Radiological criteria for atypical features of femur fractures: what we can learn when applied in a clinical study setting
The paper focuses on the identification of atypical fractures (AFFs). This paper examines the concordance between objective classification and expert subjective review. We believe the paper adds critical information about how to apply the American Society of Bone and Mineral Research (ASBMR) criteria to diagnose AFFs and is of high interest to the field.
Assess American Society of Bone and Mineral Research (ASBMR) criteria for identifying atypical femoral fractures (AFFs).
Two orthopedic surgeons independently evaluated radiographs of 372 fractures, applying ASBMR criteria. We assessed ease of applying ASBMR criteria and whether criteria-based assessment matched qualitative expert assessment.
There was up to 27% uncertainty about how to classify specific features. 84% of films were classified similarly for the presence of AFF according to ASBMR criteria; agreement increased to 94% after consensus meeting. Of 37 fractures categorized as AFFs based on ASBMR criteria, 23 (62.2%) were considered AFFs according to expert assessment (not relying on criteria). Only one (0.5%) femoral shaft fracture that did not meet ASBMR criteria was considered an AFF per expert assessment. The number of major ASBMR features present (four vs five) and whether there was periosteal or endosteal thickening (“beaking” or “flaring”) played major roles in the discrepancies between ASBMR criteria-based and expert-based determinations.
ASBMR AFF criteria were useful for reviewers but several features were difficult to interpret. Expert assessments did not agree with the ASBMR classification in almost one-third of cases, but rarely identified an AFF when a femoral shaft fracture did not meet ASBMR AFF criteria. Experts identified lateral cortical transverse fracture line and associated new-bone formation along with no or minimal comminution as crucial features necessary for the definition of atypical femoral fractures.
KeywordsAtypical femur fracture Bisphosphonate Fracture Osteoporosis
We are grateful to Donna Gleason for her assistance with data collection, Katie Essick for editorial assistance, and Cassandra Angus for manuscript preparation.
Source of funding
Funded by a research grant from Merck Sharp & Dohme Corp. All final decisions about study design, analysis, and paper content were made by the lead author, who is not employed by the sponsor.
Compliance with ethical standards
Conflicts of interest
Erin LeBlanc’s and Ana G. Rosales’s institutions received a grant from Merck & Co., Inc. to conduct this work. Erin LeBlanc’s institution has also received grant funding from Amgen, Astra Zeneca, and Bristol Meyer Squibb for unrelated projects on which she was principal or co-investigator; however, these other projects do not reflect a conflict of interest. Arthur Santora was an employee of Merck during this work but has since retired; he currently has stocks, stock options, and pension from Merck. Anne de Papp is a current employee of Merck & Co., Inc. Harry Genant, Richard Dell, Darin Friess, David Boardman, Douglas Bauer, Anne de Papp, Dennis Black, and Eric Orwoll declare that they have no conflict of interest.
- 3.Shane E, Burr D, Ebeling PR, Abrahamsen B, Adler RA, Brown TD, Cheung AM, Cosman F, Curtis JR, Dell R, Dempster D, Einhorn TA, Genant HK, Geusens P, Klaushofer K, Koval K, Lane JM, McKiernan F, McKinney R, Ng A, Nieves J, O'Keefe R, Papapoulos S, Sen HT, van der Meulen MCH, Weinstein RS, Whyte M (2010) Atypical subtrochanteric and diaphyseal femoral fractures: report of a task force of the American Society for Bone and Mineral Research. J Bone Miner Res 25:2267–2294CrossRefPubMedGoogle Scholar
- 4.Shane E, Burr D, Abrahamsen B, Adler RA, Brown TD, Cheung AM, Cosman F, Curtis JR, Dell R, Dempster DW, Ebeling PR, Einhorn TA, Genant HK, Geusens P, Klaushofer K, Lane JM, McKiernan F, McKinney R, Ng A, Nieves J, O'Keefe R, Papapoulos S, Howe TS, van der Meulen MCH, Weinstein RS, Whyte MP (2014) Atypical subtrochanteric and diaphyseal femoral fractures: second report of a task force of the american society for bone and mineral research. J Bone Miner Res 29:1–23CrossRefPubMedGoogle Scholar