The main object of this study was to use a geometric morphometric
approach to quantify the left-right symmetry of talus bones. Analysis was carried out using CT scan images of 11 pairs of
intact tali. Two important geometric parameters, volume and surface
area, were quantified for left and right talus bones. The geometric
shape variations between the right and left talus bones were also
measured using deviation analysis. Furthermore, location of asymmetry
in the geometric shapes were identified. Numerical results showed that talus bones are bilaterally symmetrical
in nature, and the difference between the surface area of the left
and right talus bones was less than 7.5%. Similarly, the difference
in the volume of both bones was less than 7.5%. Results of the three-dimensional
(3D) deviation analyses demonstrated the mean deviation between
left and right talus bones were in the range of -0.74 mm to 0.62
mm. It was observed that in eight of 11 subjects, the deviation
in symmetry occurred in regions that are clinically less important
during talus surgery. Objective
Methods
Results
Locking plate constructs for proximal humerus fractures can fail due to varus collapse, especially in the presence of osteoporosis and comminution of the medial cortex. Augmentation using a fibular allograft as an intramedullary bone peg may strengthen fixation preventing varus collapse. This study compared the ability of the augmented locking plate construct to withstand repetitive varus stresses relative to the non-augmented construct in cadaveric specimens. Proximal humerus fractures with medial comminution were simulated by performing wedge-shaped osteotomies at the surgical neck in cadaveric specimens. For each cadaver (n=8), one humeral fracture was fixated with the locking plate construct alone and the other with the locking plate construct plus ipsilateral fibular autograft augmentation. The humeral head was immobilized and a repetitive, medially-directed load was applied to the humeral shaft until failure (significant construct loosening or humeral head screw pull-out).Purpose
Method
locking plate fixation alone and locking plate fixation with intramedullary allograft fibular bone peg augmentation.
