title: Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties.
abstract: As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination. The precision of RSA corresponding to the 99% confidence interval was 1.36°, 1.36°, and 0.60° forX-,Y-, andZ-rotation and 0.40, 0.17, and 0.37 mm forX-,Y-, andZ-translation. The limit of agreement between CT and RSA was 1.51°, 2.17°, and 1.05° for rotation and 0.59, 0.56, and 0.74 mm for translation. The differences between CT and RSA are close to the described normal 99% confidence interval for precision in RSA: 0.3° to 2° for rotation and 0.15 to 0.6 mm for translation. We conclude that measurements using CT and RSA are comparable and that CT can be used for migration studies for longitudinal evaluations of patients with RSA markers.
authors.affiliation: Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden.
authors.forename: Volker
authors.identifier: 0000-0002-9966-1903
authors.initials: V
authors.lastname: Otten
authors.affiliation: School of Information and Communication Technology, KTH Royal Institute of Technology, Kista, Sweden.
authors.forename: Gerald Q
authors.identifier: 0000-0002-6066-746X
authors.initials: GQ
authors.lastname: Maguire
authors.affiliation: Department of Radiology, New York University School of Medicine, New York, NY, USA.
authors.forename: Marilyn E
authors.identifier: 0000-0002-2442-1622
authors.initials: ME
authors.lastname: Noz
authors.affiliation: School of Computing, College of Engineering, University of Utah, Salt Lake City, UT, USA.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Zeleznik
authors.affiliation: Department of Surgical and Perioperative Sciences, Umeå University, Umeå, Sweden.
authors.forename: Kjell G
authors.initials: KG
authors.lastname: Nilsson
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Henrik
authors.initials: H
authors.lastname: Olivecrona
mesh_terms: D000328:Adult; D000368:Aged; D059925:Anatomic Landmarks; D019644:Arthroplasty, Replacement, Hip; D019992:Databases as Topic; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011336:Probability; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D014057:Tomography, X-Ray Computed