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Updated: Jun 12, 2026

Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models
Published on: October 9, 2014
[A new kind of minimally invasived external fixator for orthopaedics fabricated with quick casting method]
Xangdang Liang1, Geng Sun, Zhanshe Guo
1Orthopeadic Hospital of PLA, Beijing 100853.
Objective:
A new kind of external fixator for orthopaedics is designed in order to overcome the shortcomings of high weight, hard to operate and high degree of hurt for the conventional external fixator.
Methods:
The quick casting method is used to realize fast shaping, and FEM (Finite Element Method) is used to verify the practicability of the design.
Results:
In order to verify the correctness of the design, FEM is used to simulate it. It is concluded from the simulated result that the biggest relative displacement between the borders of the separated bones is just 0.37 mm, which is much less than the requested value 1 mm. This fits the request to cure the patients whose bones are broken and shows the correctness of the design. Finally, ten sheep are used as specimen to verify the feasibility of the design. It is concluded from the X ray sketches of 2 weeks, 4 weeks and 8 weeks that there is no relative displacement happened between the border of the broken bone and the bone is well cured.
Conclusions:
This kind of device is feasible to cure the broken bones and the design scheme can be used as the final treatment means.

