title: Epidemiology of periprosthetic femoral fractures in 5417 revision total hip arthroplasties: a 40-year experience.
abstract: OBJECTIVE
  The goals of this study were to define the risk factors, characteristics, and chronology of fractures in 5417 revision total hip arthroplasties (THAs).
  
  
  METHODS
  From our hospital's prospectively collected database we identified all patients who had undergone a revision THA between 1969 and 2011 which involved the femoral stem. The patients' medical records and radiographs were examined and the relevant data extracted. Post-operative periprosthetic fractures were classified using the Vancouver system. A total of 5417 revision THAs were identified.
  
  
  RESULTS
  There were 668 intra-operative fractures, giving an incidence of 12%. Fractures were three times more common with uncemented stems (19%) than with cemented stems (6%) (p < 0.001). The incidence of intra-operative femoral fracture varied by uncemented stem type: fully-coated (20%); proximally-coated (19%); modular fluted tapered (16%) (p < 0.05). Most fractures occurred during the insertion of the femoral component (35%). One-third involved the diaphysis and 26% were of the calcar: 69% were undisplaced. There were 281 post-operative fractures of the femur (20-year probability = 11%). There was no difference in risk for cemented and uncemented stems. Post-operative fractures were more common in men < 70 years (p = 0.02). Periprosthetic fractures occurred earlier after uncemented revision of the femoral component, but later after a cemented revision. The most common fracture type was a Vancouver B1 (31%). Of all post-operative fractures, 24% underwent open reduction and internal fixation and 15% revision arthroplasty.
  
  
  CONCLUSIONS
  In revision THA, intra-operative fractures occurred three times more often with an uncemented stem. Many were undisplaced diaphyseal fractures treated with cerclage fixation. While the risk of post-operative fracture is similar between uncemented and cemented components, they occur at notably different times depending on the type of stem fixation.
  
  
  CONCLUSIONS
  In revision THA, intra-operative periprosthetic femoral fractures occur three times more often with uncemented stems. Many are non-displaced diaphyseal fractures treated with cerclage fixation. While postoperative fracture risks are equivalent between uncemented and cemented components, they occur at notably different time periods based on stem fixation type.
authors.affiliation: Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Abdel
authors.affiliation: Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: M T
authors.initials: MT
authors.lastname: Houdek
authors.affiliation: Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Watts
authors.affiliation: Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: D G
authors.initials: DG
authors.lastname: Lewallen
authors.affiliation: Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.
authors.forename: D J
authors.initials: DJ
authors.lastname: Berry
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002648:Child; D002675:Child, Preschool; D005260:Female; D005264:Femoral Fractures / Q000453:epidemiology* / Q000601:surgery; D005544:Forecasting; D005593:Fracture Fixation, Internal / Q000379:methods*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D015994:Incidence; D007223:Infant; D008297:Male; D008875:Middle Aged; D057068:Periprosthetic Fractures / Q000453:epidemiology* / Q000601:surgery; D011183:Postoperative Complications; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D014481:United States / Q000453:epidemiology; D055815:Young Adult
keywords: Peri-prosthetic fractures; femur; epidemiology; revision total hip arthroplasty; Vancouver classification