Biomedical Engineering Reference
In-Depth Information
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400000
.100E
+
07
.200E
+
07
.300E
+
07
.400E
+
07
.500E
+
07
.100E
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08
.139E
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08
712627
.143E
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07
.214E
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07
.285E
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07
.356E
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07
.428E
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07
.499E
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07
.570E
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07
.641E
+
07
(a)
(b)
FIgure 11.9
(See color insert.)
The von Mises stress distribution of the autografts in the reconstruction
models: (a) the femur in the FC-reconstructed model; (b) the tibia in the TP-reconstructed model.
41536
.500E
+
07
.100E
+
08
.200E
+
08
.300E
+
08
.450E
+
08
.600E
+
08
.700E
+
08
.725E
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08
324.256
.500E
+
07
.100E
+
08
.200E
+
08
.300E
+
08
.400E
+
08
.500E
+
08
.600E
+
08
.678E
+
08
(b)
(a)
FIgure 11.10
The von Mises stress distributions of the screws in the (a) FC-reconstructed model and
(b) TP-reconstructed model.
Because femoral strength is greater than that of the tibia, the femur in the FCR model shared
more loading than the tibia in the TPR model. The stress peaks in the right ilium (35%), sacrum
(219%), bridging bone (43%), and screws (6%) were all larger in the TPR model. The stress distribu-
tions were similar in the two reconstructed models, but the stress concentration in the TPR model
occurred at the tibial shaft and had a relatively wider area, while the stress concentration in the FCR
model was situated at the contact surface between the femur and screws and the area was narrower.
This indicated that the TPR was prone to both local and complete fracture. Under a normal sitting
posture, the stress in the bridging bone was very low. It had little biomechanical influence on the
function of the reconstruction.
Therefore, from the perspective of biomechanics, priority should be given to FCR reconstruction
due to its lower incidence of fracture. Additionally, the diameter of the screws should be appro-
priately enhanced, and their rigidity should be decreased in the healthy side to reduce the stress
shielding.
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