title: Intramedullary fixation using Kirschner wires in children with osteogenesis imperfecta.
abstract: BACKGROUND
  Surgical treatment for osteogenesis imperfecta (OI) remains controversial. The use of elongating rods has become a mainstay in this treatment, and there have been many reports of the results of this procedure. In contrast, using nonelongating rods is considered to be the classic method. This older method is still used by surgeons who are concerned about the possibility of trauma on the articular surface due to arthrotomy at the insertion of the elongating rod or who are working in developing countries with fewer resources. We are among those who prefer the use of nonelongating rods to elongating rods. This article presents the results of intramedullary fixation using nonelongating rods such as Kirschner wires (K-wires) in children with OI and the proper timing of wire exchange to prevent further fracture.
  
  
  METHODS
  We treated 29 femora in 17 patients with OI by means of stabilization using K-wires. For these patients we calculated revision-free survival and analyzed the details of any fractures that occurred after the primary surgery. We also investigated the relations between the wire length ratio, which was defined as the ratio of the intramedullary wire length divided by the femoral length, and the fracture type.
  
  
  RESULTS
  The revision-free survival for the 29 primary procedures was 63% at 3 years, and 36% at 5 years. All fractures that occurred at the wire tip required additional surgery, whereas only 51% of fractures at other sites required additional surgery. The wire length ratio of wire-tip fractures was significantly lower than that of fractures at other sites. There is a significant difference in the incidence of wire-tip fractures and other fractures between ratios of 65% and 75%.
  
  
  CONCLUSIONS
  Wire exchange surgeries should be performed before the wire length ratio drops to <70%. This information could be useful for preventing further fractures that require surgery when OI patients are treated by intramedullary fixation with nonelongating rods.
  
  
  METHODS
  Level IV.
authors.affiliation: Department of Orthopaedic Surgery, Osaka National Hospital, Osaka, Japan.
authors.forename: Yukari
authors.initials: Y
authors.lastname: Imajima
authors.forename: Motohiro
authors.initials: M
authors.lastname: Kitano
authors.forename: Takafumi
authors.initials: T
authors.lastname: Ueda
mesh_terms: D001864:Bone Wires / Q000145:classification*; D002675:Child, Preschool; D057186:Comparative Effectiveness Research; D005260:Female; D005264:Femoral Fractures / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000601:surgery; D005269:Femur / Q000473:pathology / Q000601:surgery; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods; D006801:Humans; D015994:Incidence; D007564:Japan; D008297:Male; D010013:Osteogenesis Imperfecta / Q000175:diagnosis / Q000601:surgery*; D017063:Outcome Assessment, Health Care; D011183:Postoperative Complications / Q000175:diagnosis / Q000601:surgery; D012086:Reoperation / Q000379:methods / Q000706:statistics & numerical data