title: The importance of intramedullary hip nail positioning during implantation for stable pertrochanteric fractures: biomechanical analysis.
abstract: OBJECTIVE
  Proximal femoral fractures are among the most commonly sustained fractures. The current treatment of stable proximal femoral fractures located in trochanteric region primarily involves the use of two systems: extramedullary dynamic hip screws and intramedullary hip nails. Given that these fractures are mainly found in the elderly population, the necessity of a repeat, due to failure of the first, may jeopardize the patient's life. Decisive factors contributing to the healing of a fracture (or the failure thereof) include fracture pattern, technical implementation of the operation (i.e., position of the implant), implant's properties and its changes in relation to the surrounding bone tissue during loading. Each screw insertion variant results in damage to various load-bearing bone structures, which can be expected to influence healing quality and stability of newly formed bone.
  
  
  METHODS
  With the aid of a numerical model and finite element methods, the authors analyzed several different positions of IMHN/PFH-nails in the proximal femur, with the objective of determining positions with an increased risk of failure.
  
  
  CONCLUSIONS
  In model situations, it has been shown that in stable fractures results do not depend on absolutely precise positioning and small deflections in the nails and neck screws positions do not significantly increase the risk of failure for the entire fixation. Damage to load-bearing structures relative to various implant placements does not impact the resultant overall fixation stability. Therefore, it is not necessary to re-introduce implants in the ideal position, which can lead to reduced patient radiation doses during surgery.
authors.affiliation: Department of Orthopaedy and Traumatology, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Bartoska
authors.affiliation: Department of Health Care Studies, Colleague of Polytechnics Jihlava, Tolsteho 16, 586 01, Jihlava, Czech Republic. vaclav.baca@lf3.cuni.cz.|Department of Anatomy, Third Faculty of Medicine, Charles University, Prague, Czech Republic. vaclav.baca@lf3.cuni.cz.|Center for Integrated Study of Pelvis, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic. vaclav.baca@lf3.cuni.cz.
authors.forename: Vaclav
authors.initials: V
authors.lastname: Baca
authors.affiliation: Department of Health Care Studies, Colleague of Polytechnics Jihlava, Tolsteho 16, 586 01, Jihlava, Czech Republic.|Department of Mechanics, Biomechanics and Mechatronics, Faculty of Mechanical Engineering, CTU in Prague, Prague, Czech Republic.
authors.forename: Zdenek
authors.initials: Z
authors.lastname: Horak
authors.affiliation: Department of Orthopaedics, Hospital Pelhrimov, Pelhrimov, Czech Republic.
authors.forename: Maros
authors.initials: M
authors.lastname: Hrubina
authors.affiliation: Department of Orthopaedy and Traumatology, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Skala-Rosenbaum
authors.affiliation: Department of Orthopaedy and Traumatology, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.
authors.forename: Jiri
authors.initials: J
authors.lastname: Marvan
authors.affiliation: Department of Health Care Studies, Colleague of Polytechnics Jihlava, Tolsteho 16, 586 01, Jihlava, Czech Republic.|Department of Anatomy, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
authors.forename: David
authors.initials: D
authors.lastname: Kachlik
authors.affiliation: Department of Orthopaedy and Traumatology, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.|Center for Integrated Study of Pelvis, Third Faculty of Medicine, Charles University in Prague and University Hospital Kralovske Vinohrady, Prague, Czech Republic.
authors.forename: Valer
authors.initials: V
authors.lastname: Dzupa
mesh_terms: D000368:Aged; D001696:Biomechanical Phenomena; D001858:Bone Nails; D005269:Femur / Q000293:injuries / Q000601:surgery*; D020342:Finite Element Analysis; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods*; D006620:Hip Fractures / Q000601:surgery*; D006801:Humans; D008962:Models, Theoretical; D012307:Risk Factors; D017211:Treatment Failure; D016474:Weight-Bearing
keywords: Bone fixation; Complications; Finite element method analyses; Intramedullary hip nail; Stable pertrochanteric fracture