Biomechanically, repairing a midshaft clavicle fracture with a superior plate was more favorable compared to anterior-inferior plating in terms of both load to failure and bending failure stiffness. Furthermore, superior locked CDCP plates show improved bending failure stiffness over superior CDCP plates.

Flexible intramedullary nail fixation provides excellent fixation in children with unstable tibial shaft fractures, but few published series demonstrate the results and complications with this technique in children. A retrospective review of 19 patients was performed, as well as a biomechanical analysis of two implant configurations. Outcome measures included union rates, residual deformity, and complications. Union occurred in all cases. Five patients (26%) had complications. None required repeat operation. Two (11%) angular deformities (>/=10 degrees) occurred with the medial C and S construct, versus none with the double C. The C and S construct was more stable to mechanical testing with axial and torsional loading. Flexible intramedullary nail fixation is a straightforward technique that reliably produces good results. While the C and S construct was superior in biomechanical testing, the double C construct is more reliable and straightforward and remains by far the authors' preferred technique.

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In this porcine model, mechanical tethering during growth altered spinal morphology in the coronal and sagittal planes, leading to vertebral and disc wedging proportional to the duration of tethering. The resulting concave thickening of the disc in response to the tether was not anticipated and may suggest a capacity for the nucleus pulposus to respond to the compressive loads created by growth against the tether.

There was not a clear biomechanical advantage to performing any particular fixation method in this study. This suggests that the surgeon can use their clinical judgment and experience to determine the fixation technique.

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Purpose The purpose of this study was to compare the biomechanical stability generated when utilizing increasing sizes of titanium (Ti) flexible nails for fixation of simulated comminuted femur fractures. Methods Five synthetic adolescent-sized femur models were reamed to create a 9-mm canal. A 2-cm section was removed in the mid-diaphysis to simulate comminution. Each femur was first stabilized with bilateral, retrograde 3.0-mm titanium elastic nails. Femurs were tested in axial rotation and axial compression. The constructs were removed, and femurs were re-nailed with 3.5-mm nails. Identical testing was conducted. These nails were then removed, and femurs were re-nailed with 4.0-mm nails. This provided data on ''canal fill'' representing 67, 78 and 89% of the reamed canal diameter. Data for axial rotation (degrees) and failure load (N) required to produce 5 mm of fracture shortening were analyzed with a one-way ANOVA (P \ 0.05) and a Tukey's post-hoc test for multiple comparisons. Results For axial rotation, there were statistically significant improvements in rotational control for each increase in nail size. For axial stability, each increase in nail size resulted in increased axial failure loads to 5 mm, although these data were not statistically different. A specific comparison between 3.0-and 3.5-mm nails for compressive stability found significantly greater stability afforded by using 3.5-mm nails. Conclusions Data from this study demonstrate that increasing the amount of canal fill provides significant improvements in rotational control. The largest improvement was seen when increasing from 3.0-to 3.5-mm nails. While increasing the nail size from 3.5 to 4.0 mm again provided greater stability, larger nails may be more difficult to insert. Thus, increasing the nail size for femoral fracture fixation should be considered after measuring the diameter of the canal and evaluating the potential difficulty of insertion as well as specific demands of the fracture pattern.