Pelvic Fractures Treatment & Management

Initial therapy in the acutely injured patient centers on the "ABCs," as recommended by ATLS protocols published by the American College of Surgeons.^[13] The following mnemonic defines the specific, ordered, prioritized evaluations and interventions that should be followed in injured patients^[13] :

• A = Airway with cervical spine control
• B = Breathing
• C = Circulation
• D = Disability or neurologic status
• E = Exposure (undress) with temperature control

After initial resuscitation and stabilization, other non–life-threatening injuries are evaluated and managed appropriately. Following these guidelines, under the direction of a trauma surgeon or general surgeon, patient treatment is optimized.

Symphysis pubis disruptions

Disruptions of the symphysis pubis are typically described as resulting from an anterior or posterior force impacting the pelvis; however, laterally directed compressive forces also have been implicated in creating symphyseal disruptions.^{[20, 26]} Indications to stabilize symphysis pubis disruptions operatively are determined by the amount of instability between the pubic bones. Several authors have recommended operative stabilization when the pubic diastasis is greater than 2.5 cm, based on experimental evidence demonstrating that pubic bone displacement greater than 2.5 cm implies rupture of the anterior sacroiliac, the sacrospinous, and the sacrotuberous ligaments, rendering the pelvis rotationally unstable.^{[20, 25]}

Letournel recommended operative stabilization of symphyseal disruptions when the pubic diastasis measures greater than 1.5 cm.^[38] Routt et al also noted that children and people of smaller stature may demonstrate rotational pelvic instability with pubic diastases less than 2.5 cm.^[26] It has been observed that a symphysis pubis diastasis may increase after administration of general anesthesia, implying that plain radiographs may underestimate the actual deformity because of associated muscle spasm.

Treatment options for symphyseal disruptions consist of external fixation or more mechanically sound open reduction with internal fixation. Anterior pelvic external fixation can be used in patients with small symphyseal disruptions with incomplete posterior ligamentous injury.^{[26, 38, 39]} The use of an anterior external fixator is potentially beneficial because it avoids operative exposures, potential bleeding from venous plexus injuries, and bladder perforation associated with open stabilization.^[39]

The external fixator is also useful to avoid wound contamination when suprapubic catheters are in place for the treatment of urinary bladder disruptions. The external fixator should remain in place until healing is demonstrated, which usually occurs between 6 and 12 weeks postoperatively.^{[38, 39]} External pelvic fixation is cumbersome for patients and is associated with pin-track infections and even iliac osteomyelitis.

Open reduction and internal fixation is preferred for unstable symphyseal injuries. Open reduction and internal fixation avoids the inconvenience of wearing and removing an external fixator. Surgical stabilization is performed through a Pfannenstiel surgical exposure, or an extension of a midline exposure may be used. Tenaculum clamps, Farabeuf clamps, and pelvic reduction clamps may be used to reduce the pubic diastasis. Implants commonly used to stabilize symphyseal disruptions are 3.5-mm reconstruction plates, 4.5-mm reconstruction plates, 3.5-mm low-contact dynamic compression plates, and 4.5-mm low-contact dynamic compression plates. Regardless of the plate used, at least 2 screws should be placed on each side of the defect to prevent subsequent rotatory deformities. The larger plates do not fit the symphyseal area well and for this reason, 3.5-mm pelvic reconstruction plates are preferred.

Pubic ramus fractures

Pubic ramus fractures occur as parasymphysial fractures, midramus fractures, and pubic root fractures in association with distraction and compression injuries of the pelvis.^[26] Displacement of pubic rami fractures may cause impingement or laceration of the bladder, vagina, and perineum, and, for these reasons, operative management may be considered. Operative treatment of pubic rami fractures is indicated to provide additional pelvic ring stability in association with posterior pelvic ring fixation. Stabilization of pubic rami fractures also may be considered in fractures involving the obturator neurovascular canal with accompanying neurologic injury.

Treatment options for pubic rami fractures include external fixation, percutaneous screw fixation, and open reduction and internal fixation. External fixation with either multiple pins or single pins in each hemipelvis may be used successfully in conjunction with stabilization of posterior ring injuries to impart additional stability to the pelvic fixation construct.^{[39, 40]} External fixation for pubic ramus fractures is indicated to impart additional stability after posterior pelvic ring repair and also when percutaneous or open treatment is contraindicated.

Intramedullary fixation of pubic ramus fractures has been described for treatment of pubic rami fractures.^{[24, 41]} Intramedullary pubic ramus fixation with a 4.5-mm cortical screw has demonstrated fixation strength equivalent to plate fixation and has demonstrated good results in clinical settings.^{[37, 42]} Intramedullary stabilization of ramus fractures may be performed with either a percutaneous or open technique with either antegrade or retrograde screw placement in the pubic ramus. Extramedullary plate fixation is another option to stabilize pubic rami fractures after open reduction and usually is achieved with 3.5-mm pelvic reconstruction plates.

Iliac wing fractures

Iliac wing fractures are caused by forces applied directly to the iliac wing. Simple fracture patterns without associated pelvic ring instability are managed with nonoperative measures. Comminuted iliac wing fractures are caused by high-energy injuries, and are frequently accompanied by severe soft-tissue injuries, including open wounds.^[43]

Indications for operative management of iliac wing fractures include associated skin abnormalities, significant closed degloving injuries, and open wounds. Severely displaced or comminuted iliac wing fractures, unstable iliac fractures that preclude adequate pulmonary function secondary to pain, bowel herniation or incarceration within the fracture, and fractures associated with unstable pelvic ring injuries are other indications for open reduction and internal fixation.^{[26, 43]} Preoperative pelvic angiograms are recommended for fractures involving the greater sciatic notch.

The lateral window of the ilioinguinal surgical exposure is used to access iliac wing fractures. After fracture exposure, tenaculum clamps, Farabeuf clamps, and Schanz pins used as joysticks are used to obtain fracture reduction. Fracture reduction is maintained with medullary lag screws in combination with pelvic reconstruction plates for definitive stabilization. For patients with open iliac fractures, the fixation construct should rely on medullary screws in order to seclude the implants from contamination.

Crescent fractures

Crescent fractures—fractures of the posterior ilium extending from the iliac crest into the greater sciatic notch—are associated with an articular dislocation of the anterior sacroiliac joint. They commonly result after LC injuries to the iliac wing but also may occur secondary to anteriorly or posteriorly directed forces.^{[25, 26]} Crescent fractures typically result in a stable posterior iliac fragment because of the attachment of the intact posterior SI ligaments, whereas the iliac component is rotationally unstable.^[44] When viewed laterally, the posterior iliac stable segment is crescent-shaped, hence the terminology. Surgical stabilization is indicated because of the inherent instability of the iliac wing component of the fracture and the dislocation of the SI joint.

Crescent fractures may be treated with the patient positioned either prone or supine, depending upon associated pelvic ring injuries, acetabular fractures, soft-tissue injuries, and the location of the crescent fracture. Fractures treated from the prone position are exposed with a vertical paramedian dorsal surgical approach, allowing direct reduction of the iliac fracture and indirect reduction of the SI joint. The iliac fracture is visualized directly, reduced with clamps, and stabilized with lag screws and 3.5-mm reconstruction plates along the iliac wing.^[44] Percutaneously placed iliosacral screws also may be used to supplement fixation.

Treatment of crescent fractures with the patient in the supine position allows direct reduction of the SI joint and indirect reduction of the iliac fracture.^[45] The lateral window of the ilioinguinal surgical exposure is used to access the SI joint. After the SI joint is visualized and debrided, reduction is performed under direct visualization using a combination of clamps, external fixators, and, occasionally, a femoral distractor used in compression. The SI joint is stabilized with iliosacral screws, 3.5-mm reconstruction plates placed perpendicular to one another, or both used in combination.^[26]

Isolated percutaneous treatment of crescent fractures using iliosacral screw fixation can be used if the posterior iliac fracture fragment is small, the unstable iliac wing component can be reduced with closed manipulative means, and the sacral safe zone is large enough to accommodate an iliosacral screw.^[37] This technique can be used with either prone or supine positioning using well-described techniques for placement of iliosacral screws.^{[46, 47]}

Sacroiliac joint disruptions

SI joint disruptions occur as a result of an anteriorly or posteriorly directed force to the pelvis associated with symphysis pubis disruptions or rami fractures.^{[8, 9, 18]} Incomplete disruptions of the SI joint typically are characterized by rupture of the anterior SI ligaments with a concurrent symphyseal disruption of less than 2.5 cm.^[20] These injuries are not associated with vertical instability and may be managed nonoperatively, with an external fixator or with open reduction and internal fixation.^{[20, 39]}

Complete disruptions or dislocations of the SI joint are associated with rupture of the anterior and posterior SI joint ligaments. A rotationally and/or vertically unstable pelvis characterizes these injuries. Because of the poor results with persistent SI joint subluxations and dislocations, surgical reduction and stabilization is recommended.

Open treatment of SI joint disruptions can be performed from either the supine or prone position. Stabilization in the supine position usually is achieved using the lateral window of the ilioinguinal surgical exposure. After debridement of the joint space, the dislocation is reduced. Care must be taken with exposure across the SI joint to avoid excessive medial dissection and prevent injury to the L5 nerve root. Distal ipsilateral femoral traction, Schanz pins within the ilium, tenaculum clamps, Farabeuf clamps, pelvic reduction clamps, and a femoral distractor used in compression may all be helpful in reducing SI joint disruptions.^[48]

Stabilization is achieved with either 3.5- or 4.5-mm pelvic reconstruction plates placed perpendicular to one another across the SI joint. Plates should be contoured carefully to avoid distraction at the inferior portion of the SI joint.^[26] The S1 nerve root is at risk when drilling and inserting a screw within the sacral ala, and fluoroscopic guidance is recommended.

Stabilization of SI disruptions from the prone position uses a vertical paramedian dorsal surgical exposure; however, one must be wary of significant wound problems that may develop using posterior exposures in a compromised soft-tissue envelope.^{[21, 39]} Unlike anterior surgical exposures, reduction of the SI joint is performed indirectly because visualization is compromised as the joint is brought into reduction. Reduction is verified manually by palpation of the anterior aspect of the SI joint through the greater sciatic notch, and radiographically with intraoperative fluoroscopic imaging. Reduction of the dislocated ilium to the sacrum may be assisted with clamps placed through the greater sciatic notch clamping the posterior iliac wing to the sacral ala.^{[46, 49]} Stabilization is obtained with combinations of transiliac plates using either pelvic reconstruction or dynamic compression plates, transiliac screws, and iliosacral screws.

Use of iliosacral screws has gained popularity for stabilization of SI joint disruptions. Percutaneously placed iliosacral screws have been used after both open and closed reduction of SI joint disruptions. Iliosacral screws may be placed in either the prone or supine position with good results.^{[46, 47, 50]} When using percutaneous techniques for posterior ring stabilization, it is helpful to reduce and stabilize the anterior pelvic ring injuries, which indirectly reduce the posterior ring, thereby allowing safe iliosacral screw placement.^[37]

Careful examination of plain radiographs and CT scans is essential in evaluating sacral morphology and planning for safe iliosacral screw placement.^[37] Cannulated iliosacral screws are inserted under fluoroscopic guidance using inlet, outlet, and lateral sacral images.^{[37, 51]} Others prefer solid iliosacral screw placement, with which the tactile sensation of the drill bit engaging the sacral ala and sacral body is used to assist fluoroscopic imaging in safe placement of iliosacral screws.^{[46, 52]} Still others favor CT scan–guided placement of iliosacral screws.^{[53, 54]} Each technique has its advantages and associated potential problems, but each demands that the surgeon understand the local anatomy and achieve accurate reductions.

Sacral fractures

Sacral fractures frequently occur with pelvic ring injuries. Sacral fractures commonly are classified by the location of the sacral fracture. Type I fractures involve the sacral ala, type II fractures involve the sacral foramina, and type III fractures involve the central portion of sacrum.^[55] Roy-Camille has further subclassified central sacral fractures.^[35] Operative stabilization of sacral fractures is indicated in those fractures that are displaced, those that lend themselves to pelvic ring instability, and those sacral fractures with foraminal debris causing a neurologic deficit.

Sacral fractures usually are treated by indirect reduction techniques unless a need for foraminal decompression is present or an acceptable reduction cannot be obtained by closed manipulative means. Open treatment is performed in the prone position using a vertical paramedian dorsal surgical exposure. Direct access to the posterior sacrum is achieved by elevating the paraspinal muscles from the sacrum, whereby decompression of sacral foramina may be accomplished. After fracture reduction, stabilization is obtained with transiliac bars, transiliac screws, transiliac plates, or iliosacral screws. Despite the implant, care must be taken not to over-compress the sacral fractures and potentially create an iatrogenic sacral nerve root injury.

Iliosacral screws may be placed in the supine or prone position to stabilize sacral fractures after closed manipulative means. Reduction and stabilization of associated anterior fractures facilitate reduction of sacral fractures, allowing safe iliosacral screw placement.^[37] Contraindications to percutaneous iliosacral screw technique are an inability to obtain reduction of the sacral fracture, sacral dysmorphism, or fractures of neural foramina requiring debridement. Neurodiagnostic monitoring should be considered when foraminal debris is present and/or foraminal decompression is undertaken. Several different types of monitoring have been used with good results, including somatosensory evoked potentials, continuous electromyographic monitoring, and stimulus evoked electromyography.^{[49, 56, 57]} Neurodiagnostic monitoring does not protect the patient from a surgeon with poor understanding of the anatomy and its radiographic correlations.

Preoperative traction to prevent large pelvic translations and provide patient comfort is a consideration for patients with displaced pelvic fractures. Skeletal traction is preferred in the ipsilateral distal femur if not contraindicated. Ten to 30 pounds of traction is sufficient to meet the goals of provisional stabilization. Patients with injuries of the sciatic nerve should be splinted to avoid equinus deformities.

Deep venous thrombosis (DVT) prophylaxis is recommended in the preoperative setting. Both mechanical and pharmacologic methods are available for DVT prophylaxis. Subcutaneous heparin, low-molecular-weight heparin, warfarin, and aspirin are all used for DVT prophylaxis. Compression hose and sequential compression devices also are used in combination with pharmacologic methods to prevent DVT formation. Internal venal caval filters are used occasionally when pharmacologic prophylaxis is contraindicated or a DVT has been detected. Consideration should be given to preoperative duplex ultrasonography, especially in patients with prolonged recumbency prior to surgery.

A screening hematocrit must be obtained, and the patient must have a type and crossmatch prior to surgery. Cell savers are valuable tools to decrease the need for blood transfusions and should be reserved in the preoperative period.

Patients with neurologic injuries require special consideration in the preoperative period. Sciatic nerve palsies must be recognized, and splinting of the ankle is required to prevent equinus contractures. Injuries to all, or portions of, the lumbosacral plexus may occur with pelvic ring injuries. When possible, these injuries should be clearly documented in the preoperative setting to avoid confusion about potential iatrogenic injuries. Neurodiagnostic monitoring may be desirable, and should be arranged preoperatively if so.

If intraoperative fluoroscopy is to be used and the patient has ingested oral contrast, an AP pelvic radiograph is recommended preoperatively to ensure that fluoroscopic visualization is adequate. Residual contrast should be evacuated prior to surgery and a repeat AP pelvic radiograph performed after bowel evacuation.

Preoperative templating of plates to a skeletal model may prove beneficial by decreasing operative time and increasing operative efficiency. For example, transiliac plates are easily contoured to a skeletal model and after sterilization may be applied to the ilium with minor modifications as needed.

The operative table usually is chosen to allow intraoperative fluoroscopic imaging, and a radiolucent table is recommended. For supine positioning, a lumbosacral support is placed beneath the patient's back along the axis of the spine, which allows iliosacral screw insertions if needed. The arms are placed at 90° to the body on padded arm boards to allow proper positioning of the C-arm. If traction is to be used, a traction apparatus from the table can be used, or traction may be applied by hanging the weights over the side of the table.

Prone positioning is performed on the same table using padded chest rolls, which relieve abdominal pressure and allow ventilation. Pads are placed anterior to the knees, and pillows are placed anterior to the legs to elevate the toes off the table. The arms are placed in a flying position with 45° of shoulder abduction and neutral shoulder elevation. The elbows are flexed to 90°, and the hands are positioned pronated on the arm boards.

If neurologic monitoring is used, the setup should be performed preoperatively. The technician should establish the workings of the setup, and baseline values should be obtained. An understanding should exist between the examiner and the anesthesiologist regarding the type of anesthetic agents because neurologic recordings vary with certain anesthetics.

Portable postoperative AP, inlet, and outlet pelvic radiographs are taken in the recovery room to assess pelvic ring reconstruction and implant safety. If these radiographs are inferior in quality, then consideration should be given to taking radiographs in the radiology department on discharge from the recovery room. Postoperative CT scanning is recommended to assess pelvic ring reduction and implant safety, particularly when iliosacral screws are used.

Pain control in the postoperative period is important to enhance patient mobilization. Epidural narcotics provide excellent pain relief in the acute postoperative period; however, one must be aware of potential epidural bleeding with concurrent anticoagulation. Patient-controlled analgesia machines work well to alleviate postoperative pain, and patients do not depend on nursing administration of narcotic analgesics. Long-acting oral narcotic medications may be useful as an adjunct to patient-controlled analgesia to provide sustained pain control. After discontinuation of intravenous narcotic medications, both long-acting and short-acting oral narcotics are used to manage postoperative pain.

DVT prophylaxis is important postoperatively and should be managed aggressively. Mechanical methods, such as support stockings, work to decrease venous stasis, thereby decreasing the risk of DVT formation. Sequential compression devices also work to decrease venous stasis, but they also may have a role in stimulating the fibrinolytic system and tissue factor pathway inhibitor release.^[58]

Pharmacologic DVT prophylaxis consists of subcutaneous heparin, low-molecular-weight heparin, warfarin, and aspirin. The choice of agent is beyond the scope of this discussion, but evidence suggests that combined mechanical and pharmacologic prophylaxes may result in greater protection than either alone.^[58] Inferior vena caval filters may be placed perioperatively in patients in whom pharmacologic DVT prophylaxis and treatment are contraindicated and also in patients with documented DVTs.

Patients are mobilized based on their particular injury pattern, with a goal of full weight bearing by 3 months postoperatively. After discharge from the hospital, patients are seen in follow-up 2 weeks postoperatively for a wound check. Patients are seen again 6 weeks postoperatively for repeat clinical and radiographic examination. Further postoperative visits are scheduled at 3, 6, and 12 months postoperatively.

Muscle ruptures and hernias

Muscle ruptures and hernias have been reported infrequently with pelvic ring injuries. Ryan noted that APC injuries were associated with avulsion of the medial portion of the rectus abdominus muscle, which could give rise to ventral hernias.^[59] Ryan also noted an association of direct inguinal hernias with pubic rami fractures occurring after disruption of the posterior wall of the inguinal canal.^[59] These are avoided when open reduction/internal fixation is selected for these fractures because the associated soft-tissue injuries are repaired at the time of closure. Bowel perforation, bowel entrapment, and bowel herniation also have been documented with comminuted iliac wing fractures.^[43]

Neurologic injury

Approximately 10% of all patients who sustain pelvic fractures also sustain neurologic injury. Most neurologic injuries involve the L5 and S1 nerve roots of the lumbosacral (LS) plexus; however, a significant number of patients also experience sexual dysfunction secondary to nerve injury of the lower sacral nerves.^{[18, 60]} Associated sacral fractures account for many neurologic deficits with pelvic ring injuries. Denis reported a 28% incidence of nerve injury in patients after transforaminal sacral fractures and a 56% incidence of nerve injuries if the central sacrum was fractured.^[55]

The results of a retrospective review study on patients with pelvic fractures noted that while LS plexopathy was not associated with fracture location, the incidence and severity increases with the increasing number of anatomic fracture locations and with increased fracture instability. The results suggest that LS plexopathy may be the result of both indirect injury and simple direct compression by displaced bone.^[61]

Femoral nerve palsies may develop secondary to iliac hematoma and pubic ramus or certain acetabular pattern fracture displacements. Fractures of the pubic ramus at the superolateral aspect of the obturator foramen may cause obturator nerve injury. Lateral femoral cutaneous nerve injuries also may occur as a result of a direct blow to the lateral pelvic region in proximity to the anterior superior iliac spine and fracture displacement of this area.

Postoperative wound infection

The incidence of postoperative wound infection is low after anterior surgical exposures to the pelvis; however, the incidence increases with indwelling suprapubic catheters, colostomy, or drains in the region of the surgical incisions.^[24] Posterior surgical exposures are associated with higher instances of postoperative wound infection related to the soft-tissue injury, particularly those injuries associated with closed internal degloving injuries.^{[16, 39]} Postoperative wound infections after percutaneous fixation techniques are very low in incidence, occurring only infrequently.^[62]

Nonunion after a pelvic fracture is uncommon, whereas malunion is more common. Pennal and Massiah evaluated 42 patients with delayed union and nonunion after pelvic fractures. They found that 15 of 16 patients who were treated surgically with stabilization and bone grafting demonstrated union. Nonunions in patients treated nonoperatively did not heal; these patients had poorer outcomes than the surgically treated group.^[63] Matta and Tornetta treated 37 patients with pelvic malunions and nonunions. They highlighted the need for multiple-staged procedures to achieve satisfactory results, which were achieved in 32 patients, although 19% of the patients suffered complications.^[64]

Proximal DVTs

Proximal DVT have been reported in as many as 61% of pelvic fracture patients without prophylaxis.^[65] Magnetic resonance venography has documented a 34% incidence of proximal DVT in patients with acetabular fractures who were treated prophylactically with low-dose heparin and mechanical compression devices.^[58] Documentation of proximal DVTs is important because these are most likely to embolize to the lungs. The incidence of pulmonary emboli is 2-12% in patients with pelvic fractures, whereas fatal pulmonary embolism has been reported in 0.5-10% of patients sustaining pelvic fractures.^[58] Detection of proximal DVTs with venography or magnetic resonance venography is expensive and often impractical in the polytraumatized patient; therefore, the most effective treatment of patients with pelvic fractures is adequate prophylaxis.

Genitourinary

GU complications occur in up to 37% of patients with pelvic ring injuries.^[66] The most common GU complications occurring with pelvic ring injuries are bladder disruptions and ureteral disruptions, particularly in male patients. Less commonly, the ureters and kidneys may be injured.^[17] Dyspareunia and erectile dysfunction occur in approximately 29% of patients with pelvic ring injuries.^{[66, 67]} Dyspareunia usually is caused by a displaced ramus fracture, causing pressure on the vaginal vault. Erectile dysfunction can have many causes, including vascular injury, neurologic injury, and psychological stress. A patient with erectile dysfunction should be referred to a urologist for evaluation and treatment.

Early stabilization of pelvic ring injuries has demonstrated improved outcomes in patients with pelvic fractures. Stabilization of pelvic fractures immobilizes bleeding cancellous surfaces, thereby decreasing overall blood loss.^[6] Goldstein et al noted decreased operative time, blood transfusions, and hospital stays for patients who were treated within 24 hours of hospital admission.^[21] Similarly, Latenser et al noted decreased complications, blood loss, hospital stays, long-term disability, and better survival for patients treated within 8 hours of hospital admission.^[22]

Injury pattern and reduction of fracture-related displacements have been correlated with outcome results. Injuries involving the SI joint are associated with poorer results when compared with patients with either sacral fractures or iliac wing fractures.^{[2, 7, 20]} Posterior pelvic displacement of 5 mm has been identified as leading to poorer patient outcomes.^[10] Another study noted that patients with pelvic displacements greater than 1 cm in any plane had increased levels of pain when compared with patients with displacements less than 1 cm. Limb length discrepancy greater than 2.5 cm also has been implicated in poor results.^[20]

Permanent neurologic injury contributes to poorer patient outcomes after pelvic ring injury, and is present in approximately 20% of patients with unstable pelvic ring injuries.^{[24, 68]} Tile noted that permanent nerve damage led to unsatisfactory results in 12 of 248 patients.^[24] Templeman et al also noted that neurologic injury was associated with compromised outcome in patients with sacral fractures.^[62] Most neurologic injuries after pelvic ring injuries involve the L5 and S1 nerve roots, although injury may occur along any portion of the lumbosacral trunk. Management of neurologic injuries is expectant, as neurologic recovery has been documented as long as 4 years after injury.^[68]

Controversies in treating pelvic fractures revolve around the issue of pelvic stability. Definitions of pelvic stability are vague and hard to quantify in a clinical setting. As a result of a nebulous definition of pelvic stability, determining the type and amount of pelvic stabilization is also controversial. Perhaps Bucholtz and Peters best state the problem, as follows^[69] :

"As a general rule, if a posterior ring injury is nondisplaced or impacted, the pelvis is probably stable. If there is a superior or anteroposterior displacement of the hemipelvis of 1 cm or more, the pelvis is clearly unstable. All injuries between these 2 extremes may or may not be stable and must be evaluated and treated individually."

Most clinicians responsible for the care of patients with pelvic ring injuries will base instability on the physical exam. Instability is defined as the inability to resist deformation with physiological loading.

The future of pelvic fracture management will likely involve advances in imaging techniques. Except for major pelvic disruptions, the state of the posterior ligamentous structures is inferred from clinical, plain radiographic, and CT scans. Magnetic resonance imaging may one day have a role in visualizing the posterior ligamentous structures, allowing these injuries to be better defined.

Computer-assisted surgery is being developed and studied at various locations. Computer-assisted surgery comprises robotics, image-guided surgical devices, surgical navigation systems, preoperative planners and simulators, and augmented reality or hybrid reality computer interfaces.^[70] Computer-assisted surgery has been used successfully around the pelvis to assist with pelvic osteotomies.^[71] As the technology improves and familiarity grows with these techniques, computer-assisted surgery will likely be used in the management of pelvic fractures. Surgeons should not assume that computer-assisted surgery and robotics substitute for their personal knowledge of pelvic injuries and radiographic correlations. The pelvic anatomy, its injury patterns, and their treatments are to-date best directed by knowledgeable humans rather than computer software.