**4. Radiological evaluation**

The radiographic evaluation of the acetabulum includes an anterio-posterior (AP) view and Oblique (Judet) views [19]. Minimal individual variations of the normal articular area can be visualized by comparing the anatomical landmarks of both hips. For example, comparison of the medial clear space between the head and tear drop will give a clue regarding femoral head subluxation. The iliopectineal line represents the anterior column and ilioischial line represents the posterior column. A line joining the lateral edge of sourcil to lateral edge of the inferior tear drop represents the anterior wall and a line representing the lateral edge of superior acetabulum to the lateral sclerotic area in the inferior margin of acetabulum represents the posterior wall [20].

In the AP radiograph, we have to look into certain radiological landmarks.


The iliac oblique view will clearly show anterior wall and posterior column, quadrilateral surface and posterosuperior roof arc. The obturator oblique view will show posterior wall, anterior column and anteriosuperior roof arc. The obturator ring represents parts of both columns, and fracture of the obturator ring may be associated with other pelvic injuries like lateral pelvic compression injury or sacral fracture.

Evaluation of the acetabular fracture is made easier by both 2D and 3D CT scan [21]. The entire pelvis is usually included in the tomogram to avoid missing a fracture and comparison of the opposite side. The newer spiral CT scan of 1.5 mm and continuous bone section through the pelvis and acetabulum can be obtained. The 3D reconstruction view will help the surgeon to understand the fracture pattern and its anatomical location inter-operatively. Fracture lines in sagittal and coronal planes, marginal impaction, intra-articular loose fragments, concentricity 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].
