title: Surface damage on open box posterior-stabilized polyethylene tibial inserts.
abstract: Twenty retrieved Scorpio posterior-stabilized implants were available for analysis. The mean implantation time was 22 months (range, 2 days-42 months). Favorable types and amounts of surface damage were seen on the tibiofemoral and backsides of these modular PE liners that had been packaged in an inert environment and then sterilized by gamma irradiation. Delamination represented only 0.1% of the total surface damage. Off-axis loading (varus malalignment) was associated with tibial component loosening but there was no evidence of peripheral damage of PE caused by edge loading. With this open-box design, hyperextension marks on the anterior aspect of the posterior-stabilized post from femoral component impingement occurred in 11 of 20 cases and was related to sagittal component positioning: excess tibial slope or increased tibial slope combined with a flexed femoral component. Unique coarse abrasions occurred in 16 of 20 cases and were the result of cement extrusion into the open box, especially with varus malalignment. These observations provide guidance for optimizing the surgical technique and the design of posterior-stabilized total knee components.
authors.affiliation: Joint Replacement Institute at Orthopaedic Hospital, Los Angeles, CA 90007, USA.
authors.forename: Mauricio
authors.initials: M
authors.lastname: Silva
authors.forename: Christina A
authors.initials: CA
authors.lastname: Kabbash
authors.forename: John V
authors.initials: JV
authors.lastname: Tiberi
authors.forename: Sang Hyun
authors.initials: SH
authors.lastname: Park
authors.forename: Donald T
authors.initials: DT
authors.lastname: Reilly
authors.forename: Ormonde M
authors.initials: OM
authors.lastname: Mahoney
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Schmalzried
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D020959:Polyethylene; D011475:Prosthesis Failure; D012086:Reoperation; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013977:Tibia / Q000473:pathology*
chemical_list: D020959:Polyethylene