ACETABULAR FRACTUREDr. Sandeep Gurung

• The acetabulum can be described as an incomplete hemispherical socket with an inverted horseshoe-shaped articular surface.

• This articular socket is composed of and supported by two columns of bone as an inverted Y.

• The anterior column is composed of the bone of the iliac crest, the iliac spines, the anterior half of the acetabulum, and the pubis

• The posterior column is composed of thethe ischiumthe ischial spine the posterior half of the acetabulum, and the dense bone forming the sciatic notch.

• The dome, or roof, of the acetabulum is the weight bearing portion of the articular surface that supports the femoral head.

• Anatomical restoration of the dome with concentric reduction of the femoral head beneath this dome is the goal of both operative and nonoperative treatment.

Mechanism of Injury

• generally are caused by high-energy trauma, and associated injuries are frequent.

• Acetabular fractures occur as force is transmitted from the femur to the pelvis via the femoral head.

• The fracture pattern, therefore, is dependent on the position of the hip at the time of injury, as well as the direction and magnitude of the impact.

• A relatively low-energy injury may produce a severely comminuted fracture in an osteoporotic patient.

CLINICAL EVALUATION

primary initial importance in the patient with a suspected acetabular fracture is to rule out other life-threatening injuries. Up to 57% of patients with acetabular fractures will have an associated injury.

Neurologic injuries occur in up to 30% of cases and are usually partial injuries to the sciatic nerve.

Patient may be severely shocked, and the complication associated with all pelvic fractures should be sought

There may be bruising around the hip and the limb may lie in internal rotation (if the hip is D/L).

Radiographic Evaluation

• The acetabulum is evaluated radiographically with an

anteroposterior pelvic view as well as with the two 45-degree oblique views of

the pelvis, commonly called Judet views.

The Judet views (obturator oblique and iliac oblique) are obtained by rolling the patient 45 degrees in relation to the x-ray beam.

In the iliac oblique view

is obtained with the patient tilted 45 degree with the affected hip down.the radiographic beam is roughly perpendicular to the iliac wing. posterior column and the anterior wall are will visualized

In the obturator oblique view

The obturator oblique view is obtained when the pelvis is rotated 45 degrees with the injured side up. the radiographic beam is roughly perpendicular to the obturator foramen. The anterior column and the posterior wall are well visualized

•Iliopectineal line beginning at greater sciatic notch of ilium and extending down to pubic tubercle.• Ilioischial line formed by posterior four fifths of quadrilateral surface of ilium.• Edge of anterior lip of acetabulum. • Edge of posterior lip of acetabulum.

• Fractures that traverse the anterior column disrupt the iliopectineal line,

• whereas fractures that traverse the posterior column disrupt the ilioischial line.

• The medial clear space between the femoral head and the radiographic teardrop in the injured and uninjured hips should be compared on the anteroposterior view as an indication of femoral head subluxation

Fracture Classification

• Letournel and Judet classification of acetabular fractures. simple fracture

Posterior wall fracture. Posterior column fracture. Anterior wall fracture. Anterior column fracture. Transverse fracture.

complex associated fracture typesPosterior column and posterior wall fracture. Transverse and posterior wall fracture. T-shaped fracture. Anterior column and posterior hemitransverse fracture. Complete both-column fracture

• Tiles classification of acetabular fracturesSimple fracture

Involving either the anterior or the posterior wall or column.

Transverse fractureT-type fracture involving two columnsBoth column fracture

Posterior wall fracture

involve disruption of variable amounts of the posterior rim of the acetabulum.may be a single fragment (30%) or multifragmentary. They are the most common acetabulum fracture.best viewed on the AP and obturator oblique x-rays.

Transverse acetabular fracture

Fracture runs transversely through the acetabulum, involving both the ant. And post. Column .The fracture separates the innominate bone into two pieces: the upper iliac piece and the lower ischiopubic segmentThe upper fragment is intact to the ilium while the ischiopubic fragment rotates about the symphysis pubis. This results in a medial and cephelad displacement of the head, as it follows the ischiopubic segment.

T-Shaped Fractures

transverse fracture with an associated vertical fracture line The vertical stem usually propagates from the transverse fracture.

Both Column Fractures

there is a split between an anterior and posterior column component.

Posterior Column Fractures

TREATMENT• Initial Treatment

Treatment of the entire patient should follow accepted Advanced Trauma Life Support (ATLS) protocol, with orthopaedic management of the acetabular fracture appropriately integrated into the treatment plan.

First priority is to counteract shock and reduce a dislocation.

Traction is applied to distal femur, occasionally additional lateral traction through the greater trochanter is needed.

Definitive treatment of the fracture is delayed until the patient is fit.

Indications for Nonoperative Treatment

• Nondisplaced and Minimally Displaced Fractures. Fractures that traverse the weight bearing dome but are displaced less

than 2 mm can be treated with non–weight bearing for 6 to 12 weeks.

• Fractures with Significant Displacement but in Which the Region of the Joint Involved Is Judged to Be Unimportant Prognostically.

This determination is made with the roof arc measurements. Roof arc measurements were described by Matta et al as a way to

quantify the amount of remaining intact weightbearing articular surface after fracture.

Medial, anterior, and posterior roof arcs of greater than 45 degrees as measured on the AP, obturator, and iliac oblique x-rays have been used to define the intact weightbearing dome

•The roof arc angles are measured by drawing a vertical line through the center of the femoral head on the AP and Judet views. A second line is drawn through the center of the head to the location of the fracture at the articular surface.• Roof arc measurements are not applicable to

associated both column fractures because there is no intact portion of the acetabulum to measure. fractures of the posterior wall

• Secondary Congruence in Displaced Both-Column Fractures.

That retains the ball and socket congruence of the hip by virtue of the fracture line lying in the coronal plane an displacemnt being limited by an intact labrum.

• Medical Contraindications to SurgeryLocal Soft-Tissue Problems, such as Infection, Wounds,

and Soft-Tissue Lesions from Blunt Trauma Elderly Patients with Osteoporotic Bone in Whom

Open Reduction May Not Be Feasible

Indications for Operative Treatment

• Fracture Characteristics An acetabular fracture with 2 mm or more of

displacement in the dome of the acetabulum as defined by any roof arc measurements of less than 45 degrees.

posterior wall fractures with more than 50% involvement of the articular surface of the posterior wall or

posterior wall fractures involving less than 50% of the wall but clinically unstabel with hip flexion to 90 degrees.

• Incarcerated Fragments in the Acetabulum after Closed Reduction of a Hip Dislocation

Fragments noted on CT scan to be lodged between the articular surfaces of the femoral head and the acetabulum warrant excision.

• Timing of Surgery Most authors advocate waiting 2 or 3 days after injury

before performing acetabular surgery to allow the patient to be adequately stabilized and to allow pelvic bleeding to subside.

Choice of Surgical Approach

• Acetabular fractures should be exposed to allow the surgeon to address the area of maximal displacement.

• Thus, if the major displacement occurs posteriorly, posterior approaches should be used, while anterior displacement should be addressed utilizing approaches that expose anteriorly.

• Kocher Langenbeck. This approach is used for displaced posterior column, posterior wall, and

transverse fractures that have the largest amount displacement posteriorly The patient is placed in the lateral decubitus position, or prone. The incision is centered over the greater trochanter and extends proximally

toward the posterior superior iliac spine, and distally over the shaft of the femur. The interval splits the gluteus maximus proximally, and the tensor fascia distally The short external rotators are taken down, with care to protect the sciatic

nerve. The quadratus femoris muscle is the inferior limit of the exposure around the

proximal femur, to avoid injuring the blood supply to the femoral head, the medial circumflex artery.

Proximally, the inferior aspect of the greater sciatic notch is used as a landmark to avoid injuring the superior gluteal artery, which, if severed can retract into the pelvis and bleed profusely. If this occurs, the patient should immediately be placed in the supine position, and direct hemostasis should be obtained.

• Ilioinguinal. This approach exposes the anterior column, pelvic brim,

quadrilateral surface, anterior SI joint and inner table of the ilium.

The patient is supine on a radiolucent or fracture table with the hip flexed 20 degrees to relax the hip flexors.

The incision begins 3-4 cm superior to the pubic crest and runs superior parallel to the iliac crest.

The inner table of the ilium is dissected subperiosteally to the SI joint. The external oblique aponeurosis is opened and the floor of the inguinal canal is incised, after protecting its contents (spermatic cord in males, round ligament in females).

• Extended Iliofemoral Approach. This approach is rarely indicated. It is associated with a high incidence of heterotopic

ossification It is useful for displaced both column fractures, and T-

Type fractures with displacement both anteriorly and posteriorly.

Exposure is similar to KL approach, with added trochanteric osteotomy and elevation of the gluteus medius from the outer table of the ilium to expose the anterior column.

• Posterior Wall Fractures Kocher-Langenbeck approach After reduction of the wall fragments, provisional

fixation with Kirschner wires can be used while definitive fixation is performed with lag screws

and a contoured reconstruction plate placed from the ischium, over the retroacetabular surface onto the lateral ilium

• Posterior Column FracturesThe Kocher-Langenbeck approach is used routinelyTypical fixation is with a lag screw combined with a

contoured reconstruction plate along the posterior column.

• Anterior Wall and Anterior Column Fracturesilioinguinal or iliofemoral approachfixation by a contoured plate along the pelvic brim

• Transverse Fracturesilioinguinal approachTypical fixation is a contoured plate along the pelvic brim

with lag screws directed down the posterior column

• Posterior Column Fracture with Associated Posterior Wall Fracture

A Kocher-Langenbeck approach is usedThe column fracture is reduced first, and a short

reconstruction plate is placed posteriorly along the posterior edge of the column.

A separate plate is used for the wall fragment.

• Transverse Fracture with Associated Posterior Wall Fracture

Kocher-Langenbeck approach Typical fixation is performed by fixing the transverse

component with lag screws into the anterior column while plating the posterior wall, thus further stabilizing the posterior portion of the transverse fracture.

• T-Type FracturesKocher-Langenbeck approachThe anterior column is fixed with screwsthe posterior column portion can be fixed with a lag screw and

a reconstruction plate.

• Anterior Column–Posterior Hemitransverse Fractures ilioinguinal approach typical fixation of the anterior column fracture and separate lag

screws from the iliac fossa adjacent to the pelvic brim extending down the posterior column.

• Both-Column Fractures treated through an anterior ilioinguinal approach In general, reduction is begun from the most proximal portion of the

fracture and proceeds toward the joint. Each small fragment must be anatomically reduced because small malreductions in the ilium above the fracture become magnified at the level of the joint.

Fixation is as varied as the fracture patterns and the approaches used

COMPLICATIONS

• Posttraumatic Arthrosis• Heterotopic Ossification

Heterotopic ossification is related to the degree of soft tissue disruption, from either the injury or the surgical approach

Prophylactic treatments for heterotopic ossification include 6 weeks of indomethacin use (25 mg tid), single dose external beam radiotherapy

• Venous ThromboembolismDeep venous thrombosis (DVT) and pulmonary embolism are

common complications after pelvic or acetabular fractures treated without prophylaxis

Chemoprophylaxis with low-molecular weight heparin or warfarin

• Neurologic Injury• Infection