title: A new intramedullary sustained dynamic compression nail for the treatment of long bone fractures: a biomechanical study.
abstract: OBJECTIVE
  We developed a new intramedullary interlocking nail (sustained dynamic compressive nail; SDCN) which can sustain a continuous dynamic compressive force on the fracture edges to overcome implant failure, screw loosening and nonunion complications encountered in the traditionally used static intramedullary nailing (SIMN).
  
  
  METHODS
  Six pairs of composite femurs were fixed with SIMN and SDCN. The axial compression, bending, torsional stiffness, and strain values were analyzed.
  
  
  RESULTS
  The mean axial compression stiffness values were 427.1 N/mm for the SDCN and 217.8 N/mm for SIMN, indicating a statistically significant difference (p=0.006). The mean stiffness values of rotation were 1.42 Nm/° for the SDCN and 0.89 Nm/° for SIMN. Anteroposterior bending tests were carried out. The mean results of stiffness were measured as 218 N/mm for the SDCN and 182.7 N/mm for the SIMN. The mean strain measurements in compression were 2454.5 µ-strain for the SDCN and 1123.8 µ-strain for the SIMN.
  
  
  CONCLUSIONS
  Biomechanically, the intramedullary SDCN is more stable than the SIMN system and it provides good abutment of the nail to the bone. Also, SDCN increases the stability by producing continuous compression and increasing the contact pressure of the fracture ends.
authors.affiliation: Department of Orthopedics and Traumatology, Medical Faculty of Dokuz Eylül University, 35340 Alsancak, İzmir, Turkey. karakasliahmet@gmail.com.
authors.forename: Ahmet
authors.initials: A
authors.lastname: Karakaşli
authors.forename: İsmail Safa
authors.initials: İS
authors.lastname: Satoğlu
authors.forename: Hasan
authors.initials: H
authors.lastname: Havitçioğlu
mesh_terms: D001696:Biomechanical Phenomena; D001858:Bone Nails; D005264:Femoral Fractures / Q000601:surgery*; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation*; D006801:Humans; D008422:Materials Testing; D008954:Models, Biological; D011474:Prosthesis Design