An observational study in Flexible Flatfoot, sponsored by Cairo University. Not yet recruiting at 1 site in Egypt. Open to participants aged 18 Years to 40 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-10-02.
Sponsored by Cairo University · Observational
The goal of this observational study is to assess tibialis posterior muscle morphology in adults with flexible flatfeet. The main question it aims to answer is:
Are there differences in tibialis posterior muscle morphology between adults with symptomatic flexible flatfeet, asymptomatic flexible flatfeet, and individuals with normal foot posture?
Participants will undergo clinical assessment of foot posture and symptoms and an ultrasound assessment of the tibialis posterior muscle. The study will compare muscle thickness, cross-sectional area, and echo intensity among the three groups.
Flexible flatfoot involves altered mechanics of the foot and may influence the functional demands placed on the structures responsible for maintaining the medial longitudinal arch. The tibialis posterior muscle is an important dynamic contributor to medial arch support and plays a role in controlling pronation and maintaining foot stability during functional activities.
Although flexible flatfoot has been widely investigated from clinical and biomechanical perspectives, less is known about the morphological characteristics of the tibialis posterior muscle in relation to this condition. In particular, differences associated with the presence or absence of symptoms have not been sufficiently characterized. Evaluating muscle morphology may provide additional information about the muscular adaptations associated with altered foot posture.
The rationale for this study is to investigate whether the morphological characteristics of the tibialis posterior muscle differ across individuals with different clinical presentations of foot posture. Comparing these characteristics may help clarify whether muscular morphological changes are associated with flexible flatfoot itself or with the presence of symptoms.
The study findings may contribute to a better understanding of the muscular component of flexible flatfoot and provide information that may be useful for future research investigating assessment and rehabilitation strategies for individuals with this condition.
168 studies on the registry are indexed under Flatfoot; 41 are open to participants now.
This study's planned enrollment of 45 is close to the median of 49 across 44 observational studies indexed under Flatfoot.
Browse Flatfoot studies →Cairo University is the lead sponsor of 4,780 studies on the registry; 1,427 are open to participants now.
Of its 36 completed or terminated interventional studies of FDA-regulated products, 5 (14%) have results posted.
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Participants will be recruited from individuals attending the outpatient clinics of the Faculty of Physical Therapy, Cairo University, and New Cairo Hospital. The study population will include individuals presenting with different foot postures, including those with flexible flatfoot and individuals with normal foot posture. Eligible participants who meet the study criteria and provide informed consent will be enrolled in the study.
Exclusion Criteria:
Participants with flexible flatfoot who have foot-related symptoms.
Other: Tibialis Posterior Muscle Morphology Assessment
Participants with flexible flatfoot who do not have foot-related symptoms.
Other: Tibialis Posterior Muscle Morphology Assessment
Participants with normal foot posture who do not meet the study criteria for flexible flatfoot.
Other: Tibialis Posterior Muscle Morphology Assessment
Assessment of tibialis posterior muscle morphology using B-mode diagnostic ultrasound as a non-invasive measurement method. The assessment is performed for research purposes and does not involve administration of treatment or modification of participants' usual care.
Tibialis Posterior Muscle Thickness
Tibialis posterior muscle thickness will be assessed using B-mode diagnostic ultrasonography with a high-frequency linear transducer. The ultrasound measurement site will be standardized at 30% of the shank length according to the predefined study protocol. Minimal transducer pressure will be applied to avoid muscle compression. Multiple images will be obtained, and the mean measurement will be used for statistical analysis.
Time frame: Baseline assessment during a single study visit.
Tibialis Posterior Muscle Cross-sectional Area
Tibialis posterior muscle cross-sectional area will be assessed using B-mode diagnostic ultrasonography with a high-frequency linear transducer. The ultrasound measurement site will be standardized at 30% of the shank length according to the predefined study protocol. Minimal transducer pressure will be applied to avoid muscle compression. Multiple images will be obtained, and the mean cross-sectional area measurement will be used for statistical analysis.
Time frame: Baseline assessment during a single study visit.
Tibialis Posterior Muscle Stiffness
Tibialis posterior muscle stiffness will be assessed using shear wave elastography (SWE) with an ultrasound system equipped with a high-frequency linear transducer. The ultrasound measurement site will be standardized at 30% of the shank length according to the predefined study protocol. Minimal transducer pressure will be applied to avoid muscle deformation. Multiple measurements will be obtained, and the mean stiffness value will be used for statistical analysis.
Time frame: Baseline assessment during a single study visit.
Foot Posture Index-6 (FPI-6)
Foot posture will be assessed using the Foot Posture Index-6 (FPI-6) during relaxed standing. The FPI-6 consists of six observational and palpation-based items used to assess foot posture, with each item scored from -2 to +2. The total score ranges from -12 to +12, with higher scores indicating a more pronated foot posture.
Time frame: Baseline assessment during a single study visit.
Pain intensity level
Pain intensity will be assessed using the Arabic version of the Numeric Pain Rating Scale (Arabic NPRS). Participants will rate their foot-related pain on a numerical scale from 0 to 10, where 0 indicates no pain and 10 indicates the worst pain imaginable. The Arabic NPRS will be administered according to its validated Arabic version.
Time frame: Baseline assessment during a single study visit.
Plan to share: No
No publications or documents are linked to this record.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
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Cairo University