ABSTRACT
BACKGROUND: In the clinic, 25%-35% heel pain is mostly caused by plantar fasciitis. Previous studies mainly focused on plantar fasciitis with heel pain caused by flat foot and the growth of calcaneus bone spur. There are no reports on other reasons for plantar fasciitis in large-sample studies. OBJECTIVE: Using the real-time shear wave elastography, CT scan and X-ray, the anatomic site and thickness of normal two-dimensional ultrasound standard flat plantar aponeurosis were identified to analyze the relationship between plantar elastic characteristics and plantar arch angle from non-weight-bearing to weight-bearing position so as to explore the correlation of plantar fasciitis with plantar elastics and plantar arch angle. METHODS: Fifty healthy volunteers (feet) were selected as the healthy control group. 100 cases of plantar fasciitis (one foot) were selected as the case group. Plantar arch angle from non-weight-bearing to weight-bearing position was obtained using X-ray and CT scan to identify anatomic site of plantar aponeurosis in both groups. Two-dimensional ultrasound and real-time shear wave elastography were utilized to obtain thickness and elastic modulus of plantar aponeurosis. RESULTS AND CONCLUSION: (1) From non-weight-bearing to weight-bearing, arch angle change value was (16.4±4.5)° in the healthy control group and (10.5±3.5)° in the case group. Significant differences in arch angle change were detected between the two groups (P <0.01). (2) Thickness of plantar fascia was obviously smaller in the healthy control group (2.4±0.3) mm than in the case group (3.5±0.9) mm. Elastic modulus of plantar fascia was obviously larger in the healthy control group (30.1±1.3) kPa than in the case group (9.1±1.2) kPa. Thickness of plantar fascia and elastic modulus of plantar fascia were significantly different between the two groups (P < 0.01). (3) In summary, real-time shear wave elastography combined with CT and X-ray images can investigate the morphological and elastic characteristics of the plantar aponeurosis from many aspects. Arch angle change is strongly associated with elastic modulus of plantar fascia. The decreased elastic modulus of plantar fascia is possibly one of the reasons for arch angle change from non-weight-bearing to weight-bearing conditions, and is probably one of reasons for plantar fasciitis with heel pain.