title: Distal locking in short hip nails: Cause or prevention of peri-implant fractures?
abstract: OBJECTIVE
  The most common cause of femoral fractures after osteosynthesis of trochanteric fractures with short nails is weakening of the femoral cortex via distal locking and stress concentrations at the tip of the nail. The aim of the study was to verify whether the incidence of peri-implant fractures is dependent upon the distal locking technique.
  
  
  METHODS
  We prospectively analysed a group of 849 pertrochanteric fractures (AO/ASIF 31-A1+2) managed with short nails from 2009 to 2013. Unlocked nailing was performed in 70.1% and distal dynamic locking was performed in 29.9%. The mean age was 82.0 years. Peri-implant fractures were divided into 3 groups according to the height of the fracture in relation to the tip of the nail.
  
  
  RESULTS
  In total 17 fractures (2.0%) were detected. One peri-implant fracture occurred after locked nailing, whereas 16 cases occurred after unlocked nailing (p=0.037). Patients without distal locking had an 85.7% greater risk of peri-implant fracture. Fractures of the proximal femur (Type I) occurred significantly earlier than fractures at the tip of the nail (Type II) (p=0.028).
  
  
  CONCLUSIONS
  Unlocked nails do not guarantee sufficient stability. Distal locking serves to prevent postoperative femoral fractures. We recommend the routine use of distal locking when utilizing short nails.
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic. Electronic address: jrosenbaum@volny.cz.
authors.forename: Jiří
authors.initials: J
authors.lastname: Skála-Rosenbaum
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic.
authors.forename: Valér
authors.initials: V
authors.lastname: Džupa
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic.
authors.forename: Radek
authors.initials: R
authors.lastname: Bartoška
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic.
authors.forename: Pavel
authors.initials: P
authors.lastname: Douša
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic.
authors.forename: Petr
authors.initials: P
authors.lastname: Waldauf
authors.affiliation: Department of Orthopedics and Traumatology, Charles University 3rd Faculty of Medicine and Kralovske Vinohrady Teaching Hospital, Šrobárova 50, 10034 Prague, Czech Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Krbec
mesh_terms: D000369:Aged, 80 and over; D001858:Bone Nails; D018153:Czech Republic / Q000453:epidemiology; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000009:adverse effects / Q000379:methods; D006620:Hip Fractures / Q000150:complications / Q000503:physiopathology / Q000601:surgery*; D006801:Humans; D015994:Incidence; D008297:Male; D057068:Periprosthetic Fractures / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D011183:Postoperative Complications / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D011446:Prospective Studies; D011859:Radiography; D016474:Weight-Bearing
keywords: Distal locking; Peri-implant fracture; Pertrochanteric fractures; Short intramedullary hip nail