eMedicine Specialties > Orthopedic Surgery > Hip

Pelvic Fractures

Author: George V Russell, Jr, MD, Assistant Professor, Department of Orthopedic Surgery and Rehabilitation, University of Mississippi Medical Center
Coauthor(s): Christopher A Jarrett, MD, Fellow in Adult Reconstruction, Department of Orthopedic Surgery, Lenox Hill Hospital; ML Chip Routt, Jr, MD, Professor, Department of Orthopedics, University of Washington School of Medicine; Consulting Surgeon, Department of Orthopedic Surgery, Harborview Medical Center, University of Washington Medical Center
Contributor Information and Disclosures

Updated: Mar 23, 2009

Introduction

History of the Procedure

Pelvic fractures historically have been treated nonoperatively. The earliest management of pelvic fractures consisted of prolonged recumbency followed by mobilization as fracture healing occurred and symptoms abated. Other methods also used to treat pelvic fractures included closed reduction under general anesthesia, traction, spica casts, pelvic slings, and turnbuckles.^1,2,3,4

Operative management of unstable pelvic injuries has increased because of several factors:

• Improved and coordinated treatment of polytraumatized patients
• Improved anesthetic techniques, including blood salvage systems
• Advances in intraoperative fluoroscopic imaging techniques
• Standardized pelvic implant systems
• Better understanding of injury and deformity patterns

Operative management of unstable pelvic ring injuries allows earlier patient mobilization, thereby decreasing complications associated with recumbency. Operative management also allows correction and prevention of significant pelvic deformities, improving clinical outcomes.⁵

Problem

Unstable pelvic fractures typically occur as a result of high-energy injuries. Associated organ system injuries are observed commonly with pelvic fractures because of the energy imparted to the patient. Head, chest, and abdominal injuries frequently occur in association with pelvic fractures. Fractures of the extremities and spinal column also can occur in patients with pelvic fractures.

Hemorrhage may accompany pelvic fractures. Most hemorrhage associated with pelvic fractures occurs as a result of bleeding from exposed fractures, soft-tissue injury, and local venous bleeding.⁶ Arterial injuries also may contribute to hemorrhage with pelvic fractures, albeit less commonly than venous bleeding.⁷

Unstable and displaced pelvic ring disruptions cause significant deformity, pain, and disability. Deformities resulting from pelvic ring injuries include any combination of rotational and translational deformities. Significant permanent (sustained) pelvic deformities have been identified in poorer patient outcomes and decreased activity levels.^8,9,10

Frequency

The incidence of pelvic fractures in the United States has been estimated to be 37 cases per 100,000 person-years. The incidence of pelvic fractures is greatest in people aged 15-28 years. In persons younger than 35 years, males sustain more pelvic fractures than females; in persons older than 35 years, women sustain more pelvic fractures than men.¹¹ Most pelvic fractures that occur in younger patients result from high-energy mechanisms, whereas pelvic fractures sustained in the elderly population occur from minimal trauma, such as a low fall.¹¹

Etiology

Pelvic fractures occur after both low-energy and high-energy events. Low-energy pelvic fractures occur commonly in 2 distinct age groups: adolescents and the elderly. Adolescents typically present with avulsion fractures of the superior or inferior iliac spines or with apophyseal avulsion fractures of the iliac wing or ischial tuberosity resulting from an athletic injury. Low-energy pelvic fractures in the elderly frequently result from falls while ambulating, which are highlighted by stable fractures of the pelvic ring. Elderly patients also may present with insufficiency fractures, typically of the sacrum and anterior pelvic ring.¹²

High-energy pelvic fractures most commonly occur after motor vehicle crashes. Other mechanisms of high-energy pelvic fractures include motorcycle crashes, motor vehicles striking pedestrians, and falls.

Presentation

ATLS

Because most unstable and displaced pelvic ring fractures occur as the result of high-energy mechanisms, many patients present with associated primary organ system injuries. A careful assessment of the patient must begin with an examination for immediately life-threatening injuries. Assessment should begin in an orderly fashion to avoid missing injuries. The American College of Surgeons has popularized Advanced Trauma Life Support (ATLS), a program that provides a systematic and orderly treatment protocol for traumatized patients under the direction of a general surgeon or trauma surgeon.¹³ This protocol has been used successfully at many trauma centers and is recommended by the authors.

Hilty et al performed a retrospective analysis of 68 polytraumatized patients to determine whether radiographs and CT were both necessary to definitively diagnose pelvic fracture or whether CT alone would be sufficient. They found that in hemodynamically stable patients with a clinically stable pelvis, radiographs had only a 67% sensitivity and could be safely omitted as long as CT is planned and available.¹⁴

Soft-tissue injuries

Soft-tissue injuries provide an indirect measurement of the energy sustained by the patient. Scrotal, labial, flank, and inguinal hematomas commonly accompany pelvic ring injuries and are indicative of intrapelvic hemorrhage.¹⁵ Soft-tissue injury is observed along a continuum from superficial abrasions and lacerations, to closed internal degloving injuries, to open wounds.¹⁶ Lacerations of the perineum must be sought carefully during the initial physical examinations and secondary surveys. Rectal and vaginal lacerations may be overlooked because initial examinations concentrate on more obvious injuries. Rectal, vaginal, and perineal lacerations are indicative of severe injuries and indicate likely fracture contamination by urine, stool, and other environmental contaminants.

Manual palpation

Manual palpation of the pelvis should be included in assessing patients with pelvic ring injuries. Palpation must be undertaken carefully to avoid harming the patient. Manual palpation can reveal crepitus from fractures and can assist with determination of pelvic stability. Manual compression along the iliac crests provides a tactile assessment of pelvic ring stability. Contralateral push-pull examinations of the lower extremities are rarely necessary to identify instability.

Urethral injuries

Blood at the external urethral meatus is indicative of urethral disruption. Perineal and genital swelling also reflect urethral disruption. Digital rectal examination may reveal a high-riding prostate gland in the male, which also suggests urethral disruption. Bladder disruptions occur frequently with pelvic fractures and may be intraperitoneal, extraperitoneal, or both. Gross hematuria is the most common clinical finding supporting a diagnosis of a bladder disruption.¹⁷ Gross hematuria demands evaluation of the lower genitourinary (GU) system under the direction of a urologist.

Associated skeletal injuries

Axial and appendicular skeletal injuries are frequently associated with pelvic ring fractures. Careful examination of the spine and extremities is indicated as part of complete patient evaluation. Particular attention to the lower extremities may demonstrate limb length discrepancies associated with superior hemipelvic translations. Internal and/or external rotational deformities resulting from deformities of the pelvis may be noted by similar deformities in the lower extremities.

Associated neurovascular injuries

Injuries to the pelvic ring may cause injury to any of the neurovascular structures that traverse the pelvis. Vascular injuries are usually lacerations of venous structures.⁶ Arterial injuries also occur, but much less frequently than venous injuries.⁷ Despite the source of bleeding, venous or arterial, each may contribute to hemorrhage and demand emergent or urgent management.

Associated neurologic injuries

Neurologic injuries typically occur as injuries to the L5 or S1 nerve roots.^6,18 L4 nerve root injuries also may occur with severe pelvic ring injuries. Sacral fractures frequently accompany pelvic ring fractures and may have S2-S5 sacral nerve root injuries. Lower sacral nerve root injuries may lead to bowel and bladder incontinence and sexual dysfunction. Detection of these nerve injuries is difficult acutely, but careful examination may demonstrate perineal numbness and decreased rectal tone in the acute period.

Indications

Management of pelvic fractures in the immediate setting is centered on controlling life-threatening injuries, particularly severe hemorrhage. Several techniques have been used to control hemorrhage. These techniques are based on decreasing the volume of the pelvis, thereby limiting the amount of blood that can escape into the pelvic cavity.

A study by Sharma et al focused on risk assessment for mortality associated with pelvic fracture. The study included 566 patients with pelvic fracture, categorized on arrival to a level I trauma center as high risk or low risk on the basis of blood pressure, examination, radiographs, and CT. High risk was defined as open fractures, open-book injuries, 4 or greater abbreviated injury score, and hypotension (89 mm Hg or less systolic pressure). Mortality for high-risk pelvic fracture was 24% (25 of 103 cases); for low-risk pelvic fracture, mortality was 3% (13 of 454 cases). The investigators concluded that the assessment of mortality risk in patients with pelvic fracture can be aided by trauma mechanism, initial blood pressure measurement, radiography, and CT scanning.¹⁹
 

Pelvic volume

Perhaps the simplest method to decrease pelvic volume is to wrap a sheet securely around the patient's pelvis. External fixators and other external pelvic clamps have been advocated to control pelvic volume, with the added benefit of providing bony stability, thereby preventing fracture movement and dislodgment of clots.²⁰ Pneumatic antishock garments also have been used to control hemorrhage associated with pelvic fractures. Care must be taken when using pneumatic antishock garments, as they increase intramuscular and intrathoracic pressure, potentially leading to compartment syndrome and respiratory compromise distress. Pneumatic antishock garments are contraindicated in patients with pulmonary edema and/or diaphragmatic rupture.¹³

Early fixation

The primary goal for the treatment of pelvic fractures in the acute setting is to provide early stable fixation to allow patient mobilization. Several studies of early pelvic fracture treatment have demonstrated beneficial effects, such as decreased blood transfusion requirements, decreased systemic complications, decreased hospital stays, and improved patient survival.^21,22 Secondary considerations for operative management of pelvic fractures in the acute setting are the correction or prevention of significant pelvic translational and rotational deformities that have been associated with poorer clinical outcomes.^9,20,23

Classification

Several classification systems have been developed to assist with injury-pattern recognition and management decisions; perhaps the best known are those described by Tile and by Burgess et al.^24,25 Both of these classification schemes provide recommendations for management of pelvic fractures based on the function of the posterior ligamentous structures that support the pelvic ring. Others prefer to describe injuries based on the anatomic location of the pelvic ring injuries and the associated displacements and instabilities.²⁶

Pennal and Tile developed a classification scheme for pelvic fractures that describes injuries to the pelvic ring based on the vector of the deforming force and divides these into lateral compression (LC) injuries, anteroposterior compression (APC) injuries, and vertical shear injuries.²⁷ Tile further modified this classification scheme to include radiographic signs of pelvic stability or instability. Type A injuries are classified as those that are rotationally and vertically stable. Type B injuries are categorized as those injuries that are rotationally unstable but vertically stable. Type C injuries are rotationally and vertically unstable.²⁴

The Tile classification scheme for pelvic fractures is as follows²⁴ :

• Type A - Rotationally and vertically stable
  • A1 - Avulsion fractures
  • A2 - Stable iliac wing fractures or minimally displaced pelvic ring fractures
  • A3 - Transverse sacral or coccyx fractures
• Type B - Rotationally unstable and vertically stable
  • B1 - Open-book injuries
  • B2 - LC injuries
  • B3 - Bilateral type B injuries
• Type C - Rotationally unstable and vertically unstable
  • C1 - Unilateral injury
  • C2 - Bilateral injuries in which one side is a type B injury and the contralateral side is a type C injury
  • C3 - Bilateral injury in which both sides are type C injuries

Young and Burgess further expanded the classification of Tile by adding a combined mechanism category in recognition that many pelvic fractures result from a combination of vectors. Their classification divided LC and APC fractures into subgroups I, II, and III, which are based on the amount of disruption found on anteroposterior (AP), inlet, and outlet pelvic radiographs. This classification facilitates stratification of the amount of energy imparted to the patient.^25,28 This classification also has been demonstrated to be predictive of associated injury patterns based on the type of pelvic ring deformity.²⁹

Vertical shear fractures

Vertical shear fractures are characterized by vertical rami fractures or a diastasis of the symphysis pubis anteriorly and vertical displacement of the posterior pelvic ring through the sacroiliac (SI) joint, sacrum, or ilium. Combined mechanism fractures are characterized by a combination of the above-mentioned injury patterns.

Relevant Anatomy

The pelvic ring consists of 2 innominate bones connected anteriorly at the symphysis pubis and posteriorly to the sacrum at the SI joints. Anatomically, the pelvis is divided into the false pelvis and the true pelvis. The false pelvis is defined as that portion of the pelvis from the iliac crests superiorly to the pelvic brim inferiorly. The true pelvis is defined from the pelvic brim inferiorly to the pelvic floor.

Pelvic ligaments

The bones of the pelvis are held together by strong ligaments that can be divided into 4 groups: those connecting the sacrum and ilium; those connecting the sacrum and ischium; those connecting the 2 pubic bones at the symphysis pubis, and those uniting the sacrum and coccyx.²⁸ The anterior and posterior SI ligaments link the iliac bones to the sacrum. Two distinct bands demarcate the posterior SI ligaments. The short posterior interosseus ligaments consist of fibers running from the ridge of the sacrum to the posterior superior and posterior inferior iliac spines. The long posterior SI ligament consists of fibers originating from the posterior superior iliac spine, which then intermingle with originating fibers of the sacrotuberous ligament, covering the short posterior SI ligament and attaching to the lateral sacrum. The anterior SI ligaments consist of fibrous bands that join the anterior surface of the sacrum to the adjacent anterior ilium.²⁸

The sacrospinous and sacrotuberous ligaments connect the sacrum to the ischium. The sacrospinous ligament, originating from the lateral margin of the inferior sacrum and attaching at the ischial spine, assists in resisting external rotation forces of the pelvis.²⁴ The sacrotuberous ligament has a broad origin from the posterior superior and posterior inferior iliac spines and the entire lateral margin of the posterior sacrum. The sacrotuberous ligament courses posteriorly to the sacrospinous ligament, inserting on the ischial tuberosity. The sacrotuberous ligament resists sagittal plane rotational deformities and vertical shearing of the pelvis.²⁴

The symphysis pubis is a movable, articular joint without a synovial membrane. An interpubic disk, the superior pubic ligaments, and the arcuate ligaments inferiorly connect the pubic bones. The remainder of the ligaments that surround the pelvis are ligaments that do not have significant stabilizing roles for the pelvis, including ligaments connecting the sacrum and coccyx, the lateral lumbosacral ligaments originating at the L5 transverse processes and attaching to the sacral ala, and the iliolumbar ligaments, running from the L5 transverse processes to the iliac crests.²⁴

The pelvis acts to connect the axial skeleton with the appendicular skeleton of the lower extremities and, in this role, serves as a conduit for neurovascular structures.

• Vascular structures: The common iliac blood vessels enter into the false pelvis, in which the division into the external and internal iliac vessels occurs. The external iliac vessels continue through the false pelvis atop the pubic rami medial to the iliopectineal eminence. The internal iliac vessels dive into the pelvis, in which they divide into somatic branches, visceral branches, and limb and perineal branches. Other vessels of the pelvis include the terminal branch of the aorta, the median sacral artery, and the superior rectal artery, a continuation of the inferior mesenteric artery.²⁸
  • Somatic segmental branches are as follows²⁸ :
    • Iliolumbar
    • Lateral sacral
  • Visceral branches are as follows:
    • Umbilical
    • Inferior vesicle
    • Superior vesicle
    • Middle rectal
  • Limb and perineal branches are as follows:
    • Superior gluteal
    • Inferior gluteal
    • Internal pudendal
    • Obturator
• Neurologic structures
  • The neurologic contents of the pelvis collectively have been referred to as the lumbosacral plexus. This consists of what are individually known as the lumbar plexus and the sacral plexus. Anatomically, the lumbar plexus is an abdominal structure whose branches enter the pelvis. Conversely, the sacral plexus is entirely pelvic in origin. The lumbar plexus consists of nerve roots from L1-L4. The sacral plexus consists of those more caudal nerve roots. Each plexus can be divided into ventral and dorsal branches. The larger nerves of the pelvis originate from the sacral plexus.
  • The most cephalic of the nerves of the pelvis are the ilioinguinal and iliohypogastric nerves. These originate from the L1 nerve root. Both enter the pelvis on the surface of the psoas muscle, which they cross obliquely as they travel distally. They penetrate the abdominal wall muscles to serve as cutaneous innervation of the areas surrounding the pelvis. The iliohypogastric nerve supplies the skin of the posterolateral buttock, while the ilioinguinal nerve supplies the root of the penis and scrotum.²⁸
  • The lumber plexus can be divided into nerves consisting of dorsal or ventral branches. The psoas muscle anatomically separates these nerves. The femoral and lateral femoral cutaneous nerves are the primary dorsal branches of the lumbar plexus. The femoral nerve (L2, 3, 4) lies lateral to the psoas between the psoas and the iliacus muscles as it enters the pelvis over the iliac wing.²⁸ It innervates the iliacus muscle then exits the pelvis beneath the inguinal ligament to supply both motor as well as sensory fibers to the anterior compartment of the thigh.³⁰ The lateral femoral cutaneous nerve also emerges lateral to the psoas. It travels over the iliacus and becomes superficial to supply sensation to the lateral thigh.²⁸
  • The ventral branches of the lumbar plexus are represented in the obturator nerve (L2, 3, 4). The obturator nerve appears medial to the psoas just above the pelvis, it then enters the pelvis, with the vertebral column on its medial side and the psoas lateral to it. The obturator nerve travels with the internal iliac vessels and the ureter on the lateral pelvic wall. Coursing along the surface of the obturator internus muscle, the obturator nerve then leaves the pelvis through the obturator canal.²⁸ Its main function is to provide motor innervation to the adductors of the thigh.³⁰
  • The branches of the sacral plexus originate in the pelvis, in which the sacral plexus lies anterior to the piriformis muscle. The nerves of the plexus can be divided into ventral and dorsal branches, all of which exit the pelvis through the greater sciatic foramen notch. All branches pass below the piriformis muscle, except the superior gluteal nerve (L4, 5, S1), which exits above the piriformis.²⁸ The dorsal branches of the plexus include the superior (L4-S1) and inferior (L5-S2) gluteal nerves and the common peroneal portion of the sciatic nerve (L4-S2). The anterior or ventral divisions supply the calf, plantar foot, and thigh through the tibial nerve (L4-S3).³¹

Several important muscle groups are around the pelvis. The muscles of the pelvic floor, the levator ani muscle, and the coccygeus muscles are composed of voluntary muscles, which support the pelvic viscera and control the voluntary sphincters of the rectum and urethra.³² Additionally, the muscles of the pelvic floor have been noted to impart stability to the pelvic ring.²⁰ Another muscle around the pelvis is the piriformis muscle, which is an important anatomic landmark demarcating the division of the superior and inferior gluteal vessels and assisting with identification of the sciatic nerve. Many other muscles originate and insert on the bones of the pelvis, a discussion of which is beyond the scope of this article and can be referenced from anatomy textbooks.

Contraindications

For contraindications to specific surgical procedures, see Surgical therapy.

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