Objective
Rigid foot orthosis is widely used as a treatment for pain and functional disabilities in flexible flatfoot patients with symptoms. However, there is still controversy over how the foot orthosis improves the patient's symptoms. On the other hand, in previous studies through ultrasonographic scan, it was known that the balance of invertor and evertor that stabilizes ankle is different from that of normal people in flat-footed patients. Therefore, the purpose of this study is to find clues to estimate the principle of treatment of rigid foot orthosis by examining the changes in the areas of ankle invertors and evertors after applying rigid foot orthosis for 1 year to flexible flatfoot patients.
Materials and Methods
Ten flexible flatfoot patients with foot pain and associated dysfunction were recruited. The subjects of the study were flexible flatfoot patients aged 10 to 20 who visited a shoe clinic at the Department of Rehabilitation Medicine, Chungnam National University Hospital, which had not previously been treated for flatfoot.
In the initial evaluation, cross-sectional areas of ankle invertor (tibialis anterior (TA), tibialis posterior (TP)) and evertor (peroneus longus & brevis (PLB)) were confirmed by ultrasonography, and information on the simple radiographic film, RCSP and foot functional index of the foot was collected.
Since then, Rigid foot orthosis, which supports the medial longitudinal arch, was prescribed and trained to be worn for more than 6 hours a day. Wearing was monitored through outpatient follow-up, and retesting was conducted one year later. The primary outcome is the change in the cross-sectional area of the ankle invertor and evertor.
Results
Data collected from a total of 12 feet of 6 patients were analyzed. The average change in the area sum of each muscle was +0.633cm2 in TA, +0.268cm2 in TP, and +0.713cm2 in PLB (Figure 1.). The change in the proportion of each muscle in the sum of the total muscle cross-sectional area was -1% in TA, -0.7% in TP, and +1.7% in PLB (Figure 2.). All six patients reported improvement in symptoms, and showed an average improvement of 4.3 in the foot functional index value. No significant change was observed in the results obtained from the radiographic film.
Conclusion
The use of one year of rigid foot orthosis in flatfoot patients improves symptoms. Although it does not change the alignment of the foot skeleton in the radiographic film, it affects the composition ratio of the muscle in the ankle, and the direction of the change approaches the proportion of normal people.
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