On the Failure Initiation in the Proximal Human Femur Under Simulated Sideways Fall

The limitations of areal bone mineral densitymeasurements for identifying at-risk individuals have led tothe development of alternative screening methods for hipfracture risk including the use of geometrical measurementsfrom the proximal femur and subject specific finite elementanalysis (FEA) for predicting femoral strength, based onquantitative CT data (qCT). However, these methods needmore development to gain widespread clinical applications.This study had three aims: To investigate whether proximalfemur geometrical parameters correlate with obtained femurpeak force during the impact testing; to examine whether ornot failure of the proximal femur initiates in the cancellous(trabecular) bone; and finally, to examine whether or notsurface fracture initiates in the places where holes perforatethe cortex of the proximal femur. We found that corticalthickness around the trochanteric-fossa is significantly correlatedto the peak force obtained from simulated sidewaysfalling (R2 = 0.69) more so than femoral neck corticalthickness (R2 = 0.15). Dynamic macro level FE simulationspredicted that fracture generally initiates in the cancellousbone compartments. Moreover, our micro level FEA resultsindicated that surface holes may be involved in primaryfailure events