Biomechanical properties of titanium elastic nail applied to a cadaveric clavicle model

The goal of this study was to examine biomechanical properties of titanium elastic nail fixation method that was applied to cadaveric clavicles with different thicknesses and lengths.

To test stiffness and failure load of clavicle with titanium elastic nail fixation, 12 pairs of clavicles were obtained. A short oblique fracture line (AO/OTA classification: 15-B1.2) was created at midpoint of the cadaveric bones. They were divided into four groups according to the nails with different thickness and length/diameter ratios. The fixated bones were situated on a jig that allows 3-point bending to measure stiffness and load failure.

The stiffness was measured to be mean 3.49 ± 1.49 N/mm in group 1. The stiffness for group 2 was mean 10.41 ± 2.18 N/mm, and for groups 3 and 4, the stiffness was mean 11.89 ± 2.99 N/mm and mean 24.44 ± 4.86 N/mm, respectively. When analyzed with statistics, group 1 had significant differences from groups 2 (P < 0.006), 3 (P < 0.001), and 4 (P < 0.000), and group 4 also had statistical significances from rest of the groups (P < 0.000).

For 2.5 mm titanium elastic nail, it is necessary to make fixation with a titanium elastic nail that is longer than 3 diameter lengths, and length that is longer than and equal to 3 diameter length titanium elastic nail was required for 3.5 mm titanium elastic nail to provide appropriate stiffness for firm fixation. Also, variances in both thickness and length have shown a similar effect.

Cadaveric study.