title: Early micromovement of the Articular Surface Replacement (ASR) femoral component: two-year radiostereometry results.
abstract: Radiostereometric analysis (RSA) can detect early micromovement in unstable implant designs which are likely subsequently to have a high failure rate. In 2010, the Articular Surface Replacement (ASR) was withdrawn because of a high failure rate. In 19 ASR femoral components, the mean micromovement over the first two years after implantation was 0.107 mm (SD 0.513) laterally, 0.055 mm (SD 0.204) distally and 0.150 mm (SD 0.413) anteriorly. The mean backward tilt around the x-axis was -0.08° (SD 1.088), mean internal rotation was 0.165° (SD 0.924) and mean varus tilt 0.238° (SD 0.420). The baseline to two-year varus tilt was statistically significant from zero movement, but there was no significant movement from one year onwards. We conclude that the ASR femoral component achieves initial stability and that early migration is not the mode of failure for this resurfacing arthroplasty.
authors.affiliation: University of Southern Denmark, Department of Orthopaedic Surgery and Traumatology, Clinical Institute, Odense University Hospital, Sdr. Boulevard 23, 5000, Odense, Denmark. annette.penny@yahoo.com
authors.forename: J O
authors.initials: JO
authors.lastname: Penny
authors.forename: M
authors.initials: M
authors.lastname: Ding
authors.forename: J E
authors.initials: JE
authors.lastname: Varmarken
authors.forename: O
authors.initials: O
authors.lastname: Ovesen
authors.forename: S
authors.initials: S
authors.lastname: Overgaard
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D019544:Equipment Failure Analysis; D005260:Female; D006618:Hip Dislocation, Congenital / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D011475:Prosthesis Failure; D059869:Radiostereometric Analysis