Atypical Femur Fracture | Atypical Fracture Cohort Study

Atypical Femur Fracture research study

What is the primary objective of this study?

Osteoporosis is a disease characterized by increased bone fragility and deteriorating bone micro-architecture. The main consequence of osteoporosis is low-trauma fractures, most often of the hip, spine and wrist. Recently, another type of low-trauma fracture, atypical femur fractures (AFFs), have received much attention. Little is known of the cause of these debilitating fractures; however, they have been associated with long term bisphosphonate use. What we currently know about AFFs is based on case reports or small case series, or studies using administrative databases or secondary analyses of bisphosphonate trials. While these reports provide some preliminary information on the relationship between long term bisphosphonate exposure and AFFs, detailed clinical data are absent. As we have established a network of specialists across southern Ontario our group is in a position to collect meaningful information on a larger group of patients who have experienced these debilitating fractures into a centralized AFF registry.

Who is eligible to participate?

Inclusion Criteria: - Patients over the age of 20; - Patients who have experienced an incomplete AFF that satisfies the diagnostic criteria as set forth by the American Society of Bone and mineral Research (ASBMR) International Task Force on AFFs or a low (or no) trauma fracture that mimics the features described above at other sites. Exclusion Criteria: - Peri-prosthetic fractures; - High trauma fractures; - Pathological fractures secondary to metastases or metabolic bone diseases other than osteoporosis.

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?

Atypical Femur Fracture

Atypical Subtrochanteric Fracture

Osteoporosis With AFf

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.

Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

Atypical femur fracture cohort

Study Status


Start Date: June 2009

Completed Date: December 2022


Type: Observational [Patient Registry]


Primary Outcome: Prospectively identify and diagnose atypical fracture patients in Ontario

Secondary Outcome: Examine risk factors and predictors for AFFs

Study sponsors, principal investigator, and references

Principal Investigator: Angela m Cheung, MD, PhD

Lead Sponsor: University Health Network, Toronto


More information:

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