Related Experiment Video
Updated: May 31, 2026
10:09
Adjustable Stiffness, External Fixator for the Rat Femur Osteotomy and Segmental Bone Defect Models
Published on: October 9, 2014
Rigidity of unilateral external fixators--a biomechanical study.
P T P W Burgers1, M P J M Van Riel, L M M Vogels
1Department of Surgery-Traumatology, Erasmus MC, University Medical Centre Rotterdam, Rotterdam, The Netherlands. p.t.p.w.burgers@erasmusmc.nl
Injury
|June 28, 2011
Summary
The Dynafix DFS Standard Fixator showed less rigidity under parallel and axial forces compared to the Orthofix ProCallus Fixator. However, it offered better stability against transverse forces and rotation during distraction.
Area of Science:
- Orthopedic biomechanics
- Trauma surgery
- Medical device engineering
Background:
- External fixation is crucial for temporary fracture stabilization in polytrauma patients.
- Achieving adequate stability is essential for optimal initial fracture healing.
- This study compares the rigidity of two external fixator devices: Dynafix DFS Standard Fixator (4 joints) and Orthofix ProCallus Fixator (2 joints).
Purpose of the Study:
- To compare the biomechanical rigidity of the Dynafix DFS Standard Fixator and the Orthofix ProCallus Fixator.
- To evaluate how differing joint configurations affect fixator stability under various loading conditions.
- To determine the most stable fixator for specific clinical applications in polytrauma.
Main Methods:
- Standardized testing model with 10 repetitions for each device.
- Application of loads (10N increments up to 160N) in parallel, transversal, and axial (distraction/compression) directions.
- Calculation of translation resultant and rotation resultant to quantify stability.
Main Results:
- Dynafix DFS exhibited significantly higher translation under 100N parallel force (6.65±1.43mm vs. 3.29±0.83mm).
- Dynafix DFS showed significantly lower translation under 60N transverse force (8.14±1.20mm vs. 9.83±0.63mm).
- Dynafix DFS demonstrated higher translation in axial distraction and compression, but lower rotation resultant under distraction (0.70±0.17° vs. 0.97±0.21°).
Conclusions:
- Both fixators are most susceptible to transverse forces.
- Dynafix DFS Standard Fixator offers less rigidity with parallel and axial forces.
- Dynafix DFS Standard Fixator is advantageous for transverse forces and rotational stability during distraction; neither device's rigidity was affected by repeated heavy loading.
