Applied Taguchi method for fatigue testing of customized hip implant

Area of Science:

• Biomedical Engineering
• Materials Science
• Orthopedic Surgery

Background:

• Customized hip implants are susceptible to fatigue failure due to time-varying stresses from human activities.
• Optimizing the design of patient-specific hip implants is crucial for long-term clinical success and patient well-being.

Purpose of the Study:

• To investigate fatigue testing of customized hip implants using a minimum number of experiments via the Taguchi method.
• To identify key geometrical parameters influencing the fatigue safety factor of patient-specific hip implants.

Main Methods:

• Computed tomography (CT) scans from 147 patients were used to measure hip joint parameters: horizontal offset (HO), vertical offset (VO), and neck shaft angle (NSA).
• Finite element analysis (FEA) calculated stress and strain, validated by in vitro tests.
• Fatigue safety factors were determined using Goodman, Soderberg, and Gerber theories.

Main Results:

• Analysis of variance revealed HO as the most influential parameter (54.38%), followed by NSA (29.16%) and VO (16.33%) on fatigue safety factors.
• Experiment number 8 demonstrated the highest fatigue safety factor among all tested custom hip implant designs.
• The Taguchi method proved efficient for fatigue testing, minimizing experimental requirements.

Conclusions:

• Horizontal offset (HO) exerts the greatest influence on the fatigue safety factors of customized hip implants.
• Identifying critical geometric parameters enables the redesign of custom hip implants for superior fatigue resistance.
• The Taguchi method is a suitable approach for efficient fatigue testing of custom hip implants.