atypical femur fracture atypical fracture of the thigh bone
Conditions
Interventions
None listed
Sponsors
Erasmus MC, Universitair Medisch Centrum Rotterdam
Eligibility
Age
18 Years to 99 Years
Inclusion criteria
Inclusion criteria: Inclusion criteria In order to be eligible to participate in this study, a subject must meet all of the following criteria:;- Patients must be 18 years or older. - Patients known with a recent or past atypical femur fracture based on ASBMR criteria or suggested revised radiological criteria. ;ASBMR criteria Two reports of a Task Force of the American Sociey for Bone and Mineral Research (ASBMR) resulted in diagnostic criteria for AFF. The fracture must be located along the femoral diaphysis from just distal to the lesser trochanter to just proximal to the supracondylar flare. Major features describe a localized periosteal or endosteal thickening of the lateral cortex at the fracture site and a fracture line with a transverse orientation that may become oblique as it progresses medially across the femur. The fracture must be non-comminuted or minimally comminuted and is associated with no or minimal trauma (fall from standing height or less). Complete fractures extend through both cortices and may be associated with a medial spike, while incomplete fractures only involve the lateral cortex. At least four out of five major features must be present. Minor features include generalized increased cortical thickness of the femoral diaphysis, prodromal pain, bilateral fracture and delayed fracture healing. ;Alternative criteria The ASBMR criteria are internationally acknowledged, although they remain subject of debate. For instance, Feldstein et al. (Incidence and demography of femur fractures with and without atypical features, 2012) described considerable differences between patients with only major features and patients with both major and minor features. It may be that only the latter group is truly atypical. Furthermore, cortical thickness does not appear to be a relevant feature. Therefore, patients with fractures that meet criteria suggested by Schilcher et al. (Atypical femoral fractures are a separate entity, characterized by highly specific radiographic features. A comparison of 59 cases and 218 controls, 2013) are also included. According to these alternative criteria, a fracture angle between 75° and 105°, a local callus reaction and fracture location at the diaphysis are features strongly related with bisphosphonate-associated AFF.
Exclusion criteria
Exclusion criteria: - The exclusion criteria as mentioned by the ASBMR Task Force consensus: fractures of the femoral neck, intertrochanteric fractures with spiral subtrochanteric extension, pathologic fractures associated with primary or metastatic bone tumors, periprosthetic fractures and miscellaneous bone diseases (e.g., Paget's Disease, fibrous dysplasia). ;- Patients from whom no written informed consent was obtained.
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Potential risk factors for AFF: 1. Medication use and co-morbidity 2. Genetic predisposition 3. Femur shape 1. Medication use and co-morbidity Cases are controls from whom medical information is already available in the ERGO study (~14.000 subjects), matched for sex, age and bisphosphonate use (none, more than five or less than five years). Controls are bisphosphonate users when they used bisphosphonates at the moment that their data were collected in the ERGO study. We will compare bone density scores, number of medication, corticosteroid use, use of proton pump inhibitors and co-morbidity between cases and controls, using the Chi-squared test and the Wilcoxon rank sum test. 2. Genetic predisposition (Exome) sequencing can reveal a genetic predisposition. We ask all participants about the occurrence of femur fractures in the family. For genetic analysis Plink and ProABLE packages in R are used. (Exome) sequencing data are compared to 200 controls from the ERGO study to identify genetic variants that are associated with AFF. This will be validated in the international osteoporosis consortia (GEFOS/GENOMOS). 3. Femur shape Anatomical characteristics may predispose to an AFF. Femoral morphology and lower limb alignment can be analysed with available images (see also reference 37 en 38 in the research protocol) from patient files (DEXA scan, CT-scan, long leg X-ray). The department of Orthopaedics has material for comparison. | — |
Secondary
| Measure | Time frame |
|---|---|
| Patients' characteristics are described, such as risk factors for osteoporosis and data on general health. These are no primary outcomes, but can be used for future further analyses. Alcohol use, smoking and BMI can be compared to the mean values in the Dutch population (data available in CBS) using the one sample t-test. The health condition prior to the AFF will be evaluated with the EQ-5D questionnaire. Continuous data will be presented as means and categorical data as percentages. Our findings will be compared to previous findings in the medical literature. | — |
Countries
Netherlands
Outcome results
None listed