Plantar pressure distribution in the evaluation and differentiation of flatfeet.

BACKGROUND: Although foot diseases are common, only a few studies have detailed the biomechanical and anatomical components of each disorder. The most reliable diagnostic tool for flatfoot is X-ray radiography. Achieving a similar accurate and objective diagnosis using another assessment tool, such as plantar pressure measurements, can be more convenient in clinical practice. RESEARCH QUESTION: To identify foot plantar pressure characteristics that primarily detect flatfoot based on X-ray, which addresses the use of such assessments for flatfoot diagnosis. In addition, to compare between the normal foot, flatfoot with positive Foot Posture Index-6 (FPI), and flatfoot with positive FPI and radiographic measures. METHODS: Sixty-two feet were examined from healthy female subjects aged 20.38 ± 1.10 years. According to the results of FPI and X-ray, each sample was assigned to one of the three groups (normal: negative FPI; FPI+: FPI ≥ +6; X-ray and FPI+: Arch Angle ≥ 165°, CP ≤ 12.3° and FPI ≥ +6) and compared using plantar pressure variables. RESULTS: As per normal group compared to X-ray and FPI+ group, there was a significant difference in the surface area (P-value: 0.01, 95 % CI: -26.58 to -3.62), force (P-value: 0.04, 95 % CI: -10.37 to -0.09), and pressure (P-value: 0.01, 95 % CI: -56.78 to -6.35) in the medial foot. Similarly, the arch index among the normal group and the X-ray and FPI+ group showed significant differences (Static AI; P-value: 0.003, 95 % CI: -0.21 to -0.04). CONCLUSION: There was a significant difference in plantar pressure between the normal feet and flatfeet with positive FPI and X-ray in the medial foot area. SIGNIFICANCE: To attain a consensus among diagnostic approaches to identify flatfoot, the combined comparison of observational, foot pressure, and radiographic methods that have shown considerable reliability can be useful for clinical practice.

Diagnostic Accuracy of Various Radiological Measurements in the Evaluation and Differentiation of Flatfoot: A Cross-Sectional Study.

Arch angle is used to indicate flatfoot, but in some cases, it is not easily defined. The presence of flatfoot deformity remains difficult to diagnose due to a lack of reliable radiographic assessment tools. Although various assessment methods for flatfoot have been proposed, there is insufficient evidence to prove the diagnostic accuracy of the various tools. The main purpose of the study was to determine the best radiographic measures for flatfoot concerning the arch angle. Fifty-two feet radiographs from thirty-two healthy young females were obtained. Five angles and one index were measured using weight-bearing lateral radiographs; including arch angle, calcaneal pitch (CP), talar-first metatarsal angle (TFM), lateral talar angle (LTA), talar inclination angle (TIA) and navicular index (NI). Receiver-operating characteristics were generated to evaluate the flatfoot diagnostic accuracy for all radiographic indicators and Matthews correlation coefficient was calculated to determine the cutoff value for each measure. The strongest correlation was between arch angle and CP angle [r = -0.91, p ≤ 0.0001, 95% confidence interval (CI) (from -0.94 to -0.84)]. Also, significant correlations were found between arch angle and NI [r = 0.62, p ≤ 0.0001, 95% CI (0.42 to 0.76)], and TFM [r = 0.50, p ≤ 0.0001, 95% CI (from 0.266 to 0.68)]. Furthermore, CP (cutoff, 12.40) had the highest accuracy level with value of 100% sensitivity and specificity followed by NI, having 82% sensitivity and 89% specificity for the cutoff value of 9.90. In conclusion, CP angle is inversely correlated with arch angle and considered a significant indicator of flatfoot. Also, the NI is easy to define radiographically and could be used to differentiate flat from normal arched foot among young adults.