title: Clinical and radiographic results of metal-on-metal hip resurfacing with a minimum ten-year follow-up.
abstract: BACKGROUND
  There was a need for information about the long-term performance of the modern generation of hip resurfacing implants. A retrospective review of the first 100 hips that had implantation of one resurfacing design and had been followed for a minimum of ten years was performed.
  
  
  METHODS
  Between 1996 and 1998, 100 CONSERVE PLUS hip resurfacing devices were implanted by a single surgeon in eighty-nine patients. The mean age of the patients was 49.1 years, and fifty-nine patients were male. Primary osteoarthritis was the etiology for sixty-four hips. All patients were assessed clinically and radiographically.
  
  
  RESULTS
  The mean duration of follow-up was 11.7 years (range, 10.8 to 12.9 years). Two patients were lost to follow-up, and five patients died of causes unrelated to the surgery. Eleven hips had conversion to total hip arthroplasty because of loosening of the femoral component (eight), a femoral neck fracture (one), recurrent subluxation (one), and late infection (one). The Kaplan-Meier survivorship was 88.5% at ten years. None of the resurfacing arthroplasties failed in the twenty-eight hips that had a femoral component of >46 mm and no femoral head cystic or necrotic defects of >1 cm. Five hips had narrowing of the femoral neck, three had radiolucent zones interpreted as osteolysis, and twenty had signs of neck-socket impingement. Five hips had radiolucencies around the metaphyseal stem (two partial and three complete) that had been stable for 7.8 to 10.2 years. The mean scores on the University of California at Los Angeles (UCLA) system at the time of the latest follow-up were 9.5 points for pain, 9.3 points for walking, 8.9 points for function, and 6.8 points for activity; the mean scores on the physical and mental components of the Short Form-12 (SF-12) were 47.3 and 50.5 points, respectively; and the mean Harris hip score was 90 points.
  
  
  CONCLUSIONS
  The results of the present series constitute a reference point to which subsequent series should be compared. These ten-year results in a group of young patients are satisfactory, and the low rate of osteolysis is encouraging, but longer follow-up is required for comparison with conventional total hip arthroplasty.
authors.affiliation: Joint Replacement Institute, Saint Vincent Medical Center, Los Angeles, CA 90057, USA. harlanamstutz@dochs.org
authors.forename: Harlan C
authors.initials: HC
authors.lastname: Amstutz
authors.forename: Michel J
authors.initials: MJ
authors.lastname: Le Duff
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Campbell
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Gruen
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Wisk
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000379:methods*; D015331:Cohort Studies; D005260:Female; D005270:Femur Head / Q000000981:diagnostic imaging / Q000601:surgery; D005500:Follow-Up Studies; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008670:Metals; D008875:Middle Aged; D015999:Multivariate Analysis; D019637:Orthopedic Procedures / Q000009:adverse effects / Q000379:methods; D010147:Pain Measurement; D010149:Postoperative Pain / Q000503:physiopathology; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000503:physiopathology; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology; D012189:Retrospective Studies; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D008670:Metals