title: Postoperative calculation of acetabular cup position using 2-D-3-D registration.
abstract: A method to accurately measure the position and orientation of an acetabular cup implant from postoperative X-rays has been designed and validated. The method uses 2-D-3-D registration to align both the prosthesis and the preoperative computed tomography (CT) volume to the X-ray image. This allows the position of the implant to be calculated with respect to a CT-based surgical plan. Experiments have been carried out using ten sets of patient data. A conventional plain-film measurement technique was also investigated. A gold standard implant position and orientation was calculated using postoperative CT. Results show our method to be significantly more accurate than the plain-film method for calculating cup anteversion. Cup orientation and position could be measured to within a mean absolute error of 1.4 mm or degrees.
authors.affiliation: Imaging Sciences Division, Guy's King's and St Thomas' Schools of Medicine, Kings College London, London SEI 3RB, UK. graeme.penney@kcl.ac.uk
authors.forename: Graeme P
authors.initials: GP
authors.lastname: Penney
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Edwards
authors.forename: John H
authors.initials: JH
authors.lastname: Hipwell
authors.forename: Mike
authors.initials: M
authors.lastname: Slomczykowski
authors.forename: Ian
authors.initials: I
authors.lastname: Revie
authors.forename: David J
authors.initials: DJ
authors.lastname: Hawkes
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging* / Q000601:surgery*; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation / Q000379:methods*; D006622:Hip Prosthesis; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods*; D011182:Postoperative Care / Q000379:methods; D011856:Radiographic Image Enhancement / Q000379:methods; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D013382:Subtraction Technique; D014057:Tomography, X-Ray Computed / Q000379:methods*