title: Improved survival of uncemented versus cemented femoral stems in patients aged < 70 years in a community total joint registry.
abstract: BACKGROUND
  Aseptic loosening of the femoral stem remains a significant reason for revision in total hip arthroplasty (THA). Although stem fixation methods have changed over time, there is relatively little evidence supporting cemented or uncemented stems as more durable constructs.
  
  
  OBJECTIVE
  We examined whether there was a difference in survival to revision between cemented and uncemented THA stems (1) for any reason; (2) for aseptic loosening or loosening related to wear/osteolysis; (3) based on patient age groupings (as a proxy for patient activity level); and (4) based on procedural timeframe groupings between cemented and uncemented stems.
  
  
  METHODS
  A total of 6498 primary cemented and uncemented THAs were registered in our community total joint replacement registry between 1991 and 2011. Analysis was performed to compare age, sex, procedural timeframe, and diagnosis for both groups. Our primary outcome was revision of the stem component for aseptic loosening or loosening secondary to wear/osteolysis. Analyses were done using Wilcoxon rank sum tests, Pearson's chi-square tests, Kaplan Meier methods, and Cox regression.
  
  
  RESULTS
  After adjusting for age, sex, primary diagnosis, and procedural timeframe as confounders, cemented femoral stem components were 1.63 times as likely as uncemented stems to be revised for any reason (p = 0.02) and 3.76 times as likely as uncemented stems to be revised for aseptic loosening or loosening related to wear/osteolysis (p < 0.001). When grouped by age, specifically in regard to revisions for aseptic loosening or loosening related to wear/osteolysis, uncemented stems had lower cumulative revision rates in patients aged < 70 years (p < 0.001) compared with cemented stems. There was a trend away from cemented fixation in our registry, which shifted from over 80% cemented stem use in 1996 to 3% in 2011.
  
  
  CONCLUSIONS
  We found that uncemented stems were associated with fewer revisions for aseptic loosening in patients < 70 years old, but when all reasons for revision were considered, neither group demonstrated superior survival. With a mean followup of 6.5 years, longer followup is needed to verify these results over time.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota Medical School, Minneapolis, MN, USA.
authors.forename: John
authors.initials: J
authors.lastname: Wechter
authors.forename: Thomas K
authors.initials: TK
authors.lastname: Comfort
authors.forename: Penny
authors.initials: P
authors.lastname: Tatman
authors.forename: Susan
authors.initials: S
authors.lastname: Mehle
authors.forename: Terence J
authors.initials: TJ
authors.lastname: Gioe
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D001843:Bone Cements / Q000627:therapeutic use*; D016009:Chi-Square Distribution; D005260:Female; D005269:Femur / Q000503:physiopathology / Q000601:surgery*; D006621:Hip Joint / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008910:Minnesota; D010014:Osteolysis / Q000209:etiology / Q000517:prevention & control; D016016:Proportional Hazards Models; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012042:Registries; D012086:Reoperation; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements