title: [Surgery of femoral neck fractures--higher rate of osteosynthesis failure with the use of 4,5 mm screws compared to 6,5 mm screws].
abstract: BACKGROUND
  Displaced femoral neck fractures are usually treated with screw osteosynthesis or primary hip replacement (unipolar or bipolar).
  
  
  METHODS
  In this retrospective study we compared the rate of early failure during two consecutive years using two different screw implants each year. The patient groups were demographically similar, and the relationships between the use of hip replacement and screws as primary treatment were similar in the two groups. In the first group (group A), two screws with a shaft and outer thread diameter both of 6.5 mm were used. In the second group (group B), two screws with shaft diameter of 4.5 mm and outer thread diameter of 7.3 mm were used. The number of patients operated with screws were 191 the first year and 177 the following year.
  
  
  RESULTS
  The number of patients reoperated with a hip replacement within the first 100 days was 16 (8%) in group A and 29 (16%) in group B (risk difference 0.08; 95% CI 0.013-0.147).
  
  
  CONCLUSIONS
  We recommend that when two screws are used for fixation of femoral neck fractures, they should have a shaft diameter of at least 6.5 mm.
authors.affiliation: Oslo Ortopediske Universitetsklinikk Ullevål sykehus 0407 Oslo. s-loek@online.no
authors.forename: S
authors.initials: S
authors.lastname: Løken
authors.forename: G S
authors.initials: GS
authors.lastname: Andreassen
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001863:Bone Screws; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000592:standards*; D006801:Humans; D008297:Male; D011475:Prosthesis Failure; D011859:Radiography; D012086:Reoperation / Q000706:statistics & numerical data; D012189:Retrospective Studies; D016896:Treatment Outcome