title: [Femoral neck fractures: position of the implant, unrecognized articular penetration and its consequences].
abstract: BACKGROUND
  Only two dimensions of a three dimensional object are visible on plain roentgenograms. Therefore, on gross inspection of antero-posterior and lateral roentgenograms, a screw may project as being safely within the head of the femur even though penetration has occurred. This region may be referred to as a "blind zone".
  
  
  METHODS
  Unrecognized screw penetration into the hip joint during internal fixation of femoral neck fractures was researched on intra operative roentgenograms of 30 patients. Unrecognized pin penetration through the posterior part of the neck was also analyzed on the same X Rays.
  
  
  RESULTS
  Unrecognized screw penetration into the hip joint was observed in 20 per cent and penetration at the posterior part of the neck was observed in 10 per cent of cases.
  
  
  CONCLUSIONS
  Several methods of determining screw position are described and discussed in this study.
authors.affiliation: Hôpital Henri Mondor, Créteil, France.
authors.forename: P
authors.initials: P
authors.lastname: Hernigou
authors.forename: P
authors.initials: P
authors.lastname: Besnard
mesh_terms: D001858:Bone Nails; D001863:Bone Screws; D005260:Female; D005265:Femoral Neck Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D005270:Femur Head / Q000033:anatomy & histology; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000379:methods; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008433:Mathematics; D015641:Radiography, Interventional; D012307:Risk Factors
vernacular_title: Fractures du col du fémur: position de l'implant, effraction articulaire méconnue et ses conséquences.