title: Risk factors for post-operative periprosthetic fractures following primary total hip arthroplasty with a proximally coated double-tapered cementless femoral component.
abstract: OBJECTIVE
  The aim of this study was to identify patient- and surgery-related risk factors for sustaining an early periprosthetic fracture following primary total hip arthroplasty (THA) performed using a double-tapered cementless femoral component (Bi-Metric femoral stem; Biomet Inc., Warsaw, Indiana).
  
  
  METHODS
  A total of 1598 consecutive hips, in 1441 patients receiving primary THA between January 2010 and June 2015, were retrospectively identified. Level of pre-operative osteoarthritis, femoral Dorr type and cortical index were recorded. Varus/valgus placement of the stem and canal fill ratio were recorded post-operatively. Periprosthetic fractures were identified and classified according to the Vancouver classification. Regression analysis was performed to identify risk factors for early periprosthetic fracture.
  
  
  RESULTS
  The mean follow-up was 713 days (1 to 2058). A total of 48 periprosthetic fractures (3.0%) were identified during the follow-up and median time until fracture was 16 days, (interquartile range 10 to 31.5). Patients with femoral Dorr type C had a 5.2 times increased risk of post-operative periprosthetic fracture compared with type B, while female patients had a near significant two times increased risk over time for post-operative fracture.
  
  
  CONCLUSIONS
  Dorr type C is an independent risk factor for early periprosthetic fracture, following THA using a double tapered cementless stem such as the Bi-Metric. Surgeons should take bone morphology into consideration when planning for primary THA and consider using cemented femoral components in female patients with poor bone quality. Cite this article:Bone Joint J2017;99-B:451-7.
authors.affiliation: Copenhagen University Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark.
authors.forename: K
authors.initials: K
authors.lastname: Gromov
authors.affiliation: Copenhagen University Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Bersang
authors.affiliation: Copenhagen University Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark.
authors.forename: C S
authors.initials: CS
authors.lastname: Nielsen
authors.forename: T
authors.initials: T
authors.lastname: Kallemose
authors.affiliation: Copenhagen University Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Husted
authors.affiliation: Copenhagen University Hospital, Kettegård Alle 30, 2650 Hvidovre, Copenhagen, Denmark.
authors.forename: A
authors.initials: A
authors.lastname: Troelsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects* / Q000295:instrumentation; D002484:Cementation; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000209:etiology*; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000601:surgery*; D057068:Periprosthetic Fractures / Q000000981:diagnostic imaging / Q000209:etiology*; D011474:Prosthesis Design; D011859:Radiography; D012189:Retrospective Studies; D012307:Risk Factors; D012737:Sex Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: Complications; Periprosthetic fractures; Primary hip arthroplasty