Acetabular Version Measurement in Total Hip Arthroplasty: the Impact of Inclination and the Value of Multi-Planar CT Reformation.

Background: The orientation of the acetabular cup component of a total hip arthroplasty can be evaluated in a number of ways, utilizing a myriad of imaging techniques and measurement parameters, including intraoperative surgical estimates, postoperative radiographs, and cross-sectional imaging such as computed tomography (CT) and magnetic resonance imaging (MRI).

Questions/purposes: How do traditional versus corrected measurements of acetabular version vary from one another based on the inclination of the cup? What is the reliability of the corrected acetabular version measurements based on interobserver and intraobserver consistency?

Patients And Methods: Two fellowship-trained musculoskeletal radiologists reviewed CT scans on 60 total hip arthroplasties. Acetabular inclination, traditional CT acetabular version, and CT acetabular version corrected for inclination (by utilizing multi-planar reformations to measure in the plane of the cup face) were each measured.

Measuring acetabular component version after THA: CT or plain radiograph?

Background: Although cross-table lateral radiographs are commonly used to measure acetabular component version after THA, recent studies suggest that CT-based measurement is more accurate. This has been attributed to variations in pelvic tilt, pelvic rotation, and component inclination. Furthermore, it has been suggested, based on limited data, that even with ideal positioning of the cross-table lateral radiograph, CT remains the more accurate modality.

CT outperforms radiography for determination of acetabular cup version after THA.

Precise evaluation of acetabular cup version is necessary for patients with recurrent hip dislocation after THA. We retrospectively studied 42 patients, who underwent THAs, with multiple cross-table lateral radiographs and CT scans to determine whether radiographic or CT measurement of acetabular component version is more accurate. One observer measured cup version on all radiographs.

Radiographic tools for assessment of pathologic cartilage calcification.

Both hyaline cartilage and fibrocartilage can calcify in a variety of pathologic conditions. Traditionally, plain film radiographs have been used to diagnose such calcifications; however, only when the calcifications have adequately mineralized are they radiographically apparent. Cross-sectional imaging modalities such as computed tomography, magnetic resonance imaging, and ultrasonography can often demonstrate cartilage calcifications before they are radiographically apparent, thus yielding earlier detection of disease processes.