Effective elastic properties for lower limb soft tissues from manual indentation experiment

Area of Science:

• Biomechanics
• Biomaterials Science
• Medical Engineering

Background:

• Quantitative assessment of limb soft tissue biomechanics is crucial for prosthetic socket design using CAD/CAM and finite element analysis.
• Limited clinical data exists on the site and posture-dependent material properties of lower limb soft tissues due to a lack of easy-to-use apparatus.

Purpose of the Study:

• To quantitatively assess the biomechanical properties of lower limb soft tissues.
• To investigate the influence of site and body posture on tissue mechanical properties.
• To determine gender-based differences in lower limb soft tissue biomechanics.

Main Methods:

• Utilized a previously developed ultrasound indentation system with a hand-held probe.
• Conducted indentation tests on eight healthy young subjects (4 males, 4 females) at four anatomical sites and three body postures.
• Applied a linear elastic indentation solution to calculate the effective Young's modulus from indentation responses.

Main Results:

• The effective Young's modulus of lower limb soft tissues ranged from 10.4 to 89.2 kPa.
• Tissue thickness showed minor variations with body posture.
• Young's modulus was significantly dependent on anatomical site, body posture, individual subject, and gender.
• Male subjects exhibited a mean Young's modulus approximately 40% greater than female subjects.

Conclusions:

• The ultrasound indentation system provides a viable method for assessing lower limb soft tissue biomechanics.
• Prosthetic socket design should account for the significant site, posture, and gender-dependent variations in soft tissue mechanical properties.
• Further research may explore the correlation between specific tissue layers and overall biomechanical response.