Internal Fixation of Dorsally Displaced Fractures of the Distal Part of the Radius A Biomechanical Analysis of Volar Plate Fracture Stability

Background: Volar plate fixation with use of either a locking plate or a neutralization plate has become increasingly popular among surgeons for the treatment of dorsally comminuted extra-articular distal radial fractures. The purpose of the present study was to compare the relative stability of five distal radial plates (four volar and one dorsal), all of which are commonly used for the treatment of dorsally comminuted extra-articular distal radial fractures, under load-ing conditions simulating the physiologic forces that are experienced during early active rehabilitation. Methods: With use of a previously validated Sawbones fracture model, a dorsally comminuted extra-articular distal radial fracture was created. The fracture fixation stability of four volar plates (an AO T-plate, an AO 3.5-mm small-fragment plate, an AO 3.5-mm small-fragment locking plate, and the Hand Innovations DVR locking plate) were compared under axial compression loading and dorsal and volar bending simulating the in vivo stresses that are generated at the frac-ture site during early unopposed active motion of the wrist and digits. A single dorsal plate (an AO pi plate) was used for comparison, with and without simulated volar cortical comminution. The construct stiffness was measured to as-sess the resistance to fracture gap motion, and comparisons were made among the implants. Results: The volar AO locking and DVR plates had greater resistance to fracture gap motion (greater stiffness) com-pared with the volar AO nonlocking and AO T-plates under axial and dorsal loading conditions (p < 0.01), with no sig-nificant difference between the AO volar locking and DVR plates. The volar AO locking plate had greater resistance t