Comparison of different distal radius dorsal and volar fracture fixation plates: A biomechanical study

Purpose: To compare the biomechanical properties of 6 dorsal and volar fracture fixation plate designs in a cadaver model. Method: Six different plating techniques were used on surgically simulated, unstable, extra-articular distal radius fractures in fresh-frozen cadavers. Specimens were tested to failure in axial compression with the Materials Testing System machine, and were analyzed with a motion analysis system. The 6 different fixation systems studied included an AO stainless steel Pi plate (group 1), an AO titanium Pi plate (group 2), a Forte plate (group 3), a dorsally placed Symmetry plate (group 4), a volarly placed Symmetry plate (group 5), and a volarly placed SCS/V plate (group 6). Results: All dorsal plates (groups 1, 2, 3, 4) failed in apex dorsal angulation and all volar plates (groups 5, 6) failed in apex volar angulation. No group developed an average angular deformity greater than 5degrees with a load of 100 N, which compares with the physiologic loads expected with active wrist motion. Only the volarly placed SCS/V plated specimens (group 6) resisted deformation of 5degrees or more at loads up to 250 N, which compares with the physiologic loads expected with active finger motion, and was significantly stronger and more rigid than the other 5 plate groups. Conclusions: The SCS/V plate fixation system is the most rigid of the systems tested and may offer adequate stability for the treatment of the distal radius fracture in which the anterior and/or posterior metaphyseal cortex is comminuted severely.