What Are the Biomechanical Properties of the Taylor Spatial Frame™?

Area of Science:

• Orthopedic biomechanics
• Biomaterial science
• Surgical device engineering

Background:

• The Taylor Spatial Frame (TSF) is a widely used alternative to the traditional Ilizarov circular fixator.
• Limited comparative biomechanical data exist for the TSF hexapod system versus the Ilizarov construct.

Purpose of the Study:

• To evaluate the mechanical properties of the TSF system under physiological loads.
• To compare the TSF's biomechanics against the standard Ilizarov frame, with and without a simulated bone model.

Main Methods:

• Tested three-ring TSF and Ilizarov constructs under axial compression, bending, and torsional loads.
• Utilized an acrylic-pipe fracture model with fine wires and 5mm half pins for repeated testing.
• Calculated load-deformation curves and rigidity, performing statistical comparisons with paired t-tests.

Main Results:

• TSF exhibited lower axial rigidity (645 N/mm) but greater bending and torsional rigidity compared to the Ilizarov frame.
• Half-pin TSF constructs showed no difference in axial rigidity to fine-wire Ilizarov constructs (107 N/mm) while maintaining superior bending/torsional resistance.
• A consistent laxity of 0.72 mm was observed in the TSF construct around neutral loading.

Conclusions:

• TSF provides lower axial rigidity but enhanced bending and torsional resistance under physiological loads compared to the Ilizarov frame.
• Observed TSF laxity at low loads necessitates careful preloading in clinical applications.
• Half-pin TSF constructs may replicate the axial rigidity of Ilizarov frames, potentially promoting bone healing.