Objective: To determine associations between chronic plantar heel pain (CPHP) and MRI- and US-derived imaging biomarkers.

Methods: We compared 218 participants with CPHP with 100 age- and sex-matched population controls. We assessed imaging biomarkers on MRI (calcaneal bone marrow lesions (BMLs), plantar fascia signal and thickness, spurs and fat pad signal) and B-mode/ power Doppler US (plantar fascia thickness, echogenicity and vascularity). Covariate data collected included demographics, disease history, clinical measures and physical activity by accelerometry. Data were analysed using multivariable conditional logistic regression.

Results: Plantar calcaneal BML size (mm², OR 1.03 (95% CI 1.02 to 1.05)), larger plantar spurs (>5mm, OR 2.15 (95% CI 1.13 to 4.10)), plantar fascia signal (penetrating > 50% of dorsoplantar width, OR 12.12 (95% CI 5.36 to 27.42)), plantar fascia thickness (mm, (MRI) OR 3.23 (95% CI 2.36 to 4.43), (US) OR 3.78 ( 95% CI 2.69 to 5.32) and echogenicity (diffusely hypoechoic OR 7.89 (95% CI 4.02 to 15.48), focally hypoechoic OR 24.92 (95% CI 9.60 to 64.69)) were independently associated with CPHP. Plantar fascia vascularity was uncommon, occurring exclusively in cases (cases with signal n=47(22%)) Combining imaging biomarkers into one model, plantar BMLs and plantar fascia imaging biomarkers, but not fat pad signal or heel spurs, were independently associated with CPHP.

Conclusion: Calcaneal BMLs and plantar fascia imaging biomarkers are associated with CPHP. Further research is required to understand whether these different markers represent distinct phenotypes of heel pain, and if so, whether there are specific treatment implications.