Biomechanical evaluation of a tool-less external fixator.

Area of Science:

• Orthopedic biomechanics
• Trauma surgery
• Surgical device engineering

Background:

• Current military external fixator systems require specialized tools, risking construct failure if misplaced.
• The Dolphix Temporary Fixation System offers a tool-less alternative for stabilizing extremity fractures.

Purpose of the Study:

• To compare the mechanical stiffness of the Dolphix system against the established Hoffmann III system.
• Evaluate the performance of a tool-less external fixation device in simulated battlefield conditions.

Main Methods:

• Three Hoffmann III and three Dolphix constructs were assembled on a tibia surrogate.
• A 30 mm fracture gap was created to mimic comminuted tibia or femur fractures.
• Constructs underwent cyclic axial compression testing over three consecutive days.

Main Results:

• Both systems successfully restored limb length and alignment after each testing cycle.
• Construct stiffness was maintained throughout the testing period for both systems.
• The Dolphix system achieved 54% of the stiffness of the Hoffmann III system.

Conclusions:

• The Dolphix system effectively restores limb length and alignment.
• Its tool-less mechanism offers a significant advantage in austere environments.
• The Dolphix system warrants consideration for use in mobile, resource-limited settings.