Executive Editor: Peter Trafton

Authors: Rahul Banerjee, Peter Brink, Matej Cimerman, Tim Pohlemann, Matevz Tomazevic

Pelvic ring - Unilateral complete disruption posterior arch through SI joint

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1 Introduction top


Before proceeding with definitive repairs, the patient must be fully resuscitated, fully evaluated, and fit for anesthesia and surgery by a prepared team.

Successful definitive treatment requires reduction and fixation of both the posterior and anterior injuries, generally completed in a single definitive procedure.

Complete pelvic ring instability may be obvious when displacement is gross, but it may also be occult, when initial displacement has been hidden by elastic recoil, poor imaging studies, or successful reduction by a pelvic binder.

This illustration shows inlet and outlet oblique views, with posterior and proximal translational displacement of a right sacro iliac fracture dislocation, with associated pubic symphysis disruption. Rotational deformity and instability, may also be present.

Emergency care for pelvic ring injuries should be available and preplanned at every trauma hospital. Patients with complex pelvic ring injuries may need to be referred to a specialized center. Definitive care of complex pelvic ring injuries may be centralized so that patient referral may need to be considered.

Lumbo-sacral nerve root injury

Before undertaking definitive treatment of pelvic ring injuries, It is essential to know the functional status of the patient's lumbosacral nerve roots. A careful and detailed examination is necessary, to assess perineal sensation, voluntary anal sphincter contraction, and bulbo-cavernosus reflex. Cystometrography may be helpful to assess bladder neuromotor function.

Neurologic abnormalities should be correlated with anatomic site of injury:

If a lumbo-sacral nerve deficit is present, further investigation and possible treatment must be considered.

Early pelvic realignment

Early recognition and at least partial correction of deformity is helpful, because the mobility of the pelvic fragments decreases with swelling and hematoma organization. Circumferential wrapping as soon as possible can help correct external rotation and lateral displacement. If proximal displacement is present, traction applied to the lower extremity can improve it. Such provisional corrections are best applied early during the patient's care, before swelling and hematoma consolidation progress. External fixation, if used for initial care may similarly aid subsequent definitive reduction.


Posterior injury

The posterior component of this injury is a dislocation or fracture dislocation of the sacroiliac joint.

Fracture dislocations are essentially crescent fractures, but the sacroiliac joint instability is total rather than only rotational. Identifying total instability may require stress x-rays or careful analysis of the preoperative CT.

The specific techniques of reduction and fixation will depend upon the sites of injury, the fracture pattern and displacement, as well as patient factors and available resources.


Anterior injuries

At least one site of anterior arch disruption is almost always present, involving

  • pubic symphysis disruption
  • body fracture
  • pubic ramus fracture

Their displacement and instability range from slight to extreme.

In general, pubic symphysis disruption, especially with significant displacement, should be treated with open reduction and internal fixation. Pubic ramus fractures, whose instability may be limited by soft tissue restraints may be treated with internal or external fixation. Their reduction may help reduce posterior arch displacement, and their fixation contributes to overall pelvic ring stability.

2 Preoperative planning top

An explicit, written pre-operative plan is strongly encouraged. The following provides an outline of recommended steps.

Assess and consider:

  • Whole patient (physiologic status and other injuries)
  • Pelvic region & organ systems (local details of pelvic region including soft tissues and related organ system injuries)
  • X-rays and CT scans (reviewed in detail for patients individual anatomy, each injury, and overall pelvic configuration)
    for patients individual anatomy, each injury, and overall pelvic configuration)


Identify and list each individual pelvic ring injury

For each injury, determine displacement, stability, and a strategy for reduction and fixation (relevant techniques are outlined and discussed below).


List, in order, each step of your planned procedure

Finally review the step-by-step list to:

  • Confirm plan
  • List equipment and implants
  • Consider potential problems and solutions
  • Share the plan with other members of the operative team – including nursing staff, radiographic technician, and anesthesia staff.


  • Minimizing the amount of additional soft tissue damage and operative blood loss is important. Efficient use of surgical time is required to avoid excessively long procedures.
  • Sufficient blood replacement must be available. Intraoperative blood salvage should be considered.

3 Patient preparation top

Combined supine and prone

If it is necessary to change positions intraoperatively (from supine to prone position or vice versa), the surgeon must choose the order for performing the procedures. This information must be communicated to the other members of the surgical and anesthesia teams.

In cases where both anterior and posterior approaches are required, simultaneous access is not possible. Thus, it is important not to apply fixation that might prevent satisfactory reduction of remaining ring injury components.


After completion of the initial procedure, in this example, the posterior one, the incision is closed, and a dressing applied.


The patient is turned “like a log” supine onto an adjacent stretcher.


The patient is then transferred, with a roller, sliding board or sheet, back onto the operating table.


The anterior operative area is prepared and draped as necessary.

If an anterior procedure to be performed first, followed by a posterior approach, the sequence is reversed, and the patient turned and transferred in a similar fashion.

4 Reduction top

General guideline

Once the injury sites have been identified and clarified with appropriate imaging studies, the surgeon can prepare for definitive deformity correction and pelvic fixation.

Reduction maneuvers follow the sequence below until satisfactory reduction is achieved at each site of deformity:

  • external manipulation
  • percutaneous control and manipulation of displaced pelvic segments
  • open reduction

If it is possible to obtain a satisfactory reduction without open exposure, and the bony injuries can be stabilized with percutaneous fixation techniques, this is preferable, to avoid additional blood loss and reduce the risk of wound healing problems.

Open surgery may be necessary to achieve satisfactory alignment or fixation. If so, the specific surgical approach should be planned according to the site of injury and chosen fixation technique. While preliminary reduction maneuvers may be helpful, the final direct reduction occurs after exposure.

It may be possible to achieve a satisfactory reduction of both anterior and posterior ring with initial ORIF of one site.

Restoration of overall pelvic alignment must be monitored with inlet and outlet imaging during reduction and fixation, and not lost sight of during repair of individual fractures.

Reduction of a pure SI dislocation with associated symphysis disruption

ORIF of pubic symphysis disruption, if performed first, will assist with reduction of the SI joint.

This can be assisted by manual traction on a supra-acetabular Schanz screw if necessary.

Any residual SI joint widening can usually be reduced by tightening an iliosacral lag screw. Be careful to use a washer and monitor screw-head with a tangential x-ray to avoid driving the screw through the outer table of the ilium, and compromising compressive fixation.

Before and after definitive fixation, confirm satisfactory overall alignment of the pelvis with C-arm fluoroscopy in multiple views, or inlet and outlet views with portable x-ray.

Reduction of a pure SI dislocation with associated pubic ramus fractures

Reduction of the SI joint usually results in satisfactory alignment of the ramus fractures. An external fixator can be applied for provisional fixation, and either left until the ramus fractures heal, or replaced with a ramus screw, or plate.

Before and after definitive fixation, confirm satisfactory alignment of the pelvis with C-arm fluoroscopy in multiple views.

Reduction of SI fracture dislocations

Unstable fracture dislocations of the sacroiliac joint typically involve an articular fragment of the posterior ilium (crescent fractures). This posterior iliac fragment is variably sized and remains attached to the sacrum by the posterior sacroiliac ligament.

If the majority of the iliac articular surface is intact, reduction may be performed as for a pure SI dislocation.

If satisfactory closed reduction of the SI joint cannot be achieved, anterior or posterior open reduction is performed.

With a large crescent fragment, iliosacral screw fixation may be impossible since the fracture line may interfere with the screw entry site. If so, ORIF of the crescent fracture may be the best option for repairing the SI joint. Depending on the fracture configuration and the soft tissues, this may be performed either anteriorly or posteriorly.

Reduction of the SI joint usually results in satisfactory alignment of the anterior arch, which typically involves fractured rami.

Restoration of normal pelvic alignment must be monitored during reduction and fixation, and not lost sight of during repair of individual fractures.

5 Fixation top


Pure SI joint dislocation

Many pure SI joint injuries can be reduced with closed techniques. In this case percutaneous iliosacral screw fixation has become the preferred technique in most centers.

It is essential to remember that the anatomical channels for screw placement are narrow. Unless traumatic deformity is corrected, iliosacral screw placement risks injury to nerves and vessels, as well as fixation failure.

Remember also that the congenital dysmorphic upper pelvis is fairly common. It must be recognized and iliosacral screw locations planned appropriately.

If available, the use of intraoperative navigation may be beneficial


If a satisfactory closed reduction of the SI joint cannot be achieved, open reduction through an anterior or posterior approach is indicated. The approach is selected to best address the presumed barrier to closed reduction.

Internal fixation can be with either:


The anterior SI Joint plate fixation is performed through the anterior approach to the iliac wing and SI joint.


Sacroiliac fracture dislocation

Fracture dislocations with a small crescent fragment are usually best addressed with an iliosacral screw, if satisfactory reduced.


Alternatively, such fracture dislocations can be repaired through a posterior approach using direct interfragmentary fixation with supplementary SI joint fixation if necessary.



This can be performed through the anterior approach to the iliac wing and SI joint.


Pubic symphysis

A pubic symphysis plate is indicated for symphyseal disruption and/or pubic body fractures.





Pubic ramus

Pubic ramus fractures have several options.

If alignment is satisfactory, they can be treated with external fixation until they are healed:


Alternatively, percutaneous intramedullary screw fixation can be performed to avoid external fixator complications and inconvenience.


If closed reduction of pubic ramus fractures is not satisfactory, open reduction should be considered.





6 Check of osteosynthesis top


Check the completed osteosynthesis with Imaging, and physical exam if there is any question about pelvic stability.

Using inlet and outlet views, with the C-arm, confirm that pelvic deformity has been corrected and that involved sacroiliac joints and pubic symphysis are anatomically reduced.

Unless a C-arm with a large field of view is available, it may be wise to obtain similarly oriented portable x-rays of the entire pelvis, to be certain about overall alignment.

Confirm that reduction of each fracture or joint injury is satisfactory. Make sure that all fixation devices are properly placed, and that each screw is of appropriate length. Multiple views are typically needed, including both axial and perpendicular views for questionable screws. If screws protrude from bone, consider risks to nerves, vessels, and adjacent viscera, especially urethra and bladder after pubic symphysis repair.

v1.0 2015-12-10