Determination of suitable sample sizes for multi-patient based finite element studies

Area of Science:

• Biomechanics and Biomaterials
• Orthopaedic Engineering
• Computational Mechanics

Background:

• Finite element analysis (FEA) is widely used for joint replacement assessment.
• Existing FEA studies often use single samples, neglecting inter-patient variability in bone geometry and material properties.
• Advances in CT-based analysis enable multi-sample studies, necessitating sample size determination.

Purpose of the Study:

• To investigate factors for determining the required sample size in FEA of joint replacements.
• To explore sample sizing techniques for comparing strain distribution (intact vs. implanted femur) and multiple implant designs.
• To provide guidance on sample size for statistically significant comparisons between implant designs.

Main Methods:

• Utilized sample sizing calculations based on achieving desired result precision.
• Employed sample sizing calculations for detecting significant differences between two designs.
• Conducted an example analysis on femoral head resurfacing to demonstrate sample size effects.

Main Results:

• Demonstrated that a group of femurs can achieve reasonable statistical precision in FEA.
• Determined suitable sample sizes for analyzing statistically significant differences between groups of femurs with varying design parameters.
• Highlighted the importance of sample size calculations for accurate comparative analyses.

Conclusions:

• Sample size determination is recommended for accurate FEA of joint replacements.
• Statistical precision and the ability to detect significant differences can be achieved with appropriate sample sizes.
• Practical considerations must be balanced with the need for adequate sample sizes in FEA studies.