Mechanical Evaluation of Three Methods of Plating Distal Radial Osteotomies

Eighteen intact canine cadaver radii underwent nondestructive axial testing, and were osteotomized, plated, and retested. Each bone was tested with and without mediolateral or craniocaudal restriction of motion. Fixation of the osteotomies was performed under static compression with a cranially applied 5-hole 3.5 mm dynamic compression plate, a cranially applied 7-hole 3.5 mm T-plate, or a medially applied 7-hole 2.7 mm dynamic compression plate. There was no loss of axial stiffness after osteotomy and fixation, and there were no differences in axial stiffness between the methods of fixation. Mediolateral stiffness (bending around the craniocaudal axis) was consistently greater than craniocaudal stiffness (bending around the mediolateral axis) before and after osteotomy and plate fixation. There was no difference in the axial stiffness of otherwise intact radii when craniocaudal or mediolateral screw holes were drilled; however, all radii with craniocaudal screw holes and one radius with mediolateral screw holes fractured at a screw hole at high axial loads.