Specimen-specific modeling of hip fracture pattern and repair

Specimen-specific vertebral fracture modeling: a feasibility study using the extended finite element method

“…Although the failure criterion was tuned in one vertebra to better match vertebral strain values, QCT/X-FEM analysis in the other two specimens did not involve any additional input from the user to predict the experimental failure patterns and loads. Ali et al implemented the X-FEM technique to predict femoral fracture in specimen-specific models, observing a crack and failure in the cortical bone region which was close to the experimental outcome [1]. The study showed predicted errors in failure loads and stiffness of 69% and 40%, respectively.…”

“…The extended finite element method (X-FEM) first introduced by Belytschko and Blackard [5] allows for the analysis of crack initiation without the need for repeated re-meshing or explicit geometric modeling of the discontinuity during crack propagation. Some studies have implemented X-FEM analysis to study dental, ceramics and brittle materials [3,26,33,43], cracks upon impact on windshields [42], the effects and characteristics of cracks on 2D structures [6], hip fracture pattern and repair [1] or cortical bone damage [16]. However, X-FEM has not been previously used to study complex structures such as cadaveric vertebral compression fractures.…”

To what extent can linear finite element models of human femora predict failure under stance and fall loading configurations?

“…A detailed analysis of the results seems to suggest a sound localisation of compressive failure at the trochanteric fossa, but a possible systematic error in the identification of tensile failures occurring at the head-neck junction, likely because of imaging and model limitations in reproducing the ultra-thin cortex usually present at that location. In absolute terms, the model-based failure localisation can be considered suboptimal, but our models were not specifically targeted to the prediction of fracture development, where the consideration of fracture mechanics in the constitutive model, as preliminarily proposed in Ali et al (2013) would be advisable. Similar models would also be suitable to investigate the model reproducibility of the two-stage fracture mechanism observed in some specimens tested in fall.…”

Comparison of proximal femur and vertebral body strength improvements in the FREEDOM trial using an alternative finite element methodology

“…Moreover, FEA may not only estimate the risk of fracture but may also reveal the location and mechanism of fracture for a given load case [15][16][17][18][19]. Finally, FEA may be used to understand specific clinical conditions such as the presence of an implant [20,21], metastatic defects [22][23][24], cement augmentation [25,26], or remodeling over a certain loading regime [27]. In support of its steadily growing recognition, FEA was included in several evaluations of osteoporosis treatments [28][29][30][31][32][33][34][35] and of the deleterious effect of spaceflight on bone strength [36].…”