title: Mid-term migration of a cemented total hip replacement assessed by radiostereometric analysis.
abstract: We have previously reported the short-term migration of cemented Hinek femoral components using radiostereometric analysis (RSA). We now report the mid-term migration. During the first 2 years after implantation the prosthesis subsided into varus and rotated internally. Between years 3 and 8 the prosthesis continued to rotate internally with the head moving posteriorly (0.07 mm/year, P=0.004). It also continued to fall into varus with the tip moving laterally (0.07 mm/year, P=0.04). The head (0.06 mm/year, P<0.0001), shoulder (0.04 mm/year, P=0.0001) and tip (0.04 mm/year, P=0.001) continued to migrate distally. There were two cases of failure due to aseptic loosening during the follow-up period. During the second year both of these had posterior head migration, which was abnormally rapid (>2 SD from the mean). We have demonstrated that a cemented implant has slow but significant levels of migration and rotation for at least 8 years after implantation. Our study confirms that implants with abnormally rapid posterior head migration during the second year are likely to fail.
authors.affiliation: Oxford Orthopaedic Engineering Centre, Nuffield Orthopaedic Centre, University of Oxford, Oxford, UK.
authors.forename: J
authors.initials: J
authors.lastname: Alfaro-Adrian
authors.forename: H S
authors.initials: HS
authors.lastname: Gill
authors.forename: B E
authors.initials: BE
authors.lastname: Marks
authors.forename: D W
authors.initials: DW
authors.lastname: Murray
mesh_terms: D001843:Bone Cements; D005069:Evaluation Studies as Topic; D005260:Female; D005500:Follow-Up Studies; D005548:Foreign-Body Migration / Q000000981:diagnostic imaging*; D006621:Hip Joint / Q000000981:diagnostic imaging*; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D009068:Movement; D010780:Photogrammetry; D011379:Prognosis; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography
chemical_list: D001843:Bone Cements