Advanced

Atypical femoral fractures are a separate entity, characterized by highly specific radiographic features. A comparison of 59 cases and 218 controls

Schilcher, Jorg ; Koeppen, Veronika ; Ranstam, Jonas LU ; Skripitz, Ralf ; Michaelsson, Karl and Aspenberg, Per (2013) In Bone 52(1). p.389-392
Abstract
Background: Estimations of the risk of bisphosphonate associated atypical femoral fractures vary between different population-based studies, from considerable to neglectable. A possible explanation for these discrepancies could be different definitions of atypical fractures. We aimed to identify specific radiographic fracture characteristics associated with bisphosphonate use. Methods: In a previous nationwide study, 59 atypical and 218 ordinary fractures were diagnosed. The atypical fractures were defined by their stress-type fracture pattern. All fractures were now re-assessed by a physician in training, without information about bisphosphonate use. The fracture angle (0-180 degrees) was measured. Presence of local lateral cortical... (More)
Background: Estimations of the risk of bisphosphonate associated atypical femoral fractures vary between different population-based studies, from considerable to neglectable. A possible explanation for these discrepancies could be different definitions of atypical fractures. We aimed to identify specific radiographic fracture characteristics associated with bisphosphonate use. Methods: In a previous nationwide study, 59 atypical and 218 ordinary fractures were diagnosed. The atypical fractures were defined by their stress-type fracture pattern. All fractures were now re-assessed by a physician in training, without information about bisphosphonate use. The fracture angle (0-180 degrees) was measured. Presence of local lateral cortical thickening (a callus reaction), more than 2 fragments, or a medial spike was noted. The reader then made a judgment whether the fracture appeared as an atypical fracture based on the ASBMR criteria. Results: Frequency distribution analysis of the fracture angle showed a distinct subgroup, comprising 25% of all 277 fractures, with a mean of 89 and SD of 10 degrees. Forty-two of 57 patients in this subgroup used bisphosphonates, whereas only 27 of 213 others did (specificity 0.93; 95% CI 0.88-0.96). Presence of a callus reaction had also a high specificity for bisphosphonate use (0.96; 95% CI 0.92-0.98). The ASBMR criteria had a lower specificity, increasing the number of atypical fractures without bisphosphonate use from 13 to 31. This led to a decrease in age-adjusted relative risk associated with bisphosphonate use from 47 (95% CI 26-87) to 19 (95% CI 12-29). Interpretation: Stress fractures of the femoral shaft are a specific entity, which is easily diagnosed on radiographs and strongly related to bisphosphonate use. Differences in diagnostic criteria may partially explain the large differences in relative risk between different population-based studies. (C) 2012 Elsevier Inc. All rights reserved. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Atypical femoral fracture, Bisphosphonate, Stress fracture, Osteoporosis
in
Bone
volume
52
issue
1
pages
389 - 392
publisher
Elsevier
external identifiers
  • wos:000312750700046
  • scopus:84868651511
  • pmid:23098829
ISSN
1873-2763
DOI
10.1016/j.bone.2012.10.016
language
English
LU publication?
yes
id
96552efa-a589-4e37-b5e6-bd46b442971b (old id 3481019)
date added to LUP
2016-04-01 13:28:01
date last changed
2019-11-20 02:38:41
@article{96552efa-a589-4e37-b5e6-bd46b442971b,
  abstract     = {Background: Estimations of the risk of bisphosphonate associated atypical femoral fractures vary between different population-based studies, from considerable to neglectable. A possible explanation for these discrepancies could be different definitions of atypical fractures. We aimed to identify specific radiographic fracture characteristics associated with bisphosphonate use. Methods: In a previous nationwide study, 59 atypical and 218 ordinary fractures were diagnosed. The atypical fractures were defined by their stress-type fracture pattern. All fractures were now re-assessed by a physician in training, without information about bisphosphonate use. The fracture angle (0-180 degrees) was measured. Presence of local lateral cortical thickening (a callus reaction), more than 2 fragments, or a medial spike was noted. The reader then made a judgment whether the fracture appeared as an atypical fracture based on the ASBMR criteria. Results: Frequency distribution analysis of the fracture angle showed a distinct subgroup, comprising 25% of all 277 fractures, with a mean of 89 and SD of 10 degrees. Forty-two of 57 patients in this subgroup used bisphosphonates, whereas only 27 of 213 others did (specificity 0.93; 95% CI 0.88-0.96). Presence of a callus reaction had also a high specificity for bisphosphonate use (0.96; 95% CI 0.92-0.98). The ASBMR criteria had a lower specificity, increasing the number of atypical fractures without bisphosphonate use from 13 to 31. This led to a decrease in age-adjusted relative risk associated with bisphosphonate use from 47 (95% CI 26-87) to 19 (95% CI 12-29). Interpretation: Stress fractures of the femoral shaft are a specific entity, which is easily diagnosed on radiographs and strongly related to bisphosphonate use. Differences in diagnostic criteria may partially explain the large differences in relative risk between different population-based studies. (C) 2012 Elsevier Inc. All rights reserved.},
  author       = {Schilcher, Jorg and Koeppen, Veronika and Ranstam, Jonas and Skripitz, Ralf and Michaelsson, Karl and Aspenberg, Per},
  issn         = {1873-2763},
  language     = {eng},
  number       = {1},
  pages        = {389--392},
  publisher    = {Elsevier},
  series       = {Bone},
  title        = {Atypical femoral fractures are a separate entity, characterized by highly specific radiographic features. A comparison of 59 cases and 218 controls},
  url          = {http://dx.doi.org/10.1016/j.bone.2012.10.016},
  doi          = {10.1016/j.bone.2012.10.016},
  volume       = {52},
  year         = {2013},
}