AUTHOR AND EDITOR INFORMATION

Section 1 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

INTRODUCTION

Section 2 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Fractures of the acetabulum occur primarily in young adults as a result of high-velocity trauma. These fractures are often associated with other life-threatening injuries.

Displacement of the fracture fragments leads to articular incongruity of the hip joint that results in abnormal pressure distribution on the articular cartilage surface. This can lead to rapid breakdown of the cartilage surface, resulting in disabling arthritis of the hip joint. Anatomic reduction and stable fixation of the fracture, such that the femoral head is concentrically reduced under an adequate portion of the weight-bearing dome of the acetabulum, is the treatment goal in these difficult fractures.

History of the Procedure

Fractures of the acetabulum were treated nonoperatively until the middle of the 20th century. The Judet brothers¹ and, subsequently, Emile Letournel^{2, 3} studied acetabular fractures extensively and were responsible for popularizing the surgical management of these challenging injuries. Pioneering work, such as the development of the ilioinguinal approach by Letournel, led to acetabular surgery becoming the accepted standard of care for virtually all displaced fractures of the acetabulum.

With advances in imaging technologies, performing acetabular fracture surgery through smaller incisions is now possible. In the future, computer-assisted surgery may contribute to the operative management of these injuries, as well.

Problem

Fractures of the acetabulum usually occur as a result of high-velocity injury and often affect the young and economically productive portion of the population. These intra-articular fractures can lead to considerable morbidity, especially if not correctly treated. Intra-articular malunion and joint incongruity lead to rapid destruction of the articular cartilage and ultimately to hip arthrosis.⁴

Frequency

The exact incidence of acetabular fractures in various parts of the world is not known. Studies at level I trauma centers have shown an admission rate for pelvic and acetabular fractures of 0.5-7.5%.

Relative Frequency of Acetabular Fracture Types in Various Studies

Peltier⁷ reported an incidence of 24% acetabular fractures in his series of adult pelvic fractures. In 1976, Reed documented that approximately 5-10% of pediatric pelvic injuries involve the acetabulum.⁸

See also the following related topics in eMedicine:
Pelvic Fractures
Unstable Pelvic Fractures

Etiology

Acetabulum fractures usually occur as a result of high-velocity trauma, such as vehicular accidents or falls from heights.

Pathophysiology

Fractures of the acetabulum occur as a result of the force exerted through the head of the femur to the acetabulum. The femoral head acts like a hammer and is the last link in the chain of forces transmitted from the greater trochanter, knee, or foot to the acetabulum. The position of the femur at the time of impact and the direction of the force determine the type and displacement of the fracture.

The point of impact and the resulting fracture patterns

Although it is difficult to pinpoint the exact relationship between the point of impact and the mechanism of injury in acetabulum fractures, certain relationships are well recognized. These can help in understanding the forces involved in creating the fracture, the direction of displacement, and the fracture patterns involved.

Force applied to the greater trochanter in the axis of the femoral head

The point of impact of the femoral head is decided by the degrees of adduction and abduction and rotation of the femur.

• Hip in neutral adduction-abduction: External rotation of the hip predisposes to anterior column injury and internal rotation predisposes to posterior column injury with the hip in neutral adduction-abduction. Rotations and associated fractures are as follows:
• • Neutral - Central/anterior column
  • External (about 25°) - Anterior column
  • External (about 50°) - Anterior lip
  • Internal (about 25°) - Transverse/T-shaped/bicolumnar, depending upon the degree of force applied
  • Internal (about 50°, extreme) - Posterior column with transverse element
• Differing degrees of adduction and abduction: With the hip in neutral rotation, the greater the degree of adduction of the femur, the higher the level of the fracture (greater involvement of the roof). The greater the degree of abduction, the lower (more inferior) is the fracture line. Positions of the femur and associated fractures are as follows:
• • Neutral adduction-abduction - Transverse or T-shaped fracture beginning at the inner margin of the roof of the acetabulum
  • Increasing adduction - Transverse or T-shaped fracture with increasing involvement of the roof of the acetabulum
  • Increasing abduction - Transverse or T-shaped fracture with progressively inferior shift of the fracture line

Force applied to the flexed knee in the axis of the femoral shaft

Acetabulum fracture morphology depends on the degrees of flexion or extension and adduction or abduction. The degree of hip rotation generally does not contribute significantly to the fracture pattern.

• Hip flexed to 90°: Positions of the femur and associated fractures are as follows:
• • Neutral adduction-abduction - Posterior wall
  • Maximum abduction - Posterior column with transverse element
  • Mild (about 15°) abduction - Posterior column
  • Adduction - Posterior dislocation of the hip with or without posterior wall fracture
• Different degrees of hip flexion: Positions of the femur and associated fractures are as follows:
• • Increasing flexion - Progressively lower involvement of the posterior column
  • Decreasing flexion (<90°) - Involvement of the posterosuperior portion of the acetabulum

Force applied to the foot with the knee extended

Positions of the femur with associated acetabulum fractures are as follows:

• Hip extended (eg, fall from a height) - Transtectal transverse fracture
• Hip flexed (eg, frontal collision in a vehicle, with force transmitted through the foot pedal) - Depending on the position, similar to force acting through a flexed knee

Force applied to the lumbosacral region

A force applied to the lumbosacral region is a rare cause of acetabular fractures.

In actuality, however, it is very difficult to pinpoint the exact site of impact and the mechanism of injury. These mechanisms are important as they help in understanding the acting forces, direction of displacement, and the fracture patterns involved.

Classification

Various classifications of acetabular fractures have been propounded, but the easiest classification is that of Judet¹ and Letournel.², who classified acetabular fractures according to the fracture morphology as elementary fracture patterns. These have only 1 fracture line and include the following:

• Posterior wall fractures (see Images 1-3): These fractures typically involve the rim of the acetabulum, a portion of the retroacetabular surface, and a variable segment of the articular cartilage. The articular cartilage may also be impacted. Impacted articular cartilage should be diagnosed preoperatively on CT scan, as these impacted fragments require elevation at the time of surgery. Extended posterior wall fractures can involve the entire retroacetabular surface and include a portion of the greater or lesser sciatic notch, the ischial tuberosity, or both. The ilioischial line, however, remains intact on the anteroposterior (AP) view.
• Posterior column fractures: These fractures include only the ischial portion of the bone. The entire retroacetabular surface is displaced with the posterior column. As the vertical line separating the anterior column from the posterior column traverses inferiorly, it most commonly enters the obturator foramen. An associated fracture of the inferior pubic ramus is present. Sometimes, the fracture line traverses just posterior to the obturator foramen, splitting the ischial tuberosity. The ilioischial line is typically displaced and disassociated from the teardrop. However, when a large portion of the quadrilateral surface remains intact with the posterior column, the teardrop and a portion of the pelvic brim displace with the posterior column.
• Anterior wall fractures (see Images 4-5): These fractures are uncommon injuries and often occur in conjunction with anterior dislocations.
• Anterior column fractures: Low fractures involve only the superior ramus and pubic portion of the acetabulum. High fractures can involve the entire anterior border of the innominate bone. The pelvic brim and iliopectineal line are displaced. Medial translation of the entire roof or a portion of the roof is typical of displacement of a high or intermediate anterior column fracture.
• Transverse fractures (see Image 6): These fractures divide the innominate bone into 2 portions. A horizontally displaced fracture line crosses the acetabulum at a variable level. The innominate bone is then divided into a superior part and a lower part. The superior part is composed of the iliac wing and a portion of the roof of the acetabulum. The lower part of the bone, the ischiopubic segment, is composed of an intact obturator foramen with the anterior and posterior walls of the acetabulum. Letournel subclassified transverse fractures as follows:
• • Transtectal, in which a transverse fracture line crosses the superior acetabular articular surface
  • Juxtatectal, in which a transverse fracture line crosses at the junction of the superior acetabular articular surface and superior cotyloid fossa
  • Infratectal, in which a transverse fracture line crosses through the cotyloid fossa

Fracture patterns

Associated acetabulum fracture patterns are the more complicated fracture patterns and include the following:

• Anterior with posterior hemitransverse fractures: These fractures combine an anterior wall or anterior column fracture with a horizontal transverse component, which traverses the posterior column at a low level. The distinction between the associated anterior column and associated posterior hemitransverse and T-shaped patterns is often subtle. In the anterior plus posterior hemitransverse fracture, the anterior component is typically at a higher level and is more displaced than the posterior component.
• Posterior column with posterior wall (see Images 7-8): This pattern divides the posterior column into a larger posterior column component and an associated posterior wall component. The ilioischial line is typically displaced and disassociated from the teardrop.
• Transverse with posterior wall (see Image 9): This pattern combines a normal transverse configuration with 1 or more separate posterior wall fragments. A fracture of the inferior pubic ramus is not typically seen.
• T-shaped fracture (see Images 10-11): This fracture is similar to the transverse fracture except for the addition of a vertical split along the quadrilateral surface and acetabular fossa (the stem of the T), which divides the anterior column from the posterior column. An associated fracture of the inferior pubic ramus is typically present.
• Both-column fractures (see Images 12-14): In these fractures, the anterior and posterior columns are separated from each other, and all articular segments are detached from the intact portion of the posterior ilium, which remains attached to the sacrum. A fracture of both columns is associated with the spur sign, in which the fractured edge of the intact posterior iliac wing is seen prominently relative to the medially displaced articular segments on the obturator oblique radiographic view. This sign is pathognomonic of an injury to both columns.
• The Arbeitsgemeinschaft für osteosynthesefragen–Association for the Study of Internal Fixation (AO-ASIF) classification is more comprehensive and is shown in the figure below (see Image 15). This can be simplified as the following:
• • Type A fractures - Involving either a single wall or column (anterior or posterior)
  • Type B fractures - Include both anterior and posterior columns but not bicolumnar fractures (transverse, T-shaped, anterior with posterior hemitransverse type injuries)
  • Type C fractures - Bicolumnar fractures, with the roof as a separate fragment

Clinical

History

The nature and mechanism of injury help predict the fracture pattern and the associated injuries. The premorbid level of function and status of the joint should be established. In the presence of preexistent arthrosis, a total hip replacement may be a better option than open reduction of the acetabular fracture.^{9, 10}

Associated injuries are also important to assess. Patients often have multiple traumatic injuries, and a high likelihood of associated injury exists (in up to 50% of patients). One must diligently look for these injuries, as some are subtle and can be missed.

Physical examination

Assess the following:

• Vital parameters: Life-threatening injuries to the chest, abdomen, and cranium must be the first priority. The basic principles of trauma care and resuscitation apply because many acetabular fractures are associated with severe trauma.
• Associated injuries: Associated limb injuries may be in the form of a patella or upper tibial fracture or a posterior cruciate ligament (PCL) injury, indicating the mechanism of injury. Associated femoral shaft fractures may also be present, which could have a bearing on the management of the acetabular fracture. Associated concomitant pelvic fractures may be present in up to 20% of patients.
• It is also important to exclude injury to the bowel and the urinary tract, as such injuries influence decision-making about an open reduction of the acetabular fracture.

The local orthopedic examination includes an assessment of the following:

• Position of the lower limb
  • It is adducted, flexed, and internally rotated in a posterior dislocation.
  • The lower limb is abducted and externally rotated in an anterior dislocation.
  • Eversion of the iliac wing, with the anterior superior iliac spine on the affected side being more laterally placed, is a subtle clue to a central dislocation.
• Skin - Including local wounds, abrasions, and closed degloving injury
• Morel-Lavele lesion - A closed degloving injury occurring over the greater trochanter, in which the subcutaneous tissue is torn from underlying fascia creating a cavity, which places this tissue at risk for infection and/or poor healing
• Abduction and adduction of the hip - To detect instability (manual traction can aid in determination of vertical instability)
• Limb-length inequality - May be a subtle clue to the presence of incarcerated intra-articular fragments
• Neurologic examination - To exclude preoperative sciatic/lateral popliteal nerve palsy

INDICATIONS

Section 3 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Indications for open reduction and internal fixation include the following^{11, 12}:

• All displaced fractures (>2 mm articular step)
• Intact roof-arc angle less than 30°
• Failure to achieve or maintain concentric reduction by closed means
• Fractures that have a medial roof-arc angle of 45° or less, an anterior roof-arc angle of 25° or less, or a posterior roof-arc angle of 70° or less across the weight-bearing portion of the acetabulum, according to Vrahas et al,¹³ on the basis of a cadaveric study; persistent instability after closed reduction
• Incarcerated intra-articular fragments or impaction of the articular surface
• Emergency open reduction and internal fixation (ORIF) if associated vascular injury or sciatic palsy develops after a closed reduction

Nonoperative treatment should be considered in the following circumstances:

• Undisplaced fractures
• Displaced fractures if the following conditions are met:
  • A large portion of the acetabulum remains intact and the femoral head remains congruous with this portion of the acetabulum
  • A secondary congruence is present after only moderate displacement of a both-column fracture and the patient presents late (>3 wk after injury)
• Small posterosuperior wall fractures that are associated with a stable hip joint and a congruent reduction (Careful follow-up is needed to monitor for signs and symptoms of late instability in the initial months after injury.)
• A posterior wall injury that is minimally displaced or nondisplaced and is part of a more complex pattern requiring an ilioinguinal approach
• If surgery is contraindicated (see Contraindications)

RELEVANT ANATOMY

Section 4 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

The acetabulum is formed by a portion of the innominate bone. It lies at the point where the ilium, ischium, and pubis are joined by the triradiate cartilage, which later fuses to form the innominate bone. The acetabulum is enclosed by the anterior and the posterior columns like the 2 limbs of an inverted Y (see Images 16-18). The anterior column comprises the anterior border of the iliac wing, the entire pelvic brim, the anterior wall of the acetabulum, and the superior pubic ramus. The posterior column makes up the ischial portion of the bone, including the greater and lesser sciatic notch, the posterior wall of the acetabulum, the majority of the quadrilateral surface, and the ischial tuberosity. The roof of the acetabulum is the thick weightbearing portion and forms a separate fragment in bicolumnar fractures. The thin quadrilateral plate forms the medial wall or the floor of the acetabulum.

The innominate bone is irregular in shape and has differing thickness in cross section in different areas. The posterior column and sciatic buttress provide the best purchase for screws. The areas suitable for implant placement are shown in Images 28-38.¹⁴

An intimate knowledge of the nerves and vessels in the area is essential to prevent iatrogenic complications at the time of surgery. Details of the relevant anatomy are further elaborated in the discussion on surgical approaches.

CONTRAINDICATIONS

Section 5 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Contraindications to surgery include the following:

• General - Severe systemic illness or secondary multiorgan failure secondary to polytrauma; systemic infections or sepsis
• Local - Local infection; extreme osteoporosis
• Relative - Severe comminution; preexisting arthrosis

Surgical intervention may be carried out in these cases to facilitate a salvage procedure later.

WORKUP

Section 6 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Lab Studies

• Hemoglobin and hematocrit levels
• Type and crossmatch blood
• Routine evaluation for fitness for anesthesia and major surgery

Imaging Studies

• The complicated anatomy of the acetabulum necessitates clear-cut visualization of the fracture fragments and their relationships with each other and the rest of the pelvis if anatomic reconstruction of the acetabulum is planned. The following imaging modalities can be used:
• • Plain radiographs - Pelvis with both hips (AP view), Judet views, and, if required, inlet and outlet views of the pelvis (in cases in which concomitant pelvic injury is present)
  • CT scanning - Plain and with 3-D reconstructions
• Radiograph of the pelvis with both hips
• • This is an essential radiograph and may depict the following:
  • • Associated pelvic ring fractures independent of the acetabular fracture passing through the iliac wing, obturator foramen, or the sacrum
    • Dislocation through or disruption of one or more joints in the pelvic ring
    • Bone quality
    • Rarely, a bilateral acetabular fracture (see Image 18)
    • The acetabular fracture itself
  • The 6 fundamental radiologic landmarks of the acetabulum are seen in this view.
  • • The borders of the anterior wall (acetabulo-obturator line) and posterior wall of the acetabulum
    • The roof or the dome of the acetabulum
    • Teardrop of Köhler
    • Ilioischial line of Duverney-Parent
    • Pelvic inlet
    • Innominate line
• Judet views
• • Obturator oblique: In this technique, the injured hip is raised to 45° and the beam is centered over a point 1 fingerbreadth below and medial to the anterior superior iliac spine. In a correctly taken obturator oblique, the anterior and posterior iliac spines are superimposed, the iliac wing is seen in section as narrow as possible, and, correspondingly, the obturator foramen is seen as large as possible. Features to be studied include the following:
  • • Pelvic brim
    • Articular surface, especially the posterior lip
    • Obturator foramen and the anterior column
    • Iliac wing in section
    • Junction of the anterior and posterior columns as seen as a line just above the roof
  • Iliac oblique: In this technique, the uninjured hip is elevated to 45°, with the injured part resting on the table. The beam is centered 1 fingerbreadth below the level of the anterior superior iliac spine and at the midpoint of a transverse line from the anterior superior iliac spine to the midline. In a correctly positioned iliac oblique, the iliac wing is seen widely spread out and the obturator ring is as thin as possible. Features to be studied include the following:
  • • Anterior lip of the acetabulum
    • Posterior column and posterior border of the iliac bone
    • The iliac wing
• Radiographic analysis
• • Interpretation of the plain films is based on understanding the normal radiographic lines of the acetabulum and what each line represents. Disruption of any of the normal lines of the acetabulum represents a fracture involving that portion of the bone. Displacement of the articular surface is inferred by displacement of these normal lines of the acetabulum.
  • • On the AP view, the inferior three fourths of the iliopectineal line represents the pelvic brim and is a landmark of the anterior column. The superior fourth of this line is formed by the tangency of the x-ray beam to the superior quadrilateral surface and the greater sciatic notch. The ilioischial line is formed by the tangency of the x-ray beam to the posterior portion of the quadrilateral surface and is therefore a radiographic landmark of the posterior column.
    • The teardrop and ilioischial line both result from the tangency of the x-ray beam to a portion of the quadrilateral surface. Thus, they are always superimposed in the normal acetabulum. Separation of the teardrop and the ilioischial line indicates rotation of the hemipelvis or fracture of the quadrilateral surface.
    • The roof of the acetabulum is a radiographic landmark resulting from the tangency of the x-ray beam to the subchondral bone of the superior acetabulum. Interruption of the radiographic line of the roof is indicative of a fracture involving the superior acetabulum.
    • The anterior rim is the lateral margin of the anterior wall of the acetabulum and is contiguous with the inferior margin of the superior pubic ramus. The posterior rim is the lateral margin of the posterior wall of the acetabulum. Inferiorly, the posterior rim is contiguous with the posterior horn of the acetabulum.
  • In most cases, the fracture can be properly classified from plain films alone. Plain films are usually best for assessing the congruence between the femoral head and the roof of the acetabulum.
• Roof-arc angles: These are used to assess the size of the intact portion of acetabulum.^{15, 16, 17}
• • The technique is as follows:
  • • The roof-arc angles are made on the AP, obturator, and iliac oblique radiographic views. A vertical line is drawn to the geometric center of the acetabulum. Another line is drawn through the point where the fracture line intersects the radiographic roof of the acetabulum and again to the geometric center of the acetabulum. The angle drawn in this way represents the medial, anterior, or posterior roof arc as seen on the AP, obturator oblique, or iliac oblique view, respectively. The roof-arc measurements roughly describe the position and orientation of the acetabular fracture and, therefore, the intact portion of superior acetabular articular surface.
    • A similar determination can be made from the CT scan. The CT scan of the superior acetabular articular surface from the vertex to 10 mm inferior to the vertex is equivalent to an area described by all 3 roof-arc measurements of 45° At 10 mm below the acetabular vertex, the subchondral bone appears as a ring or arc.
  • Interpretation and clinical application
  • • If nonoperative treatment is to be considered, the head should remain congruous with the roof of the acetabulum on the three views of the pelvis with the patient out of traction, and all roof-arc measurements should be more than 45°, or there should be no displaced fracture lines involving the superior acetabular articular surface in the superior 10 mm of the acetabulum on CT scan. Vrahas et al,¹³ in a cadaveric study, concluded that fractures that have a medial roof-arc angle of 45° or less, an anterior roof-arc angle of 25° or less, or a posterior roof-arc angle of 70° or less across the weight-bearing portion of the acetabulum should be treated operatively.
    • Roof-arc measurements are rarely used. This technique is most applicable to the anterior column and less applicable to the posterior column. Roof-arc measurements are particularly helpful in evaluating the anterior column component of a T-shaped fracture. If the anterior column component is low (<10 mm of the acetabular vertex), only the posterior portion of the fracture needs to be addressed surgically.
• CT scanning of acetabular fractures: Use of CT scanning for acetabular fractures has revolutionized the imaging for a particularly difficult area and, with 3-D reconstruction, has facilitated enormously the visualization of the fracture anatomy, the degree of comminution, and associated fracture patterns; it has also helped in the preoperative planning of the surgical reconstruction.^{18, 19, 20} Salient features are as follows:
• • It is important to have sections taken at 2- or 3-mm intervals, as incarcerated fragments may be missed if sections are taken at 5-mm intervals.
  • Three-dimensional CT is an invaluable tool for demonstrating the overall fracture orientation in displaced fractures and for deciding the choice of operative approach to the fracture. It may, however, not depict minimally displaced fractures due to smoothening artifacts.
  • Special views that enable selective study of the details of the acetabular fracture with the femoral head being subtracted from the image by the computer are available. These provide unrestricted access for visualization of the fracture.
  • Axial images are more sensitive than plain radiographs for the demonstration of the following:
  • • Location and extent of the acetabular fracture
    • Degree of comminution, rotation of the fragments, and impaction of the weight-bearing dome and the posterior wall
    • Intra-articular/incarcerated fragments (see Image 20)
    • Injury to the femoral head (see Image 20)
    • Minimally displaced iliac wing fractures and quadrilateral plate fractures that may have been missed on plain films
    • Pelvic hematoma
    • Sacroiliac joint integrity
    • Rarely, a dislocation that is missed on a plain radiograph
  • Postoperatively, CT scanning is an invaluable investigative tool whenever joint penetration by a fixation device is suspected (see Image 38).

Other Tests

• Doppler ultrasound or venography may be performed in cases in which deep vein thrombosis (DVT) is suspected.

TREATMENT

Section 7 of 12  

• Authors and Editors
• Introduction
• Indications
• RELEVANT ANATOMY
• Contraindications
• Workup
• Treatment
• Complications
• Outcome and Prognosis
• Future and Controversies
• Multimedia
• References

Medical therapy

Medical therapy consists of the following:

• Resuscitation of the patient - Basic and advanced life support
• Diagnosis - Clinical and radiologic, once the patient stabilizes
• Treatment of associated life-threatening head, chest, abdominal, or other injuries
• Urgent reduction of dislocations
  • Gentle closed reduction of posterior dislocations on an emergent basis
  • For central fracture-dislocations, heavy longitudinal skeletal traction by an upper tibial or lower femoral Steinmann pin and, if required, lateral skin traction at the upper thigh. (Reduction under general anesthesia may be necessary. This is maintained with skeletal traction. The authors do not recommend the use of an upper femoral pin for lateral traction, as this acts as an infective focus and may preclude surgery.)

Preoperative details

A preoperative evaluation is used to either exclude other injuries or, if other injuries are present, to formulate a treatment plan for them. The preoperative evaluation consists of the following:

• Ensure that the patient is medically stable for surgery.
• Type and crossmatch an adequate amount of blood, as there can be significant bleeding at the time of surgery.
• Plan preoperatively with plain radiographs (AP and both Judet oblique views) and CT scans. Keep a bone model handy at the time of surgery. With advances in technology, it is now possible to generate a model of the fracture pattern and preoperatively plan the position of interfragmentary screws.
• Determine timing of surgery. The ideal time for surgery is between the 3rd and the 10th day after injury. It is best to wait 2-3 days after the injury so that the initial bleeding from the intrapelvic vessels subsides. However, it is not advisable to wait for too long, as surgery becomes more complicated 2-3 weeks after the injury. If the surgery is performed beyond 3 weeks, the chances of obtaining a good result decrease significantly.²¹ Intraoperatively, various difficulties are possible, some of which are as follows:
  • Increased blood loss because of disruption of the forming soft callus
  • Loss of definition of the fracture lines that can cause difficulty in obtaining a good reduction
  • Difficulty in identification of vital structures, thereby giving rise to increased chances of neurovascular damage and other complications
  • Contraction of the soft tissues, leading to difficulty in mobilization of the fracture fragments

Intraoperative details

The choice of approach is usually dictated by the fracture anatomy, but it also depends on the personal preference and experience of the operating surgeon. Guidelines for the choice of approach are as follows^{11, 22, 23}:

• Anterior fracture, cephalad to iliopectineal eminence - Iliofemoral
• Anterior fracture, patients with complex injuries requiring exposure of the symphysis or quadrilateral plate - Ilioinguinal
• Posterior wall/column - Kocher-Langenbeck
• Transverse with posterior lip - Kocher-Langenbeck or transtrochanteric
• Transverse without posterior lip - Depending on the rotation of the fracture
• T-shaped - Depending on the fracture pattern, ilioinguinal/Kocher-Langenbeck/combined/extensile
• Both columns - Ilioinguinal, modified ilioinguinal/combined/extensile

Of these exposures, the ones commonly performed are the ilioinguinal exposure for anterior column or T-shaped or bicolumnar fractures with mild comminution in the posterior column and the Kocher-Langenbeck exposure for posterior column injuries.

Common approaches

Kocher-Langenbeck approach

The ideal indication for the Kocher-Langenbeck approach (see Images 22-24) is an isolated fracture of the posterior wall and/or column with or without dislocation (types A1 and A2 on the AO-ASIF classification). The approach can also be used in types B1 and B2 fractures on the AO-ASIF classification. This approach can be used when the major rotation and displacement are posterior.

The patient is placed in the lateral or prone position. The lateral position is more common with most surgeons because it allows easy maneuverability of the limb. The prone position is used particularly with the transverse or T-type fractures, where, if a lateral position is used, the femoral head tends to keep the fracture surfaces apart because of gravity. This creates difficulty in reduction. The advantages of the prone position in this situation are that it requires one less assistant and facilitates relaxation of the sciatic nerve. The hip should be kept extended and the knee flexed throughout the procedure to avoid any tension on the sciatic nerve.

The incision starts at the posterior superior iliac spine, proceeds to the greater trochanter, and then continues distally along the femur as necessary. The fascia lata and the gluteus maximus fascia are divided in line with the incision. The maximus is split along its fibers, with care taken to protect the inferior gluteal nerve. The insertion of the gluteus maximus on the femur may be partially or completely divided to increase exposure. The gluteus medius, the external rotators, and the sciatic nerve are now seen. The short external rotators are incised close to the greater trochanter, with care taken to avoid cutting the quadratus femoris to protect the ascending branch of the medial circumflex femoral artery. The plane between the external rotators and the capsule of the hip joint is carefully developed by gentle dissection.

The gluteus medius and minimus are subperiosteally raised from the ilium and retracted with a Steinmann pin. The superior gluteal vessels and nerve, which emerge from the inner pelvis in this area, must be protected.

The fracture fragments are usually found attached to the capsule, which forms the only soft tissue attachment to the fragments and, hence, their only source of blood supply. Care should be taken not to denude the attachment.

The entire posterior column and the posterior wall of the acetabulum are now exposed from the top of the notch to the ischial tuberosity. Retraction of the gluteus medius may not be adequate for fixation of some high posterior column or transverse fractures. To increase the exposure of the roof of the acetabulum, a trochanteric osteotomy may be carried out.  Ebraheim et al reviewed 30 patients in whom a sliding trochanteric osteotomy was used as an adjunct procedure for treating acetabular fratures.²⁴  They concluded that the technique was reliable for providing adequate exposure of the dome of the acetabulum without associated complications that can occur with standard oblique osteotomy.

Another alternative is to do a "trochanteric flip," in which the abductor and the vastus lateralis, in continuity with a small medallion of the trochanter (which is osteotomized in a sagittal plane), are retracted anteriorly to expose the dome of the acetabulum. The advantage of this over a routine trochanteric osteotomy is that the abductors and the vastus lateralis remain in continuity through the trochanter, so easy restoration of anatomy is possible.

A careful arthrotomy, if needed, can be performed. By flexion and external rotation of the hip with lateral traction, and by retracting the fragment, an excellent view of the entire cavity is possible. Soft-tissue release of the inner surface of the quadrilateral plate can be performed through the sciatic notches subperiosteally, if necessary, after osteotomizing the ischial spine (especially in late fractures).

A constant vessel exists within the gluteus muscle 1-2 cm from the sciatic notch, which, if not taken proper care of while retracting or dissecting, tends to produce troublesome bleeding.

Ilioinguinal approach

Described by Letournel, the ilioinguinal approach (see Images 25-26) is suitable for the following fracture types:

• Anterior wall
• Anterior column
• Combined anterior column with posterior hemitransverse extension
• Types A3 and B3 fractures (AO-ASIF) where the major rotation and displacement are anterior
• Both-column fractures

The ilioinguinal approach provides exposure of the entire inner table of the innominate bone from the symphysis pubis to the anterior aspect of the sacroiliac joint, including the quadrilateral surface and the pubic rami.

Merits of this approach include the following:

• Excellent visualization of the entire anterior column of the acetabulum
• Less incidence of heterotopic ossification as compared to the posterior approaches
• Rapid postoperative rehabilitation is possible

Dangers of the ilioinguinal approach include injury to the iliac vessels, lymphatic system, femoral nerve, and lateral cutaneous femoral nerve.

The patient is positioned supine. If a combined approach (anterior and posterior) is planned, the floppy lateral position is then preferred.

The incision is placed 2 cm above the inguinal ligament and parallel to it, from the midline to the anterior superior iliac spine, and then curved along the anterior two thirds of the iliac crest.

The origin of the abdominal muscles from the iliac crest is erased sharply and retracted medially. Now the iliacus origin from the inner pelvic wall is seen. The iliacus origin is then erased subperiosteally, and the dissection is carried out posteriorly and inferiorly to expose the anterior sacroiliac joint and pelvic brim.

Through the medial part of the incision, the external inguinal ring is identified and the spermatic cord (round ligament in females) is protected with a rubber catheter. The external oblique aponeurosis is incised 1 cm proximal to the ring, keeping the ring intact and leaving the lateral 5 mm of the aponeurosis near the anterior superior iliac spine to protect the lateral cutaneous femoral nerve. Care should be taken to protect the inferior epigastric artery. The distal flap of the external oblique aponeurosis is raised to reach the reflected part of the inguinal ligament. This ligament is incised along its length so as to leave 1 mm of the ligament attached to the internal oblique and transversus abdominis origins and the transversalis fascia.

The next step is to identify the iliopectineal fascia, which divides the iliopsoas with the femoral nerve (lacuna musculorum) from the external iliac vessels (lacuna vasorum). This is the most dangerous and most important part of the approach. The iliac vessels are retracted, the iliopectineal fascia is identified and then cut with blunt-tip scissors from lateral to medial, and the cut is continued laterally behind the psoas. Next, the psoas with the femoral nerve is retracted as a unit after inserting a rubber catheter around them.

After dissecting the iliac vessels with the associated lymphatic tissues as a single unit, along with the areolar tissue around them (to protect the lymphatics and prevent postoperative swelling of the limb), these tissues are held together with a third rubber catheter. Take care to identify the obturator vessels and nerve. Be aware of the abnormal origin of the obturator artery as an anatomic variant. If found to be present, the abnormal vessel must be ligated. The periosteum on the inner surface of the pelvis along the quadrilateral plate is now cleared.

The exposure is now established through 3 windows, as follows:

• Retracting the psoas medially allows exposure of the internal iliac fossa, the pelvic brim, and the anterior sacroiliac joint. This exposure is facilitated by flexing and internally rotating the hip to relax the iliopsoas.
• The middle window is created by retracting the psoas laterally and the vessels medially. This allows the superior pubic ramus and the quadrilateral plate to be visualized.
• The medial window is seen by retracting the vessels laterally and the spermatic cord medially. This maneuver provides access to the remainder of the pubic ramus, the pubic symphysis, and the quadrilateral surface. The most medial part can be best visualized with lateral retraction of the spermatic cord.

If necessary, the inguinal ligament and the sartorius from the anterior superior iliac spine, the tensor fascia lata, and the gluteal muscles from the lateral surface of the ilium can be released to aid exposure.

The entire anterior column is now easily visualized. Useful access to the posterior column can be obtained through the second (middle) window by manipulating the quadrilateral plate. The interior of the joint can be visualized by distracting the fracture fragments. Intra-articular visualization can be improved by combining the iliofemoral approach (the distal part of the approach) with this procedure.

Before closure, drains are left in the retropubic space and internal iliac fossa. All structures are repaired.

Iliofemoral approach

Letournel modified the Smith-Petersen approach to define the iliofemoral approach for the acetabulum. This procedure is indicated for anterior column fractures in which the fracture line does not extend medial (caudal) to the iliopectineal eminence.

The patient is positioned supine. If combined with a posterior approach, a floppy lateral position is preferred. The incision is made on the iliac crest, from the middle of the crest to the anterior superior iliac spine, and then along the sartorius. The periosteum is sharply raised from the iliac crest, and the iliopsoas is stripped from the interior of the ilium. The lateral cutaneous nerve of the thigh is identified and protected. The interval between the sartorius and the tensor fascia lata is developed to expose the rectus femoris if exposure of the hip joint is required. The exposure can be extended along the lateral aspect of the ilium by stripping the gluteal muscles to see the anterior aspect of the hip joint and anterior inferior iliac spine. The exposure can be improved as needed with division of the sartorius and inguinal ligament insertion and the direct head of the rectus femoris, which is part of the hip joint capsule.

An advantage of this approach is easy access. No dissection of the femoral vessels, as in the ilioinguinal approach, is required. A disadvantage of the approach is limited anterior column access. Another disadvantage is that medial to the iliopectineal eminence, the exposure should be established with the ilioinguinal approach, which usually limits fixation options to screws or short plates in this approach. Also, injury to the lateral cutaneous nerve of the thigh is difficult to prevent with this approach.

Combined approach

When access to both columns is required, a combined approach is used.^{25, 26, 27} This involves the combination of one anterior and one posterior approach (described above), under the same anesthesia.

The patient is placed in the floppy lateral position and is rocked back and forth as needed. The anterior approach is more difficult, as the procedure with this approach is best performed with the patient in the supine position. Technical details of exposure remain the same as for the individual approaches.

An advantage of a combined procedure is that the entire posterior wall and column (with or without trochanteric osteotomy), the entire anterior wall and column, the sacroiliac joint, and the pubic symphysis can be visualized. The disadvantages inherent in a single extensile approach, such as the incidence of heterotopic ossification, weakness of abductors, and jeopardy for the vascularity of the abductors, are significantly lower with a combined approach. A disadvantage of a combined approach is that the entire fracture is not visualized through a single approach.

Extensile approaches

Extended iliofemoral approach

Letournel developed an extended iliofemoral approach that provides complete exposure of the inner and outer tables of the ilium and the acetabulum. This is an extended approach for difficult transtectal transverse, T-type, and both-column fractures with posterior wall involvement.

The patient is placed in the lateral position. Keep the hip extended and the knee flexed throughout the procedure to prevent traction injury to the sciatic nerve. The inverted J–shaped incision starts at the posterior superior iliac spine, courses along the iliac crest to the anterior superior iliac spine, and then turns distally parallel to the femur on the anterolateral aspect of the thigh.

The periosteum over the iliac crest is sharply incised; the gluteal muscles and tensor fascia lata are elevated from the outer aspect of the iliac bone. The fascia lata over the tensor fascia lata muscle is opened, the muscle is retracted posteriorly, and the rectus femoris, which lies beneath it, is identified. The ascending branch of the lateral circumflex femoral artery, which is found between the rectus femoris and the vastus lateralis, is identified and ligated. The tendons of the gluteus minimus and gluteus medius are cut in the mid portion, and tag sutures are inserted at the cut ends. The piriformis and obturator internus are cut and tagged, with care being taken to preserve the quadratus femoris muscle and the underlying ascending branch of the medial circumflex femoral artery.

Alternatively, the insertion of these external rotators can be osteotomized. Now, the entire posterior column can be seen with a retractor inserted near the sciatic notch. This also brings into view the ischial spine and ischial tuberosity. The reflected head of the rectus femoris is elevated from its origin to aid exposure of the hip joint. The abdominal muscle origin from the iliac crest, sartorius origin from the anterior superior iliac spine, and the iliacus from the inner table of ilium are erased to expose the anterior column of the acetabulum. The capsule can be incised along the rim of the acetabulum to allow intra-articular exposure as the femoral head is pulled laterally.

During closure, the rectus femoris, sartorius, fascial layers of the hip abductors, and the tensor fascia lata are reattached to the iliac bone by transosseous sutures. The gluteus minimus and medius tendons are repaired. The short external rotators are also reattached.

An advantage of this approach is that it is a lateral approach to the innominate bone, which allows excellent simultaneous exposure of both columns. A disadvantage is that the extensive stripping of muscles from the lateral side of the ilium that is required impairs the vascularity of the abductors. Although this has been studied through in vivo²⁸ and cadaveric²⁹ studies, definite evidence of muscle necrosis and significant weakness as a result of this approach has not been proven to be an invariable consequence, but heterotopic ossification is much more common in this approach. This is understandable in view of the extensive attachment of the abductors to the ilium. Injury to the femoral nerve has also been documented.

Reinert et al³⁰ have modified the extended iliofemoral approach to allow later reconstructive procedures (Maryland approach). The incision is positioned more laterally and is T shaped. The hip abductor muscles are mobilized by an oblique osteotomy of the origin and the insertion. Rigid bone-to-bone reattachment allows early rehabilitation with less risk of failure than when the abductors are reattached through soft tissue. Some authors have prescribed a preoperative arteriogram (as in the extended iliofemoral approach) if a displaced fracture is present at the sciatic notch to prevent necrosis of the hip abductors, in view of the stripping required for exposure.

Triradiate approach

Mears and Rubash^{22, 23} have described an extensile approach to the lateral aspect of the ilium, the entire anterior column and wall, the entire posterior column and wall, the anterior aspect of the sacroiliac joint, and the inner iliac wall. This procedure is referred to as the triradiate approach (see Image 27)and is indicated for transtectal transverse fractures, T-shaped fractures, and both-column fractures with posterior wall involvement. This approach is an alternative to the extended iliofemoral approach.

The patient is placed in a lateral position. A Y-shaped incision is made, the posterior segment of which is the same as in the Kocher-Langenbeck approach. The anterior limb of the Y starts at the greater trochanter from this incision at an angle of 120° and extends beyond the anterior superior iliac spine to the front of the abdomen. The fascia lata is cut along the longitudinal part of the incision. The interval anterior to the tensor fascia lata is developed by dissecting it from the fascia, and then the muscle along with the abductors is stripped from the lateral aspect of the ilium. The gluteus maximus is split along the posterior limb of the incision parallel to its fibers. A trochanteric osteotomy is performed. The short external rotators' insertion on the femur is erased.

The rest of the posterior exposure is obtained by retracting the muscles from the greater sciatic notch. The anterior incision is developed as in the ilioinguinal approach by dividing the sartorius and rectus femoris and opening the external oblique aponeurosis and dissecting through the 3 windows available beneath the inguinal ligament. During closure, the muscles, especially the abductors, tensor fascia lata, rectus femoris, and sartorius, are reattached. The trochanteric osteotomy is fixed, and the 3 fascial limbs of the triradiate incision are closed, beginning with a single apical suture.

Reduction and fixation

Reduction

Reducing acetabular fractures is one of the most challenging tasks the orthopedic surgeon faces.^{31, 32} Often, because of the high velocity of the injury, comminution is extensive, and piecing all the fracture fragments together is similar to solving a jigsaw puzzle. It requires patience and skill. One tends to improve with experience, but the learning curve is fairly steep. Analysis of the fracture pattern, displacement of the fragments, and meticulous preoperative planning go a long way in easing the difficulties faced in the surgical treatment of acetabular fracture. A hip with a malreduced acetabular fracture is doomed to a posttraumatic arthrosis. It is, therefore, essential to obtain anatomic reduction to ensure longevity of the hip. There has been a good correlation between the accuracy of the reduction and good long-term clinical outcomes.

Reduction in acetabular fractures usually proceeds from the periphery to the center, that is, in a centripetal fashion. The articular surface is reconstructed to the mold of the peripherally reconstructed innominate bone. Thus, it is easy to understand the need for perfect alignment of the peripheral fracture lines, as a small peripheral step may lead to significant articular incongruity and may necessitate revision of fixation. It is also important to appreciate that the malalignment of any one column precludes anatomic fixation of the other column in injuries involving both the columns. (Therefore, the authors recommend simultaneous anterior and posterior approaches as opposed to staged procedures for fractures that require an anterior and a posterior approach.)

In reduction and fixation of acetabular fractures, the need for a thorough knowledge of the local anatomy, both normal and pathologic, cannot be overemphasized. This knowledge is helpful not only to avoid injury to surrounding vital structures (eg, the femoral neurovascular bundle) and intra-articular hardware but also to place screws in the areas that provide the best purchase and therefore ensure stable fixation of the fracture.

Provisional fixation

Provisional fixation is usually established by means of Kirschner wires (K-wires) and, sometimes, cerclage wires.

Definitive fixation

Definitive fixation is established with the following:

• Screws: The primary fixation is usually by means of an interfragmentary screw. This is usually a 3.5-mm cortical screw used as a lag screw or a 4-mm cancellous screw. Screws measuring 6.5 mm are rarely used but can provide excellent hold. The exact nature and placement requires careful preoperative planning and depends on the fracture pattern.
• Plates: Because of the curvaceous pelvic anatomy, implants that are too rigid must be avoided, as they need to be perfectly molded to avoid malreduction. The 3.5-mm reconstruction plate, either curved or straight, is ideal for this purpose. It is thin and easily contoured in both planes, so it can be perfectly applied to the pelvis. The curved plates are slightly thicker and have a sloping undercut screw hole, allowing more oblique placement of the screw through the plate.

The other types of plates that can be used in special situations are the following:

• Spring plates²⁰: In cases with comminution of the quadrilateral plates, especially near the dome or above the fovea, the hip tends to subluxate in spite of fixation of the anterior and posterior columns. In this situation, a plate placed buttressing the medial wall can control the medial migration. This is usually a reconstruction or a small fragment T-plate with a sharp right-angled bend going over the pelvic brim down to the quadrilateral surface. It is overcontoured to function almost like a spring and hold the comminuted medial wall.
• Spike plate or the spring hook plate²⁰: This is a one-third tubular plate cut through a hole at the end, creating two small spikes that help hold a small fragment of a comminuted posterior lip.
• Cerclage wires^{2, 20}: The use of cerclage wires through the greater sciatic notch or, sometimes, the lesser sciatic notch, around and over the anterior aspect of the pelvis at the level of the anterior inferior iliac spine is a very effective technique for provisional fixation in certain fracture patterns. This technique is useful in some difficult-to-hold posterior column fractures, transverse, T-shaped, and both-column fractures in which the posterior fracture line exits high in the sciatic notch, providing a beak for the cerclage wire to hold. The use of cerclage wires, however, does entail slightly more dissection of the outer table when using the ilioinguinal approach or an extensile approach (not often used). These wires may be left as definitive fixation.

Reduction and stabilization of common fracture patterns

Reduction and stabilization of some of the common fracture patterns are discussed below.

Posterior wall or lip fracture

For posterior wall or lip fractures (see Images 28-31), after exposure by a Kocher-Langenbeck approach, the fracture hematoma is washed out and the fracture site cleaned. The interior of the joint is inspected, and loose bodies, if any, are washed out. Anatomic reduction and temporary stabilization with K-wires is carried out. The fracture is stabilized with 3.5-mm lag screws (or 4-mm cancellous screws) with washers, and a neutralization plate is applied.

In about 25% cases, the articular cartilage is impacted. This needs to be derotated and elevated and the metaphyseal defect filled with cancellous bone graft (usually from the greater trochanter) before dealing with the wall fragment. A subchondral screw is usually used to support the reconstructed articular surface.

In a highly comminuted posterior wall fracture, it may not be possible to lag each individual fragment with a lag screw. In this situation, the use of spring hook plates (2/3/4-holed one-third tubular plates with the ends cut off and the prongs bent to create hooks) is recommended. These plates are affixed in a loaded fashion underneath the buttress plate more medially but with the spring-loaded lateral hooks providing a buttressing effect to the comminuted posterior wall.

Posterior column fractures

Posterior column fractures generally result in medial displacement and internal rotation of the distal fragment (as seen from the back). Therefore, after cleaning the fracture site, the reduction of the displaced posterior column is facilitated by correcting the rotation using a Schanz screw in the ischium and a small bone hook or pelvic reduction clamps for correcting the medial displacement. Adequacy of the reduction is confirmed by digital palpation of the quadrilateral surface and the smooth contours of the greater and lesser sciatic notches.

Once reduction is obtained, the column is stabilized using an accurately contoured 3.5-mm (preferably flexible) reconstruction plate from the sciatic buttress down to the ischium. The distal portion of the plate should go low enough on the ischium to permit the most distal screw to be placed into the ischiopubic ramus. Screw placement in the central area of the posterior column is avoided to prevent intra-articular placement. Usually, 2 screws distally and 2-3 screws proximally are sufficient for adequate fixation.

Transverse fractures

A Kocher-Langenbeck approach can be used for fractures with a major posterior displacement or associated with posterior wall fractures (see Image 32). In these fractures, it is necessary to reduce not only the posterior column but also the anterior column displacement and malrotation. Generally, it is advisable to reduce the column first, check the articular surface continuity, and rule out articular penetration by hardware before fixing the wall fracture.

The reduction is carried out in a fashion similar to that in a posterior column fracture. The adequacy of the anterior reduction is confirmed by digital palpation of the quadrilateral plate to the iliopectineal line. If the anterior column is still displaced, then it is corrected with a pusher or a pelvic reduction clamp in the greater sciatic notch. A 3.5-mm reconstruction plate is then placed on the medial border of the posterior column, from the sciatic buttress to the ischium, and is fixed with 3.5-mm screws. It is very important to slightly overcontour the posterior plate to prevent the anterior column from opening up on application of the posterior plate.

A posterior-to-anterior lag screw is then inserted across the obliquity of the transverse fracture line into the anterior column. The starting point of this screw is approximately 3 fingerbreadths above the acetabulum and requires a significant retraction of the abductor musculature. This screw starts proximal to the thin part of the quadrilateral plate and runs parallel to the plate, taking purchase in the anterior column. Its position in the anterior column is checked using the obturator oblique view and its extra-articular placement confirmed on the iliac oblique view intraoperatively. It is important to avoid excessive anterior penetration with the drill bit so as to prevent damage to the femoral vessels, which are stuck down there by the iliopectineal fascia.

T-shaped fractures

Reduction of T-shaped fractures (see Image 33)with a single nonextensile approach is somewhat more difficult than it is for transverse fractures. When one uses the posterior approach, the reduction of the posterior column is carried out as outlined under Posterior column fractures above, ensuring that none of the screws cross into the anterior column.
 
Indirect reduction of the anterior column is then attempted by using a bone hook to pull the displaced anterior column into the acute angle created by the intact anterior column and the reconstructed posterior column. The bone hook or a pusher on the quadrilateral plate controls the rotation of the anterior column. Reduction is digitally confirmed by palpation of the quadrilateral plate, and the anterior column is stabilized to the reconstructed posterior column using posterior-to-anterior lag screws. A finger is placed on the  quadrilateral  surface,  and the hip is taken through a range of movement to rule out intra-articular hardware penetration.

When using the anterior approach, the anterior column is reduced first, and indirect reduction of the posterior column is attempted through the quadrilateral plate by using a small bone hook or a cerclage wire, after establishing lateral traction using a Schanz screw in the femoral head. Fixation is carried out using cerclage wires or an anterior-to-posterior lag screw.

Anterior column fractures, wall fractures, or both

With the ilioinguinal approach, the fracture site is cleaned and the reduction is carried out in a centripetal fashion. The iliac crest fracture is reduced by using a pointed reduction holding forceps or a specially designed pelvic reduction clamp. The gliding hole for lag-screw fixation can be created prior before reduction to ensure optimal screw placement in the thin iliac crest. The crest can be stabilized by using a lag screw or 3.5-mm reconstruction plates. The column is then stabilized to the crest temporarily with a K-wire, later to be replaced by a 3.5-mm lag screw into the sciatic buttress through the lateral window of the ilioinguinal approach. The wall fracture is then addressed through the middle window and reduced. Finally, the superior pubic rami and displaced pubic body fractures are reduced through the medial window.

A 3.5-mm reconstruction plate is molded along the iliac fossa, across the iliopectineal eminence to the pubic tubercle and the body of the pubis. The symphysis needs to be crossed only if an associated symphyseal disruption is present or if fractures are present in the pubic body. It is essential that the plate be perfectly contoured; otherwise, tightening down the plate may result in malreduction of the column fracture.

Cortical screws 3.5 mm in length are then placed in the pubis and the pubic tubercle medially and in the area of the sciatic buttress and the quadrilateral plate proximal to the acetabulum to provide stable fixation of the anterior column to the posterior column (anterior-to-posterior lag screws). These screws start at the pelvic brim superior to the acetabulum and are directed from proximal to distal into the posterior column paralleling the quadrilateral surface, aiming for the ischial spine. Care must be taken to avoid intra-articular placement of these screws; therefore, it is important to appreciate the location of the acetabulum relative to the fixed pelvic landmarks, that is, inferior to the anterior inferior iliac spine and under the iliopubic eminence.

Both-column fractures

The ilioinguinal approach is the best approach for both-column fractures (see Image 34). Anterior column reduction is performed from the iliac crest to the symphysis. This provides an anatomic template for the subsequent reduction of the posterior column. Usually, the anterior column piece of the both-column fracture is externally rotated and shortened. A Schanz screw in the femoral head is used to apply traction, with the hip flexed to correct the shortening and external rotation. The anterior column is thus reduced to the intact iliac wing and stabilized.

The posterior column, which is usually medially rotated and displaced, is then reduced to the anterior column using the Schanz screw in the femoral head for anterior and lateral traction. Pelvic reduction clamps—with one tine on the outer surface of the ilium and the other tine through the lateral or middle window—on the quadrilateral plate or the posterior column helps achieve reduction. Reduction may also be achieved by means of a small bone hook or a cerclage wire. The posterior column is stabilized using anterior-to-posterior lag screws. The reduction is checked radiographically, and the hip is taken through a range of movement to look for intra-articular placement of hardware.

Percutaneous fixation

Percutaneous fixation is a relatively recent addition to the armamentarium of the acetabular surgeon.^{33, 34, 35, 36} This technique is recommended for use by experienced acetabular surgeons in certain unstable minimally displaced fracture types in elderly persons or, particularly, in those at high risk for surgery due to comorbid factors.

Fixation is carried out using 4.5-mm cannulated screws under fluoroscopic control. The technique usually involves the use of 2 screws in the anterior inferior iliac spine, directed posteriorly, perpendicular to the fracture surface, toward the greater sciatic notch or just superior to it. On the obturator view, the insertion site of each screw is centered along the mid axis of the anterior inferior spine; in the iliac view, the screw is directed posteriorly across the fracture site. This permits fixation of high anterior or posterior column fractures.

Percutaneous fixation of the posterior column, though rarely done, has been reported by insertion of the screw into the ischial tuberosity.

These techniques are useful only in experienced hands; the complexities of the local anatomy and the small target zones for proper screw insertion preclude their widespread use.

Quadrilateral surface comminution

An anterior column fracture with comminution of the quadrilateral surface and central migration of the femoral head is one of the most difficult acetabular fractures to stabilize, as there is always a tendency for late central migration of the head because of lack of support there. Reconstructing the quadrilateral surface is extremely difficult. Different techniques have been described to this end. These include the following:

• Use of a contoured reconstruction or T-plate (spring plate) (see Image 35), bent at right angles to buttress the quadrilateral surface, as described by Tile²⁰ and Matta et al.¹¹
• Tile²⁰ also describes the use an inner table iliac crest autograft, fixed with heavy wires or braided cables to reconstitute the quadrilateral surface.

Helpful hints during surgery

• A femoral distractor (see Image 36) can be used to facilitate visualization and identification of structures for reduction.
• A Schanz screw can be used on a T-handle in the ischial tuberosity to manipulate the posterior column. This technique is especially useful in transverse fractures.
• Holes may be drilled into the outer cortex of the pelvic bone to obtain purchase for reduction holding clamps.
• K-wires can be used to temporarily hold reduction. This technique is especially useful when there is no place to apply pointed reduction holding clamps.

Pediatric acetabular fractures

Classification

Pediatric acetabular fractures are classified as follows:

• Type A: Small fragments are typically seen with dislocations.
• Type B: These are linear fractures with a stable hip. Type B fractures generally occur with pelvic fractures and are the only fracture types in which the force exerted is not through the femoral head but the pelvis. These fractures are also generally stable and do not often require any specific treatment.
• Type C: Type C fractures are linear fractures with hip instability.
• Type D: These are central fracture dislocations. Type D fractures have the poorest prognosis even after operative treatment. A variant of this type of fracture is the Walther fracture, which is a fracture through the acetabulum and ischium, which displaces medially.

Pediatric acetabular fractures are important, as the triradiate cartilage remains open until children are aged approximately 12 years. Therefore, if the acetabulum is injured before its closure, growth arrest may result, leading to a shallow acetabulum and progressive subluxation of the hip.³⁷ Conversely, in patients older than 12 years, the chance of significant growth disturbance is minimal. Bucholz et al³⁸ recognized 2 main types of physeal disturbances with triradiate cartilage injuries, as follows:

• Type I or II Salter-Harris injuries: These have a good prognosis for continued acetabular growth.
• Type IV Salter-Harris (crush) injuries: These have a poor prognosis with premature closure of the triradiate cartilage because of formation of a medial osseous bridge.

Dora et al monitored 10 patients with posttraumatic acetabular dysplasia and reported that all 10 patients demonstrated marked retroversion averaging 27°, whereas the contralateral acetabuli showed 23° of anteversion; the average center-edge angle was 9.5°.³⁹ The hip joint was typically in a lateral and caudal position, and a significant posterolateral deficiency was present.

Total hip replacement in acetabular fractures

For total hip replacement in acetabular fractures (see Image 37), Weber et al reported a 10-year follow-up study with a survival rate of 78%, with noncemented cups doing better than cemented ones.⁴⁰ Bellabarba et al compared the results of arthroplasty in patients who had had prior operative treatment of their acetabular fracture with those in patients who had had prior closed treatment of their acetabular fracture.⁴¹ The average duration of follow-up was 63 months. Operative time (P <.001), blood loss (P <.001), and perioperative transfusion requirements (P <.001) were greater in the patients with posttraumatic arthritis than they were in the patients with nontraumatic arthritis.

Of the patients with posttraumatic arthritis, those who had had ORIF of their acetabular fracture had a significantly longer index procedure (P=.01), greater blood loss (P=.008),  and  a  higher  transfusion  requirement  (P = .049)  than  those  in  whom  the  fracture  had  been  treated  by  closed  methods.  Two  of  the  15 patients with a previous ORIF required bone grafting of acetabular defects, compared with 7 of the 15 patients treated by closed means (P = .04).

The Kaplan-Meier 10-year survival rate, with revision or radiographic loosening as the end point, was 97%; results were similar to those of the patients who underwent primary total hip arthroplasty for nontraumatic arthritis. The only failure occurred in a patient with an unsupported acetabular discontinuity. They concluded that plate fixation is required in conjunction with acetabular reconstruction in such patients.

Mears and Velyvis assessed the role of acute total hip replacement in a selected group of patients with a displaced acetabular fracture and complicating features that greatly diminished the likelihood of a favorable outcome after open reduction and internal fixation.⁹ Fifty-seven patients underwent an acute total hip arthroplasty for a displaced acetabular fracture. The mean follow-up was 8.1 years, and the mean time from the injury to the arthroplasty was 6 days (range, 1-20 d). The mean age of the patients at the time of the arthroplasty was 69 years. Indications for the acute arthroplasty included intra-articular comminution and full-thickness abrasive loss of the articular cartilage, impaction of the femoral head, and impaction of the acetabulum that involved more than 40% of the joint surface and included the weight-bearing region.

At the time of the latest follow-up, the mean Harris hip score was 89 points (range, 69-100 points). Forty-five patients (79%) had an excellent or good outcome. Six patients had heterotopic bone formation, and 1 patient had symptomatic grade IV ossification. During the initial 6 postoperative weeks, the acetabular cups subsided an average of 3 mm medially and 2 mm vertically; all of the cups then stabilized, and none were loose at the latest follow-up evaluation. Six patients had excessive medialization of the cup, but none had late loosening or osteolysis. No cup or stem had late clinical or radiographic evidence of loosening.

The authors prefer a posterior approach with a generous incision. Identification and mobilization of the sciatic nerve is an important step. In cases with central dislocation, the head may be incarcerated and may have to be removed piecemeal; however, whenever possible, the authors prefer to excise the head en bloc and use it as bone graft to fill all of the defects. Only the implants that interfere with reaming need to be removed at surgery. Displaced large fragments must be realigned and stabilized, if possible, by using standard fracture fixation techniques.

The authors prefer uncemented cups (only if at least 75% contact exists in between the host bone and the cup) to cemented cups. It is essential to have a large inventory of implants available, as larger cups may be necessary if the acetabulum is reamed to get a better fit for the cup. Larger deficiencies may require the use of acetabular reinforcement rings, cages, or even allograft. Acetabular deficiency and distorted local anatomy may result in difficulty in proper orientation of the cup; this must be guarded against. Selection of a proper neck length and version of the prosthesis is essential to maintain optimal soft tissue tension around the hip and reduce the chances of dislocation.

Dislocations have been reported to occur more frequently after total hip replacement for acetabular fractures than after routine total hip replacements. This may commonly result from malorientation of the components or improper soft tissue balance around the hip. The infection rate is increased, possibly because of prolonged surgery, increased blood loss, and preexistent infection. Nerve damage occurs because of difficulty in identification of the nerves tied down in scarred fibrous tissue. Loosening of the prosthesis, myositis ossificans, and other complications are possible.

Arthroscopy in acute acetabular fractures

Arthroscopy has been used in certain cases of acetabular fractures to remove intra-articular loose fragments. However, potentially fatal complications such as intra-abdominal compartment syndrome due to extravasation of fluid under pressure have been reported with its use.⁴²

Postoperative details

The goals of postoperative management are to maximize the functional status of the patient, facilitate early return to function, and detect complications quickly and manage them appropriately. ¹⁴

Postoperative management includes the following general measures:

• Fluid and electrolyte balance: Acetabular surgery can be long and complicated and may involve significant bleeding. It is, therefore, important to adequately replace fluid volume and monitor the electrolyte balance. Blood should be given to maintain the hemoglobin level above 8-9 g/dL.
• Pain relief: This is one of the most important aspects of the postoperative management of patients who have undergone acetabular surgery, as surgery can involve a great deal of dissection. The best way to provide pain relief is by means of continuous epidural infusion of opiates. This decreases the need for systemic administration of analgesics significantly.
• Antibiotics: The authors recommend IV antibiotics for 72 hours postoperatively in uncomplicated cases. These should be broad-spectrum and provide gram-positive and gram-negative coverage.
• Prophylaxis against heterotopic ossification and DVT: The authors routinely recommend the use of indomethacin, 25 mg 3 times daily for 6 weeks, for the prevention of heterotopic ossification. The authors have no experience with the use of radiation for this purpose. The authors do not use anticoagulation, except in individuals at high risk, as they have rarely encountered significant DVT in the Indian population. The authors do, however, encourage the use of elastic stockings, sequential compression devices (SCDs), and active ankle mobilization. In patients at high risk, standard DVT prophylaxis must be used. The risks of development of a wound hematoma and protection against pulmonary embolism must be carefully weighed in selecting patients for anticoagulant prophylaxis.
• Nutrition: This is an often-neglected aspect of rehabilitation, especially in patients with multiple injuries. These patients have sustained severe trauma and tend to go into severe negative nitrogen balance, unless nutrition is specifically assessed. They often may have associated abdominal injuries that preclude enteric feeding. These patients must be put on parenteral hyperalimentation to ensure the best nutritional status to heal.
• Catheter care: Patients often are unable to void spontaneously and require a urinary catheter. Care must be taken to prevent the catheter from becoming a source of sepsis, and therefore, the catheter should be removed as soon as possible.
• Bowel care: Patients may also be constipated and may require a high fluid intake, high-fiber diet, and stool softeners. An enema may be justified if these measures are unsuccessful.

Postoperative local measures include the following:

• Immobilization: Patients with simple fractures, such as a posterior lip fracture, need not be put on traction but should be confined to bed on the first postoperative day. Patients with more complex injuries may have to be put on gentle (2- to 3-kg) traction until pain subsides, usually in about 10-14 days. A longer period of immobilization may be indicated if the fixation is not deemed stable at the time of surgery. A longer period of immobilization may also be indicated in extensile approaches; in these patients, the rehabilitation, especially abductor strengthening, may also have to proceed at a slower pace.
• Drains: The posterior drains usually are removed at 48 hours. The retropubic drain should stay in place longer, for 72-96 hours. The drains may be removed earlier if they drain less than 10 mL/d.
• Scrotal care: Scrotal elevation may be required for some patients in whom there has been excessive handling of the spermatic cord, as this may lead to significant scrotal edema.
• Exercises: Exercises may include the following:
  • The patient must be taught static quadriceps exercises preoperatively and must start them again postoperatively as soon as he or she is comfortable.
  • The patient must also begin ankle mobilization and, especially, dorsiflexion exercises on the first postoperative day itself. This not only prevents the development of a postural footdrop but also helps in circulation of blood in the lower limb and guards against development of DVT.
  • The patient should also begin with upper limb strengthening exercises to make crutch walking easier during rehabilitation.
  • Dynamic quadriceps exercises may be started as soon as the patient can sit up with his or her legs dangling by the side of the bed, usually in 5-7 days.
• Suture removal: Sutures are usually removed after 10-12 days; ilioinguinal wounds may sometimes take longer to heal.

Follow-up

Radiographs

Postoperative radiographs are usually obtained at the completion of the operation for preliminary confirmation of the reduction. A minimum of an AP pelvis radiograph is obtained in the operating room; the iliac oblique and obturator oblique views can be obtained in the operating room or later. After gait training and before discharge, another AP pelvic radiograph is generally obtained to confirm that loss of reduction has not occurred during ambulation. A single AP pelvis radiograph is obtained at