title: Factors influencing K-wire migration in tension-band wiring of olecranon fractures.
abstract: BACKGROUND
  Tension-band wiring is a popular method of internal fixation for simple olecranon fractures. Although fracture union rates and clinical outcomes are good, up to 80% of patients require removal because of prominent/symptomatic metalwork. The current literature remains unclear as to the best orientation of the longitudinal wires to minimize hardware failure. The aim of this study was to determine the surgically modifiable factors related to spontaneous wire pullout.
  
  
  METHODS
  A retrospective review of hospital theater records over a period of 6 years was performed to identify all olecranon tension-band wire procedures. Preoperative radiographs were used to confirm and classify the fracture. Intraoperative and postoperative radiographs were analyzed for a number of wire-associated variables: wire length within the ulna, medullary/cortical position, parallelism of wires, proximal wire prominence, wire angle relative to the ulna, distance from the articular surface, fracture gap, and subsequent pullout.
  
  
  RESULTS
  A total of 182 wires were analyzed. The mean age was 52.5 years, and the mean radiographic follow-up period was 7.3 months. Intramedullary wires had a mean pullout of 5.5 mm compared with 2.4 mm for transcortical wires (P < .0001). A multiple regression model noted 7 independent variables affecting wire pullout: age, bent wires, medullary/transcortical wire positioning, proximal prominence, ulnar shaft angle, distance from the articular surface, and articular step.
  
  
  CONCLUSIONS
  To minimize postoperative pullout of wires, we suggest anatomic reduction and transcortical wire orientation, without bending, in the subchondral bone close to the articular surface.
authors.affiliation: Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK. Electronic address: zubair.saeed@doctors.org.uk.
authors.forename: Zubair M
authors.initials: ZM
authors.lastname: Saeed
authors.affiliation: Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK.
authors.forename: Ryan W
authors.initials: RW
authors.lastname: Trickett
authors.affiliation: Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK.
authors.forename: Alun D
authors.initials: AD
authors.lastname: Yewlett
authors.affiliation: Department of Trauma and Orthopaedics, University Hospital of Wales, Cardiff, UK.
authors.forename: Timothy J W
authors.initials: TJ
authors.lastname: Matthews
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001864:Bone Wires / Q000009:adverse effects*; D004551:Elbow Joint / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D056740:Olecranon Process / Q000000981:diagnostic imaging* / Q000293:injuries / Q000601:surgery; D011859:Radiography; D012189:Retrospective Studies; D014458:Ulna Fractures / Q000000981:diagnostic imaging* / Q000601:surgery; D055815:Young Adult
keywords: Kirschner wires; Olecranon fracture; configuration; hardware failure; radiologic study; tension-band wiring