Double plate fixation improves stiffness in a comminuted canine scapula fracture gap model compared to single plate...

To determine whether a secondary plate on the caudolateral aspect of the scapula increases stiffness and reduces primary plate strain compared to a single plate along the cranial scapula spine in a comminuted fracture gap model.

Ex vivo mechanical study.

A total of 14 paired canine scapulae.

A comminuted fracture gap model was created. A 2.4 mm plate was secured along the cranial aspect of the scapula spine in 28 scapulae. A secondary 2.0 mm plate was secured on the caudolateral border of 14 scapulae. Scapula were sinusoidally loaded from -20 to -200 N for 7200 cycles at 2 Hz. The displacement was measured, and stiffness calculated. Digital image correlation calculated primary plate surface strain. A two-way ANOVA assessed displacement and stiffness. Primary plate strain was assessed with a paired t-test. Statistical significance was set at p < .05.

Mean displacement was higher in the single plate group, -0.81 mm (± 0.14) compared to the double plate group, -0.48 mm (± 0.08) (p < .0001). Mean stiffness was lower in the single plate group, 392.8 N/mm (± 13.72) compared to the double plate group, 563.7 N/mm (± 5.89) (p <.0001). There was no difference in primary plate surface strain between the two groups.

Double plate fixation improved stiffness in a comminuted scapula fracture gap model compared to single plate fixation.

The placement of an additional plate placed on the caudolateral aspect of the scapula improves stiffness in comminuted scapula body fractures.