Optimizing clavicle hook plate fixation through biomechanical analysis of pre-bent plate condition and screw configurations

TL;DR

This study identifies optimal configurations for clavicle hook plates to improve fracture fixation strength and reduce implant failure.

Contribution

The study provides new biomechanical evidence on plate contouring, screw types, and hole placement for clavicle fixation.

Findings

Forward-bent plates showed the highest fracture force (202.75 N) compared to no or reverse bends.

Common screws provided greater stability (204.08 N) than locked screws (145.76 N).

Distal empty holes reduced strength more than proximal ones (135.38 N vs. 160.3 N).

Abstract

Clavicle hook plates are widely used for internal fixation of clavicle fractures, yet little biomechanical evidence exists to guide optimal plate contouring, screw selection, and screw-hole management. This study aimed to systematically evaluate the biomechanical effects of plate bending configuration, screw type, empty hole location, and invalid hole placement on clavicle hook plate fixation strength to optimize surgical strategies for clavicle fracture fixation.

This was a controlled bench-top biomechanical study. A series of biomechanical tests were conducted using an electronic universal testing machine. Clavicle hook plates were fixed onto synthetic clavicle models under different experimental conditions: (1) plate bending (forward bend, no bend, reverse bend), (2) screw type (common screws vs. locked screws), (3) empty screw hole location (distal vs. proximal), and (4) invalid hole placement (under the plate vs. beyond the plate). Axial force was applied to the distal hook until fracture occurred, and the maximum fracture force was recorded. One-way ANOVA with post-hoc Bonferroni correction was used for statistical analysis (p < 0.01 considered significant).

Plate bending significantly influenced fixation strength, with the forward bend group exhibiting the highest fracture force (202.75 N), significantly greater than the no bend and reverse bend groups (p < 0.01). Common screws provided greater mechanical stability than locked screws, with significantly higher fracture force (204.08 N vs. 145.76 N, p < 0.0001). Distal empty screw holes significantly reduced fixation strength (135.38 N) compared to proximal empty holes (160.3 N, p < 0.0001). Invalid holes beyond the plate weakened structural integrity more than holes under the plate (144.75 N vs. 169.27 N, p < 0.0001).

The study demonstrates that forward bending of the plate, the use of common screws, and avoiding distal empty screw holes or invalid holes beyond the plate significantly improve fixation strength in clavicle hook plate fixation. These findings provide critical biomechanical insights to enhance surgical decision-making and reduce the risk of implant failure. Future research should focus on clinical validation, multi-axial loading analysis, and long-term fatigue testing to further refine fixation techniques for optimal patient outcomes.

Figures