eMedicine Specialties > Orthopedic Surgery > Hip

Unstable Pelvic Fractures: Treatment

Author: Kenneth W Graf Jr, MD, Consulting Surgeon, Department of Orthopedic Trauma Services, Mission Hospitals
Coauthor(s): Madhav Karunakar, MD, Consulting Surgeon, Section of Orthopedic Surgery, Department of Surgery, University of Michigan Medical Center
Contributor Information and Disclosures

Updated: Jan 18, 2008

Treatment

Medical Therapy

The initial evaluation and treatment of a patient with polytrauma occur in the ED. The ATLS recommendations of airway stabilization followed by breathing and circulation are performed. A multidisciplinary approach is used and should include the following, as needed: ED, general surgery, neurosurgery, and orthopedic surgery.²⁰

Patients with high-energy pelvic fractures often have abdominal, head, and thoracic injuries. Between 60% and 80% of patients have musculoskeletal injuries, 12% have urogenital injuries, and 8% have lumbosacral injuries. Aggressive fluid resuscitation is critical in the patient who is hemodynamically unstable. The severity of blood loss can be determined by assessing the pulse, blood pressure, and capillary refill. These indicators can be used to evaluate a patient's response to the resuscitative effort. Two large-bore (16-gauge) intravenous catheters should be established. Replacement volume is estimated by using the formula of 3 mm of crystalloid for each 1 mm of blood loss. A minimum of 2 L of crystalloid solution is given over 2 minutes or is given more rapidly for patients in shock. If an adequate blood pressure measurement is obtained, crystalloid is administered until type-specific blood of non–cross-matched universal donor (O-negative) is prepared.

Displaced pelvic fractures can be stabilized temporarily by simple means during the initial evaluation and transportation. These methods rely on immobilization and partial reduction of displacement. A sheet can be tied around the pelvis, or the legs can be tied together in an internally rotated position to approximate an anterior pelvic diastasis. Military antishock trousers (MAST) have proven to be effective in the prehospital treatment of patients who are hypotensive and have pelvic fractures. Their use in the hospital is not common, because they limit access to injured areas of the body, decrease expansion of the lungs, and may contribute to the development of compartment syndrome in patients who are hypoperfused.

Most incidents of blood loss from a pelvic injury occur from cancellous bone at the fracture site or from a retroperitoneal lumbar plexus venous injury.²¹ Only 20% of deaths from pelvic hemorrhage are attributed to a major arterial injury. Posterior arterial bleeding is more common in patients with unstable posterior pelvic fractures, and anterior arterial bleeding (pudendal or obturator) is more common in patients with lateral compression injuries.²² The most frequently injured arterial vessel associated with a posterior fracture is the superior gluteal artery.

Hemorrhage from a pelvic fracture is seldom the only source of bleeding. Poole found a large series of patients with polytrauma and pelvic fractures in whom the major source of bleeding was from nonpelvic sites.²³ The abdomen and bladder are frequently injured and should be evaluated as a source of hemorrhage. As mentioned, a supraumbilical diagnostic peritoneal lavage can be used as a quick and accurate diagnostic tool.

If diagnostic peritoneal lavage results are negative and the patient remains hemodynamically unstable, external fixation may have a role in the patient's immediate treatment.²⁴ Riemer documented an overall decrease in the mortality rate, from 26% to 6%, after initiating a protocol, including external fixation and early mobilization for pelvic fractures.⁷ The mortality rate for patients who are hypotensive decreased from 41% to 21%. Benefits of external fixation include immobilization of fractures limiting the clot disruption that may occur during patient movement and transfer. Studies have shown that reduction of an open-book pelvis leads to an increase in the retroperitoneal pressure, which may aid in the tamponade of venous bleeding.

The use of external fixation remains somewhat controversial. For example, Gruen et al reported that in 36 patients with trauma who were hemodynamically unstable, pelvic fractures were not immediately stabilized by external fixation.²⁵ These patients received both volume resuscitation and treatment of associated injuries. Thirty-nine percent of the fractures were rotationally unstable, and 61% were both rotationally and vertically unstable. The overall mortality rate was 11%. All of the deaths were attributed to associated injuries or comorbidities.

Continued unexplained blood loss despite fracture stabilization and aggressive resuscitation mandates angiographic exploration to look for continued arterial bleeding. The techniques for arteriography and embolization were developed in the 1970s. Embolization provides the most direct and beneficial means of controlling arterial hemorrhage. It avoids the retroperitoneal contamination associated with operative ligation of bleeding vessels while preserving the tamponade effect in the retroperitoneal space. The timing of arteriography and embolization is controversial. Most authors recommend arteriography after the initial stabilization, laparotomy, or both. A skilled radiologist is critically important. Aggressive fluid resuscitation must be continued during angiography. Hypothermia may develop during a prolonged radiographic procedure if the patient is not adequately warmed and resuscitated.

Surgical Therapy

The goals of pelvic fracture treatment are the same as those of other bones—a healed fracture with the prevention of nonunion, malunion, or other complications. External fixation also has been used in rotationally unstable pelvic fractures.

ORIF is preferred for definitive management and has been demonstrated to give superior results. Operative indications include diastasis of the pubic symphysis greater than 2.5 cm, sacroiliac joint dislocations, displaced sacral fractures, crescent fractures, posterior or vertical displacement of the hemipelvis (>1 cm), rotationally unstable pelvic ring injuries, sacral fractures in patients with unstable pelvic ring injuries that require mobilization, and displaced sacral fractures with neurologic injury.

Preoperative Details

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

Plain radiographs, including AP pelvis, inlet views, and outlet views, should be obtained and reviewed. A CT scan is helpful in evaluating the sacrum and sacroiliac joint for injury.¹⁹ A catalog of injuries also should be reviewed before proceeding to the operating room.

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

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

Intraoperative Details

External fixation

External fixation is indicated for patients who are hemodynamically unstable with pelvic fractures. It should be avoided in patients who are hemodynamically stable unless it will serve as definitive stabilization. Infected or contaminated pin sites may compromise future approaches to the anterior sacroiliac joint and the iliac wing.

The surgeon must be familiar with the external fixation equipment so that it can be used quickly and effectively in patients who are hemodynamically unstable. Pins may be placed along the iliac crest or in the supra-acetabular region. Placement in the iliac crest is simple and direct; this location is most appropriate for rapid pin placement in a patient who is hemodynamically unstable (see Image 9). The thickest bone for pin insertion is the anterior pillar of the iliac wing.

Anatomically, the iliac crest overhangs laterally. A pin placed in the center of the crest will miss the iliac wing. The optimal starting point is in the medial one third of the anterior pillar.

Supra-acetabular pins are placed at the level of the anterior inferior iliac spine in a direction perpendicular to the floor. This pin is near the hip joint and must be inserted with great care. The skin incisions should be placed in line with the direction of the planned reduction. This avoids the need for additional relaxing incisions. A spinal needle or Kirschner wire (K-wire) can be placed along the inner table of the pelvis to help determine the orientation of the hemipelvis. Frame constructs are varied. The frame should be far enough away from the abdomen to allow for distention, future surgical approaches, and upright positioning.

Iliosacral screws

Iliosacral screws can be used in the treatment of crescent fractures, sacral fractures, and sacroiliac dislocations. They can be placed through either open or percutaneous techniques.^5,26

If percutaneous techniques are chosen, an anatomic reduction is required because sacral displacement narrows the safe window for screw placement.

• The procedure can be performed in either the supine or the prone position. The technique is technically demanding and requires good C-arm visualization. A thorough understanding of the radiographic anatomy is critical in performing this procedure. The pelvic inlet, outlet, and lateral sacral views must be obtained to define the safe corridor for screw placement.
  • The ideal pelvic inlet view superimposes the upper sacral vertebral bodies as concentric circles. If the anterior cortex of S1 overlies the coccyx, the concavity of the sacrum may not be appreciated. This may result in a screw penetrating the S1 body.
  • The ideal pelvic outlet view is obtained when the symphysis is superimposed on the second sacral vertebral body. The outlet view allows visualization of the S2 foramina.
  • A lateral sacral view is obtained by superimposing the greater sciatic notch images.
• The iliac cortical density denotes the anterior extent for safe placement of the iliosacral screw insertion. The angle of screw placement may vary between sacroiliac dislocation and a sacral fracture. The screw placement for a sacral fracture must be in a transverse position to allow the screw to achieve fixation in the sacral body.
• Sacral fractures are treated with fully threaded cancellous screws to avoid overcompression of the sacral foramina. SI dislocations are compressed with cancellous lag screws.

If an open approach is necessary for reduction of the SI dislocation, an anterior or posterior approach may be used.

• For the posterior approach, a vertical incision is made 2 cm lateral to the posterior superior iliac spine. The gluteal muscle is elevated from the posterior iliac crest, and the gluteus maximus origin is reflected from the sacrum. The greater sciatic notch must be exposed for assessment of reduction. For sacral fractures, the multifidus muscle is elevated to provide visualization of the sacral foramina. A Matta-angled jaw clamp can be used to obtain reduction by placing one tip on the sacrum through the sciatic notch and the other along the outer table of the ilium. Fixation is performed with iliosacral screws.
• For an anterior approach, the incision is from the anterior superior iliac spine to the iliac tubercle. The iliacus muscle is sharply dissected subperiosteally off of the iliac wing. The L5 nerve root lies 2 cm medial to the SI joint and must be protected during the dissection. Fixation is usually limited to two 2-hole plates placed at 90° to each other. Lange et al reported on 27 patients with SI dislocations treated with an anterior approach. Of the 27 patients, 3 (11%) with incomplete L5 nerve injuries were noted postoperatively, with full improvement occurring in 2 of these patients.²⁷

Crescent fractures can be approached via an anterior or posterior approach.¹³ The posterior approach provides an easier dissection, without requiring special care for the L5 nerve root. The iliac wing fragment can be reduced to the intact posterior superior iliac spine and fixed in place with 1 or 2 cortical lag screws (3.5 mm) placed between the pelvic tables from posterior to anterior. A 3.5-mm reconstruction plate can be placed along the outer table to help neutralize the rotational and shear forces across the fracture site. If the intact posterior superior iliac spine fragment is small, iliosacral screws may be required to stabilize the iliac wing.

Postoperative Details

Postoperative weight-bearing status depends on the fracture pattern and associated injuries. Most unstable fractures require non–weight-bearing restrictions for 3 months. Early weight-bearing may be allowed in individuals with rotationally unstable but vertically stable fractures. All patients should be out of bed or upright in bed on postoperative day 1 to help pulmonary function.²⁸

Follow-up

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

Complications

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

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

Open debridement is the preferred treatment. The incision should be placed close to the middle of the degloved area to decrease the risk of flap necrosis. The hematoma should be evacuated, and the necrotic fatty and connective tissue should be sharply debrided. The wounds should be packed with gauze, and dressings soaked with isotonic sodium chloride solution should be changed regularly. Prophylactic antibiotics should particularly cover gram-positive organisms. If the overlying skin is intact, debridement can be performed at the time of fracture fixation. The deep fascia should be closed tightly, and the distal portion of the wound should be left open for dressing changes.

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

Fatal pulmonary embolism occurs in 0.5-2% of patients with pelvic trauma. The risk factors most consistently observed with a trauma population are increasing age, spinal cord injury, fractures of the lower extremity and pelvis, and duration of immobilization. The typical clinical findings of DVT include leg tenderness, swelling, and increased temperature. The sensitivity of detecting DVT in a patient with trauma is unreliable because lower extremity fracture, edema, and soft tissue injury are often present. Duplex ultrasonography is the most widely used screening test for the evaluation of DVT in trauma patients.

Given the high incidence of DVT in the pelvic trauma population, routine prophylaxis is recommended. Common forms of prophylaxis include low-dose heparin (LDH), low molecular weight heparin (LMWH), mechanical devices, and vena caval filters. Knudson et al performed a randomized trial of LDH with no prophylaxis in 154 trauma patients.^30,31 Serial duplex Doppler ultrasonography was performed every 3-5 days. Patients treated with LDH received no additional protection, as compared with controls.

Intermittent pneumatic compression has been demonstrated by itself to be ineffective prophylaxis for trauma patients. Fisher et al performed a randomized study of intermittent pneumatic compression in patients with pelvic fractures.³² They found no significant difference in DVT rates. LMWH is more efficacious than LDH in preventing DVT (19% vs 12%). The use of LMWH has been associated with an increased risk of wound hematoma formation. The authors prefer warfarin prophylaxis for postoperative patients.

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

Postoperative prophylaxis is started with warfarin (international normalized ratio [INR] goal of 2.0-3.0). Because of the risk of intraoperative embolization, all patients with pelvic fractures receiving delayed surgical reconstruction (>4 d) should undergo bilateral lower extremity venous ultrasonography or venography. If DVT is found, the patient should receive a vena caval filter. If no DVT is found, routine postoperative prophylaxis is performed. For patients with contraindications to anticoagulation, such as intracranial bleeding, prophylactic vena caval filter and screening ultrasonography or magnetic resonance venography should be considered.

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

In 1966, Huittinen and Slatis reviewed the nonoperative treatment of 1476 patients with unstable pelvic fractures and found a 46% rate of persistent nerve injury.³³ Helfet et al evaluated 28 patients with 30 vertically unstable fractures of the hemipelvis.³⁴ Preoperative ipsilateral neurologic injury to the sciatic lumbosacral plexus was found in 50% of patients with these fractures. Posterior approaches and reduction led to significant unilateral changes in the somatosensory-evoked potentials (SSEPs) concurrent with manipulation of the hemipelvis for reduction. Routine careful identification and retraction of the L5 nerve root intraoperatively did not result in SSEP monitoring changes during anterior approaches.

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

Matta and Saucedo reported on the operative correction of 37 nonunions and malunions.⁴ The procedure is technically demanding, with a complication rate of 19%. The average operating time was 7 hours, and average blood loss was 2000 mL. A 3-stage reconstruction is often required. The first stage involves an anterior approach to mobilize structures and to perform osteotomies. The patient is then repositioned, and a posterior approach is used to complete the mobilization or osteotomy. ORIF of the posterior pelvis is performed. The third stage involves a repeat anterior approach for ORIF of the anterior pelvis.

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