title: Backside Wear Analysis of Retrieved Acetabular Liners with a Press-Fit Locking Mechanism in Comparison to Wear Simulation In Vitro.
abstract: Backside wear due to micromotion and poor conformity between the liner and its titanium alloy shell may contribute to the high rates of retroacetabular osteolysis and consequent aseptic loosening. The purpose of our study was to understand the wear process on the backside of polyethylene liners from two acetabular cup systems, whose locking mechanism is based on a press-fit cone in combination with a rough titanium conical inner surface on the fixation area. A direct comparison between in vitro wear simulator tests (equivalent to 3 years of use) and retrieved liners (average 13.1 months in situ) was done in order to evaluate the backside wear characteristics and behavior of these systems. Similar wear scores between in vitro tested and retrieved liners were observed. The results showed that this locking mechanism did not significantly produce wear marks at the backside of the polyethylene liners due to micromotion. In all the analyzed liners, the most common wear modes observed were small scratches at the cranial fixation zone directly below the rough titanium inner surface of the shell. It was concluded that most of the wear marks were produced during the insertion and removal of the liner, rather than during its time in situ.
authors.affiliation: Aesculap AG Research and Development, 78532 Tuttlingen, Germany; Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, Ludwig Maximilians University Munich, Campus Grosshadern, 81377 Munich, Germany.
authors.forename: Ana Laura
authors.identifier: 0000-0002-1861-4452
authors.initials: AL
authors.lastname: Puente Reyna
authors.affiliation: Department of Orthopaedics and Trauma Surgery, University of Duisburg-Essen, 45147 Essen, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Jäger
authors.affiliation: Department of Orthopaedic Surgery, Hannover Medical School, 30625 Hannover, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Floerkemeier
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Frecher
authors.affiliation: Department of Orthopaedic and Trauma Surgery, Martin Luther University Halle-Wittenberg, 06120 Halle (Saale), Germany.
authors.forename: Karl-Stefan
authors.initials: KS
authors.lastname: Delank
authors.affiliation: Aesculap AG Research and Development, 78532 Tuttlingen, Germany.
authors.forename: Christoph
authors.identifier: 0000-0002-0502-7101
authors.initials: C
authors.lastname: Schilling
authors.affiliation: Aesculap AG Research and Development, 78532 Tuttlingen, Germany; Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, Ludwig Maximilians University Munich, Campus Grosshadern, 81377 Munich, Germany.
authors.forename: Thomas M
authors.identifier: 0000-0002-1068-7497
authors.initials: TM
authors.lastname: Grupp
mesh_terms: D000077:Acetabulum / Q000601:surgery*; D000497:Alloys / Q000627:therapeutic use; D016268:Internal Fixators; D008422:Materials Testing / Q000379:methods; D009038:Motion; D010014:Osteolysis / Q000517:prevention & control*; D011095:Polyethylenes / Q000737:chemistry; D011475:Prosthesis Failure / Q000209:etiology; D013314:Stress, Mechanical; D013499:Surface Properties; D014025:Titanium / Q000627:therapeutic use
chemical_list: D000497:Alloys; D011095:Polyethylenes; D014025:Titanium