Biomechanical stability of different fixation constructs for ORIF of radial neck fractures

Radial head and neck fractures are common and at times require operative fixation. There is no consensus on the ideal fixation construct for unstable radial neck fractures. Using 7 fresh frozen cadaveric radii, fractures of the radial neck were created 2 cm from the articular surface. The fractures were stabilized with 5 different commonly used constructs: crossed K-wires; a 2.4-mm T-plate using screws in the head (T-plate and nonlocked screw construct); a T-plate using a screw and locked buttress pin in the head (T-plate and locked buttress pin construct); a T-plate with an interfragmentary screw from the shaft retrograde, through the plate into the head (retrograde interfragmentary screw construct); and a T-plate with an interfragmentary screw from a nonarticular portion of the head antegrade into the shaft (antegrade interfragmentary screw construct). All constructs were tested for bending and torsional rigidity using an Instron mechanical testing machine (Model 306; MTS Systems, Eden Prairie, Minnesota). The highest rigidity in both bending and torsion was the antegrade interfragmentary screw construct. During bending, the antegrade interfragmentary screw construct was significantly stronger than a T-plate and nonlocked screw construct. In torsion, the retrograde interfragmentary screw construct was significantly stiffer than K-wires and approached significance over a T-plate and locked buttress pin construct. Locking bolts vs screws into the head did not significantly increase rigidity in torsion or bending. In this model, plating showed an increase in stiffness in torsional loading as compared to K-wires. The addition of a lag screw across the neck fracture consistently showed an increase in torsional and bending stiffness of the constructs. These data may assist orthopedic surgeons in determining the best fixation for radial neck fractures.