G. Lowet et al., STUDY OF THE VIBRATIONAL BEHAVIOR OF A HEALING TIBIA USING FINITE-ELEMENT MODELING, Journal of biomechanics, 29(8), 1996, pp. 1003-1010
Two finite element models of a fractured tibia with healing callus wer
e developed. In the first model, the callus was modelled at the middle
of the diaphysis, while in the second one the callus was located at t
wo-thirds of the length, distal from the knee. From these two models t
he static torsional stiffness as well as the resonant frequencies and
mode shapes of the first four vibration modes were calculated for a se
ries of increasing values of Young's modulus of the callus. Two situat
ions were considered. In the first situation, the geometry of the call
us was kept constant, while in the second, the dimensions of the callu
s were reduced while its Young's modulus was increased. The resonant f
requencies were found to increase with increasing stiffness of the cal
lus. The single bending modes were found to be more sensitive when the
callus was at the middle of the diaphysis, whereas the double bending
modes were more sensitive when the callus was situated distally. Mode
shapes were similar to those for the intact tibia when the stiffness
of the callus was 5% of the stiffness of the intact bone or higher. A
basically linear relation was found between the torsional stiffness an
d the resonant frequencies. A theoretical relation between resonant fr
equencies and torsional stiffness was evaluated and found to be valid
if the Young's modulus of the callus was equal to or greater than 5% o
f the Young's modulus of the intact bone. The present results support
the quantitative interpretation of vibration analysis measurements for
the assessment of tibial fracture healing. Copyright (C) 1996 Elsevie
r Science Ltd.