC III)

APC III injuries consist of symphysis pubis dislocation and injury to the anterior and posterior SI ligaments (Fig. 17–27C). These fractures are very unstable, as the integrity of the pelvic ring has been abolished. APC III injuries are unstable to both vertical and rotational forces. The ligamentous injuries of the APC III mechanism are similar to VS injuries, except that the hemipelvis is not displaced superiorly. Associated injuries—vascular, visceral, and neurologic—frequently complicate the management of these fractures resulting in a high morbidity and mortality. It is imperative that the emergency physician aggressively evaluates all of these patients for the presence of accompanying life-threatening injuries. Like APC II injuries, external fixation is often necessary in the acute setting to control hemorrhage. Patients with this fracture pattern are more likely to require emergent arterial embolization. The reader is referred to the “Associated Injuries” section later in the chapter for further discussion.

Definitive treatment is similar to APC II injuries anteriorly, but also requires stabilization of the posterior injury. Stabilization of the posterior-ring injury is performed with percutaneous iliosacral screws.

Vertical Shear Mechanism

These fractures are distinguished by displacement of the anterior and posterior pelvis vertically and were originally described by Malgaigne (Fig. 17–29). Anteriorly, there is usually disruption of the symphysis pubis, although fracture through the pubic rami is a less common presentation. Posteriorly, the injury may occur through the ilium, sacrum, or SI joint. In some cases, there is a small avulsion fragment of the ilium that remains attached to the sacrum.

The classic mechanism for this injury is a fall from a height. If the patient lands on an extended lower extremity, the hemipelvis is displaced vertically upward. In a motor vehicle collision, the patient may suffer from this injury when an extended leg is superiorly displaced into the pelvis by the floor of the car.

The physician will note shortening of the lower extremity on the involved side. Shortening is due to cephalad displacement of the pelvic fragment. Careful measurements from the umbilicus to the anterosuperior iliac spine or the medial malleolus will demonstrate shortening on the involved side. Measurements from the anterosuperior iliac spine to the malleolus will be the same on both sides, thus excluding a femoral neck fracture. Sacral neurologic deficits may accompany these injuries and must be excluded early on the basis of examination. Visceral injuries frequently accompany these fractures and require a thorough physical and radiographic evaluation.

The emergency management of these fractures includes immobilization along with a rapid and thorough assessment for life-threatening–associated injuries. Patients with unstable pelvic fractures with hemodynamic instability despite appropriate fluid therapy should be considered candidates for emergent external fixation. Early external fixation may be a valuable option in reducing blood loss. Patients with VS injuries are more likely to require arterial embolization. The reader is referred to the “Associated Injuries” section later in the chapter for further discussion.

Definitive treatment depends on the location of the posterior injury. Fractures involving the SI joint or the sacrum require traction for reduction followed by percutaneous iliosacral screw fixation. Anterior stabilization with open reduction or external fixation is also required. The external fixator must be left in place for 12 weeks.

Combined Mechanism

These fractures are very unstable as the integrity of the pelvic ring has been abolished (Fig. 17–30). Associated injuries frequently complicate the management of these fractures resulting in a high morbidity and mortality.

As these injuries are frequently accompanied by other life-threatening injuries, they should be considered within the context of trauma management rather than as isolated fractures of the pelvis. Emergent orthopedic consultation is strongly recommended. The emergency management of these fractures includes immobilization along with a rapid and thorough assessment for life-threatening–associated injuries. Patients with unstable pelvic fractures with hemodynamic instability despite appropriate fluid therapy should be considered candidates for emergent external fixation. The reader is referred to the “Associated Injuries” section for further discussion.

Definitive treatment depends on the types of injury involved and is best guided by an experienced orthopedic surgeon.

Associated Injuries

The mortality rate from pelvic ring disruptions is high (10%–20%) and is a result of the high incidence of multisystem injury.^1,6,27–29 The clinician must consider these injuries in the overall context of the patient. Multiple associated injuries can occur due to the fracture fragments and their effect on adjacent anatomic structures. Early identification of patients with specific pelvic fracture patterns is useful because it predicts the type of associated injury.²¹ Pelvic fractures result in associated injuries that affect structures within the vasculature, genitourinary tract, neurologic system, and alimentary tract. Hemorrhage control is the primary concern in the initial stages of management.

Up to 4 L of blood can accumulate in the retroperitoneum after a significant pelvic fracture.¹⁰ Half of patients suffering from blunt pelvic fractures admitted to the hospital will require blood transfusions (mean volume 6–8 units).^5,19 With these facts in mind, it is not surprising that hemorrhagic shock is the major cause of death in patients with pelvic fractures. Characteristics of patients who are at risk for death from pelvic fractures include male gender, severe multiple trauma, and major hemorrhage.³⁰

However, the emergency physician assessing these patients must also consider other sources of hemorrhage. A large review established that the majority of patients suffering from hemorrhagic fatality after a pelvic fracture did not die as a result of pelvic hemorrhage.²⁷ Other sources of bleeding, such as the thorax and abdomen, must be evaluated.

The initial pelvic radiograph may be useful to predict significant pelvic hemorrhage. In hemodynamically unstable patients with mechanically stable LC I and APC I fracture patterns, ongoing hypotension was due to intra-abdominal hemorrhage in 85% of cases. In contrast, in patients with mechanically unstable LC II, LC III, APC II, APC III, and VS injuries, significant hemorrhage from the pelvis occurred in 60%.²¹ APC injuries have the largest transfusion requirement (15 units), whereas LC injuries required the smallest (4 units).¹⁹ Limitations include the potential difficulty in interpreting these initial films in patients who are often too unstable to undergo CT scanning.³¹

Other radiographic patterns that predict significant hemorrhage include double breaks in the pelvic ring and posterior fracture patterns. Fractures that involve a displaced double-ring break have a twofold increase in the incidence of bleeding requiring transfusion when compared with single-ring fractures. Posterior pelvic fractures are associated with more bleeding than are anterior fractures.

Direct surgical control and repair of bleeding vessels associated with pelvic fractures is not routinely indicated. Bleeding is venous in many cases and surgical exploration is often futile due to extensive collateral circulation. In addition, loss of a tamponade effect following incision into the retroperitoneum makes this option potentially harmful.¹⁰

Interventions that have proven useful to control pelvic bleeding include pelvic fixation and angiography. Decisions made regarding the need and appropriate timing of pelvic fixation, angiography, or laparotomy to repair intra-abdominal injury are the source of debate, may be institution-dependent, and are the subject of the following discussion (Table 17–4).

Unstable fractures may be treated with external fixation in an attempt to reduce the intrapelvic volume, tamponade bleeding by opposing bony structures, and prevent clot dislodgement by immobilizing bony fragments.^10,19 Mortality has been shown to decrease with its use.^32,33 In mechanically unstable fractures, acute application of an external fixator should be considered for APC II, APC III, LC III, and VS.¹⁰ The type of external fixator and its application should be determined by the orthopedic surgeon based on the specific fracture pattern (Fig. 17–31). Many orthopedists recommend fixator placement before emergency laparotomy whenever possible.³³ Pelvic fixators can be inserted in the ED under local anesthesia with minor skin incisions. Early external fixation of unstable pelvic fractures may be a valuable option in reducing blood loss.

Downsides of external fixator application in the critically injured patient include the time required to place the device, approximately 40 minutes, which may unnecessarily delay other important life-saving interventions. The other limitation of an external fixator is that it does not provide tremendous support to the posterior pelvis. In addition, some believe that an anteriorly applied external fixator may actually further distract a posterior injury.^34,35

Posterior-ring reduction clamps (C-clamps, pelvic clamps, Ganz clamps) are available but are more difficult to apply—generally requiring a skilled orthopedist and fluoroscopy to avoid misplacing the device (Fig. 17–32). These devices are effective in stabilizing the posterior pelvic ring by mechanically compressing the SI joints. Laparotomy is not interfered in a patient with the clamp.³⁶ Posterior-ring reduction clamps are most common in European centers.

Another simple method for obtaining temporary pelvic stabilization is application of either a commercially available pelvic binder or a sheet wrapped around the pelvis (Fig. 17–33).³⁷ Advantages of a circumferential pelvic antishock sheet (CPAS) include the fact that it is inexpensive, readily available, and no special training is required for application. Lower extremity and abdominal access is maintained after the sheet is placed. Caution is required in patients with LC pelvic ring injuries or sacral neuroforaminal fractures. Forceful or aggressive CPAS application could worsen visceral injury or sacral nerve root injury in these instances.

Angiography with embolization is another important option to halt arterial bleeding from pelvic fractures. Traditional teaching is that pelvic bleeding is due to an arterial source in approximately 10% of cases. However, in patients with pelvic fracture who are hemodynamically unstable and refractory to volume resuscitation, arterial bleeding is more likely than venous bleeding, and up to 80% of these patients will have a significant component of arterial bleeding amenable to embolization.^38–40 For that reason, angiography with arterial embolization is potentially lifesaving in such a patient and should be considered early.¹⁹ Hereto, the fracture pattern may also help indicate which patients might benefit from angiography. Twenty percent of patients with APC II, APC III, and VS injury patterns required embolization in Burgess et al.’s¹⁹ study, whereas only 2% of patients with an LC injury pattern benefited from embolization.³³

Before angiography, aggressive resuscitation and stabilization with a circumferential sheet should be performed. If the patient remains hypotensive, and no other source of bleeding is evident (chest, abdomen), then angiography is indicated.³³ In hypotensive patients without other sources of hemorrhage, angiography will reveal an arterial hemorrhage that can be embolized in 73% of patients.³⁸ In these patients, the emergency physician should not wait for placement of an external fixator if it delays angiography. In hemodynamically unstable patients with evidence of both pelvic and abdominal hemorrhage (positive pelvic radiograph and focused abdominal sonography in trauma examination), the traditional order of laparotomy and then angiography has been questioned. Angiography before laparotomy has potential advantages in being able to embolize abdominal arteries and in avoiding the increase in pelvic volume that comes with opening the abdomen.^16,31,41

Visceral injuries in conjunction with high-energy pelvic fractures are associated with a high mortality. The most common visceral injury is to the lower urinary tract, specifically, the urethra and bladder. Urethral injuries occur with an incidence of 4% to 14% after pelvic ring disruptions, whereas bladder injuries are present in 6% to 11%. Simultaneous bladder and urethral injuries occur in 0.5% to 2.5% of pelvic fractures.⁴²

The clinician should consider urinary tract injury after all pelvic fractures. Examination findings such as a difficult-to-palpate prostate (“high riding”), scrotal/perineal swelling, and blood at the urethral meatus are often absent in the early period after injury. For this reason, specific fracture patterns that are associated with a high likelihood of urinary tract injury should be sought. The incidence of lower urologic injury is most common after disruption of the anterior pelvic ring, especially bilateral pubic rami involvement (straddle injury).⁴² Urologic injuries occur in 15% of patients with unilateral pubic ramus fractures and increase to 40% in patients after bilateral ramus fractures (straddle injury).⁴³ Other fracture patterns associated with urinary tract injury include pubic symphysis subluxation (APC I), open-book injuries (APC II, APC III), VS fractures (Malgaigne), and pubic rami fractures with associated SI injury.⁴ Urethral injury is uncommon after an isolated posterior injury.⁸

The urethra is divided into posterior and anterior portions in the male. The posterior portion consists of the prostatic and membranous urethra, whereas the anterior portion consists of the bulbous and penile urethra. The area most susceptible to urethral injury after a pelvic fracture is the bulbomembranous junction. To understand why requires some knowledge of the surrounding anatomy. The prostate is fixed to the pubic bone via the puboprostatic ligaments. The prostate is similarly fixed to the urogenital diaphragm, which attaches to the membranous urethra. When injury to the pelvic ring occurs, the movement of the pubic bone displaces the prostate and creates a shearing force that partially or completely tears the urethra.⁴³

Female patients have a smaller incidence of urethral injuries (4.6%) due to the urethra’s shorter length and the fact that there is less surrounding structural support.⁴⁴ However, a meticulous examination should be performed in a female patient whenever blood is seen at the introitus.

All patients with physical examination findings suggesting a urethral injury should undergo a retrograde urethrogram prior to the passage of a Foley catheter. A Foley catheter inserted prematurely may convert a partial tear into a complete one. Because physical examination findings are unreliable, especially within the first hour after injury, male patients with anterior pelvic ring disruptions should undergo a retrograde urethrogram despite a negative examination.⁸

Using a bulb syringe or a Foley catheter inserted into the fossa navicularis, 30 to 40 cc of water-soluble contrast medium is injected into the urethra while a radiograph is obtained (Fig. 17–34A). If a Foley has been placed prematurely, the urethrogram can be obtained by using an angiocatheter inserted alongside the Foley. A complete tear is diagnosed by extravasation of contrast without filling of the bladder, whereas an incomplete tear is present with extravasation and partial filling of the bladder.⁴² Treatment remains controversial, but in general, small anterior urethral tears usually do not require surgical repair as they heal well over an indwelling Foley catheter. A complete tear and posterior urethral injuries are best treated surgically.

Bladder injury can involve an intraperitoneal or extraperitoneal rupture. In 93% of cases of bladder rupture, a pelvic fracture is present concomitantly. Extraperitoneal rupture of the bladder is due to a bony spicule lacerating the anterolateral portion of the bladder in one-third of cases.⁴² Another common mechanism of extraperitoneal rupture is compression of an empty bladder. Intraperitoneal rupture occurs through the weakest part of the bladder, the dome, when a force is applied to the full bladder. Gross hematuria will be present in 82% to 97% of patients with a bladder rupture, although this finding does not distinguish between injury of the upper and lower genitourinary tract.⁴²

Fractures that disrupt the pelvic ring require a retrograde cystogram following the urethrogram. A retrograde cystogram is performed by instilling 300 cc of water-soluble contrast medium, by gravity alone, into the bladder (Fig. 17–34B). Radiographic views in distention and post voiding should be examined carefully for any evidence of extravasation. False-negative cystograms may result if the bladder is not fully distended or postvoid films are not obtained. Retrograde CT cystograms are also an acceptable alternative for the workup of bladder rupture.⁴² Bladder ruptures are treated with operative repair.

Neurologic injuries are present in 20% of patients with unstable fractures of the pelvic ring. Neurologic injury is more common after SI injury, sacral fractures, or acetabular fractures. Sciatic nerve injury is present in 13% of patients with acetabular fractures.⁴

Over half of patients with neurologic injury due to pelvic fractures will suffer from both sensory and motor deficits. In one study, 50% of patients had a persistent neurologic deficit at 24 months post injury.⁴⁵ Following sacral fractures, nerves are damaged due to stretching, small bony fragments, or hematoma formation. These injuries are detected by a thorough neurologic examination, particularly of the L5, S1, and S2 nerve roots.

Denis classified sacral fractures by the location of injury (Fig. 17–35).²⁶ In patients with fractures through the sacral ala (zone I), the incidence of neurologic injury was 6%, with the most likely injury being partial injury to the L5 nerve root. Fractures through the sacral foramina (zone II) had a 28% incidence of neurologic injury. Zone II fractures were most commonly associated with injury to the ventral roots of L5, S1, or S2. Fractures medial to the sacral foramina or horizontal fractures (zone III) had the highest incidence of neurologic injury at 57%. These fractures were not only the most common, but also the most devastating as nearly 80% affected bowel, bladder, or sexual function. Horizontal sacral fractures above the S2 level are uncommon, but are associated with a much higher incidence of neurologic injuries than fractures below S2.⁴

Gastrointestinal injuries associated with fractures are typically seen with penetrating trauma or open fractures. If a lower gastrointestinal injury is suspected, endoscopy should be obtained.

Open pelvic fractures carry a mortality ranging from 25% to 50%. In the acute phase, death is most often due to hemorrhage, whereas sepsis is the cause of death in late cases. High-risk groups include those patients with involvement of the rectum or perineal area. In these patients, a diverting colostomy should be performed early.⁴⁶ Rectal involvement is present in one-fourth of patients. One-fourth of women will have an open fracture heralded by a vaginal laceration. Associated injuries are common, with one-third of patients suffering from genitourinary injury. Treatment principles include irrigation and debridement of the open wounds and colostomy when the rectum or perineum are involved.⁴⁷ Open pelvic fractures require the early administration of broad-spectrum antibiotics.

Complications

Pelvic fractures may be associated with many long-term complications.¹

1. Chronic SI arthritis presenting as constant low sacral pain may follow SI joint injury.

2. Malunion or delayed union.

3. Pulmonary and fat emboli (early).

4. Sepsis from a ruptured viscus.

5. Persistent neurologic deficits, especially following sacral fractures.

Acetabular Fractures

The acetabulum is divided into four segments—an anterior column and anterior rim (wall) and a posterior column and posterior rim (wall). Fractures of the acetabulum are classified on the basis of their involvement of these structures (Fig. 17–36). The anterior column extends from the iliac crest to the symphysis pubis and includes the anterior rim of the acetabulum. The posterior column starts at the sciatic notch and includes the posterior rim of the acetabulum and ischial tuberosity. The acetabular dome (roof) is the superior weight-bearing area of the acetabulum and includes portions of both the anterior and posterior columns. Transverse fractures of the acetabulum involve portions of the anterior and posterior columns.

The most common fracture pattern involves both columns. Isolated fractures of the posterior column are more common than the anterior column. Posterior rim fractures occur frequently with posterior hip dislocations. Displaced acetabular fractures are referred to as central fracture dislocations when the head of the femur becomes medially displaced into the pelvis (Fig. 17–37).

Acetabular fractures are classified, as described by Letournel and Judet, into simple fracture types and associated fracture types. Simple fracture types include transverse fractures or fractures isolated to a single column or rim. Associated fracture types are more complex and include T- or Y-shaped fractures as well as those fracture patterns that include more than one simple fracture. T-shaped fractures involve both the anterior and posterior columns and have a transverse component (Fig. 17–38). They account for approximately 5% to 10% of acetabular fractures.

Mechanism of Injury

Acetabular fractures are usually the result of high-energy trauma. The most common mechanism of injury is indirect, as with a medially directed blow to the greater trochanter. When this occurs, the femoral head acts as a hammer to fracture the acetabulum. If the femoral head is internally rotated at the time of the injury, a posterior column fracture is produced. Likewise, external rotation of the femoral head causes an anterior column fracture, adduction results in a superior dome fracture, and abduction causes the inferior acetabulum to be injured. This mechanism is commonly seen when a pedestrian is struck by a car.

Another indirect mechanism of injury is by the axial transmission of a force from a blow to the knees transmitted to the femoral head and the acetabulum. This mechanism is encountered frequently in drivers or passengers of cars involved in collisions. The result is often a transverse acetabular fracture or, less commonly, a posterior column fracture.

Examination

The patient will present with pain and tenderness, which increases with attempts at weight bearing. Patients with central acetabular fractures may have ipsilateral leg shortening if associated with displacement or dislocation. Patients with acetabular fractures may have accompanying vascular, visceral, or neurologic injuries. A thorough examination and evaluation for accompanying injuries is strongly recommended.

Imaging

Acetabular fractures may be difficult to detect on the initial AP pelvic radiograph. It is essential that the normal anatomic landmarks surrounding the acetabulum be carefully scrutinized when these injuries are suspected (Fig. 17–39).⁴⁸ Disruption of any of these lines suggests a fracture to the corresponding portion of the acetabular bone as below:

• Iliopubic (iliopectineal) line. Fracture of the anterior column.

• Ilioischial line. This line represents the medial border of the posterior column with any disruption corresponding to fracture of the posterior column.

• Posterior lip. Fracture of the posterior rim. The posterior lip is larger and projects more laterally than the anterior lip.

• Anterior lip. This line runs contiguous with the inferior border of the superior pubic rami. Disruption represents fracture of the anterior rim.

• Teardrop. This “U”-shaped shadow represents the anterior margin of the acetabular notch. It is contiguous with the ilioischial line and any separation of these structures represents either rotation of the hemipelvis or a fracture of the posterior column.

• Roof of the acetabulum. Fracture of the superior acetabulum.

In some cases, an acetabular fracture will be obvious on the AP radiograph (Fig. 17–40). If an acetabular fracture is suspected, but not evident on AP views of the pelvis or hip, oblique (Judet) views and a CT scan should be obtained. The posterior column and the anterior rim are best visualized on a 45-degree external oblique view, whereas the posterior rim and the anterior column are projected best on the 45-degree internal oblique view. Central acetabular fractures are best visualized on a posterior oblique radiograph. Certain pelvic fractures are frequently associated with acetabular fractures that may not be easily visualized radiographically. Eighty percent of intra-articular fragments in the hip joint are not seen on plain film radiography.¹⁴ CT scanning is recommended in all suspected acetabular injuries and has supplanted specialized plain radiographs in most cases. CT scanning, frequently with 3D reconstructions, can be especially helpful in detecting intra-articular bone fragments and for the planning of operative management (Figs. 17–41 and 17–42).

Associated Injuries

Acetabular fractures may be associated with the vascular, visceral, and neurologic complications. In addition, acetabular fractures may be associated with fractures of the femur, femoral head, pubic rami, and the ipsilateral extremity. Posterior hip dislocations are frequently associated with displaced posterior rim fractures, while anterior hip dislocations are associated with anterior rim fractures. Sciatic nerve injuries occur in 10% to 13% of acetabular fractures.⁴⁹

Treatment

Emergent orthopedic referral is recommended, especially in the setting of a hip dislocation. The emergency management of these fractures includes immobilization of the extremity and a thorough evaluation for accompanying vascular, visceral, or neurologic injuries.

Early normalization of the femoral acetabular relationship is the treatment goal. Surgery is indicated if the femoral head is subluxated out of traction. Open reduction with internal fixation is also recommended for displaced fractures >2 mm.⁵⁰ Fractures with impaction of the femoral head are associated with a worse outcome.

Nonoperative treatment of acetabular fractures ranges from traction to full weight-bearing status. For nondisplaced fractures involving the weight-bearing dome, closed treatment with traction to prevent further displacement is required (Fig. 17–43). If the weight-bearing dome is not involved, the patient is allowed to bear weight as tolerated.

Complications

The management of acetabular fractures may be complicated by the development of several disorders.

1. Osteoarthritis commonly follows even the smallest fractures.

2. Traumatic arthritis is commonly noted, especially after displaced central fracture dislocations.

3. Avascular necrosis may occur up to a year after the injury.⁴⁹ The incidence is dependent on the fracture type and the reduction time. Central acetabular fracture dislocations, which were reduced early, had an avascular necrosis incidence of 15%. If reduction was delayed, there was an incidence of 48%.⁵¹ Other authors report no cases of aseptic necrosis after central acetabular fracture dislocations.⁶

4. Sciatic nerve injury may complicate the management of these injuries, especially central displaced fractures.

Contusions

Buttocks

Contusions are a common injury to the buttocks resulting from a direct blow, such as during a fall. The buttocks are protected by a large amount of fatty tissue, and contusion of the gluteus maximus requires a significant force. The patient will complain of pain on sitting and on ambulation, and the examiner will note tenderness to palpation. Other conditions resulting from blunt force to the buttocks include periostitis of the ischial tuberosity, contusion of the ischial tuberosity, and fractures of the tuberosity. These conditions can be differentiated by appropriate x-rays and clinical evaluation. In the patient with periostitis of the ischial tuberosity, the examiner will note exquisite pain over the tuberosity with very little discomfort elsewhere.

The treatment of contusions to the buttocks is symptomatic, with ice packs and rest in a prone position. A pillow or a cushion affords relief from the discomfort until the condition improves. In the patient with periostitis of the ischial tuberosity, injection of the tuberosity with bupivacaine affords good relief. In addition, the patient should be discharged with instructions to use a cushion until the condition clears, as well as appropriate analgesics and ice packs during the first 24 to 48 hours.

Sacrum and the Coccyx

A contusion is a common injury and is due to a direct blow over the sacrum or the coccyx. Owing to the subcutaneous nature of these bones, contusions may be extremely painful, and the patient usually complains of a sharp, localized area of pain that may be quite disabling. On examination, one finds a well-localized area of tenderness over the sacrum or the coccyx with little discomfort elsewhere. Appropriate radiographs should be ordered to exclude fractures.

Although other authors have stated that this condition is not disabling, we have found that it tends to be extremely disabling to the patient. Contusions of the coccyx can lead to a condition called coccydynia, which has a poor prognosis and for which there is little in the way of adequate treatment. The emergency treatment of contusions of the sacrum and the coccyx includes the early application of cold compresses and the dispensing of a “doughnut” seat and appropriate analgesics, along with referral for follow-up care. Because of the guarded prognosis in contusions of the coccyx, we believe that all contusions of this bone should be referred for follow-up care.

Perineum

Contusions of the perineum are uncommon and result from direct blows such as during a fall on a hard object. On examination, the patient will have a painful, ecchymotic and swollen perineum and may have a painful hematoma. Any patient with a large hematoma in the perineum warrants a urethrogram to exclude urethral injury. The treatment is cold compresses for the first 48 hours followed by warm sitz baths.

Iliac Crest

The most common injury to occur at the iliac crest is a contusion. Contusions of the iliac crest have been called “hip pointers.”^52,53 This diagnosis should not be made without considering an intra-abdominal injury. Periostitis of the iliac crest results from a contusion of the bone and usually poses no problem in diagnosis and treatment. On examination, the patient presents with tenderness localized to any region along the iliac crest from the anterosuperior spine to the posterosuperior spine. Treatment of the condition is symptomatic.

Sacroiliac Ligament Sprain

This is an uncommon traumatic injury; however, missing its diagnosis in the ED can lead to inappropriate treatment for a herniated disk. The SI articulation is the strongest joint in the body, which is rarely injured. When injury does occur, the patient complains of pain localized to the region of the SI joint and referral to the groin and the posterior aspect of the thigh. The mechanism of injury involves wide abduction of the thighs or extremes of hyperextension or hyperflexion.^54,55 The best maneuver to diagnose this condition is to have the patient lie on their side and compress downward over their iliac crest. This action compresses the SI joint and will cause pain when there is a SI joint sprain. Alternatively, wide abduction of the supine patient’s elevated extended legs will elicit pain over the injured iliosacral or lumbosacral ligaments.

Localized injection of the joint with bupivacaine, analgesics, hot packs, and bed rest are usually all that is needed. If symptoms persist, referral is indicated. For more information about SI joint disease, refer to Chapter 8.

Hamstring Attachment Strain

This condition results from forcible flexion of the hip while the knee is extended. In the adolescent, when the epiphysis is not closed, avulsion of the tuberosity with wide separation of the epiphysis can occur. On examination, the patient will present with tenderness over the attachment to the bone with little swelling. A history compatible with the aforementioned mechanism accompanied by pain increased with passive flexion of the hip with the knee extended or active extension of the hip against resistance will help make the diagnosis. X-rays should be obtained to exclude an avulsion fracture.

With incomplete avulsion, treatment consists of splinting the knee in a flexed position to relieve the pressure on the ischial attachment of the tendons. Discharge the patient with crutches for 3 weeks. Active flexion of the thigh should be avoided. In cases where complete avulsion is suspected, the patient should be referred for evaluation of the need for surgical repair.

Sciatic Nerve Compression

Sciatica is most commonly thought to be secondary to a herniated nucleus pulposus within the lumbosacral spine. Other causes include posterior facet syndrome, central spinal stenosis, or direct sciatic nerve compression by tumor, aneurysm, or hematoma.⁵⁶ This condition is also seen in patients who undergo anesthesia and are recumbent for a prolonged period of time or bedridden. In patients with the piriformis syndrome, trauma to the piriformis muscle results in hematoma formation and subsequent scarring that causes mechanical irritation of the anatomically adjacent sciatic nerve (Fig. 17–44).⁵⁷

Piriformis syndrome accounts for 0.5% to 5% of cases of sciatica.⁵⁶ Patients with piriformis syndrome will suffer with the classic symptoms of sciatica, including pain in the buttock and posterior thigh. There is intolerance to sitting and pain with flexion, adduction, and internal rotation of the hip. Tenderness to palpation of the greater sciatic notch is often noted. Functional loss of the piriformis is present, but this does not affect strength because three stronger, short external rotators of the hip exist. The diagnosis of sciatic nerve compression at the level of the piriformis can be confirmed by electrodiagnostic tests.⁵⁸

Conservative therapy includes NSAIDs, physical therapy, ultrasound, or lidocaine injection.⁵⁶ Sectioning of the piriformis muscle at its tendinous origin releases the fibrous band and is curative if conservative measures fail. Release of the piriformis muscle can be successfully performed through a minimally invasive arthroscopic procedure.⁵⁹

Pudendal Nerve Palsy

Pudendal nerve palsy is caused by a compression neuropathy due to forces applied to the perineal region. This is usually a condition that occurs postoperatively following an intramedullary nailing of the femur; however, it can be seen posttraumatically.⁶⁰ Numbness of the penis and scrotum along with erectile dysfunction is present. The sensory terminal branches of the pudendal nerve are more susceptible to this palsy postoperatively than the motor branches.

Gluteal Compartment Syndrome

Gluteal compartment syndrome is an extremely rare condition; however, it is one the emergency physician must be aware of because its consequences may be quite serious.⁶¹ The syndrome may result after prolonged immobility, often following drug and alcohol abuse, blunt trauma, or operative positioning.^62–64 This syndrome has also been reported after bone marrow biopsy and may also be misdiagnosed as deep venous thrombosis.^65,66

The gluteal muscles behave as if they were divided into three separate compartments: the (1) tensor fascia lata compartment; the (2) gluteus medius–minimus compartment; and the (3) gluteus maximus compartment. After severe contusions to the buttocks, as would occur during a fall from a height, the patient may present to the ED with tensely swollen buttocks and increasing pain that, over the ensuing 4 to 6 hours, may result in necrosis of the muscles.⁶¹ Patients complain of pain in the buttocks with hip movement, especially in flexion and adduction.^67,68 In addition, because of the inverse relationship between peripheral nerve conduction block and intracompartmental pressure, the high pressures may cause sciatic neuropathy.^61,64,69

Patients who have a history and examination compatible with this syndrome should be admitted and receive consultation from an orthopedic surgeon. A fasciotomy is performed if the pressure within the compartment is 30 mm Hg or more for a duration of 6 to 8 hours.⁷⁰ For further discussion of the compartment syndromes, the reader is referred to Chapter 4.

External Oblique Aponeurosis Rupture

This uncommon condition results from forceful contraction of the abdominal muscles while the trunk is rapidly pushed to the contralateral side. The patient presents with very severe pain over the iliac crest and characteristically walks into the ED in a stooped-over posture from which he/she cannot straighten out due to pain. Examination discloses exquisite tenderness along the entire iliac crest and, in the early stages, one may feel a palpable defect if a large rupture has occurred (Fig. 17–45).^54,55 In mild cases, only tenderness is noted to palpation. Contraction of the involved muscle elicits significant pain that aids in making the diagnosis and distinguishes it from contusion of the iliac crest. The patient will also complain of pain at the involved iliac crest on flexion to the opposite side.

Treatment for incomplete avulsions of the muscle includes ice for the first 24 to 48 hours followed by heat, analgesics, and rest. Some physicians have used strapping and taping; however, this has not proved to be entirely beneficial and is not used in the acute stage of this injury. When extensive tears of the aponeurosis exist and a hematoma is present, consultation should be obtained from the orthopedic surgeon.