Related Experiment Video
Updated: Jun 2, 2026

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models
Published on: October 9, 2014
Strength of the Joshi External Stabilising System
Rajeev Kumar1, Anupam Gupta, V P Sharma
1Department of Mechanical Engineering, Institute of Engineering and Technology, Lucknow, UP, India.
Purpose:
To conduct an in vitro strength test for the Joshi External Stabilising System (JESS) for stabilisation of tibial fractures using a cadaveric tibia and steel rods.
Methods:
The configuration of the JESS specimens was based on a 62-year-old man with a metaphyseal tibial fracture. Two types of JESS specimens were prepared, using either the tibia of an average male adult cadaver (n=1) or stainless steel cylindrical rods (n=3). The strength of the JESS rather than that of the rods was measured using a universal testing machine. The axial compressive load was gradually increased at 1 mm/min to 35 N. Axial deformation of the fracture fragment was recorded. Each experiment was repeated 3 times in identical manner. A finite element analysis of the JESS was developed. The axial compressive loads and corresponding interfragmentary displacement in the experimental specimens and in the finite element analysis were compared.
Results:
The mean strength of the JESS was 32.5 N/mm in experiments and 35.3 N/mm in finite element analysis; the difference was 8.4%. The interfragmentary displacement was directly proportional to the axial compressive load.
Conclusion:
The strength of the JESS is one fourth of that of the Ilizarov fixator, and therefore not suitable for full load bearing activities.
Related Concept Videos
Stability of structures
Pole and System Stability
Simple poles are unique roots of the denominator polynomial. Each simple pole corresponds to a distinct solution to the system's characteristic equation, typically resulting in exponential decay terms in the system's response.
Stability
The stability of an LTI system is determined by the roots of its characteristic equation, known as poles. A system is stable if it produces a bounded...
Applications of Stress
The...
Stability of Equilibrium Configuration
A stable equilibrium occurs when a system tends to return to its original position when given a small displacement, and the potential energy is at its minimum. An example of a stable equilibrium is when a cantilever beam is fixed at one end and a weight is attached to the other end. If the weight...
Support Reactions
The purpose of the supports is to prevent the translational motion of the system by applying an equal and opposite force and to prevent the system's rotation by applying a...
