Capacity of Installed Commercial Bone Fixation Plates

SUMMARY In vitro tests of commercial internal fixation plates installed on whole equine metacarpal bone were performed. The modes of loading the plated bones were compression, torsion with simulated transverse and oblique fractures, and flexure with load applied to the side, palmar, and dorsal surfaces of the bone, all with the plates fixed to the dorsal surfaces of the bone. The lowest capacity resulted with flexural load on the dorsal surface, and the maximum capacity occurred with a flexural load applied to the palmar surface. The capacity of the installed plates with respect to the unfractured strength of whole bone was between 16 and 67%.