Background
Medical imaging is frequently used to assist in the diagnosis of plantar heel pain (PHP). However, no studies investigating the association of imaging features with PHP have combined x-ray, ultrasound and MRI, nor have they used a control group matched for important characteristics. The aim of this study was to investigate the association of imaging findings with PHP.
Methods
In this cross-sectional study, 50 participants with PHP were compared to 25 participants without PHP (i.e. controls) matched for age, sex and body mass index (BMI). Imaging included x-ray, ultrasound and MRI.
Results
On x-ray, participants with PHP were 2.4x (95% CI 0.8, 6.7) more likely on the right and 3.7x (95% CI 1.3, 10.5) more likely on the left foot to have a plantar calcaneal spur. On ultrasound, plantar fascia thickness was 0.85 mm (95% CI 0.31, 1.40) thicker on the right and 0.74 mm (95% CI 0.23, 1.25) thicker on the left foot. Hypoechogenicity was 5.2x (95% CI 1.8, 14.7) more likely in the right and 3.0x (95% CI 1.1, 8.0) more likely in the left plantar fascia. On MRI, delamination was 5.0x (95% CI 1.7, 14.3) more likely in the right and 3.6x (95% CI 1.3, 10.0) more likely in the left plantar fascia. A tear of the plantar fascia was at least 9.3x (95% CI 1.2, 75.5) more likely in the right and at least 5.9x (95% CI 1.2, 28.2) more likely in the left foot. Bone marrow oedema of the calcaneus was 10.6x (95% CI 2.3, 49.9) more likely in the right and 5.3x (95% CI 1.4, 20.1) more likely in the left foot.
Discussion and Clinical Relevance
Our study is the first of its kind to compare participants with and without PHP when matched for age, sex, and significantly, BMI. Our findings highlight that PHP does not just involve the plantar fascia. While pathology of the plantar fascia is part of the clinical picture, increased odds of bone marrow oedema – an indication of bone stress – is an important finding from our study. Our findings may impact treatment of this condition.