A mechanical comparison of veterinary linear external fixation systems.

Area of Science:

• Orthopedic biomechanics
• Biomaterials science
• Surgical innovation

Background:

• The Kirschner-Ehmer (KE) system is a traditional external fixation system.
• Recent advancements have led to the development of new external fixation systems (EFSs).
• Comparing the fixation rigidity of these new EFSs to the traditional KE system is crucial for orthopedic applications.

Purpose of the Study:

• To compare the fixation rigidity of recently developed external fixation systems (EFSs) against the traditional Kirschner-Ehmer (KE) system.
• To evaluate the biomechanical performance of various EFS configurations.

Main Methods:

• An in vitro biomechanical study was conducted.
• Five different EFSs were assembled into seven frame geometries to stabilize plastic rods.
• Constructs were tested under axial compression, torsion, medial-lateral bending, and cranial-caudal bending to determine stiffness.

Main Results:

• The large SK EFS demonstrated significantly higher stiffness in most configurations compared to the KE system.
• The small SK EFS with a titanium connecting bar showed greater stiffness than the KE system across multiple loading modes and frame types.
• The Secur-U system with an augmentation plate also exhibited significantly greater stiffness than the KE system.

Conclusions:

• Newer external fixation systems provide fixation rigidity equal to or greater than the traditional KE system.
• Increased frame rigidity in EFSs can potentially lead to less complex frame designs.
• These findings support the use of advanced EFSs for enhanced fracture stability.