Biomechanical properties of volar hybrid and locked plate fixation in XXXX .

@entity3604 @entity85 @entity19215 @entity174
PURPOSE: We compare the biomechanical properties of a volar hybrid construct to an all-locking construct in an @entity3604 and normal comminuted distal radius @entity174 model. METHODS: Groups of 28 normal, 28 @entity3604 , and 28 over-drilled @entity3604 left distal radius synthetic bones were used. The normal group consisted of synthetic bone with a standard foam core. The @entity3604 group consisted of synthetic bone with decreased foam core density. The over-drilled @entity3604 group consisted of synthetic bone with decreased foam core density and holes drilled with a 2.3 mm drill, instead of the standard 2.0 mm drill, to simulate the lack of purchase in @entity3604 bone. Within each group, 14 synthetic bones were plated with a volar locking plate using an all-locking screw construct, and 14 synthetic bones were plated with a volar locking plate using a hybrid screw construct (ie, both locking and nonlocking screws). A 1-cm dorsal wedge osteotomy was created with the @entity19215 cm from the volar surface of the lunate facet. Each specimen was mounted to a materials testing machine, using a custom-built, standardized axial compression jig. Axial compression was delivered at 1 N/s over 3 cycles from 20 N to 100 N to establish stiffness. Each sample was stressed to failure at 1 mm/s until 5 mm of permanent @entity85 occurred. RESULTS: Our results show no difference in construct stiffness and load at failure between the all-locking and hybrid constructs in the normal, @entity3604 , or over-drilled @entity3604 synthetic bone models. All specimens failed by plate bending at the osteotomy site with loss of height. CLINICAL RELEVANCE: Although volar locking plates are commonly used for the treatment of @entity174 , the ideal screw configuration has not been determined. Hybrid fixation has comparable biomechanical properties to all locking constructs in the fixation of metaphyseal fractures about the knee and shoulder and might also have a role in the fixation of @entity174 .
