title: Incomplete atypical femoral fractures: assessing the diagnostic utility of DXA by extending femur length.
abstract: Atypical femoral fractures (AFFs) are associated with prolonged bisphosphonate therapy. A feature of incomplete AFF is a localized periosteal reaction. It has been suggested that extending the length of the femur image at the time of dual-energy X-ray absorptiometry (DXA) may diagnose an incomplete AFF. In patients older than 50 yr on bisphosphonate therapy for more than 5 yr, we extended femur length at the time of routine DXA. Abnormal DXA images were suggested in 19 of 257 patients (7.4%). On X-ray, 7 patients (2.7%) showed no abnormality, 7 patients (2.7%) showed evidence of AFF, and 5 patients (2.0%) showed an unrelated radiographic abnormality. Of the 7 cases with X-ray evidence of AFF, 5 had a periosteal flare and 2 had a visible fracture line, both of whom needed insertion of an intramedullary nail. We demonstrated that it is feasible to detect incomplete AFF early using extended femur length imaging with a prevalence in our sample of 2.7% (95% confidence interval: 1.7%-3.7%).
authors.affiliation: DXA Unit, St. Vincent's University Hospital, Dublin, Ireland; School of Medicine and Medical Sciences, University College Dublin, Dublin, Ireland. Electronic address: mjmckenn@iol.ie.
authors.forename: Malachi J
authors.initials: MJ
authors.lastname: McKenna
authors.forename: Susan
authors.initials: S
authors.lastname: van der Kamp
authors.forename: Eric
authors.initials: E
authors.lastname: Heffernan
authors.forename: Conor
authors.initials: C
authors.lastname: Hurson
mesh_terms: D015502:Absorptiometry, Photon / Q000706:statistics & numerical data*; D000368:Aged; D015519:Bone Density; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging*; D005269:Femur / Q000000981:diagnostic imaging* / Q000293:injuries; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012189:Retrospective Studies
keywords: Atypical femoral fracture; DXA; bisphosphonate