Locking plates have increased torsional stiffness compared to standard plates in a segmental defect model of clavicle fracture

Objective: To evaluate the effect of locked plate technology to resist torsion in a clavicle fracture model of segmental bone loss. Methods: Forty-four synthetic clavicles were repaired with either 3.5 mm locked compression plate (LCP) or 3.5 mm low-contact dynamic compression plate (LCDCP). They were divided into two groups of 22 specimens. Each group was tested to evaluate torsional stiffness, load at failure, deflection at failure, and unconstrained plate motion. Results: LCP group showed significantly greater stiffness in torsion compared to the LCDCP group (p < 0.001). Average difference was 20.9%. Load at failure was not significantly different (p < 0.07). Deflection at failure was significantly less for the LCP group (p < 0.03). Unconstrained motion or plate 'looseness' was significantly less for the LCP group (p < 0.017). Conclusions: In a simulated model of segmental clavicle fracture, a LCP provided more stiffness and less deflection than a low-contact dynamic compression plate.