Predicting osteosynthesis screw failure by peri-implant bone morphology in multiple loading conditions.

Area of Science:

• Orthopaedic Surgery
• Biomaterials Science
• Medical Imaging

Background:

• Osteosynthesis screws are vital for bone fracture stabilization.
• Screw failure is a common complication, often linked to implant-bone interface micromotion.
• Understanding factors influencing screw stability is crucial for improving surgical success.

Purpose of the Study:

• To investigate the relationship between peri-implant trabecular bone morphology and osteosynthesis screw failure.
• To analyze screw failure under various loading conditions (axial, shear, mixed) and plate elevations.
• To identify bone morphometric predictors of screw mechanical failure.

Main Methods:

• Utilized high-resolution micro-computed tomography (micro-CT) for bone morphology analysis.
• Conducted mechanical testing on 100 porcine epiphyseal bone samples under ten loading configurations.
• Measured CT-based trabecular morphometric indices and correlated them with screw failure forces.

Main Results:

• Bone volume (BV) and bone volume over total volume (BV/TV) were identified as strong predictors of screw failure force.
• These indices explained 70-90% of the variance in failure forces across different loading scenarios.
• Plate elevation did not significantly alter the predictive power of BV and BV/TV.

Conclusions:

• Peri-implant bone morphology, specifically BV and BV/TV, is a critical determinant of osteosynthesis screw stability.
• These findings offer a predictive model for selecting optimal screw implantation sites based on local bone characteristics.
• This can lead to enhanced surgical outcomes and reduced postoperative complications in orthopaedic fracture repair.