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Published on: August 17, 2017
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Experimental and numerical failure analysis of Thompson hip prosthesis
Ali Motameni1, Ömer Can Farukoğlu2, Rıza Gürbüz1
1Department of Metallurgical and Materials Engineering, Middle East Technical University, Ankara, Turkey.
Bio-Medical Materials and Engineering
|June 30, 2025
Summary
This study investigated a fractured Thompson hip prosthesis, finding that manufacturing defects initiated fatigue cracks. Cyclic loading from body movement propagated these cracks, leading to the ultimate failure of the femoral stem.
Area of Science:
- Biomaterials Science
- Mechanical Engineering
- Orthopedic Surgery
Background:
- Femoral head-neck fractures are treated with hip prostheses like total hip arthroplasty or hemiarthroplasty.
- Prosthetic longevity is crucial, but failures can occur due to wear, creep, fatigue, or corrosion.
- This study focuses on a specific case of Thompson hip prosthesis failure.
Purpose of the Study:
- To investigate the failure mechanisms of a fractured Thompson hip prosthesis.
- To determine the root causes of the femoral stem's fracture within a patient.
Main Methods:
- Fractographic examination using scanning electron microscopy (SEM).
- Microstructural analysis via optical microscopy and energy dispersive spectroscopy (EDS) for chemical composition.
- Vickers hardness testing and finite element method (FEM) analysis to assess mechanical properties and stress distribution.
Main Results:
- Fatigue cracks initiated on the prosthesis's outer surface near areas of maximum stress identified by FEM.
- FEM analysis indicated that applied loads alone were insufficient to initiate these cracks.
- Material defects likely played a role in crack initiation.
Conclusions:
- Crack initiation is attributed to material defects originating from the prosthesis manufacturing process.
- Cyclic loading during normal body motion propagated the fatigue cracks.
- These factors culminated in the fracture of the Thompson hip prosthesis.
