ABSTRACT
The purpose of this study is to establish a database and to compare mechanical properties between various types of small bone fixators. Hollow maple dowels are uniformly produced to simulate small bones in this study. Furthermore, transverse osteotomy, transverse osteotomy with 2 mm gap, and 45 degrees oblique osteotomies are created to simulate stable, unstable, and spiral fractures. Each fracture pattern is then approximated with four types of fixators: (1) Aesculap mini external fixator, (2) mini A-O plate and screw, (3) cross pin, and (4) self-assembled mini external fixator. Finally, tension, torsion, and bending tests are performed with INSTRON. In three different fracture patterns, dorsal plating has the strongest tensile rigidity and lateral bending rigidity. In stable and unstable fractures, Aesculap mini external fixator has the strongest torsional rigidity. However, mini A-O plate has the strongest torsional rigidity in 45 degrees oblique fractures. In stable fractures, dorsal plating, lateral plating, and mini external fixator all have good anterior bending rigidity without significant differences. Nevertheless, only lateral plating and mini external fixator show good anterior bending rigidity in unstable and 45 degrees oblique fractures. Except in torsional rigidity, Aesculap mini external fixator is not significantly stiffer than the self-assembled external fixator. As expected, cross pin is the weakest fixator. Differences in mechanical stiffiness between the four types of small bone fixators are provided in this study. Additionally, one should also consider the indication when choosing a proper fixator. Complication rate can then be lowered to achieve successful surgery in treating small bone fractures.
