title: The effect of a low radiation CT protocol on accuracy of CT guided implant migration measurement: A cadaver study.
abstract: The current study compared the impact of low radiation CT protocols on the accuracy, repeatability, and inter- and intra-observer variability of implant migration studies in total hip arthroplasty. Two total hip replacements were performed in two human cadavers and six tantalum beads were inserted into the femur similar to radiostereometric analysis. Six different 28 mm heads (-3 mm, 0 mm, 2.5 mm, 5.0 mm, 7.5 mm, and 10 mm) were added to simulate five reproducible translations (maximum total point migration) of the center of the head. Three CT scans with varying levels of radiation were performed for each head position. The effective dose (mSv) was 3.8 mSv for Protocol A (standard protocol), 0.7 mSv for Protocol B and 1.6 mSv for Protocol C. Implant migration was measured in a 3-D analysis software (Geomagic Studio 7). The accuracy was 0.16 mm for CT Protocol A, 0.13 mm for Protocol B and 0.14 mm for Protocol C; The repeatability was 0.22 mm for CT Protocol A, 0.18 mm for Protocol B and 0.20 mm for Protocol C; ICC for inter observer reliability was 0.89, intra observer reliability was 0.95. The difference in accuracy between standard protocol A and the two low radiation protocols (B, C) was less than 0.05 mm. The accuracy, inter- and intra-observer reliability of all three CT protocols is comparable to radiostereometric analysis. Reducing the CT radiation exposure to numbers similar to an AP Pelvis radiograph (0.7 mSv protocol B) does not affect the accuracy of implant migration measurements.
authors.affiliation: Adult Reconstruction & Joint Replacement Division, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.
authors.forename: Friedrich
authors.initials: F
authors.lastname: Boettner
authors.affiliation: Adult Reconstruction & Joint Replacement Division, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.
authors.forename: Peter K
authors.initials: PK
authors.lastname: Sculco
authors.affiliation: Department of Biomechanics, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.
authors.forename: Joseph
authors.initials: J
authors.lastname: Lipman
authors.affiliation: Department of Radiology and Imaging, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.
authors.forename: Gregory
authors.initials: G
authors.lastname: Saboeiro
authors.affiliation: Adult Reconstruction & Joint Replacement Division, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.
authors.forename: Lisa
authors.initials: L
authors.lastname: Renner
authors.affiliation: Adult Reconstruction & Joint Replacement Division, Hospital for Special Surgery, Weill Medical College of Cornell University, 535 East 70th Street, New York City, New York, 10021.|Department of Orthopedic Surgery, University Ulm, Oberer Eselsberg 45, 89081 Ulm, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Faschingbauer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis; D014057:Tomography, X-Ray Computed / Q000592:standards*
keywords: 2016.; CT; CT protocol; Inc. J Orthop Res 34:725-728; Radiation dose; cadaver; cadaver. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals; femoral migration; low radiation; migration analysis