**3. Radiological anatomy**

position of femoral head at the time of injury, force vector and quality of bone .This fracture are usually associated visceral and neurovascular injuries. In this chapter, we are going to

The most common cause of injury in acetabular fractures is road traffic accidents and fall from a height [1, 2]. Usually acetabular fractures are associated with other major visceral injuries. There are very few literature available on the relationship of non-orthopedic injuries associated with acetabular fractures. Even though most of the acetabular fractures are caused due to axial compression along the femur, driving the femoral head into the acetabulum [3]. In a study on patients with combined pelvic and acetabular fractures, Dalal et al. reported 27% with traumatic brain injuries, even though there was relatively low rate of abdominal injuries [4]. According to him, some of the causative energy of the injury pattern is distributed to long bones before it reaches pelvis and torso, thus producing lower extremity fractures. Most of the posterior wall or column fractures are caused by axial forces transmitted to the acetabulum by knee and femur with the hip in adducted and flexed position—Dashboard injury. The other fracture pattern is caused by direct lateral compression force transmitted through the trochanter or indirect axial force along the femur in extended position of hip joint [5, 6]. In yet another study, it was noted that axial load pattern of injuries were associated with lung injury, retroperitoneal haematoma, traumatic brain injury and lower extremity fractures whereas incidence of genito-urinary injury, hepatic and splenis injury, pelvic vascular injury are more

Life threatening injuries like head injury, abdominal and other visceral injury must get priority in the initial evaluation of acetabular fracture. Other skeletal injuries, like fractures of patella-ipsilateral shaft of femur, tibial plateau fractures and knee ligamentous injury are also looked into. The lower limb will be flexed, adducted and internally rotated in posterior dislocation of hip which is usually associated with posterior wall or column fracture whereas it will be in abducted, extended and externally rotated in anterior dislocation. Lateral displacement of the anterior superior iliac spine on the affected side might give clue regarding central fracture dislocation of hip. Local injuries including skin, open acetabular fractures and perineum and scrotal injury must be excluded. A closed degloving injury of the subcutaneous tissue which is detached from the underlying fascia—Morel-Lavele lesion must be looked into because of the risk of high infection and wound healing in post-operative period. These lesions are not apparent initially but become evident later [8]. A careful neurological examination to rule out sciatic and common peroneal nerve injury should be done. There are isolated reports of injury to iliofemoral artery associated with high anterior column fracture and superior gluteal artery injury in displaced fracture into the greater sciatic notch. Hence, high index of suspicion should be there to rule out vascular injury of the ipsilateral lower limb [9, 10].

Sometimes acetabular fracture can produce profuse bleeding and shock. According to Letournel and Judet "the cause of shock relates to severity of trauma and to hemorrhage from the fracture site and often from other visceral lesions. The respective part played by the various elements producing the shock may be difficult to apportion" [4]. According to Dalal et al. patients with

describe the clinical feature and classification of acetabular fractures.

associated with lateral compressive type of acetabular fracture [7].

**2. Clinical features**

42 Trauma Surgery

Accurate classification of acetabular injury is important for its proper treatment. Various classification system have been suggested because of the complex anatomy of the acetabulum. Judet and Letournel classification is the most widely accepted and commonly used classification. Radiograph provides most of the essential information for classifying acetabular fractures. Computerized tomography with 3D reconstruction imaging is also useful in classifying acetabular fractures [12–16].

The acetabulum is an incomplete hemispherical socket with an inverted horseshoe shaped articular surface surrounding the non-articular cotyloid fossa. The articular socket is composed of and supported by two lamda [λ] shaped columns as described by Judet and Letournel (**Figure 1**). The anterior and posterior walls are extensions of the respective column and forms the cup of the acetabulum [16–18]. The anterior column is longer and larger and composed of

**Figure 1.** Columns of acetabulum. Blue—Posterior column. Green—Anterior column. Red—Sciatic buttress.

iliac crest, iliac spine, anterior half of the acetabulum and pubis. The posterior column extends superiorly from the ischiopubic ramus and consists of ischim, ischial spine and the posterior half of the acetabulum and the dense bone forming the sciatic notch. The anterior and the posterior columns meet at the sciatic buttress. The sciatic buttress extends posteriorly from anterior and posterior column to become the articular surface of the sacroiliac joint thus connecting the columns with the axial skeleton. The roof (dome) of the acetabulum is the weight bearing area that supports the femoral head. The quadrilateral plate is flat thin bone which is forming the medial wall of acetabulum. The iliopectineal eminence is the prominent part in the anterior column that lies directly over the femoral head.

of the reduction, rotation of the articular fragment and other associated pelvic injuries can be very well visualized in CT scan. Fracture lines in the sagittal plane represent transverse and wall fractures. Fracture lines in the coronal plane represent column fracture and the vertical limb of T-fracture. Magnetic resonance imaging (MRI) has no value in the immediate evaluation or classification, but is useful in determining the vascularity of femoral head at a later date [22].

Clinical and Radiological Assessment of Acetabular Fracture

http://dx.doi.org/10.5772/intechopen.76114

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The universally accepted classification of acetabular fracture was described by Judet and Letournel in 1964 and later modified by Letournel [12, 14]. This classification helps the surgeon to approach acetabular fracture in a more anatomical and fracture biomechanics. The Orthopaedic Trauma Association (OTA) modified Letournel classification and gave computerized coding according to AO comprehensive classification of fractures of long bones [23]. According to Judet and Letournel classification, acetabular fractures are divided into two basic groups: simple fracture type and complex fracture type. Each group consists of five types. The simple fracture pattern includes isolated anterior and posterior wall fractures, isolated anterior and posterior column fractures and transverse fracture (**Figure 2**). The Associated fracture pattern includes T-type fracture, combined fractures of posterior column and wall, transverse fracture with posterior wall fracture, anterior column with posterior hemitransverse fracture and bicolumnar

**Figure 2.** Simple acetabular fractures. (A) Posterior wall fracture (B) Posterior column fracture (C) Anterior wall fracture

(D) Anterior column fracture (E) Transverse fracture.

**5. Classification**
