title: Results at a minimum of 10 years of follow-up for AMS and PerFix HA-coated cementless total hip arthroplasty: impact of cross-linked polyethylene on implant longevity.
abstract: OBJECTIVE
  The purpose of this study was to report results at a minimum of 10 years for hydroxyapatite (HA) coating on the titanium arc-sprayed cementless total hip arthroplasty (THA) and to evaluate the impact of cross-linked polyethylene (XLPE) on implant longevity.
  
  
  METHODS
  A total of 131 consecutive primary THAs in 123 patients using an AMS acetabular cup and a PerFix HA stem were retrospectively reviewed. Conventional PE was used for 62 hips (CPE group) and cross-linked PE for 69 hips (XLPE group), with mean follow-up periods of 13 and 11.5 years, respectively. These patients were reviewed using the Japanese Orthopaedic Association (JOA) Hip Score and evaluated in terms of PE wear, osteolysis, and implant survival.
  
  
  RESULTS
  The JOA score improved from 42.6 to 83.9 points at the final follow-up. The mean wear rate of 0.12 mm/year in the CPE group was significantly greater than that of XLPE at 0.007 mm/year. In the CPE group, ten (16.1 %) and two (3.2 %) hips, respectively, underwent PE exchange due to severe wear and acetabular revision due to loosening associated with osteolysis. Three patients had revision in the XLPE group: one cup for aseptic loosening, one PE for recurrent dislocation, and one stem for neck fracture. No evident osteolysis was seen in the XLPE group. Kaplan-Meier survivorship with any revision as the end point shows that the 12-year survival rate was 97.7 % for cups, 93.8 % for PE liners, and 99.2 % for stems. Multivariate analysis revealed that the use of XLPE significantly reduced the risk of revision, with the odds ratio (OR) of 4.3.
  
  
  CONCLUSIONS
  AMS and PerFix HA components in this series show excellent implant fixation; however, high rates of PE wear and subsequent osteolysis were limiting factors in long-term success. Low wear rates with XLPE suggest improved implant longevity.
authors: Department of Orthopaedic Surgery, Kyushu University, 1-3-3 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan, yasunaka@ortho.med.kyushu-u.ac.jp.
authors: Yasuharu
authors: Y
authors: Nakashima
authors: Taishi
authors: T
authors: Sato
authors: Takuaki
authors: T
authors: Yamamoto
authors: Goro
authors: G
authors: Motomura
authors: Masanobu
authors: M
authors: Ohishi
authors: Satoshi
authors: S
authors: Hamai
authors: Mio
authors: M
authors: Akiyama
authors: Masanobu
authors: M
authors: Hirata
authors: Daisuke
authors: D
authors: Hara
authors: Yukihide
authors: Y
authors: Iwamoto
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D015331:Cohort Studies; D017886:Durapatite; D019544:Equipment Failure Analysis; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D011095:Polyethylenes; D016016:Proportional Hazards Models; D011474:Prosthesis Design / Q000379:methods; D011475:Prosthesis Failure; D060489:Prosthesis Retention / Q000379:methods*; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D014025:Titanium; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D020099:Coated Materials, Biocompatible; D011095:Polyethylenes; D017886:Durapatite; D014025:Titanium