Reliability of sonographic measurement of thickness and echogenicity of the plantar fascia

Objective To evaluate the intra-and inter-rater reliability in ultrasonographic measurement of thickness and echogenicity of the plantar fascia.Methods Enrolled in this study were 22 patients (42 feet) who had been diagnosed with plantar aponeurositis from January 2012 to January 2013 and 28 normal volunteers (56 feet).Ultrasonography was performed to measure the thickness and echogenicity of the plantar fascia in both longitudinal and transverse planes.The mean gray level in the region of interest was quantified using Histgram software.Two sonographers independently conducted the measurements in a double-blind manner.Volunteers were assessed twice in an interval of one week by the same sonographer to evaluate intrarater reliability.Results The intraclass correlation coefficients (ICC) for intra-and interrater measurements of plantar fascia thickness ranged from 0.82 to 0.95 in longitudinal and transverse planes in the control group; the ICC of the plantar fascia thickness were 0.80 and 0.56 in the study group in the longitudinal and transverse planes; the ICC for the average gray level by Histgram measurement were 0.74 and 0.53 in the study group in longitudinal and transverse planes; the Kappa values for evaluation of presence and absence of low echogenicity were 0.34 and 0.35 in the study group in the transverse and longitudinal planes.Conclusion Ultrasonography can be used as an effective diagnostic tool for the plantar fascia,because it is reliable in evaluation of its thickness and the mean gray-level of echogenicity. Key words: Ultrasonography;  Heel pain;  Diagnosis;  Reliability;  Plantar fascia