Altered stiffness of microchamber and macrochamber layers in the aged heel pad: Shear wave ultrasound elastography evaluation.

ABSTRACT

BACKGROUND/PURPOSE: To compare shear modulus of heel pad microchamber and macrochamber layers between young and elderly people using shear wave ultrasound elastography (SWUE), with the intent to clarify age-related changes. METHODS: This single-center prospective cross-sectional study was conducted between March, 2014 and March, 2016. Shear modulus of entire heel pad (Gentire), macrochamber layer (Gmac), and microchamber layer (Gmic) were measured with SWUE. RESULTS: Elderly participants (15 men, 15 women; age = 66.9 ± 6.2 years) had significantly higher Gmic (103.8 ± 20.7 vs. 60.1 ± 9.8 kPa; p < 0.001) and Gentire (39.4 ± 10.5 vs. 34.1 ± 5.4 kPa; p = 0.005), but a significantly lower Gmac (21.7 ± 7.5 vs. 27.9 ± 4.9 kPa; p < 0.001) compared with those of young participants (15 men, 15 women; age = 26.4 ± 2.9 years). Positive correlations were observed between age and Gmic (r = 0.79, p < 0.001) and between age and Gentire (r = 0.28, p = 0.03), and negative correlation between age and Gmac (r = -0.46, p = 0.001). CONCLUSION: SWUE revealed that the heel pad macrochamber layer was slightly softer but the microchamber layer was exaggeratedly stiffer, making the entire heel pad stiffer in the elderly group than in the younger group, implying age-related compensation in heel pad layers to retain foot function.