Internal fixation of the distal humerus: a comprehensive biomechanical study evaluating current fixation techniques

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Trauma care

Background:

• Distal humerus fractures are complex injuries requiring stable fixation.
• Current fixation techniques involve various plating strategies, including locked and non-locked options.
• Optimizing implant orientation (parallel vs. orthogonal) is crucial for biomechanical stability.

Purpose of the Study:

• To compare the biomechanical performance of different plate fixation techniques for distal humerus fractures.
• To evaluate the efficacy of parallel versus orthogonal locked plating constructs.
• To assess the superiority of locked plating over conventional non-locked plating.

Main Methods:

• Biomechanical testing of four distinct implant constructs using cadaveric upper extremities.
• Simulated distal humerus fractures via supracondylar osteotomy.
• Assessment of stiffness (axial and sagittal), fatigue properties, and ultimate strength.

Main Results:

• Parallel locking plates demonstrated significantly higher axial stiffness and ultimate strength.
• Locked plating constructs outperformed non-locked plating across all tested parameters.
• No significant differences in sagittal stiffness or fatigue life were observed between locked plate orientations.

Conclusions:

• Parallel locking plate configuration offers biomechanical advantages in axial load and ultimate strength for distal humerus fractures.
• Locked plating is superior to non-locked plating, irrespective of orientation.
• Clinical implementation of parallel plating may face challenges due to soft tissue and exposure considerations.