Helical plating - a novel technique to increase stiffness in defect fractures

Area of Science:

• Orthopedic biomechanics
• Trauma surgery
• Implant engineering

Background:

• Single-plate fixation for bone defects can lead to nonunion and implant failure due to insufficient stiffness.
• Under-dimensioned implants in bridging osteotomies compromise fracture healing.
• Load sharing is critical for successful bone defect repair.

Purpose of the Study:

• To compare the biomechanical performance of different fixation constructs in a synthetic femoral shaft fracture model.
• To evaluate the impact of adding a helical plate to a lateral locking plate on construct stiffness and strain.
• To assess construct stability in both contact and gap fracture scenarios.

Main Methods:

• Eight groups of synthetic femora were tested, including intact, laterally plated, and dual-plated (lateral and helical) constructs.
• Constructs were subjected to quasi-static axial and torsional loading to measure stiffness.
• Plate surface strain was quantified under axial load.

Main Results:

• Dual plating (lateral and helical plates) significantly increased axial and torsional stiffness compared to lateral plating alone (p < 0.01).
• Torsional stiffness with dual plating in gap fractures was superior to that achieved with a long proximal femoral nail (p < 0.01).
• Plate surface strain decreased significantly with dual plating in gap fractures (< 0.1%) compared to single lateral plating (0.3%).

Conclusions:

• Additional helical plating substantially enhances construct stiffness and promotes balanced load sharing in synthetic bone models.
• Dual plating is recommended for demanding gap or defect fractures where single-plate fixation is inadequate.
• This technique may mitigate risks of nonunion and plate-fatigue failure in complex fracture management.