Biomechanical Comparison of Clavicular Hook vs. Adjustable Loop Plates for Neer IIB Fractures

Overview

This finite element analysis study compared clavicular hook plates and adjustable loop plates for Neer Type IIB distal clavicle fractures. Both fixation methods provided adequate biomechanical stability, with distinct stress distribution patterns and implications for clinical use.

Background

Neer Type IIB distal clavicle fractures involve rupture of the conoid ligament, leading to poor fracture stability and high rates of delayed union or nonunion. Clavicular hook plates are commonly used for fixation but are associated with complications such as subacromial impingement and require implant removal after healing. Adjustable loop (strap) plates have emerged as an alternative, potentially reducing complications and allowing simultaneous treatment of associated shoulder injuries. Biomechanical comparisons of these fixation methods remain limited.

Data Highlights

Key Findings

• Both clavicular hook plates and adjustable loop plates provide effective biomechanical fixation for Neer Type IIB distal clavicle fractures under simulated loading.
• Maximum clavicle deformation was lower with hook plates (0.54 mm) than with adjustable loop plates (0.79 mm), but this difference was not statistically significant.
• Mean equivalent stress at the clavicular path node was significantly higher in hook plate fixation (3.42 MPa) compared to adjustable loop plates (2.87 MPa).
• Stress concentration in hook plates occurred at the hook bend, potentially causing localized high pressure on the subacromial surface, which may contribute to complications.
• Adjustable loop plates showed maximum stress at the midpoint of the strap connection line, with overall stress levels below material yield strengths, indicating low risk of implant failure.
• Adjustable loop plates allow simultaneous arthroscopic treatment of concomitant shoulder injuries and avoid the need for secondary implant removal surgery.

Clinical Implications

Both fixation methods offer sufficient biomechanical stability for Neer Type IIB distal clavicle fractures, but their differing stress distributions have clinical relevance. The hook plate’s stress concentration near the subacromial space may increase risk of impingement and related complications, often necessitating implant removal. Adjustable loop plates may reduce such risks and facilitate arthroscopic management of associated injuries, potentially improving patient outcomes and reducing the need for additional surgeries.

Conclusion

Finite element analysis demonstrates that clavicular hook plates and adjustable loop plates provide comparable biomechanical fixation for Neer Type IIB distal clavicle fractures, with adjustable loop plates offering advantages in stress distribution and complication risk. These findings support consideration of adjustable loop plates as a favorable alternative in clinical practice.

References

1. Neer Classification and Fracture Stability Context
2. Complications of Clavicular Hook Plates (76.6% rate)
3. Advantages of Arthroscopic Sling Plate Fixation