Ultrasound Imaging of Plantar Fascia in Apparently Healthy Individuals, Diabetics and Patients With Plantar Fasciitis: A Case-Control Study.

INTRODUCTION

The plantar fascia (PF) is a critical load-bearing structure of the foot, contributing to arch support and gait mechanics. Diabetes mellitus (DM) and plantar fasciitis (PFis) are two distinct conditions that affect the structure and function of the PF. While PFis is typically linked to mechanical overload and localized degeneration, diabetes may lead to more widespread changes in connective tissue consistency and thickness. Although both conditions impact PF morphology, no meta-analysis to date has systematically distinguished the ultrasound features of diabetic fascial thickening versus plantar fasciitis, highlighting a critical gap that this study addresses.

METHODS

This case-control ultrasound study included 90 participants aged 30-60 years (30 per group): (1) healthy controls, (2) patients with type 2 DM (duration five or more years, no heel pain), and (3) non-diabetic individuals with clinically diagnosed unilateral PFis. High-resolution ultrasound was performed to assess PF thickness was measured 1 cm distal to the calcaneal insertion (a standardized site with good reproducibility), echogenicity (normal vs. reduced), and power Doppler vascularity. The examiner was blinded to group assignment. Group comparisons were conducted using ANOVA and chi-square tests.

RESULTS

PF thickness was significantly increased in both diabetic (3.4 ± 0.6 mm) and PFis (5.6 ± 1.1 mm) groups compared to controls (2.6 ± 0.5 mm, p<0.001). Hypoechogenicity was observed in 90% of PFis subjects but only 7% of individuals with diabetes and none of the controls (p<0.001). Doppler vascularity was absent in controls and nearly all diabetics (3%) but present in 33% of PFis cases (p < 0.01), typically indicating neovascularization.

CONCLUSION

Ultrasound effectively distinguishes PF changes in diabetes and PFis. While both conditions show PF thickening, PFis is characterised by hypoechoic hypervascular fascia, reflecting localised degeneration. Diabetic PF changes are diffuse and subclinical, without significant echo-textural disruption or inflammation. These findings underscore the diagnostic utility of ultrasound in evaluating heel pain and in the early detection of diabetic foot tissue remodelling.