The lag screw technique has historically been a successful and accepted way to treat oblique metacarpal fractures. However,
it does take additional time and involve multiple steps that can increase the risk of fracture propagation or comminution
in the small hand bones of the hand. An alternate fixation technique uses bicortical interfragmentary screws. Other studies
support the clinical effectiveness and ease of this technique. The purpose of this study is to biomechanically assess the
strength of the bicortical interfragmentary screw versus that of the traditional lag screw. Using 48 cadaver metacarpals,
oblique osteotomies were created and stabilized using one of four methods: 1.5 mm bicortical interfragmentary (IF) screw,
1.5 mm lag technique screw, 2.0 mm bicortical IF screw, or 2.0 mm lag technique screw. Biomechanical testing was performed
to measure post cyclic displacement and load to failure. Data was analyzed using one-way analysis of variance (ANOVA). There
was no significant difference among the fixation techniques with regard to both displacement and ultimate failure strength.
There was a slight trend for a higher load to failure with the 2.0 mm IF screw and 2.0 mm lag screw compared to the 1.5 mm
IF and 1.5 mm lag screws, but this was not significant. Our results support previously established clinical data that bicortical
interfragmentary screw fixation is an effective treatment option for oblique metacarpal fractures. This technique has clinical
importance because it is an option to appropriately stabilize the often small and difficult to control fracture fragments
encountered in metacarpal fractures.
Keywords Metacarpal fracture - Hand fracture - Metacarpal fixation - Screw fixation metacarpal fracture - Biomechanical metacarpal fracture