Musculoskeletal Ultrasound for the Diagnosis of Plantar Fasciitis: An Accuracy and Diagnostic Yield Study.

Objective: To evaluate the accuracy of musculoskeletal ultrasound measurement of plantar fascia thickness and shear wave elastography (SWE) calculation of Young's modulus in the diagnosis of plantar fasciitis (PFis), and to explore whether it will have any impact on clinical decision-making, rather than just using established diagnostic methods of clinical symptoms and signs.

Methods: A diagnostic single-center study was conducted in 60 patients with PFis and 64 patients with other types of heel pain. The sensitivity and specificity of musculoskeletal ultrasound in the diagnosis of PFis were calculated according to the diagnostic criteria for PFis recommended by the Clinical Practice Guide for PFis of the American Physical Therapy Association (APTA) Orthopaedic Branch. The analysis of the receiver operating characteristic curve of the subjects was used to study the accuracy of the diagnosis of PFis by two indicators alone and two indicators jointly.

Results: The thickness of plantar fascia measured by musculoskeletal ultrasound and the area under the curve (AUCs) calculated by shear wave elastography for diagnosing PFis were 0.925 and 0.917, respectively, and the optimal cutoff values were 3.15 mm (sensitivity: 100.0%, specificity: 81.3%) and 63.24 kPa (sensitivity: 78.3%, specificity: 92.2%), respectively. The area under the curve (AUCs) for the combined diagnosis of the two is 0.973 (sensitivity: 93.3%, specificity: 93.8%).

Conclusion: The thickness of plantar fascia measured by musculoskeletal ultrasound and Young's modulus calculated by SWE have high accuracy in diagnosing PFis, and the combined diagnosis of the two can improve the diagnostic accuracy of patients with PFis.