Chapter 52

Pelvic Fractures

A. J. Ward

Most pelvic fractures are relatively simple and do not render the pelvic ring unstable. These injuries are the result of low-energy trauma, such as a simple fall in an elderly patient, and do not require surgical intervention. In contrast, high-energy trauma in a road traffic accident or a fall from height may result in an unstable pelvic ring disruption and some degree of associated pelvic soft-tissue injury. The injury may be restricted to the pelvic region or in two-thirds of cases be associated with other injuries; most common are head injuries, chest injuries and long-bone fractures. The term “complex pelvic trauma” defines the 10% of pelvic injuries with associated soft-tissue injuries to the urological system (bladder or urethra), hollow viscera (bowel), neurovascular structures (pelvic vessels or sacral plexus), or integumen of the perineum (open fracture) in which patients have an increased rate of mortality of 10% to 50% [1]. Major haemorrhage and other life-threatening injuries must be dealt with urgently by a multidisciplinary team that is trained in the critical assessment and surgical treatment of abdominal, pelvic and other injuries. A pelvic fracture should be considered to be an indicator of major trauma until further assessment rules out the presence of associated injuries. The aims of treatment of pelvic fractures are to identify and treat the life- threatening associated injuries, to control haemorrhage, and to restore the mechanical stability and alignment of the pelvic ring. The first concern is to save life and the second is to stabilise the pelvis in order to provide pain relief, facilitate the mobilisation and rehabilitation of the patient, and prevent late instability of the pelvic ring. A fracture of the acetabulum may occur as an isolated injury or in association with other pelvic fractures. Being an intraarticular fracture, the aims of treatment are to prevent post-traumatic arthritis of the hip joint and long-term disability. If displaced, the fracture requires anatomical reduction and stable internal fixation of the joint surfaces, with early mobilisation of the hip joint and of the patient. The definitive management of patients with complex pelvic and acetabular fractures requires special expertise and equipment. It is recommended that early advice is sought from and prompt referral made to a pelvic trauma unit [2].

Surgical anatomy and stability The pelvis is a strong ring-like structure that transmits weight-bearing forces from the spine to the legs (through the hip joints) while providing protection for the pelvic organs and attachment for the muscles of the pelvic floor, abdomen and legs. In the adult the pelvic ring comprises of three bones bound together by strong ligaments with the pelvic joints allowing only very limited movement under load. The left and right innominate bones are joined at the symphysis pubis anteriorly and to the sacrum posteriorly at the sacroiliac joints.The symphysis pubis is a secondary cartilaginous joint, with a disc of fibrocartilage interposed between and binding to the hyaline cartilage surfaces of each pubic bone, that is strong and slightly flexible. The sacroiliac joint on each side is a synovial joint with interdigitating surfaces of hyaline cartilage which transmit body weight from the sacrum to each innominate bone. The sacroilac joints are supported by the thick posterior sacroiliac ligaments which are the strongest in the body. The anterior sacroiliac ligaments are relatively weak. Accessory ligaments help stabilise the pelvis such as the iliolumbar ligament that suspends the posterior sacrum and iliac crest from the transverse process of the fifth lumbar vertebra . The sacrospinous and sacrotuberous ligaments in the pelvic floor bind the sacrum to the ischial spine and to the ischial tuberosity of the innominate bone respectively . In the child the innominate bone is formed from three bones: the pubis, ischium and ilium join at the triradiate cartilage in the acetabulum and fuse in the early teens. As the pelvis is a bony ring, a break in one part of the ring will be accompanied by a break in another part of the ring. It has been shown that even minor anterior fractures (pubic rami) are associated with some degree of posterior injury (sacral impaction) that can be detected with scintigraphy. The mechanical stability of the pelvis depends on the integrity of the “posterior pelvic complex”, which transmits load to the hip joint. Disruption of this complex, comprising of the sacrum, posterior ilium, sacroiliac joint and supporting ligaments, causes rotational or vertical instability of the affected hemipelvis. The direction of displacement and instability forms the basis of current classifications of pelvic ring injuries. The acetabulum is the socket of the synovial hip joint. The articular surface is C- shaped, open inferiorly, with the thickest hyaline cartilage on the main weight-bearing surface at the dome superiorly. There is congruent articulation with the spherical head of the femur. The bony structure of the acetabulum is composed of anterior and posterior columns which merge at the dome in the shape of an inverted Y. This concept, described by Letournel, forms the basis of the anatomical classification of acetabular fractures [3]. Pelvis is Latin for bowl. The pelvic visceral organs (the bladder, the lower colon and rectum, and the uterus and adnexa in females) are contained within the true pelvis, the deepest part of the bowl lying below the pelvic brim. The viscera and the rich plexus of blood vessels arising from and draining to the internal iliac artery and veins are prone to injury if the pelvis is fractured. Posterior pelvic ring disruptions may be associated with injury to the major blood vessels and nerve roots of the lumbosacral plexus (L4,5, S1,2,3) that lie on the anterior surface of the sacrum and sacroiliac joint. The superior gluteal artery is vulnerable as it passes out under the superior margin of the greater sciatic notch to supply the gluteal musculature. The sciatic nerve is at risk of injury, typically from posterior acetabular fracture or dislocation of the hip, after it leaves the sacral plexus, exits the greater sciatic notch below piriformis muscle, and runs posterior to the hip joint into the posterior thigh. Nerve injuries may occur at the time of fracture or during subsequent surgical exposure of the fracture.

Classification of pelvic fractures Pelvic fractures may be closed (intact soft-tissue envelope) or open, in which the fracture communicates with an overlying skin laceration (perineum, buttock, loin) or with rectal or vaginal tears. The mechanical stability (or degree of instability) of the pelvic ring forms the basis of the two complimentary classification systems used in assessment and in decision- making for treatment. The AO comprehensive classification [4,5], derived from the system of Tile [6], is based on the direction of mechanical instability: Type A injury - stable, with intact “posterior ring complex”- the pelvic floor is intact and the pelvis is able to withstand normal physiological load without displacement; Type B injury – rotational instability, with incomplete disruption of the “posterior pelvic complex”- partial instability present with, in some cases, an intact pelvic floor – the subtypes are B1 external rotation, B2 internal rotation, B3 bilateral involvement; Type C injury – rotational and vertical instability, with complete disruption of the “posterior pelvic complex”- complete instability of pelvic ring with pelvic floor always disrupted. It can be difficult to differentiate between partial and complete posterior instability. The primary evaluation, based on plain radiographs, may need to be amended after review of CT scans or in time if progressive displacement of the pelvis is detected. The decision about appropriate surgical treatment is guided by the AO classification [Table 1]. TheYoung and Burgess classification [7] predicts the degree of instability based on the direction of force that was applied to the pelvis and the resulting fracture pattern [Table 2]. The pelvic injury is caused by an anteroposterior compression (APC), a lateral compression (LC), or a vertical shear injury (VS). There is also a combined mechanical (CM) group of complex multidirectional injuries. The APC and LC injuries are subdivided into types I, II, and III, representing the increasing degree of disruption. The Young and Burgess fracture type can be related to the risk of major pelvic haemorrhage and associated injuries, making the classification useful in the initial assessment of the patient [7,8]. The greatest risk of haemorrhage is in the more severe APC injuries. Initially (APC Type I) only the symphysis pubis is split (widened less than 2.5 cm), then the pelvic floor tears (sacrospinous ligament rupture) and the anterior sacroiliac joint is ruptured but the posterior ligaments remain intact (acting as a hinge as the “book opens”) with external rotation of the hemipelvis (Type II). In the final stage (Type III) the posterior ligaments rupture with complete separation and lateral displacement of the hemipelvis (but without vertical displacement, which distinguishes this from the VS injury, but both are AO Type C injuries). The APC III injury is associated with mean blood loss of 15 units, due to the degree of internal pelvic soft- tissue disruption with torn pelvic venous plexus and occasionally from avulsed arteries, especially the superior gluteal. The APC III injuries are associated with circulatory shock (67%), ARDS (19%) and death (37%). The LC injuries are the most common type of pelvic fracture but are least likely to cause pelvic haemorrhage (LCII mean blood loss 3 units). The LC injuries range from a simple fracture of the pubic ramus (LCI) following a fall on the side to more severe internal rotation of the whole hemipelvis (LCII) after a road traffic accident or fall onto the side from height. Further internal rotation of one hemipelvis may cause external rotation of the contralateral hemipelvis (LCIII). There is a high incidence of head injury, lateral chest injury and bladder or urethral injury. The VS injury, often due to a fall from height, results in the whole hemipelvis being displaced upwards (disruption of both sacrospinous and sacrotuberous ligaments). There is an intermediate risk of pelvic haemorrhage (mean blood loss 9 units) and higher risks of head injury and splenic rupture. Clinical assessment The initial assessment of the injured patient aims to detect the presence of life-threatening or multiple injuries and haemodynamic instability or shock, assess the degree of mechanical instability of the pelvic ring, and diagnose associated pelvic soft-tissue or organ injuries. In most cases of pelvic injury, the patient is haemodynamically stable and a detailed clinical and radiological workup for detection and grading of the pelvic injury can be made before definitive treatment is given. The mechanism of injury is determined from the history and may indicate the type of pelvic injury sustained as well as the presence of associated injuries. The clinical features of a pelvic fracture are pain, crepitus or tenderness over the symphysis pubis, anterior iliac crest or sacrum. Skin abrasions or contusions may be present at the point of impact or overlying the fracture sites, including the perineum. In the absence of lower limb fractures, leg length discrepancy and malrotation point to a displaced pelvic fracture or hip dislocation. Manual assessment of pelvic stability should be performed carefully and not repeatedly, so as to avoid causing further internal bleeding: bimanual compression and distraction of the iliac wings may detect rotational instability but “push-pull” techniques of applying manual traction to the leg while palpating the pelvis should only be performed by an experienced surgeon. The presence of associated pelvic injuries must be sought. Rectal and vaginal examinations are mandatory to detect the bleeding from wounds of an occult open fracture. Neurological assessment is made looking for signs of lumbosacral plexus injury. Peripheral pulses are checked. A urethral injury must be suspected with all displaced anterior pelvic ring injuries and an ascending urethrogram performed prior to urethral catheterisation. Signs of urethral injury which include bleeding from the urethral meatus, perineal contusion, inability to pass urine and , in a male, a high-riding prostate may be absent. If a urethral tear is found the advice of the urological surgeon must be sought before catheterisation. If haematuria is detected, a cystogram is performed to exclude a bladder rupture [Chapter X]. The diagnosis of the pelvic injury is based on the radiological examination. The standard AP pelvic radiograph is obtained early in the resuscitation process and provides a reliable working diagnosis in 90% of cases. Additional pelvic inlet and outlet views are obtained to evaluate further the fracture sites and degree of pelvic displacement. Radiographic signs of pelvic instability include: (1) displacement of more than 5 mm of the “posterior pelvic complex”; (2) the presence of a posterior fracture gap (as opposed to impaction); and (3) avulsion fractures of the transverse process of L5 vertebra (iliolumbar ligament) or of the sacral or ischial spine attachments of the sacrospinous ligament. A computerised tomography (CT) scan is performed to further define the posterior pelvic injury and any associated acetabular fracture. The CT scan is not used for the emergency evaluation of the pelvis and is delayed usually until the general condition of the patient is stable. However, using a modern spiral CT scanner, the pelvic CT scan can be combined with the emergency CT evaluation of the chest and abdomen if indicated. A 3D-CT scan reconstruction can be made to aid visualisation of the fracture displacement and rotational deformity. Emergency management of pelvic haemorrhage In the presence of haemodynamic instability, immediate resuscitation of the patient is commenced using Advanced Trauma Life Support (ATLS) guidelines [9] or a similar protocol [see Chapter on Multiple Injuries]. Plain AP radiographs of the chest and pelvis are obtained. If an unstable pelvic fracture is present, the principles are to confirm the pelvis as the site of internal bleeding, exclude or treat other sources of bleeding and gain immediate control of the haemorrhage [Table 3]. Other sources of blood loss include bleeding into the chest or abdomen, multiple limb fractures, open wounds or retroperitoneal haematoma. Intraperitoneal bleeding is evaluated using diagnostic peritoneal lavage (open supraumbilical cannula placement), FAST abdominal ultrasound or CT scan [10]. The “Trauma Scan” is a spiral CT scan consisting of head and neck CT, chest, abdomen and pelvis CT with iv contrast given 15 minutes before scanning, which obviates the need for a cystogam [1]. Immediate laparotomy may be required to control intraperitoneal bleeding, in which case a pelvic external fixator must be applied first to stabilise the pelvic ring injury and prevent further bleeding from loss of the tamponade effect when the abdomen is opened. Bleeding from open wounds may be controlled temporarily by manual pressure and packing. Limb fractures are splinted. Hypothermia and coagulopathy must be prevented or corrected urgently. If the bleeding is of pelvic origin, mechanical stabilisation of the unstable pelvic ring will often reduce blood loss and restore haemodynamic stability [11]. Compression of the pelvis can be achieved with a circumferential sheet and towel clamp (“sheeting”), use of a proprietary pelvic binder or application of an external fixator in the emergency room. Currently the pelvic binder is recommended as it can be applied simply and rapidly, is inexpensive and does not require any surgical expertise. The binder can be maintained temporarily until surgical stabilisation of the pelvis is undertaken in the operating theatre. External fixation of the pelvis is achieved by placing percutaneous pins in each anterior iliac crest and linking the two sides of the pelvis with an anterior frame. Manual compression of the pelvis (in APC types) and longitudinal traction (in VS types) will facilitate reduction of the pelvis prior to tightening the fixator. A single pin fixator (with one pin inserted in each ilium) can be applied rapidly to “close the book” prior to laparotomy [12], otherwise a conventional fixator (with 3 pins in each side) is recommended for definitive stabilisation to reduce the risks of pin cut-out, loosening and infection. The pelvic C-clamp is an alternative form of fixator that can used to compress the posterior pelvis more effectively but requires careful pin placement under fluoroscopy screening [13]. The sites of bleeding of pelvic fractures are venous or osseous in 80-90% of cases and arterial in only 10%. If the patient remains haemodynamically unstable after external fixation, arterial bleeding is suspected and pelvic angiography with embolisation of any bleeding vessels is indicated [14]. The procedure is successful in controlling bleeding in 67-95% of cases but two-thirds of patients will die later from other injuries or complications of multiple trauma. In Europe, some centres prefer to proceed directly to open and pack the pelvis with simultaneous application of a pelvic C-clamp to stabilise the posterior pelvis [1,15], reserving angiography for cases in which bleeding continues after packing. Open fractures of the pelvis with wounds in the perineum, vagina or rectum require emergency surgery: wound debridement and irrigation; diversion of the faecal stream by defunctioning colostomy (placed in the upper abdomen away from the pelvis) and distal colonic washout; external fixation of the pelvis; and antibiotic prophylaxis [16]. As well as pelvic bleeding, there is a high risk of deep infection and of death (20- 50%).

Definitive Fixation Undisplaced fractures are treated with early mobilisation of the patient; those with LC1 injuries can mobilise safely weight-bearing to tolerance of pain within a few days and others remain partial weight-bearing on the affected side until union of the fracture by 8 weeks. A check AP pelvic radiograph is advisable within a week of mobilisation to detect the rare progressive displacement. More severe displaced pelvic fractures require closed or open reduction and stabilisation by external or internal fixation until adequate ligamentous and bony healing occurs. Detailed descriptions of surgical approaches and operative techniques are available in specialist textbooks [3,5,17]. If an external fixator was applied as an emergency and satisfactory alignment of the pelvic ring is maintained, then the fixator may be used for definitive treatment until healing of the pelvic ring. The fixator may be used alone in Type B injuries or in combination with internal fixation of the posterior pelvis in Type C injuries [Table 3]. Fracture union may occur within 8 weeks but ligamentous healing may take 12 to 16 weeks. Prolonged use of the external fixator is associated with an increased risk of pin site loosening, infection and loss of reduction. In general, internal fixation is preferred unless the patient has soft-tissue injuries or an indwelling suprapubic catheter that pose a risk of infection in the operative field. Anterior pelvic injuries include symphysis pubis diastasis, pubic rami fractures or a combination of both. The symphysis pubis is reduced using a modified pfannelsteil midline approach between the rectus abdominus muscles and stabilised with a 4 or 6 hole plate and screws. A longer plate can be extended to bridge an associated pubic ramus fracture. Isolated or bilateral pubic rami fractures may be stabilised with plates through a modified Stoppa approach or by percutaneous “retrograde medullary screw” fixation and image guided surgery [18]. Posterior pelvic injuries include iliac wing fractures, sacral fractures, sacroiliac joint dislocation or a combination of these. Open reduction of an iliac wing fracture can be achieved using either a lateral exposure reflecting the gluteal muscle attachments or an internal exposure using a limited ilioinguinal approach, reflecting iliacus muscle medially. Surgical fixation is achieved with a combination of plates and lag screws. Sacroiliac joint disruptions may be reduced through: (1) an anterior (limited ilioinguinal) approach and stabilised with two small bridging plates on the anterior aspect of sacrum and ilium; or (2) a dorsal approach exposing the posterior sacrum and ilium, enabling stabilisation of the posterior pelvic complex with cannulated iliosacral screws, a posterior pelvic tension plate (bridging the lateral surfaces of each posterior ilium) or two sacral bars (rarely used now). Percutaneous techniques of insertion of cannulated iliosacral screws from the lateral ilium, across the SI joint into the S1 sacral body are preferred if closed reduction of the posterior pelvis can be achieved [18]. Postoperatively, early mobilisation of the patient is undertaken if associated injuries allow, with partial weight-bearing for 8-12 weeks on the affected side.

Complications and outcome The mortality rate associated with displaced pelvic fractures is 5–10% overall, rising to 30-40% in patients who are hypotensive on admission (SBP<90mmHg), and 50-70% if still shocked after external fixation of the pelvis. The cause of death may be related to pelvic bleeding in 25% of cases but is most often due to associated injuries, such as head injury, and the late consequences of polytrauma, such as Adult Respiratory Distress Syndrome and Multiple Organ Failure. The outcome of a pelvic ring injury is related to the type of fracture, the quality of reduction of the posterior pelvic complex, the presence of neurological injury and of associated injuries. Permanent disability is due to chronic pain in the posterior pelvis or low back, persisting pelvic instability or pelvic deformity (causing apparent leg length difference or sitting imbalance), nerve injury (neuralgia, paralysis), genitourinary or bowel dysfunction (urethral stricture, impotence, incontinence, dyspareunia), and other limb injuries. When treated non-operatively, long-term pain and disability have been reported in 40% of patients after stable Type A fractures, 55% of Type B and 90% of Type C fractures [19]. Surgical fixation of the unstable pelvic ring improves the outcome [20]. Studies from Germany and USA [21,22,23,24] have reported a good or excellent outcome in 79% of patients after internal fixation of Type B injuries but in only 27% in Type C cases, with patients being pain free in 69-89% of Type B and 33-50% of Type C injuries. Neurological injuries (L5, S1 or lower sacral roots) have a poor prognosis, being a cause of permanent disability in one-third of patients with Type C fractures. Thromboembolic complications are common in patients with pelvic (or acetabular) fractures and prophylaxis with low molecular weight heparin or similar treatment is recommended [25,26]. Proximal DVT occurs in 25-35% of these patients, symptomatic pulmonary embolus in 2-10% and fatal PE in 0.5-2% if prophylaxis is not employed [27,28].

Fractures Of The Acetabulum

A fracture of the acetabulum occurs when an excessive force is transmitted through the femoral head onto the acetabulum, and the position of the leg at the time of impact determines the pattern of fracture sustained. With an impact to the front of the knee in a patient sitting with the hip flexed, as when driving, the direction of force results in a posterior wall or column fracture. The acetabular fracture may occur in isolation or in association with other pelvic ring injuries, femoral fractures or other limb injuries. Clinical and radiological assessments of the patient are performed to detect the presence of associated injuries and to determine the pattern of fracture (classification). Pain in the hip, lateral bruising and an abnormal posture of the leg may indicate an acetabular fracture. Neurovascular assessment of the limb is important; sciatic nerve injury is common with posterior acetabular fracture-dislocations and femoral or obturator nerve palsies may result from anterior acetabular fractures. Full radiological assessment includes an anteroposterior radiograph of the pelvis and hip joints, Judet oblique (450 orthogonal) views of the acetabulum and a CT scan (with fine cuts of 2-3 mm). The degree of displacement of fracture fragments, the size of a posterior wall fracture, the presence of intraarticular fragments preventing congruent reduction of the femoral head, marginal impaction (depression) of the articular joint surface and femoral head fractures can be documented. The 3-D CT reconstruction views are useful to visualise the fracture pattern. The Letournel classification of acetabular fractures is widely used [3], subdividing fractures into 5 “simple” types and 5 “complex” types, based on the site of the fracture lines through the anterior and/or posterior columns and walls. This classification is useful in planning the surgical approach for internal fixation and determining the prognosis. This has been incorporated into the AO comprehensive classification, which divides acetabular fractures (62-) into Types A, B and C and subtypes 1-3, and is used for documentation purposes. [4,29]. A dislocation of the femoral head mandates urgent closed reduction of the hip joint to reduce the risk of consequent avascular necrosis of the femur and worsening sciatic nerve palsy. Open surgical reduction may be needed if closed reduction fails or if there is an associated femoral neck fracture (to prevent secondary displacement during manipulation). The stability of the joint, the congruence of the femoral head in the acetabulum , and the displacement of the acetabular fracture are noted on radiological screening following reduction. Sciatic nerve function should be noted before and after reduction as entrapment of the nerve can occur. Skeletal traction is applied to the leg with a distal femoral pin (to avoid traction to potentially injured knee ligaments). In the presence of an acetabular fracture and persisting posterior instability, recurrent dislocation can occur despite traction, and an “anti-rotation” below-knee cast that holds the leg in external rotation may be needed. Close clinical review is necessary while awaiting definitive surgical treatment. The aim of definitive treatment is to obtain healing of the acetabular fracture with anatomical reduction of the articular surface and preservation of normal joint congruity, stability and mechanics, in order to reduce the risk of post-traumatic osteoarthritis. Residual displacement or incongruity greater than 1-2 mm is unsatisfactory and more likely to lead to a poor long-term outcome [3,30]. An undisplaced fracture of the acetabulum may be treated nonoperatively with initial bed rest for 3 weeks (traction is not needed), minimal weight-bearing on the affected leg for 3 weeks, and increasing partial weight-bearing until union after 8-10 weeks. Nonoperative treatment may be indicated for a displaced acetabular fracture if the patient is medically unfit to undergo major surgery, has severe osteoporosis or has a fracture that is low (with preservation of congruity of the femoral head in the weight- bearing dome of the acetabulum). In general, acetabular fractures that are displaced 2-3 mm in the major weight- bearing area will require open reduction and internal fixation to achieve anatomical reduction of the articular surface, restoration of congruity and stability of the joint, and to allow early mobilsation of the hip joint and of the patient. Surgery should be performed early while the fracture fragments remain mobile as this allows limited surgical approaches and indirect reduction techniques to be used. The acetabular fracture type dictates the surgical approach needed for internal fixation. The Kocher-Langenbeck approach exposes the posterior and superior parts of the hip and innominate bone, allowing access inside the hip joint following distraction or dislocation of the femoral head. The exposure can be increased by a “Trochanteric Flip”, reflecting anteriorly the greater trochanter of the femur with attached muscles [31]. The ilioinguinal approach exposes the inner aspect of the pelvis and is used to access the anterior acetabulum and to treat some more complex fractures. Extensile approaches, such as the Extended Iliofemoral or Triradiate, provide large exposure of inner and outer aspects of the pelvis and acetabulum simultaneously for stabilisation of complex fractures but are associated with higher wound morbidity (blood loss, infection, muscle weakness and heterotopic ossification). Combined approaches (Kocher-Langenbeck + Ilioinguinal) are favoured by some surgeons. Various methods of fracture fixation are practiced using combinations of special pelvic plates or long screws. Special expertise and equipment is required to treat these fractures and patients should be referred to a specialist pelvic and acetabular unit for definitive management. Minimally invasive surgical techniques, using percutaneous screw fixation and computer-assisted image guided surgery (fluoroscopy or CT-based imaging), are being refined [32]. Postoperative AP radiograph and CT scans of the acetabulum are obtained to document the fracture reduction, hip congruity and position of implant screws (to exclude intraarticular penetration). The hip joint may be mobilised on a “continuous passive motion” machine and the patient mobilised from bed as soon as possible (other injuries allowing); “touch” minimal weight-bearing for 6 weeks and increasing partial weight- bearing for another 6 weeks until fracture union. As with pelvic fractures, peroperative antibiotic and pre- and postoperative DVT prophylaxis protocols should be followed [26]. Indomethacin (25mg for 3-6 weeks) has been used as prophylaxis against heterotopic ossification (not needed after ilioinguinal approach) but a prospective randomised study has not shown any benefit of its use [33]. Alternatively, irradiation (single dose 700 cGy) appears to be effective, used 24 hours before surgery or postoperatively within 3 days [34]. Long-term clinical and radiological review of patients is advisable to determine the outcome and manage complications. Complications include deep infection (1-3%), proximal DVT (10-20%), PE (1% fatal), sciatic nerve palsy (12-39%), heterotopic ossification (limiting function in 4-6%), avascular necrosis (2-10%), and post-traumatic osteoarthritis (PTOA)(20-35%). The long-term outcome is good or excellent in 75-85% of surgical treated cases. Factors associated with PTOA include the severity of initial trauma (type of fracture, degree of comminution), the quality of reduction (residual displacement in the weight-bearing dome), persisting incongruency and instability of the joint. Hip arthrodesis is difficult to achieve and total hip replacement is preferred for late reconstruction of the hip. References

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Computer-assisted closed techniques of reduction and fixation. In: Fractures of the pelvis and acetabulum, 3rd edn. Tile M, Helfet DL, Kellam JF, eds. Lippincott Williams & Wilkins, Philadelphia, 2003: 604-615. 33. Matta JM, Siebenrock KA. Does indomethacin reduce heterotopic bone formation after operation for acetabular fractures? A prospective randomised study. J Bone Joint Surg 1997; 79-B: 959-963. 34. Burd TA, Lowry KJ, Anglen JO. Indomethacin compared with localised irradiation for the prevention of heterotopic ossification following surgical treatment of acetabular fractures. J Bone Joint Surg 2001; 83-A: 1783-1788. Table 1. AO classification of pelvic ring injuries (61-)

Table 2. Young and Burgess classification

Table 3. Control of haemorrhage from pelvic fractures