Dual-energy X-ray absorptiometry based biofidelic finite element models for simulating falls to the hip: Impact of trochanteric soft tissue thickness on fracture risk.

BACKGROUND

We predicted the fracture outcomes of simulated falls from standing height using biofidelic finite element models of older adults in Singapore. We further investigated the influence of trochanteric soft tissue thickness, measured from scans and equations estimating standing trochanteric soft tissue thickness from DXA and BMI, on predicted fracture outcomes.

METHODS

Biofidelic finite element models were built using DXA scans from 280 older Singaporean adults enrolled in the Targeted Assessment and Recruitment of Geriatrics for Effective Fall Prevention Treatments study. Models were created using different trochanteric soft tissue thickness: measured from 3D optical scans in standing (reference), measured from whole-body DXA, estimated from whole-body DXA, and estimated from BMI. Predicted fracture outcomes from sideways falls were compared across these models.

FINDINGS: The number of predicted hip fractures was higher among Chinese participants compared to Indians (females: 2.4×, males: 2.3×) and Malays (females: 2.5×, males: 1.3×). Trochanteric soft tissue thickness was the dominant factor influencing impact force and force attenuation at the greater trochanter. The whole-body DXA model had a 26 % false prediction rate compared to the reference model, while the models using estimated values from whole-body DXA and BMI had false prediction rates of 1 % and 9 %, respectively.

INTERPRETATION: Biofidelic finite element models built using image data captures population-based differences in hip fracture risk for the three main ethnic groups in Singapore. In the absence of 3D optical scans, predicting soft tissue shapes based on whole-body DXA scans, commonly available in clinical practice, yields similar fracture predictions based on simulated falls.