Integrated Compression Screw Versus Unicortical Locking Screw for Fixing the Dorsal Critical Corner in Distal Radius...

Area of Science:

• Orthopedic surgery
• Biomechanics
• Trauma surgery

Background:

• Optimal fixation for intra-articular distal radius fractures with dorsal critical corner fragments remains less understood than for extra-articular fractures.
• Previous studies suggest 75% radius width locked screws suffice for extra-articular fractures, but their efficacy in complex intra-articular cases requires further investigation.

Purpose of the Study:

• To biomechanically evaluate and compare different volar plate fixation constructs for distal radius fractures involving a dorsal critical corner fragment.
• To assess fixation stiffness and failure loads for three distinct fixation methods in a synthetic model.

Main Methods:

• A dorsal critical corner fracture model was created in 18 synthetic distal radius specimens.
• Fixation was achieved using either a posteroanterior integrated compression screw (Group 1) or volar locking screws of 90% (Group 2) or 75% (Group 3) radius width.
• Biomechanical testing involved applying a load to the lunate facet to measure stiffness and failure loads.

Main Results:

• All constructs demonstrated similar fixation stiffness, with no significant differences among the groups.
• The integrated compression screw (Group 1) exhibited a significantly higher load to catastrophic displacement (532.9 N) compared to the volar locking screws (307.4 N and 230.8 N).
• Loads to produce 2-mm translation were comparable across all three groups.

Conclusions:

• Fixation of dorsal critical corner fragments with an integrated compression screw provides superior resistance to catastrophic failure.
• This construct offers comparable stiffness and initial fragment stability to volar locking screws.
• An integrated compression screw may be a suitable option for rigid fixation, potentially facilitating early return to activity.