12.47 Pelvic fracture: definitive management

The aim during definitive management is to produce a stable, pain-free pelvis with minimal functional limitations and avoidance of complications.

Ideally optimal treatment in the acute and definitive phases of treatment should be complementary but can, however, conflict. This can be problematic if definitive treatment is to be performed in another facility. Even if the admitting facility is not involved with definitive management it is important that definitive treatment options are understood.

During the period between early and definitive management the patient must be actively managed and steps should be taken to avoid complications.

Timing of definitive fixation needs to consider the disadvantages of early and late surgery. In the physiologically unstable patient, definitive fixation can be associated with higher levels of blood transfusion, organ failure, multiple organ failure, and death. Long operations have a greater physiological impact and are associated with a worse outcome. It is therefore appropriate to postpone definitive fixation until the patient is fit for surgery. Problems associated with the ‘second hit’ are believed to be minimized if surgery is delayed until after day 4. Fracture stability is part of the optimal treatment of open fractures and this will influence timing and method of fixation. Prolonged delay to surgery increases the risks associated with immobilization. It also increases the technical difficulty of achieving anatomical results and this has been associated with worse outcome. The technical difficulties of delay can be mitigated to a degree by holding the pelvis in a reduced position with external fixation and skeletal traction in the case of vertical displacement.

Venous thromboembolism (VTE) is a significant problem in pelvic fracture patients as they frequently have many of the well established risk factors:

The presence of any of these risk factors in association with pelvic fracture results in a significantly higher incidence of VTE. In addition, these patients may not have received appropriate thromboprophylaxis due to haemodynamic instability. Deep venous thrombosis (DVT) has been reported with an incidence as high as 61% in pelvic fractures that have not received DVT prophylaxis. With DVT prophylaxis the incidence is reported as 2–33%. Pulmonary embolus (PE) is reported as occurring in 2–13%. Fatal PE is reported with an approximate incidence of 1%. Early thromboprophylaxis is important as 6% of PEs occur within the first 24h.

Strategies to minimize the problems associated with VTE include early mobilization, screening, mechanical and chemical prophylaxis, and inferior vena cava (IVC) filters.

Although the majority of DVTs originate in the legs, in pelvic fractures approximately half involve the pelvic veins. Ultrasound and venography are poor investigations for deep pelvic vein thrombosis and magnetic resonance (MR) venography has been reported as the gold standard. There is no consensus at present with regard to screening.

Where possible, chemical thromboprophylaxis with low-molecular-weight heparin should be used; however, this can be problematic in this patient group due to both the acute haemorrhage and the need for operative intervention. Pulsatile compression devices are an alternative in those patients in which chemical thromboprophylaxis is contraindicated. Their use is limited in the presence of lower extremity injury and the benefit, on their own, has not been conclusively proven.

IVC filters can be used in high risk patients, those with established DVT and as an alternative to chemical prophylaxis (Figure 12.47.1). A review of studies (1983–2005) reporting on IVC filter use reports a 13% complication rate. Complications include malposition, migration, insertion site thrombosis, difficulty removing the device, and occlusion. Occlusion has been reported as 15%, but can be reduced to 8% with anticoagulation.

Pressure areas must be protected particularly in the unconscious patient and those on traction. Wound care will minimize the risk of sepsis from wounds and pin sites prior to definitive surgical treatment. Constipation should also be avoided as faecal loading causes discomfort and can greatly limit intraoperative image intensifier visualization.

Treatment strategies need to consider residual pelvic stability, strength of fixation, deformity, pain and neurologic deficit.

Stability is the key to managing pelvic fractures. Stability can usually be interpreted from the clinical assessment, x-rays and CT (see Chapter 12.46). Where stability, in the vertical and horizontal planes, has been maintained, non-operative treatment can be considered with immediate full weight bearing as tolerated.

Where stability is deficient, fixation can be used to compensate until sufficient healing has occurred (pubic rami 4–6 weeks, sacroiliac (SI) joint 12 weeks). It is important therefore that the fixation used is capable of performing the task. Bone quality and the condition of the soft tissues will have a significant impact on the choice of fixation technique.

In displaced rotationally unstable fractures where vertical stability is maintained, as a result of the intact posterior ligament complex, anterior fixation alone is adequate. Posterior fixation is usually required in pelvic injuries with complete instability of the posterior pelvic ring.

Deformity also influences the treatment strategy. In lateral compression (LC) injuries significant internal rotation of the hemipelvis is also associated with rotation in the sagittal plane and subsequent relative leg length discrepancy (Figure 12.47.2). Significant leg-length discrepancy and internal rotation are indications for operative intervention. Thresholds for acceptable displacement will be dependent on the patient and it has been recommended that operative intervention should be considered for rotation greater than 10 degrees and leg-length discrepancy of more than 0.5cm. When the rotation deformity is sufficient to prevent external rotation it will prevent normal gait. Prominence and asymmetry of the pelvic bony prominences can also cause problems. Fractures involving the relative height of the ischial tuberosities will affect sitting stability.

Pain is a factor in both short- and long-term goals. Stabilization of fractures reduces pain and allows for easier and earlier mobilization. There are occasions in patients with minimally displaced stable pelvic ring injuries where a short period of temporary stabilization, provided by an anterior external fixation, for pain relief will be of benefit. Pubic rami fractures can heal quickly and allow the frame to be removed.

In the long term, pain significantly affects outcome. Pubic rami fractures may cause dyspareunia and displacement of more than 5mm has been demonstrated to be problematic in females. Pain is particularly problematic in pelvic fractures involving disruption of the SI joint. Anatomical reduction of the posterior ring (<5mm displacement) is believed to correspond to a better outcome. However, this appears to be more significant in injuries involving the SI joint.

Treatment must avoid causing neurological deficit and there are certain circumstances and techniques that may place neurological structures at risk. Percutaneous techniques in particular SI screws require experience and adequate intraoperative imaging. Sacral fractures may result in neurological compromise as a result of compression at the time of injury or treatment.

The indications and outcomes of sacral nerve root decompression have not been fully established. Denis zone II and III fractures with identifiable compression may benefit from open reduction and decompression; delays of 2–3 days are believed to be acceptable. It is reported that there will be an overall improvement in at least 30% of cases regardless of treatment. Higher rates of recovery have been reported following decompression.

The categorization provided by classification systems helps to establish the residual stability of the pelvic ring. It is this understanding which allows the correct treatment decisions to be made.

These fractures do not compromise the stability of the pelvic ring and the vast majority can be treated non-operatively.

Fractures of the anterior superior and anterior inferior iliac spines occurs as a result of avulsion of the sartorius and rectus femoris muscles, respectively. This most frequently occurs in adolescents. Treatment is symptomatic.

Transverse fractures of the sacrum, below the level of the sciatic buttress, occur as the result of a direct blow. Operative treatment is considered when there is significant angulation particularly in association with a neurological deficit, but this is rare.

These fractures also occur as a result of a direct blow and may be associated with significant overlying soft tissue injury. Treatment is usually non-operative. When there is gross displacement that is likely to result in unacceptable cosmesis or gluteal muscle dysfunction, operative intervention can be considered (Figure 12.47.3). These injuries can be very painful.

When displacement of the symphysis pubis is less than 2.5cm the ligaments of the pelvic floor and the integrity of the posterior ring is likely to be intact. Non-operative treatment is appropriate with weight bearing as tolerated.

These fractures are associated with horizontally orientated pubic rami fractures and an impaction fracture of the sacrum. The pelvic floor and posterior ligaments remain intact. This is a stable fracture pattern that can usually be treated non-operatively. The patient can weight bear as tolerated.

These fractures can occur without disruption of the posterior pelvic ring and are associated with straddle injuries, e.g. fuel tank of motorcycle. As pelvic ring stability has not been compromised the injury can be managed non-operatively; however, operative fixation should be considered with significant displacement.

This fracture pattern is seen in APC injuries with disruption of the pelvic floor ligaments and displacement greater than 2.5 cm. The hemipelvis externally rotates on a hinge (intact posterior SI ligaments) and maintains vertical stability. Plating the symphysis restores stability of the pelvic ring in the horizontal plane and facilitates healing of the soft tissues in an anatomical position. Late plate failure as a result of fatigue is frequently seen, however at this stage stability has usually been achieved by the healed soft tissues. An external fixator can be considered instead of a plate if the soft tissues are not appropriate. The anterior fixation will be under tension in double leg stance and compression in single leg stance. Following operative fixation weight bearing is protected for 6–8 weeks although some authors have advocated weight bearing as tolerated.

This fracture pattern is seen with lateral compression associated with complete disruption of the posterior ring. Horizontally orientated pubic rami fractures are associated with a fracture line that runs through the posterior ilium and often involves the SI joint. In both circumstances it is only the pelvic floor ligaments that remain intact, providing ‘relative’ vertical stability. Fractures of the ilium with significant displacement resulting in significant leg-length discrepancy or internal rotation should be considered for operative intervention. When a fracture/subluxation involves the SI joint, it is described as a ‘crescent fracture’ (Figure 12.47.5). This refers to the posterior ilium that remains attached to the posterior SI ligaments. These fractures are more unstable than lateral compression with anterior sacral crush and are usually treated operatively. Anterior fixation is usually achieved by plating, external fixation or percutaneous screw fixation of the superior pubic rami. Posterior fixation is required to anatomically reduce the SI joint and this can be achieved using closed or open techniques.

These fractures are vertically and rotationally unstable as a result of complete disruption of the anterior and posterior parts of the pelvic ring. Posterior disruption occurs through the ilium, SI joint, or sacrum. These fractures require both anterior and posterior fixation to restore stability.

In SI joint disruption, treated with open reduction, some surgeons will routinely fuse the SI joint.

Consideration and treatment is directed towards the individual components, as described earlier. However as the contralateral side cannot be relied upon to ‘anchor’ the fixation additional posterior fixation may be required to restore stability e.g. LC III or CMI (Figure 12.47.6).

Complex fractures through the sacrum, with vertical and transverse components, or traumatic spondylolisthesis from bilateral L5/S1 fracture dislocations may result in complete mechanical discontinuity between the lumbar spine and pelvis. These are rare high energy injuries that are frequently fatal. More frequently, vertical sacral fractures running through or medial to the L5/S1 facet joint may cause instability between L5 and S1. Sacral fixation in isolation may be inadequate and lumbo-pelvic fixation should be considered (Figure 12.47.7).

In the majority of pelvic fractures the optimal treatment will be non-operative. There will also be a small group of patients who will have indications for operative management but due to other circumstances are managed non-operatively. The aim is to mobilize early. The main limitations are pain and sufficient upper body strength to mobilize partial weight bearing. The patient will require adequate analgesia, a short period of bed rest followed by progressive mobilization with walking aids. Pain is a good indicator of healing and should be used as a guide to determine the progression from bed rest to mobilization with weight bearing as tolerated.

Anterior external fixation can be used in isolation or in conjunction with posterior internal fixation. Anterior external fixation is insufficient to maintain posterior reduction. Pins are placed into the iliac crest (Fig 12.47.8A) or supra-acetabular bone (Fig 12.47.8B). During the course of treatment external fixator pin sepsis may be problematic and both sites may be used consecutively.

External fixation using convergent pins placed in the thick strut of bone running from the anterior iliac crest to the acetabulum is relatively quick and familiar to most orthopaedic surgeons. Three pins are placed between the inner and outer table of the iliac crest. It is preferable to only drill the outer cortex and use 5-mm pins. The use of self-drilling pins increases the risk of breaking out of the inner or outer table. An appreciation of the anatomy of the iliac crest is important to ensure correct pin placement, pins are commonly placed too vertical in both the sagittal and coronal planes. As the iliac crest overhangs the outer table there is also a tendency for the entry point to be too lateral. A K-wire placed on the inside of the inner table can provide a useful guide. Considerations must be given to the surrounding soft tissues. When an external fixator is used to reduce an open book fracture the position of the optimum skin incisions will change. To accommodate the change in position it is often helpful to place the skin incisions perpendicular to the iliac crest directed towards the umbilicus. It is very common for the abdomen to swell following pelvic fracture and if this is not anticipated, problems with skin necrosis and infection arise (Figure 12.47.8C).

The main purpose of anterior external fixators used in isolation is to restore horizontal stability in a rotationally unstable pelvis. Biomechanically this reduction is best achieved with supra-acetabular pins placed adjacent to the anterior inferior iliac spine directed posteriorly into the thick bone of the sciatic buttress. One or two pins can be linked with a simple frame to achieve this goal. Placement of these pins requires the image intensifier and therefore is rarely suitable in the acute management of haemodynamic instability.

External fixation, either used temporarily or definitively, is associated with a significant incidence of sepsis and aseptic loosening

Fixation of the pubic rami or symphysis pubis can restore the anterior pelvic ring. Not all pubic rami fractures will require fixation and those fractures with up to 1.5cm of displacement will have sufficient retained soft tissue stability that fixation may not be necessary. In vertical shear posterior injuries the risk of failure is related to the anterior fixation, plate fixation is stronger than external fixation and has been associated with less late displacement.

The approach used will depend on the position of the fracture. Disruption of the symphysis pubis and medial pubic rami fractures can be obtained through a Pfannensteil approach. Access to the superior aspect of the pubic symphysis is achieved by a split between the distal rectus abdomini. This allows access to the extraperitoneal space. Often the recti are torn and some of the dissection will have already been accomplished by the injury. A limited amount of sharp dissection of the rectus abdominis insertion will improve exposure. Reduction can be achieved with reduction forceps. In rotationally unstable injuries a single 3.5-mm reconstruction plate is usually sufficient when the bone quality is adequate (see Figure 12.47.4). Specialized plates are available that avoid leaving a stress riser (unfilled screw hole or thin part of the plate) directly over the symphysis. In completely unstable injuries double plating, with an additional plate applied anteriorly, can be consi dered in addition to the posterior fixation; however, some surgeons believe a single plate is adequate.

An alternative to plating the pubic rami fractures involves using pubic rami screws that can be inserted percutaneously in an antegrade or retrograde direction. Their trajectory is similar to that described for anterior column screws (see Chapter 12.49).

Many methods and combinations have been described. The technique used will depend on the fracture position, configuration, and displacement. In addition the surgeon must also take into account the soft tissues, neurological deficit, patient positioning, available equipment, and experience.

Open or closed reduction techniques have been described. Open reduction techniques have the benefit of reducing under direct visualization but incur the risk of the open approach. Posterior approaches use either a midline incision or a longitudinal incision 2.5cm lateral to the posterior superior spine. The gluteus maximus and multifidus muscles can then be mobilized. Posterior open approaches have been associated with a high incidence of wound problems and infection (3–27%).

Mechanical differences have been identified between the fixation techniques. In general, two points of fixation are preferable and none of the techniques are sufficiently strong to allow unrestricted weight-bearing. Two SI screws or one SI screw and anterior SI plating have been shown to be the strongest constructs most commonly used. A lumbopelvic triangular construct can also be considered, however this is overtreatment for many fractures.

SI screws are commonly placed through the posterior aspect of the ilium into the body of S1. If space permits, two screws can be placed in S1 or alternatively a second screw can be placed in S2 (Figure 12.47.9). The screws can be placed with the patient supine or prone. The percutaneous technique is very dependent on operator experience and good image intensification. The technique requires using the image intensifier to obtain good quality inlet, outlet and lateral views. Inaccurate placement is associated with the risk of injury to L5, sacral nerve roots (within the foramen and canal), iliac vessels, superior gluteal nerve and vessels. The risk has been shown to increase significantly when the sacral fracture is incompletely reduced or there is sacral dysmorphism. Nerve injury has been reported as less than 1%; however, it must be appreciated that this complication rate is not transferable.

Transforaminal vertical sacral fractures stabilized posteriorly with SI screws should be closely observed over the first 3 weeks as loss of fixation has been reported in 13%.

Anterior SI plating can be performed through the lateral window of the ilioinguinal approach (see Chapter 12.49) using two orthogonal plates passing from the sacral ala to the anterior aspect of the posterior ilium. It has the advantage of being performed with the patient supine using an incision with low morbidity. In addition it facilitates direct visualization of the reduction, direct placement of fixation and allows the SI joint to be debrided to facilitate fusion if required. However, it is restricted as it can only be used in a pure SI joint injury with an intact sacral ala. Only one screw in each plate can be inserted into the sacral ala due to the close proximity of the L5 nerve root which runs over the sacral ala approximately 1cm from the anterior aspect of the SI joint.

These devices require posterior incisions that are associated with problems of wound breakdown; however, minimally invasive techniques have been described. Metal work prominence can be problematic in thin patients. Posterior plating can be used in conjunction with neural decompression and can maintain distraction in fra cture patterns associated with compression.

This is considered to provide the highest mechanical stability. Pedicle screws can be placed into L4 and L5 and linked to screws placed into the posterior ilium (see Figure 12.47.7). Cross links create a triangular construct. This can be used in lumbosacral injuries and can be considered in Denis II and III fractures.

The posterior ilium retains attachment to the posterior SI ligament complex. Anatomical reduction and fixation of this fragment to the rest of the ilium restores posterior stability. The choice of fixation techniques is dependent on the size of the crescent fragment. Large fragments are suitable for open or percutaneous fixation. Open techniques use the lateral window of the ilioinguinal approach (described in Chapter 12.46) with direct visualization of the fracture and SI joint. Anterior plating techniques can be used. Closed techniques have also been described. Following closed reduction one or two partially threaded ‘LC II’ screws can be passed through the supra acetabular corridor (similar to supra acetabular external fixator pin) across the sciatic buttress into the crescent fracture (Figure 12.47.12).

Smaller fragments may necessitate a posterior approach with fixation performed directly using plates and screws or closed reduction and SI screws to stabilize the SI joint (Figure 12.47.5).

Open reduction and internal fixation can be painful and this is often best managed during and after the operation with epidural analgesia. The epidural catheter is usually removed over the following 3 days so that the patient can start to mobilize.

Weight bearing as tolerated can be considered for fractures that retain horizontal and vertical stability. Fractures that require posterior fixation require protective weight bearing until sufficient healing has been achieved (8–12 weeks). The patient should be instructed by the physiotherapists to only touch weight bear (equivalent of the weight of their leg). Bilateral injuries will necessitate wheelchair mobilization until full weight bearing on one limb can be tolerated.

X-rays (AP, inlet, and outlet) should be performed postoperatively and if there are concerns about hardware placement a CT scan may be required. Further x-rays should be performed frequently if there are concerns about stability, otherwise routine follow-up at 6-weekly intervals until the fracture is united.

In addition to mobilization, physiotherapy should help with breathing exercises, hip range of motion exercises, and general conditioning.

Complications related to specific problems and techniques have already been discussed. General problems are discussed below.

Infection rate is very dependent on the technique used. Posterior approaches are the most problematic (3–27%). Percutaneous approaches have generally very low rates of infection; however it has been considerable in some studies and is believed to be secondary to soft tissue injury. Large series generally report infection rate at less than 5%.

The overall incidence of this complication is unknown but appears to be very small. The risk of non-union increases with displacement and instability.

There are no controlled trials to allow direct comparison of the outcomes of non-operative and operative treatment options. Much of the evolution has been based on comparison with historical studies and expert opinion. Many studies have attempted to correlate features related to pelvic fracture and outcome. The results of these studies are not conclusive. This has been attributed to significant confounding variables, in particular the measurement methods and associated injury.

In general there is acceptance that the outcome is worse with increased severity of pelvic injury. However, severe pelvic injury is more likely to be associated with a higher incidence of significant associated injuries and neurological deficit. In addition it can also make reduction harder. Pure SI joint injury appears to have worse outcome than fractures and fracture dislocations of the posterior ring, especially when associated with non-anatomical reduction. However anatomical reduction of any pelvic ring injury pattern does not guarantee a good outcome. The opposite is also demonstrated with some displaced unstable injuries reporting relatively good outcomes. Correction of leg length discrepancy has been correlated with better outcome scores in some studies.

Outcome measurement varies amongst studies and the methods used influence the ability to identify good and bad outcome groups. Health survey questionnaires such as SF-36 and Sickness Impact Profile are useful measures of general health but are influenced by the cumulative severity of all injuries. Some authors have used more pelvic specific scoring systems, e.g. Iowa Pelvic Score, Majeed, etc.

Many studies have inconsistently correlated outcome with classification systems that amalgamate very different osteoligamentous injuries into groups based on stability. Outcome based on injury types has demonstrated clear differences within these groups. APC injuries in general have worse outcome than lateral compression injuries however both are classified as rotationally unstable. In a large study comparing functional outcome rotationally unstable lateral compression patterns (LC II + III) had a good or excellent outcome in 92% compared with 74% in rotationally unstable APC injury (APC II); despite a difference in anatomical reduction 75% vs 94%. In the same study completely unstable fracture patterns had an anatomical reduction in 63% and a good or excellent outcome in 71%. It is also apparent that within the completely unstable fracture group there are different outcomes depending on the type of posterior injury.

A significant proportion of pelvic fractures are not associated with multisystem trauma and are satisfactorily managed non-operatively or with minor surgical intervention. As a result they will not need transfer to a specialist centre for treatment. Due to the relative rarity of the injury only the specialist centres are in a position to publish on the subject, resulting in a bias in the study population presented.

One of the most frequently used outcome measures is return to work. Although not directly comparable it does allow for the physical impact of the injury to be appreciated. Not all patients who return to work will return to the same job, however in most studies the majority do. Overall approximately 75% of pelvic fractures return to their original employment. In studies looking at rotationally unstable injuries, 85% return to work has been reported in contrast to 33–69% of completely unstable injuries. Difficulty in sitting has been reported as high as 60% in rotationally and completely unstable injuries.

Pelvic pain is a significant feature in the outcome of pelvic fractures. Low back pain is common in sacral and sacroiliac injury and the overall incidence has been reported at 17–90%.

In rotationally unstable injuries, pain of some degree is reported in 11–45%. In a study reviewing patients treated with external fixation they were functionally normal if the pelvis remained reduced but 80% required analgesia for posterior pain if reduction was not maintained. A German multicentre study identified persistent pain in 32% of rotationally unstable APC type injuries in contrast to 18% in those rotationally unstable fracture patterns that result from lateral compression.

In vertically unstable fracture patterns significant pain is reported in 30–90% and has been correlated with residual displacement. In these fractures the average patient has been reported as having an average visual analogue score (VAS) at rest of 2.8 and 4.1 when ambulating. This was noted to be higher in those patients with an unresolved lumbosacral injury or extremity injury.

The outcome of pelvic fractures is very dependent on the contribution of the frequently occurring significant associated injuries.

A significant proportion of severe pelvic injury have an associated neurological deficit. It is the presence of a neurological injury that has been a consistent determinant of poor outcome. In addition to neurological deficit the neurological injury is believed to contribute to pain. Nerve injuries have been reported in 5–17% of rotationally unstable (more common in APC type injuries) and 25–40% of completely unstable fractures. Nerve injuries seen in rotationally unstable fractures have been noted to be more likely to recover than in completely unstable injuries, 70 vs 29% respectively. In sacral fractures displaced more than 10mm, 87% were identified as having a sensory deficit, 45% motor dysfunction of the lower extremities, 52% voiding dysfunction, 36% bowel dysfunction, 39% altered sexual function, and 65% gait impairment. In this group only 33% returned to work.

In completely unstable pelvic fractures the frequency of long-term urinary dysfunction (frequency, incontinence, retention, urethral stricture and urgency) is 37%.

The psychological impact of being involved in an accident and sustaining serious injuries is becoming increasingly understood. Treatment of the physical problems in isolation may be inadequate in optimizing a patient’s outcome.

Sexual function is an important aspect of pelvic fracture outcome as a result of residual pain, urological, neurological, vascular, and psychological injury. Overall approximately 75% of pelvic fracture patients return to normal sexual function. Unstable pelvic injury patterns are associated with a 29–40% incidence of sexual dysfunction. Male sexual dysfunction has a reported incidence of 30% within the general pelvic fracture population. Although the cause may be multifactorial, a vascular rather than neurological cause is most frequently reported. An important relationship has been identified between mental and sexual health. Within the group returning to their original work without sexual dysfunction, the psychosomatic and affective status is near normal, unlike those with sexual dysfunction who demonstrate depressive affectation.

Pelvic fractures and the associated injuries represent complex problems with variable outcomes. Many of the factors that determine outcome are predetermined by the injury. It is therefore important to optimize those factors that are amenable to treatment.