title: Periprosthetic fracture torque for short versus standard cemented hip stems: an experimental in vitro study.
abstract: In an attempt to preserve proximal femoral bone stock and achieve a better fit in smaller femora, especially in the Asian population, several new shorter stem designs have become available. We investigated the torque to periprosthetic femoral fracture of the Exeter short stem compared with the conventional length Exeter stem in a Sawbone model. Forty-two stems; 21 shorter and 21 conventional stems both with three different offsets were cemented in a composite Sawbone model and torqued to fracture. Results showed that Sawbone femurs break at a statistically significantly lower torque to failure with a shorter compared to conventional-length Exeter stem of the same offset. Both standard and short-stem designs are safe to use as the torque to failure is 7-10 times that seen in activities of daily living.
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Takkan
authors.initials: T
authors.lastname: Morishima
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Bastiaan L
authors.initials: BL
authors.lastname: Ginsel
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Godwin G H
authors.initials: GG
authors.lastname: Choy
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Lance J
authors.initials: LJ
authors.lastname: Wilson
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Whitehouse
authors.affiliation: Institute of Health and Biomedical Innovation, Queensland University of Technology, The Prince Charles Hospital, Brisbane, Queensland, Australia.
authors.forename: Ross W
authors.initials: RW
authors.lastname: Crawford
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D002484:Cementation; D005269:Femur / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D008953:Models, Anatomic; D057068:Periprosthetic Fractures / Q000209:etiology / Q000503:physiopathology*; D011474:Prosthesis Design; D019415:Torque
keywords: biomechanical study; fracture load; sawbones; short femoral stem; stress shielding