TY - JOUR
T1 - Structural consequences of transcortical holes in long bones loaded in torsion
AU - Hipp, J. A.
AU - Edgerton, B. C.
AU - An, K. N.
AU - Hayes, W. C.
N1 - Funding Information:
Acknowlrcl~rmrflrs--This work was suppurred by a National Cancer Institute Grant No. l-R01 CA 40211. bv the Annus Foundation. Wcllcslcy Hospital. Toronto, &&da. and-by the Maurice E. Mucllcr Prokssorship of Biomcchanics at Harvard Medical School.
PY - 1990
Y1 - 1990
N2 - Finite element models were used to predict the structural consequences of transcortical holes through long bones loaded in torsion. Several parameters were investigated including hole size, anelastic behavior of the bone, cortical wall thickness, cortical wall symmetry, curvature along the bone's long axis and the axial length of the defect. Finite element model predictions of percent intact bone strength were compared to experimental data for sheep femora with transcortical drill holes loaded to failure in torsion. Hole size was expressed as hole diameter divided by the outer bone diameter. Linear finite element model predictions were in conservative agreement with the experimental data for large hole sizes. A transcortical hole with a diameter 50% of the outer bone diameter reduced the torsional strength by 60%. However, the linear models predict a 40% drop in strength for small holes whereas in vitro data suggest that small holes have no significant effect on strength. Models which represent non-linear anelastic behavior in bone over-predicted torsional strengths. Asymmetric cortical wall thickness and long bone bowing have minor effects, while the length of an elongated defect strongly influences the torsional strength. Strength reductions are greatest for bones with thin cortical walls.
AB - Finite element models were used to predict the structural consequences of transcortical holes through long bones loaded in torsion. Several parameters were investigated including hole size, anelastic behavior of the bone, cortical wall thickness, cortical wall symmetry, curvature along the bone's long axis and the axial length of the defect. Finite element model predictions of percent intact bone strength were compared to experimental data for sheep femora with transcortical drill holes loaded to failure in torsion. Hole size was expressed as hole diameter divided by the outer bone diameter. Linear finite element model predictions were in conservative agreement with the experimental data for large hole sizes. A transcortical hole with a diameter 50% of the outer bone diameter reduced the torsional strength by 60%. However, the linear models predict a 40% drop in strength for small holes whereas in vitro data suggest that small holes have no significant effect on strength. Models which represent non-linear anelastic behavior in bone over-predicted torsional strengths. Asymmetric cortical wall thickness and long bone bowing have minor effects, while the length of an elongated defect strongly influences the torsional strength. Strength reductions are greatest for bones with thin cortical walls.
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U2 - 10.1016/0021-9290(90)90383-E
DO - 10.1016/0021-9290(90)90383-E
M3 - Article
C2 - 2292605
AN - SCOPUS:0025610753
VL - 23
SP - 1261
EP - 1268
JO - Journal of Biomechanics
JF - Journal of Biomechanics
SN - 0021-9290
IS - 12
ER -