ARUP; ISBN: 978-0-9562121-5-3 - CMBBE 2012 - Cardiff University

did not allow gap closure. Maximum Von Mises stress and maximum equivalent strain
on the proximal and distal osteotomy surfaces are shown in figures 4 and 5 respectively.
Maximum stresses and strains within the osteotomy are found in the areas of contact at
gap closure. These areas are found on the lateral side of the tibia, opposite the plate. For
the entire construct, the highest stress found in any of the analyses is found on the head
of the fifth screw of the Standard-Ti-Ti construct (Fig. 6). At 8162 MPa, the stresses on
screw #5 are nearly 4 times the next highest amount.
Figure 7 displays the Von Mises stress map of the plates and screws for each construct
configuration with maximum stress positions labeled. The maximum stress for each
construct is found on screw #5 except for the Reinforced-Pk-Pk construct, which has
maximum stress on screw #1. Maximum stresses also occur on the near cortex for each
construct except for the Standard-Ti-Ti construct upon which the maximum stress
occurs at the base of the screw head near the bottom (lateral) side of the plate.
5. DISCUSSION
Reinforced-Pk-Ti Reinforced-Pk-Pk
Max: 1470
MPa
Standard-Ti-Ti Standard-Pk-Pk
Max: 8162
MPa
Max: 1014
MPa
Reinforcement Reinforcement
Max: 1060
MPa
Figure 7: Front view of plate and screw stress results, 0 - 1000 MPa scale. Ti-reinforced PEEK plates
also show stress results of inner reinforcement (front view) at bottom right of the figure.
Interfragmentary motion (IFM) for the four constructs was high. Claes et al. found that
0.5 mm IFM produces the most stable fracture callus for secondary fracture healing in
fracture gaps of 2 mm or smaller. For larger gap sizes (3 to 6 mm), delayed healing can