Assessment of acetabular version by plain radiograph

Radiographs are routinely used to assess the condition and position of the acetabular component. The condition of the cement mantle, or the ingrowth potential, is usually easily recognized. Component-bone position can be assessed by using the method of Ranawat or by measuring abduction angles. Assessment of the version of an acetabular component is often overlooked. This angle or position is important relative to instability, impingement, and motion abnormality. The opening angle or version can be implied from a true acetabular or cross-table lateral radiograph, but good-quality views are often difficult to obtain on an outpatient basis. Using the simple technique presented here, clinicians can assess the acetabular component for version on the basis of plain anteroposterior pelvis and hip radiographs.