While positioning you on the exam table, the technologist will explain your procedure and answer any questions you may have. Enter your email address below and we will send you your username, If the address matches an existing account you will receive an email with instructions to retrieve your username. Viewer If you received an injection of contrast dye, you should drink plenty of liquid to help flush it out of your system. Periprosthetic Fractures.—Periprosthetic femur fractures can occur intraoperatively, particularly with uncemented stems that are tightly fit and “tapped” into place at surgery. and Department of Orthopedic Surgery (J.A.P. Finally, radiologists must be familiar with the normal and abnormal CT appearances of hip prostheses and be able to recognize common complications on CT scans. This finding was clinically suspected, but the fracture line was radiographically occult. It is important to carefully review the patient’s prior hip radiographs (beginning with the most recent) when interpreting a CT examination. CT can also depict the position of hardware relative to adjacent soft tissues, such as cup overhang and its relationship to the iliopsoas muscle (overhang >12 mm is associated with iliopsoas impingement) (34) or the position of a screw tip (Fig 6). At the very least, pedestal formation should be closely followed up (28,29).Figure 13 Periprosthetic sclerosis. 1, 19 July 2016 | Acta Radiologica, Vol. Imaging technologies used at HSS to diagnose hip pain include X-ray, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound. Punctate pieces of metal around an in-growth component indicate breakage at the surface (bead shedding) (Fig 14), and they are worrisome for loosening if they are new findings that were not seen on the immediate postoperative images (28,29). Coronal reformatted CT image shows a loose femoral stem with a fractured cement mantle (arrow). Our team of expert physicians, nurses and technologists is led by Cindy Kallman, MD, chief of Body Imaging. 43, No. Small voids representing air bubbles in the mantle of cemented components are also acceptable (Fig 11) (36).Figure 11 Normal low-attenuation areas. Coronal reformatted CT images show a unipolar implant (a) and a bipolar implant (b). Osteolysis.—CT is particularly useful in evaluating periprosthetic bone around the acetabular cup, where assessment with radiography is difficult. A basic understanding of hip reconstruction and hip implants is required for proper image interpretation. 42, No. Image interpretation requires a basic understanding of hip reconstruction and hip implants, as well as use of a systematic method of analysis that incorporates prior radiographic findings and CT findings. A unipolar hemiprosthesis has one articulation between the metal implant head and the native acetabular cartilage surfaces. 208, No. 39, No. 3, Diagnostic and Interventional Imaging, Vol. [ Back to Top] To speak with an orthopedic surgeon about hip … 46, No. The resurfacing femoral head component is seated with a pegged stem that fits inside a preserved femoral neck. At surgery, the cup was firmly fixed, and only the modular acetabular cup liner and femoral head were exchanged. (c) Total hip prosthesis with a cemented acetabular cup (arrow). Other complications include neurovascular injury, leg length discrepancy, periprosthetic fracture, dislocation or subluxation, osteolysis, loosening, heterotopic ossification, pseudobursa formation, metal sensitivity or toxicity, and wear or breakage of hardware. In the postoperative period, CT can also be used to detect nondisplaced stress or traumatic fractures around a prosthesis, which often occur near the tip of the stem (Fig 20). The fluid collection proved to be an abscess caused by Staphylococcus aureus. Your physician will discuss these results with you and explain what they mean in relation to your health. (c) What are the bearing surfaces? Multidetector computed tomography (CT) is an excellent way to supplement the radiographic evaluation of problematic hip prostheses. Findings Indicating Possible or Probable Loosening.—. Component wear in a patient with a left total hip prosthesis. Discuss a CT protocol for evaluating hip prostheses, with the application of specific principles to minimize metal artifact. This procedure soft tissues ( eg, searching for an abscess ) problems in the anus and! A small amount of ossification may be subtle, and endosteal scalloping can be fixed to bone to unwanted. Want a copy of your pelvis/hip bones occurring more rapidly at first attenuation of the stem ( shown. 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