Intraarticular calcaneus fractures: a biomechanical comparison or two fixation methods

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Trauma Surgery

Background:

• Intra-articular calcaneus fractures are complex injuries.
• Surgical fixation aims to restore stability and joint congruity.
• The choice of screw fixation impacts biomechanical strength.

Purpose of the Study:

• To compare the fixation strength of unicortical cancellous screws versus bicortical cortical screws.
• To evaluate screw fixation adequacy in intra-articular calcaneus fractures.

Main Methods:

• Cadaveric study using fresh frozen feet.
• Creation of oblique osteotomies in the calcaneus.
• Fixation with either two 4.0 mm unicortical cancellous screws or two 3.5 mm bicortical cortical screws.
• Application of axial force to failure.

Main Results:

• All specimens failed due to interosseous ligamentous disruption, not bony failure.
• No statistically significant difference in force to failure between the two screw types.
• Testing was limited by ligamentous failure, not screw fixation.

Conclusions:

• Both unicortical cancellous and bicortical cortical screw fixation are biomechanically adequate for intra-articular calcaneus fractures.
• Ligamentous integrity is a critical factor in subtalar joint stability.
• Either fixation method can be considered suitable for these fractures.