The comparative strengths of internal fixation techniques

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Hand surgery

Background:

• Metacarpal fractures are common hand injuries.
• Effective internal fixation is crucial for optimal bone healing and functional recovery.
• Various fixation techniques exist, but their comparative biomechanical strength requires further elucidation.

Purpose of the Study:

• To compare the biomechanical strength of different internal fixation techniques for metacarpal fractures.
• To evaluate the efficacy of Kirschner wires, intraosseous wire loops, and bone plates under simulated physiological loading.

Main Methods:

• Human cadaver metacarpals were fractured and fixed using Kirschner wires, intraosseous wire loops (three configurations, four wire gauges), and dorsal bone plates.
• Constructs were subjected to mechanical bending forces simulating flexion to failure.

Main Results:

• Intraosseous wire loops demonstrated significantly greater strength than Kirschner wires alone.
• Right-angle intraosseous loops were the strongest configuration among the tested loops.
• Combining Kirschner wires with dorsopalmar loops enhanced strength, but not with right-angle loops.
• Dorsal bone plates exhibited strength comparable to the optimal intraosseous loop configurations.

Conclusions:

• Intraosseous wire loops, particularly the right-angle configuration, provide robust fixation for metacarpal fractures.
• Bone plates offer comparable stability to the best intraosseous loop constructs.
• The choice of fixation technique should consider the specific fracture pattern and desired stability.