J Korean Fract Soc.  2002 Apr;15(2):114-122. 10.12671/jksf.2002.15.2.114.

The Biomechanics of Hybrid External Fixator: The Effect of Periarticular Half Pin on Frame Stiffness

• Oh JK
• Jung DY
• Kim IS

• KMID: 1999389
• DOI: http://doi.org/10.12671/jksf.2002.15.2.114

Abstract

OBJECTIVES
The purpose of this study was to identify the biomechanical effect of periarticular half pin in the hybrid external fixator.
METHODS
Simulated tibial plateau fractures were created using a polyvinylchloride pipe. Seven frame configurations were tested : a four-ring Ilizarov frame, a hybrid frame with three wires on peri-articular fragment, hybrid frames with wires and half pins on peri-articular fragment by four different configurations, a hybrid frame constructed with multiple levels of fixation in the periarticular fragment. A materials testing machine was used to apply pure compression, anterior and posterior bending, medial and lateral bending, and torsion. Stiffness values were calculated from the load deformation and torque angle curves
RESULTS
The overall stiffness of the hybrid frame was increased up to 30% by replacing a coronal tension wire with a half pin placed on the sagittal plane. The hybrid frame constructed with two wires and a half pin on the sagittal plane of the periarticular fragment showed overall stiffness compatible with that of multi-level peri-articular fixation frame.
CONCLUSION
Our results show that the half pin placed on the periarticular fragment can be a effective tool to increase the stiffness of hybrid external fixators in this periarticular tibia fracture model.

Keyword

Tibia; Plateau fracture; Hybrid external fixator; Biomechnics; Half pin

MeSH Terms

External Fixators*
Materials Testing
Tibia
Torque