title: Precision of EBRA-Digital software for monitoring implant migration after total hip arthroplasty.
abstract: We assessed the precision of the EBRA-Digital software (EBRA, University of Innsbruck, Innsbruck, Austria) for measuring implant migration after total hip arthroplasty. Study subjects (n = 29) underwent consecutive, standardized, plain radiographic examinations of the hip on the same day after repositioning. The resulting radiograph pairs were digitized and analyzed using EBRA. The precision (95% confidence interval) of the method for measuring migration and wear was <+/-0.9 mm for both implant components. The 95% confidence intervals for measurement of cup inclination and anteversion and femoral stem/shaft angle were <+/-1.7 degrees. Measurement precision was not strongly related to patient gender, digitization method, or observer. The EBRA-Digital method has sufficient precision to detect clinically relevant migration to allow individual patient monitoring after total hip arthroplasty. The method requires careful patient positioning and radiographic technique to produce consistently images suitable for analysis.
authors.affiliation: Bone Metabolism Group, Section of Medicine, Division of Clinical Sciences (NGHT), University of Sheffield, Northern General Hospital, Sheffield, United Kingdom. wilkomark@aol.com
authors.forename: J M
authors.initials: JM
authors.lastname: Wilkinson
authors.forename: A J
authors.initials: AJ
authors.lastname: Hamer
authors.forename: R A
authors.initials: RA
authors.lastname: Elson
authors.forename: I
authors.initials: I
authors.lastname: Stockley
authors.forename: R
authors.initials: R
authors.lastname: Eastell
mesh_terms: D019644:Arthroplasty, Replacement, Hip; D005260:Female; D006621:Hip Joint / Q000000981:diagnostic imaging; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008297:Male; D015588:Observer Variation; D011475:Prosthesis Failure; D011859:Radiography; D012984:Software