Authors (including presenting author) :
Lao LM, Koo LP, Chan KF, Lai HY, Wong PL, Chiu TY, Mak MY
Affiliation :
Department of Physiotherapy, Tuen Mun Hospital
Introduction :
Flat foot refers to the collapse of medial foot arch in weight-bearing position. It might induce pain and discomfort not only on foot but also all lower limbs joints and spine due to the uneven pressure distribution and altered lower limb biomechanics. Previously in our Flat Foot Programme, we assessed the flat foot with Foot Arch Index which was measured by static footprint. However, the dynamic loading during walking was rarely reported. Pedography is an advanced tool that enables measurement of pressure distribution over the foot during walking. This shows advantage over static footprint measure due to its capabilities of detecting pressure points in different time of gait cycle. With this information, the area upon where high pressure act and deformities can be determined which can supplement and extend standard clinical assessment of flat feet.
Objectives :
To document the dynamic foot geometry and loading in patients with flat feet diagnosed clinically by using a pedography system.
Methodology :
Thirty patients clinically diagnosed with flat feet (mean age=8.7±2.6 years old) were recruited in this study. Dynamic measurements of arch index (AI), peak pressure of hindfoot (PPhf), peak pressure of midfoot (PPmf), peak pressure of forefoot (PPff) and peak pressure of big toe (PPbt) were acquired by the pedography system. Two-step approach was used as it was relatively easier for subject to step within the platform and yielded similar results as the gold-standard of mid-gait method.
Result & Outcome :
Results: Sixty feet were measured and analyzed from July 2017 to November 2018. According to the measured AI, five feet were classified to have low AI (mean=0.17±0.01). Eighteen feet showed normal AI (mean=0.26±0.02) and thirty-seven feet were found to have high AI (mean=0.35±0.03). It was shown that the maximum loading in feet with low AI or normal AI occurred in hindfoot region. The mean PPhf in low AI and normal AI were 329.2±133.5 kPa and 255.3±64.9 kPa respectively. For the feet with high AI, the maximum loading was seen in big toe (mean PPbt=260.5±120.3 kPa). A trend was also observed that the peak pressure in midfoot was increasing with increased AI. The PPmf in low AI, normal AI and high AI were 71.0±10.0 kPa, 84.3±20 kPa and 113.5±59.7 kPa respectively. Conclusions: The pedography system might provide accurate and reliable data that revealed clearly where the high pressure located. A portion of subjects with clinically diagnosed flat foot showed normal foot pressure during walking which indicated that the foot arch was not as flat as that in standing posture. This provided further information on the severity of the condition so that appropriate treatment plan could be executed.
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