title: Subsidence of uncemented stems in osteoporotic and non-osteoporotic cadaveric femora.
abstract: The increased use of uncemented stems for hip arthroplasty and of fast-recovery protocols in elderly patients make initial stem stability and resistance to fracture critical factors in osteoporotic bone. In this paper, the subsidence and failure of two uncemented stem designs (M/L Taper and VerSys Fullcoat, Zimmer, Inc, Warsaw, Indiana, USA) in osteoporotic and non-osteoporotic cadaveric femora were compared under simulated walking conditions (axial compression and external rotation). Osteoporotic femora implanted with either stem design failed significantly more frequently than did non-osteoporotic femora. Femora implanted with the M/L stems (seven of ten by 1000 cycles) fractured earlier than did femora implanted with the Fullcoat stem (one of ten by 1000 cycles). The use of early weight-bearing protocols with uncemented stem designs in osteoporotic bone should be approached with caution.
authors.affiliation: International Center for Orthopaedic Advancement, Department of Orthopaedic Surgery, The Johns Hopkins Bayview Medical Center, Baltimore, MD 21224, USA. ehenze1@jhmi.edu
authors.forename: S C
authors.initials: SC
authors.lastname: Mears
authors.forename: A M
authors.initials: AM
authors.lastname: Richards
authors.forename: T A
authors.initials: TA
authors.lastname: Knight
authors.forename: S M
authors.initials: SM
authors.lastname: Belkoff
mesh_terms: D002102:Cadaver; D002484:Cementation; D019544:Equipment Failure Analysis; D005269:Femur / Q000503:physiopathology* / Q000601:surgery*; D006622:Hip Prosthesis; D006801:Humans; D010024:Osteoporosis / Q000503:physiopathology* / Q000601:surgery*; D011475:Prosthesis Failure; D016474:Weight-Bearing