title: Application of Far Cortical Locking Technology in Periprosthetic Femoral Fracture Fixation: A Biomechanical Study.
abstract: Lack of fracture movement could be a potential cause of periprosthetic femoral fracture (PFF) fixation failures. This study aimed to test whether the use of distal far cortical locking screws reduces the overall stiffness of PFF fixations and allows an increase in fracture movement compared to standard locking screws while retaining the overall strength of the PFF fixations.
  
  
  
  Twelve laboratory models of Vancouver type B1 PFFs were developed. In all specimens, the proximal screw fixations were similar, whereas in 6 specimens, distal locking screws were used, and in the other six specimens, far cortical locking screws. The overall stiffness, fracture movement, and pattern of strain distribution on the plate were measured in stable and unstable fractures under anatomic 1-legged stance. Specimens with unstable fracture were loaded to failure.
  
  
  
  No statistical difference was found between the stiffness and fracture movement of the two groups in stable fractures. In the unstable fractures, the overall stiffness and fracture movement of the locking group was significantly higher and lower than the far cortical group, respectively. Maximum principal strain on the plate was consistently lower in the far cortical group, and there was no significant difference between the failure loads of the 2 groups.
  
  
  
  The results indicate that far cortical locking screws can reduce the overall effective stiffness of the locking plates and increase the fracture movement while maintaining the overall strength of the PFF fixation construct. However, in unstable fractures, alternative fixation methods, for example, long stem revision might be a better option.
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Mehran
authors.initials: M
authors.lastname: Moazen
authors.affiliation: Academic Orthopaedics and Trauma Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Andreas
authors.initials: A
authors.lastname: Leonidou
authors.affiliation: Academic Orthopaedics and Trauma Unit, Aristotle University Medical School, Thessaloniki, Greece.
authors.forename: Joseph
authors.initials: J
authors.lastname: Pagkalos
authors.affiliation: Department of Mechanical Engineering, University College London, London, UK.
authors.forename: Arsalan
authors.initials: A
authors.lastname: Marghoub
authors.affiliation: Medical and Biological Engineering, School of Engineering, University of Hull, Hull, UK.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Fagan
authors.affiliation: Academic Orthopaedics and Trauma Unit, Aristotle University Medical School, Thessaloniki, Greece; Academic Department of Orthopaedic and Trauma, University of Leeds, Leeds, UK; Division of Surgery, Department of Surgery and Cancer, Imperial College London, London, UK.
authors.forename: Eleftherios
authors.initials: E
authors.lastname: Tsiridis
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D005264:Femoral Fractures / Q000601:surgery*; D005269:Femur; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D008962:Models, Theoretical; D057068:Periprosthetic Fractures / Q000601:surgery*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D013314:Stress, Mechanical
keywords: Vancouver type B1; biomechanics; fracture movement; fracture stability; stiffness; strain