Does a volar locking plate provide equivalent stability as a dorsal nonlocking plate in a dorsally comminuted distal radius fracture?: a biomechanical study

Objectives The purpose of this study was to compare the fixation afforded by a dorsal nonlocking plate with a volar locking plate in a fracture model simulating an extra-articular distal radius fracture with dorsal comminution (OTA [Orthopaedic Trauma Association] type 23-A3.2). Methods In 10 matched pairs of fresh-frozen cadaveric arms, a comminuted extra-articular dorsally unstable distal radius fracture (OTA type 23-A3.2) was created. The fractures were fixed with either dorsally placed nonlocking T-plate or volarly placed locking plate within matched pairs. The precycling stiffness with axial and torsional loading of the specimens was determined. The specimens were then loaded axially for 5000 cycles, and postcycling axial and torsional stiffness and load to failure were determined. Results The mean axial and torsional stiffness before and after cyclic loading of fractures stabilized with dorsal nonlocking plate was not significantly different than fractures fixed with volar locking plate. Although the mean load to failure was greater for the volar locking plate group than dorsal nonlocking plate group, the difference was not significant. Conclusions This study suggests that the fixation obtained with volar locking plates is as stable as fixation with a dorsal plate in acute healing period and can withstand the functional demands of the immediate postoperative period in dorsally comminuted unstable extra-articular distal radius fractures. Elimination of dorsal tendinopathy by using volar locking plates may lead to fewer long-term complications. Locking plates provided better stability in specimens with osteoporosis.