PELVIS Fractures and Dislocations

EPIDEMIOLOGY

• The incidence of pelvic fractures in the United States has been estimated to be 37 cases per 100,000 population per year.

• 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.

• 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.

  ANATOMYS

• The pelvic ring is composed of the sacrum and two innominate bones joined anteriorly at the symphysis and posteriorly at the paired sacroiliac joints (Fig. 25.1A,B).

   

   

   

• The innominate bone is formed at maturity by the fusion of three ossification centers: the ilium, the ischium, and the pubis through the triradiate cartilage at the dome of the acetabulum.

• The pelvic brim is formed by the arcuate lines that join the sacral promontory posteriorly and the superior pubis anteriorly. Below this is the true or lesser pelvis in which are contained the pelvic viscera. Above this is the false or greater pelvis that represents the inferior aspect of the abdominal cavity.

• Inherent stability of the pelvis is conferred by ligamentous structures. These may be divided into two groups according to the ligamentous attachments:

  1. Sacrum to ilium: The strongest and most important ligamentous structures occur in the posterior aspect of the pelvis connecting the sacrum to the innominate bones.

     • The sacroiliac ligamentous complex is divided into posterior (short and long) and anterior

       ligaments. Posterior ligaments provide most of the stability.

     • The sacrotuberous ligament runs from the posterolateral aspect of the sacrum and the dorsal aspect of the posterior iliac spine to the ischial tuberosity. This ligament, in association with the posterior sacroiliac ligaments, is especially important in helping maintain vertical stability of the pelvis.

       • The sacrospinous ligament is triangular, running from the lateral margins of the sacrum and coccyx and inserting on the ischial spine. It is more important in maintaining rotational control of the pelvis if the posterior sacroiliac ligaments are intact.

  2. Pubis to pubis: Symphyseal ligaments

• Additional stability is conferred by ligamentous attachments between the lumbar spine and the pelvic ring:

  1. The iliolumbar ligaments originate from the L4 and L5 transverse processes and insert on the posterior iliac crest.

  2. The lumbosacral ligaments originate from the transverse process of L5 to the ala of the sacrum.

• The transversely placed ligaments resist rotational forces and include the short posterior sacroiliac, anterior sacroiliac, iliolumbar, and sacrospinous ligaments.

• The vertically placed ligaments resist shear forces (vertical shear, VS) and include the long posterior sacroiliac, sacrotuberous, and lateral lumbosacral ligaments.

  PELVIC STABILITY

• A mechanically stable injury is defined as one that can withstand normal physiologic forces without abnormal deformation.

• Penetrating trauma infrequently results in pelvic ring destabilization.

• An unstable injury may be characterized by the type of displacement as:

  • Rotationally unstable (open and externally rotated, or compressed and internally rotated)

  • Vertically unstable

• Sectioned ligaments of the pelvis determine relative contributions to pelvic stability (these included bony equivalents to ligamentous disruptions):

  • Symphysis alone: pubic diastasis <2.5 cm

  • Symphysis and sacrospinous ligaments: >2.5 cm of pubic diastasis (note that these are rotational movements and not vertical or posterior displacements)

  • Symphysis, sacrospinous, sacrotuberous, and posterior sacroiliac: unstable vertically,

  posteriorly, and rotationally

  MECHANISM OF INJURY

• These may be divided into low-energy injuries, which typically result in fractures of individual bones, or high-energy fractures, which may result in pelvic ring disruption.

  • Low-energy injuries may result from sudden muscular contractions in young athletes that cause an avulsion injury, a low energy fall, or a straddle-type injury (motorcycle or horse).

  • High-energy injuries typically result from a motor vehicle accident, pedestrian-struck mechanism, motorcycle accident, fall from heights, or crush mechanism.

• Impact injuries result when a moving victim strikes a stationary object or vice versa. Direction,

  magnitude, and nature of the force all contribute to the type of fracture.

• Crush injuries occur when a victim is trapped between the injurious force, such as motor vehicle, and an unyielding environment, such as the ground or pavement. In addition to those factors mentioned previously, the position of the victim, the duration of the crush, and whether the force was direct or a “rollover” (resulting in a changing force vector) are important to understanding the fracture pattern.

• Specific injury patterns vary by the direction of force application:

  1. Anteroposterior (AP) force (motorcycle crash)

     • This results in external rotation of the hemipelvis.

     • The pelvis springs open, hinging on the intact posterior ligaments.

  2. Lateral compression (LC) force (fall onto side, “T-bone” in motor vehicle crash): This is most common and results in impaction of cancellous bone through the sacroiliac joint and sacrum. The injury pattern depends on location of force application:

     • Posterior half of the ilium: This is classic LC with minimal soft tissue disruption. This is often a stable configuration.

     • Anterior half of the iliac wing: This rotates the hemipelvis inward. It may disrupt the

       posterior sacroiliac ligamentous complex. If this force continues to push the hemipelvis across to the contralateral side, it will push the contralateral hemipelvis out into external rotation, producing LC on the ipsilateral side and an external rotation injury on the contralateral side.

     • Greater trochanteric region: This may be associated with a transverse acetabular fracture.

     • External rotation abduction force: This is common in motorcycle accidents.

       • Force application occurs through the femoral shafts and head when the leg is externally rotated and abducted.

       • This tends to tear the hemipelvis from the sacrum.

     • Shear force

       • This leads to a completely unstable fracture with triplanar instability secondary to disruption of the sacrospinous, sacrotuberous, and sacroiliac ligaments.

       • In the elderly individual, bone strength will be less than ligamentous strength and will fail

         first.

       • In a young individual, bone strength is greater and, thus, ligamentous disruptions usually occur.

  CLINICAL EVALUATION

  Perform patient primary assessment (ABCDE): airway, breathing, circulation, disability, and exposure. This should include a full trauma evaluation (see Chapter 2).

• Identify all injuries to extremities and pelvis, with careful assessment of distal neurovascular status.

• Pelvic instability may result in a leg-length discrepancy involving shortening on the involved side or a markedly internally or externally rotated lower extremity.

• The AP–LC test for pelvic instability should be performed once only and involves rotating the pelvis internally and externally.

  • “The first clot is the best clot.” Once disrupted, subsequent thrombus formation of a retroperitoneal hemorrhage is difficult because of hemodilution by administered intravenous fluid and exhaustion of the body’s coagulation factors by the original thrombus.

• Massive flank or buttock contusions and swelling with hemorrhage are indicative of significant bleeding.

• Palpation of the posterior aspect of the pelvis may reveal a large hematoma, a defect representing the fracture, or a dislocation of the sacroiliac joint. Palpation of the symphysis may also reveal a defect.

• The perineum must be carefully inspected for the presence of a lesion representing an open fracture.

• Digital rectal in all and a vaginal exam in women should be performed in all trauma patients who present with a pelvic ring disruption. A missed rectal or vaginal perforation in association with a pelvic ring injury has a poor prognosis.

  HEMODYNAMIC STATUS

  Retroperitoneal hemorrhage may be associated with massive intravascular volume loss. The usual cause of retroperitoneal hemorrhage secondary to pelvic fracture is a disruption of the venous plexus in the posterior pelvis. It may also be caused by a large-vessel injury, such as external or internal iliac disruption. Large-vessel injury causes rapid, massive hemorrhage with frequent loss of the distal pulse and marked hemodynamic instability. This often necessitates immediate surgical exploration to gain proximal control of the vessel before repair. The superior gluteal artery is occasionally injured and can be managed with rapid fluid resuscitation, appropriate stabilization of the pelvic ring, and embolization.

• Options for immediate hemorrhage control include:

  1. Application of military antishock trousers (MAST). This is typically performed in the field.

  2. Wrapping of a pelvic binder circumferentially around the pelvis (or sheet if a binder is not available) (Fig. 25.2). This should be applied at the level of the trochanters to provide access to the abdomen.

  3. Consider application of a bean bag.

  4. Consider angiography or embolization if the hemorrhage continues despite closing of the pelvic volume.

  5. Consider application of a pelvic C-clamp (posterior).

  6. Consider an anterior external fixator.

  7. Open reduction and internal fixation (ORIF): This may be undertaken if the patient is

     undergoing emergency laparotomy for other indications; it is frequently contraindicated by itself because loss of the tamponade effect may encourage further hemorrhage.

  8. Open packing of the retroperitoneum is an option in the unstable patient who is brought to the operating room for laparotomy and exploration.

   

   

   

  NEUROLOGIC INJURY

• Lumbosacral plexus and nerve root injuries may be present, but they may not be apparent in an unconscious patient.

• Higher incidence with more medial sacral fractures (Denis classification)

  GENITOURINARY AND GASTROINTESTINAL INJURY

• Bladder injury: 20% incidence occurs with pelvic trauma.

  • Extraperitoneal: treated with a Foley or suprapubic tube if unable to pass

  • Intraperitoneal: requires repair

• Urethral injury: 10% incidence occurs with pelvic fractures, in male patients much more frequently than in female patients.

  • Examine for blood at the urethral meatus or blood on catheterization.

  • Examine for a high-riding or “floating” prostate on rectal examination.

  • Clinical suspicion should be followed by a retrograde urethrogram.

   

  Bowel Injury

  Perforations in the rectum or anus owing to osseous fragments are technically open injuries and should be treated as such. Infrequently, entrapment of bowel in the fracture site with gastrointestinal

  obstruction may occur. If either is present, the patient should undergo diverting colostomy.

  RADIOGRAPHIC EVALUATION

  Standard trauma radiographs include an AP view of the chest, a lateral view of the cervical spine, and an AP view of the pelvis.

• AP of the pelvis (Fig. 25.3):

  • Anterior lesions: pubic rami fractures and symphysis displacement

  • Sacroiliac joint and sacral fractures

  • Iliac fractures

  • L5 transverse process fractures

   

   

   

• Special views of the pelvis include:

  • Obturator and iliac oblique views: They may be utilized in suspected acetabular fractures (see Chapter 26).

  • Inlet radiograph (Fig. 25.4): This is taken with the patient supine with the tube directed 60

    degrees caudally, perpendicular to the pelvic brim.

    • This is useful for determining anterior or posterior displacement of the sacroiliac joint, sacrum, or iliac wing.

    • It may determine internal rotation deformities of the ilium and sacral impaction injuries.

       

       

       

  • Outlet radiograph (Fig. 25.5): This is taken with the patient supine with the tube directed 45 degrees cephalad.

    • This is useful for determination of vertical displacement of the hemipelvis.

    • It may allow for visualization of subtle signs of pelvic disruption, such as a slightly widened sacroiliac joint, discontinuity of the sacral borders, nondisplaced sacral fractures, or disruption of the sacral foramina.

   

   

   

• Computed tomography: This is excellent for assessing the posterior pelvis, including the sacrum and sacroiliac joints.

• Magnetic resonance imaging: It has limited clinical utility owing to restricted access to a critically injured patient, prolonged duration of imaging, and equipment constraints. However, it may provide superior imaging of genitourinary and pelvic vascular structures.

• Stress views: Push–pull radiographs are performed while the patient is under general anesthesia to assess vertical stability.

  • Tile-defined instability is defined as ≥0.5 cm of motion.

  • Bucholz, Kellam, and Browner consider ≥1 cm of vertical displacement unstable.

• Radiographic signs of instability include:

• Sacroiliac displacement of 5 mm in any plane

• Posterior fracture gap (rather than impaction)

• Avulsion of the 5th lumbar transverse process, the lateral border of the sacrum (sacrotuberous ligament), or the ischial spine (sacrospinous ligament)

CLASSIFICATION

Young and Burgess

The Young and Burgess system (Table 25.1 and Fig. 25.6) is based on the mechanism of injury.

 

 

 

 

 

 

1. LC: This is an implosion of the pelvis secondary to laterally applied force that shortens the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments. One may see oblique fractures of the pubic rami, ipsilateral or contralateral to the posterior injury.‌

   Type I: Sacral impaction on the side of impact. Transverse fractures of the pubic rami are stable.

   Type II: Posterior iliac wing fracture (crescent) on the side of impact with variable disruption of the posterior ligamentous structures resulting in variable mobility of the anterior fragment to internal rotation stress. It maintains vertical stability and may be associated with an anterior sacral crush injury.

   Type III: LC-I or LC-II injury on the side of impact; force continued to contralateral hemipelvis to produce an external rotation injury (windswept pelvis) owing to sacroiliac, sacrotuberous, and sacrospinous ligamentous disruption. Instability may result with hemorrhage and neurologic injury secondary to traction injury on the side of sacroiliac injury.

2. AP compression (APC): This is anteriorly applied force from direct impact or indirectly transferred via the lower extremities or ischial tuberosities resulting in external rotation injuries, symphysis diastasis, or longitudinal rami fractures.

   Type I: Less than 2.5 cm of symphysis diastasis. Vertical fractures of one or both pubic rami occur, with intact posterior ligaments.

   Type II: More than 2.5 cm of symphysis diastasis; widening of sacroiliac joints; caused by anterior sacroiliac ligament disruption. Disruption of the sacrotuberous, sacrospinous, and symphyseal ligaments with intact posterior sacroiliac ligaments results in an “open book” injury with internal and external rotational instability; vertical stability is maintained.

   Type III: Complete disruption of the symphysis, sacrotuberous, sacrospinous, and sacroiliac ligaments resulting in extreme rotational instability and lateral displacement; no cephaloposterior displacement. It is completely unstable with the highest rate of associated vascular injuries and blood loss.

3. VS: Vertically or longitudinally applied forces caused by falls onto an extended lower extremity, impacts from above, or motor vehicle accidents with an extended lower extremity against the floorboard or dashboard. These injuries are typically associated with complete disruption of the symphysis, sacrotuberous, sacrospinous, and sacroiliac ligaments and result in extreme instability, most commonly in a cephaloposterior direction because of the inclination of the pelvis. They have a highly associated incidence of neurovascular injury and hemorrhage.

4. Combined mechanical (CM): This is a combination of injuries often resulting from crush mechanisms. The most common are VS and LC.

   Orthopaedic Trauma Association Classification of Pelvic Fractures See Fracture and Dislocation Classification Compendium at http://www.ota.org/compendium/compendium.html.

   FACTORS INCREASING MORTALITY

   • Type of pelvic ring injury

     • Posterior disruption is associated with higher mortality (APC-III, VS, LC-III).

   • High Injury Severity Score (Tile, 1980; McMurty, 1980)

   • Associated injuries

     • Head and abdominal, 50% mortality

   • Hemorrhagic shock on admission (Gilliland, 1982)

   • Requirement for large quantities of blood (McMurty, 1980)

   • Perineal lacerations, open fractures (Hanson, 1991)

   • Increased age (Looser, 1976)

     Associated Morel-Lava lée Lesion (Skin Degloving Injury)

   • Colonized in up to one-third of cases

   • Requires thorough debridement before definitive surgery

     TREATMENT

   • The recommended management of pelvic fractures varies from institution to institution, a finding highlighting that these are difficult injuries to treat and require an algorithmic approach (Fig. 25.7).

      

      

      

     Nonoperative

     Fractures amenable to nonoperative treatment include:

   • Most LC-1 and APC-1 fractures

   • Gapping of pubic symphysis <2.5 cm

   • Rehabilitation

     • Protect weight bearing typically with a walker or crutches initially.

     • Serial radiographs are required after mobilization has begun to monitor for subsequent displacement.

     • If secondary displacement of the posterior ring >1 cm is noted, weight bearing should be

       stopped. Operative treatment should be considered for gross displacement.

       Absolute Indications for Operative Treatment

   • Open pelvic fractures or those in which there is an associated visceral perforation requiring operative intervention

   • Open-book fractures or vertically unstable fractures with associated patient hemodynamic instability

     Relative Indications for Operative Treatment

   • Symphyseal diastasis >2.5 cm (loss of mechanical stability)

   • Leg-length discrepancy >1.5 cm

   • Rotational deformity

   • Sacral displacement >1 cm

   • Intractable pain

     Operative Techniques

   • External fixation: This can be applied as a construct mounted on two to three 5-mm pins spaced 1 cm apart along the anterior iliac crest, or with the use of single pins placed in the supra-acetabular area in an AP direction (Hanover frame).

     External fixation is a resuscitative fixation and can only be used for definitive fixation of anterior pelvis injuries; it cannot be used as definitive fixation of posteriorly unstable injuries.

   • Internal fixation: This significantly increases the forces resisted by the pelvic ring compared with external fixation.

     • Iliac wing fractures: Open reduction and stable internal fixation are performed using lag screws and neutralization plates.

     • Diastasis of the pubic symphysis: Plate fixation is most commonly used. Presence of an open

       injury or rectal or bladder injury requires coordination between orthopaedics, trauma, and genitourinary surgery services to identify the best care plan.

     • Sacral fractures: Transiliac bar fixation may be inadequate or may cause compressive neurologic injury; in these cases, plate fixation or noncompressive iliosacral screw fixation may be indicated.

     • Unilateral sacroiliac dislocation: Direct fixation with iliosacral screws or anterior sacroiliac plate fixation is used.

     • Bilateral posterior unstable disruptions: Fixation of the displaced portion of the pelvis to the

       sacral body may be accomplished by posterior screw fixation. In addition, lumbopelvic fixation may be utilized in these cases.

       Special Considerations

   • Open fractures: In addition to fracture stabilization, hemorrhage control, and resuscitation, priority must be given to evaluation of the anus, rectum, vagina, and genitourinary system.

     • Anterior and lateral wounds generally are protected by muscle and are not contaminated by internal sources.

     • Posterior and perineal wounds may be contaminated by rectal and vaginal tears and

       genitourinary injuries.

     • Colostomy may be necessary for large bowel perforations or injuries to the anorectal region. Colostomy is indicated for any open injury where the fecal stream will contact the open area.

   • Urologic injury

     • The incidence is up to 20%.

     • Blood at the meatus or a high-riding prostate may be noted.

     • Retrograde urethrogram is indicated in patients with suspicion of urologic injury, but one should ensure hemodynamic stability as embolization may be difficult because of dye extravasation.

     • Intraperitoneal bladder ruptures are repaired. Extraperitoneal ruptures may be observed.

     • Urethral injuries are repaired on a delayed basis.

   • Neurologic injury

     • L2 to S4 are possible.

     • L5 and S1 are most common.

     • Neurologic injury depends on the location of the fracture and the amount of displacement.

     • Sacral fractures: neurologic injury

       • Lateral to foramen (Denis I): 6% injury

       • Through foramen (Denis II): 28% injury

       • Medial to foramen (Denis III): 57% injury

     • Decompression of sacral foramen may be indicated if progressive loss of neural function occurs.

     • It may take up to 3 years for recovery.

   • Hypovolemic shock: origin

     • Intrathoracic bleeding

     • Intraperitoneal bleeding

       • Diagnostic tables

       • Ultrasound

       • Peritoneal tap

       • Computed tomography

     • Retroperitoneal bleeding

     • Blood loss from open wounds

     • Bleeding from multiple extremity fractures

   • AP injuries are associated with the largest amount of blood loss and greatest mortality.

   • Postoperative management: In general, early mobilization is desired.

     • Aggressive pulmonary toilet should be pursued with incentive spirometry, early mobilization, encouraged deep inspirations and coughing, and suctioning or chest physical therapy, if necessary.

     • Prophylaxis against thromboembolic phenomena should be undertaken, with a combination of elastic stockings, sequential compression devices, and chemoprophylaxis if hemodynamic and injury status allows.

     • High-risk patients unable to be chemically anticoagulated should undergo vena caval filter placement.

       • Newer designs are retrievable up to 6 months after placement.

     • Weight-bearing status may be advanced as follows:

       • Full weight bearing on the uninvolved lower extremity/sacral side occurs within several days.

       • Partial weight bearing on the involved side is recommended for at least 6 weeks. Recently, weight-bearing as tolerated (WBAT) has been supported in low-energy LC1 fractures.

       • Full weight bearing on the affected side without crutches is indicated by 12 weeks.

       • Patients with bilateral unstable pelvic fractures should be mobilized from bed to chair with aggressive pulmonary toilet until radiographic evidence of fracture healing is noted. Partial weight bearing on the “less” injured side is generally tolerated by 12 weeks.

         COMPLICATIONS

   • Infection: The incidence is variable, ranging from 0% to 25%, although the presence of wound infection does not preclude a successful result. The presence of contusion or shear injuries to soft tissues (Morel lesion) is a risk factor for infection if a posterior approach is used. This risk is minimized by a percutaneous posterior ring fixation.

   • Thromboembolism: Disruption of the pelvic venous vasculature and immobilization constitute major risk factors for the development of deep venous thromboses.

   • Malunion: Significant disability may result, but it is rare. It is associated with chronic pain, limb length inequalities, gait disturbances, sitting difficulties, low back pain, and pelvic outlet obstruction.

   • Nonunion: This is rare, although it tends to occur more in younger patients (average age 35 years) with possible sequelae of pain, gait abnormalities, and nerve root compression or irritation. Stable fixation and bone grafting are usually necessary for union.

   • Mortality

     • Hemodynamically stable patients: 3%

     • Hemodynamically unstable patients: 38%

     • LC: head injury major cause of death

     • APC: pelvic and visceral injury major cause of death

     • AP3 (comprehensive posterior instability): 37% death

     • VS: 25% death