Is Bridge Plating of Comminuted Humeral Shaft Fractures Advantageous When Using Compression Plates with Three versus...

Area of Science:

• Orthopedic Surgery
• Biomechanics
• Trauma Surgery

Background:

• Minimally invasive plate osteosynthesis (MIPO) is a standard technique for humeral shaft fractures.
• Complications persist despite high bone union rates with MIPO.
• Limited data exists comparing MIPO anterolateral approaches with varying screw counts.

Purpose of the Study:

• To biomechanically compare comminuted humeral shaft fractures fixed with dynamic compression plates using two versus three screws per fragment.
• To evaluate the performance of anterolateral MIPO in treating AO/OTA 12-C1/2/3 fractures.
• To assess construct stability under various loading conditions.

Main Methods:

• Six pairs of human cadaveric humeri were used.
• Comminuted fractures (AO/OTA 12-C1/2/3) were simulated and bridge-plated with dynamic compression plates.
• Specimens were tested under lateral bending, anterior bending, axial bending, and internal rotation torsion, followed by cyclic torsional loading until failure.

Main Results:

• No significant difference in initial stiffness was observed between two-screw and three-screw groups for any bending or torsional load.
• The three-screw group demonstrated significantly more cycles to 10°, 15°, and 20° torsional deformation compared to the two-screw group.
• Construct failure occurred at a significantly higher number of cycles in the three-screw group.

Conclusions:

• Biomechanical analysis shows no significant difference in primary stability between two and three screws per fragment for bridge plating comminuted humeral shaft fractures.
• Three-screw configurations provide superior secondary stability and greater resistance to reduction loss under dynamic loading.
• Employing a third screw is justified when enhanced secondary stability is critical for fracture treatment.