Development and Testing of a Novel Locking Pin Cap to Create a Fixed-Angle K-Wire Plate Construct

Area of Science:

• Orthopedic surgery
• Biomechanical engineering
• Trauma fixation devices

Background:

• Distal radius fractures are common, often requiring surgical fixation.
• Current methods using bent K-wires may lack rigidity and lead to fixation failure.
• Improved techniques are needed to enhance stability for small fragment fixation.

Purpose of the Study:

• To evaluate the effectiveness of a novel locking pin cap system.
• To compare its ability to rigidly attach K-wires to volar locking plates against existing alternatives.
• To assess its resistance to fracture displacement.

Main Methods:

• Twelve Sawbones models with volar shear distal radius fractures were used.
• Fixation was achieved using either industry-standard pin plates or a novel system with a locking pin cap.
• Constructs underwent axial load conditioning and sinusoidal loading; fragment movement and load to failure were measured.

Main Results:

• The industry-standard pin plate showed pin disassociation after fatigue, unlike the locking pin cap group.
• The locking pin cap construct demonstrated significantly higher load resistance to achieve a 2-mm gap.
• The novel locking pin cap significantly increased the ultimate load to failure compared to the standard.

Conclusions:

• The novel locking pin cap creates a rigid, fixed-angle K-wire attachment to volar locking plates.
• This system offers superior strength in preventing gap formation and resisting ultimate failure.
• It outperforms commercially available plates utilizing bent K-wires.