title: Superior 11-year survival but higher polyethylene wear of hydroxyapatite-coated Mallory-Head cups.
abstract: Hydroxyapatite (HA) coating of implant surfaces is believed to improve longevity of uncemented total hip arthroplasty (THA). However; it is speculated that HA particles may cause third body wear of the polyethylene (PE) liner with subsequent osteolysis and aseptic loosening of implants. We performed a retrospective comparison of two patient populations with cementless Mallory-Head acetabular components. The patients were identified in the Danish hip arthroplasty Registry (DHR); 77 patients had HA-coated cups and 73 patients had non-HA coated cups. Anteroposterior (AP) radiographs were analysed for PE wear, osteolysis was quantified and survival of the acetabular components was compared. The mean follow-up was 11 years. There were no cup revisions in the HA group and 7 cup revisions in the non-HA group (P<0.01). The reason for revision in all cases was aseptic loosening of both stem and cup. The amount of osteolysis was significantly increased around cups in the non-HA group. The two-dimensional linear PE wear-rate of 0.18 mm/year was higher (P<0.001) in the group with HA coated cups compared with 0.12 mm/year in the group with non-HA coated cups. The mean age was lower (P=0.001) in the HA group (57 years) compared with the non-HA group (63 years). After 11.1 years of follow-up non-HA coated cups had a higher revision rate. Increased PE wear with HA-coated cups did not have a negative influence on the revision rate, but may result in a need for revision surgery over time.
authors.affiliation: Department of Orthopaedics, Aarhus University Hospital, Aarhus, Denmark. martin.gottliebsen@gmail.com
authors.forename: Martin
authors.initials: M
authors.lastname: Gottliebsen
authors.forename: Ole
authors.initials: O
authors.lastname: Rahbek
authors.forename: Per F
authors.initials: PF
authors.lastname: Ottosen
authors.forename: Kjeld
authors.initials: K
authors.lastname: Søballe
authors.forename: Maiken
authors.initials: M
authors.lastname: Stilling
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology; D020959:Polyethylene; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D020099:Coated Materials, Biocompatible; D020959:Polyethylene; D017886:Durapatite