Functional and Morphological Analysis of the Transverse Arch of the Foot by Using Precise Pressure Sensors and 2D Ultrasound

抄録

【Background/Purpose】

Hallux Valgus (HV) is a deformity that alter foot function and weight bearing patterns; causes pain, gait abnormalities, other toes deformity and increase risk of falling. The Transverse Arch - distance between the first and the fifth metatarsal heads - absorbs and propels forces during gait, preventing injuries. Reports found a link between toe deformities and its height. At Terminal Stance, the contact is mainly on the forefoot where 90~110 percent of the body weight is being supported. Pressure distribution under the foot has been studied widely using different methods. Meanwhile, the pressure under the metatarsal heads was measured based on areas instead of specific location to each of them. Therefore, our purposes are to: 1) Develop a device that measures the pressure specifically under the metatarsal heads (MTH), and 2) Find a link between MTH pressure distribution and MTH heights and the height of the Transverse Arch.

【Methods or Cases】

Feet were divided into two groups: 1) without-HV, 2) with-HV (HV≥20º). The pressure under the MTH was measured using individual sensors attached directly on the skin, connected to a computer.

While the height of the Transverse Arch and the MTHs were measured using a weight-bearing ultrasound device. Measurements were done in three positions: sitting, quiet standing and 90% weight shift.

【Results】 Ultrasound data show decrease in the Transverse Arch height as load increases. We noticed that the height of the 2nd MTH in with-HV group is unexpectedly slightly higher. Force data show varied patterns between MTHs and between groups, which needs further detailed analysis.

【Discussion/Conclusion】

The height of the 2nd MTH in with-HV group could be related to the rotational movements of the sesamoids and the 1st MTH. The clarification of force distribution pattern under the Transverse Arch would help in decreasing pain and avoid further deformity.

【Ethical consideration】

This experiment was in accordance with the Declaration of Helsinki and approved by the Ethical Committee for Human Experiments of Kyoto University (Kyoto, Japan) (approval number R0450-1), and written consents were obtained from all participants.