Ultrasound-based evaluation of plantar fascia and heel fat pad thickness in patients with type 2 diabetes: an observational cross-sectional study.

INTRODUCTION

The plantar fat pad plays a key role in shock absorption and heel protection. In patients with controlled type 2 diabetes mellitus (cT2DM), advanced glycation end products (AGEs) may alter the structure of plantar tissue and affect its thickness and functionality. This study used ultrasound to compare the thickness of the plantar fat pad and plantar fascia between individuals with and without cT2DM and assessed the reliability of the ultrasound measurements.

METHODS

This prospective observational cross-sectional study examined 168 participants aged ≥60 years, including 84 with cT2DM and 84 without diabetes matched by sex. The plantar tissue thickness was measured in loaded and unloaded conditions using a portable ultrasound device. Intra-observer reliability was calculated using the intraclass correlation coefficient (ICC).

RESULTS

The ultrasound measurements showed excellent intra-observer reliability (ICC = 0.86-0.99). The groups showed no statistically significant differences in thickness of the heel plantar fat pad in loaded and unloaded conditions. However, the plantar fascia thickness showed significant differences between participants with diabetes and the control group in unloaded conditions (p = 0.040) and under load (p = 0.008). Differences between sexes were observed in height (p < 0.001) and weight (p < 0.001). Differences between the cT2DM group and the control group were also found in age (p = 0.001) and height (p = 0.010). After adjustment for age and height using linear regression analysis, the association between cT2DM and the plantar fascia thickness remained significant for only loaded conditions (p = 0.034).

DISCUSSION: Ultrasound demonstrated high intra-observer reliability, and the findings suggest a possible load-dependent association between cT2DM and plantar fascia thickness in the present study.