title: A biomechanical comparison of epiphyseal versus metaphyseal fixed bone-conserving hip arthroplasty.
abstract: BACKGROUND
  The Birmingham Mid-Head Resection (BMHR) is a bone-conserving, short-stem alternative to hip resurfacing for patients with abnormal femoral head anatomy.
  
  
  METHODS
  The current study examines whether a bone-preserving femoral component that is fixed into the femoral neck metaphysis provides a mechanical advantage in terms of resisting femoral neck fracture in comparison with a conventional hip resurfacing implant in a human cadaveric femoral model.
  
  
  RESULTS
  Femora with a BMHR femoral component failed at an average of 23% less load than those prepared with a conventional hip resurfacing component (mean and standard deviation, 5434 ± 2297 compared with 7012 ± 2619 N; p < 0.001).
  
  
  CONCLUSIONS
  An uncemented, metaphyseal fixed, bone-conserving femoral implant does not provide superior mechanical strength or increased resistance to femoral neck fracture in comparison with a conventional hip resurfacing arthroplasty.
authors.affiliation: Martin Orthopaedic Biomechanics Laboratory, St. Michael's Hospital, University of Toronto, 30 Bond Street, Toronto, ON M5B 1W8, Canada. olsenmi@smh.ca
authors.forename: Michael
authors.initials: M
authors.lastname: Olsen
authors.forename: Michael
authors.initials: M
authors.lastname: Sellan
authors.forename: Rad
authors.initials: R
authors.lastname: Zdero
authors.forename: James P
authors.initials: JP
authors.lastname: Waddell
authors.forename: Emil H
authors.initials: EH
authors.lastname: Schemitsch
mesh_terms: D015502:Absorptiometry, Photon; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001696:Biomechanical Phenomena; D015519:Bone Density; D002102:Cadaver; D004838:Epiphyses / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D016014:Linear Models