Purpose:
The aim of this study was to determine the biomechanical characteristics of locking plates with the trilock system with different design and screw settings compared to a non-locking plate in a diaphyseal metacarpal fracture.
Methods:
Oblique diaphyseal shaft fractures in porcine metacarpal bones were created in a biomechanical fracture model. after reduction they were fixed with three different locking plates with the trilock interlocking mechanism or a non-locking linear plate in mono- or bicortical screw fixations. in load to failure tests the maximum load and stiffness were measured.
Results:
For linear plates, the maximum load was higher for the non-locking plate compared with the locking plate. the maximum load could be increased for the locking plates using a double-row design and a higher screw number. no differences were found for the stiffness between all groups. in contrast to the non-locking plate, the mode of failure of the locking plates in many cases (86 %) was a loss of the interlocking mechanism.
Conclusions:
The results suggest that the locking plates with the trilock system achieve no higher stability compared to a non-locking plate in load to failure tests. adaptions to increase the stability of the interlocking mechanism are desirable.