title: Real frequency of ordinary and atypical sub-trochanteric and diaphyseal fractures in France based on X-rays and medical file analysis.
abstract: OBJECTIVE
  Atypical sub-trochanteric and femoral shaft fractures have been reported in patients treated with bisphosphonates. Their incidence has been determined from registered data analysis using international codes. Therefore, the aim of our study was to estimate the real frequency of typical and atypical sub-trochanteric or diaphyseal fractures, based on radiological and clinical data compared to registered data.
  
  
  METHODS
  In the registers of three large French University Hospitals, patients identified with International Classification of Diseases, 10th Revision diagnosis codes for sub-trochanteric or diaphyseal fracture were selected. Frequencies of ordinary and atypical fractures were calculated after both registered data, radiological and clinical files analysis.
  
  
  RESULTS
  Among the 4592 patients hospitalized for a femoral fracture over 5 years, 574 were identified to have had a sub-trochanteric or femoral shaft fracture. 47.7% of the sub-trochanteric and femoral shaft fractures were misclassified, predominantly in the sub-trochanteric fractures subset. 12 patients had an atypical fracture (4% of the sub-trochanteric and femoral shaft fractures) and 11 fractures presented radiological features of atypical fractures, whereas clinical files analysis revealed they were pathological or traumatic fractures.
  
  
  CONCLUSIONS
  Atypical fractures frequency is very low. Because of their low frequency and the unreliability of registered databases, the risk of atypical fractures is very difficult to estimate retrospectively. A prospective study is needed to clarify the risk factors associated with these fractures.
authors.affiliation: Service de rhumatologie B, Hôpital Cochin, Université Paris Descartes, Paris, France. const.beaudouin@gmail.com
authors.forename: Constance
authors.initials: C
authors.lastname: Beaudouin-Bazire
authors.forename: Noémie
authors.initials: N
authors.lastname: Dalmas
authors.forename: Julie
authors.initials: J
authors.lastname: Bourgeois
authors.forename: Antoine
authors.initials: A
authors.lastname: Babinet
authors.forename: Philippe
authors.initials: P
authors.lastname: Anract
authors.forename: Christophe
authors.initials: C
authors.lastname: Chantelot
authors.forename: Frédéric
authors.initials: F
authors.lastname: Farizon
authors.forename: Florence
authors.initials: F
authors.lastname: Chopin
authors.forename: Karine
authors.initials: K
authors.lastname: Briot
authors.forename: Christian
authors.initials: C
authors.lastname: Roux
authors.forename: Bernard
authors.initials: B
authors.lastname: Cortet
authors.forename: Thierry
authors.initials: T
authors.lastname: Thomas
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001847:Bone Diseases / Q000000981:diagnostic imaging / Q000453:epidemiology; D018483:Diaphyses / Q000000981:diagnostic imaging / Q000293:injuries; D004282:Documentation / Q000592:standards / Q000706:statistics & numerical data; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D005269:Femur / Q000000981:diagnostic imaging / Q000293:injuries; D005598:Fractures, Spontaneous / Q000000981:diagnostic imaging / Q000453:epidemiology; D005602:France / Q000453:epidemiology; D006620:Hip Fractures / Q000000981:diagnostic imaging* / Q000453:epidemiology*; D006785:Hospitals, University / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D008297:Male; D008499:Medical Records / Q000592:standards / Q000706:statistics & numerical data; D008875:Middle Aged; D011859:Radiography; D012042:Registries / Q000592:standards / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors