title: Results of total hip arthroplasties in the young patient; further evidence for a barrier against articular wear debris by hydroxyapatite coatings.
abstract: We examined the hypothesis that the circumferential osseous apposition around HA-coated implants forms a protective barrier against articular wear debris. Sixty-five hydroxyapatite-coated total hip arthroplasties in 57 patients (age <50years) with polyethylene-metal articulation were evaluated regarding PE-wear, osteolysis, and clinical outcome at a minimum of 10 years follow-up. There was no correlation between PE-wear and osteolysis of the femoral zones or cup zones I and III. A strong Pearson correlation was found between polyethylene wear and osteolysis around cup zone II, where the cup only consisted of polyethylene (p<0,01). The aseptic failure rate was 1.5% for the femoral component and 4.5% for the cup after 10 years of follow-up. The average Harris Hip Score was 90 and the average Engh score for fixation was 23 after 10 years . Around HA-coated parts of the prosthesis bone formation remained stable, regardless of the degree of polyethylene wear. The average linear polyethylene wear was 0,16 mm/year. The circumferential osseous apposition of the HA-coated implants possibly formed a protective barrier against articular wear debris. The use of cups with a backside gap resulted in PE-wear associated osteolysis in cup zone II and may be considered to be best avoided.
authors.affiliation: Department of Orthopaedic Surgery, Maastricht University Medical Centre, Maastricht - The Netherlands. pj.emans@orthop.unimaas.nl
authors.forename: Pieter J
authors.initials: PJ
authors.lastname: Emans
authors.forename: Rene H M Ten
authors.initials: RH
authors.lastname: Broeke
authors.forename: Jeroen M J
authors.initials: JM
authors.lastname: Van Mulken
authors.forename: Roel
authors.initials: R
authors.lastname: Kuijer
authors.forename: Lodewijk W
authors.initials: LW
authors.lastname: Van Rhijn
authors.forename: Rudolph G T
authors.initials: RG
authors.lastname: Geesink
mesh_terms: D000293:Adolescent; D000328:Adult; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D020099:Coated Materials, Biocompatible; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006615:Hip / Q000000981:diagnostic imaging; D006622:Hip Prosthesis / Q000009:adverse effects; D006801:Humans; D006882:Hydroxyapatites; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D010014:Osteolysis; D020959:Polyethylene; D011446:Prospective Studies; D011474:Prosthesis Design; D011859:Radiography; D013499:Surface Properties; D055815:Young Adult
chemical_list: D020099:Coated Materials, Biocompatible; D006882:Hydroxyapatites; D020959:Polyethylene