ABSTRACT
Objective According to clinical demand of quantification evaluation on flat foot and high arch, an intelligent and rapid method to diagnose arch shape based on principal component analysis (PCA) of plantar pressure is proposed, and its clinic validity is tested. Methods Volunteers diagnozed as abnormal arch and healthy arch were included in this study, and a portable intelligent arch test system was designed and developed. By adopting thin-firm piezoresistive sensor array with 44 rows, 52 columns of sensing units, the system could collect plantar pressure distribution data from the subjects under static standing. Foot axis could be fitted automatically by using the self-programmed PCA, so that foot diagnosis was completed with diagnostic report. The plantar pressure results from the system were compared with those from the existing plantar pressure acquisition device, so as to verify precision of collected data. The accuracy of the diagnosis algorithm for flat foot, high arch and healthy foot was verified through comparison with clinical diagnosis. Results The result of the system had a good correlation with that of the existing plantar pressure acquisition device, the deviation of contact area acquired by the system was smaller than 3.2%, and the angle deviation of the fitted foot axis with clinically defined angel was less than 1°. The system was capable of making diagnosis on arch shape that was 92.6% consistent with the clinical diagnosis. Conclusions PCA is introduced to automatically fit foot axis to achieve the purpose of fast and accurate extraction of foot arch information. The method can be used to assist clinical diagnosis of flat foot and high arch foot, and contribute to quantative analysis on foot arch deformity and its pathogenesis study.
ABSTRACT
Objective To design a kind of customized insole with zonal gradient hardness for people with high arch foot in need of plantar decompression. Methods A functional gradient structure was designed and applied to the customized insole. Porous elements with corresponding elastic modulus were used in different areas of insole. The relationship between structural element parameters and modulus was studied through mechanical tests. The foot geometry and plantar pressure distribution data of volunteers were collected, and the plantar region was divided according to the pressure contour line, so as to assemble the structural unit. Four kinds of customized insoles were designed: ordinary flat insole, optimized flat insole, ordinary full contact insole and optimized full contact insole. Through plantar pressure test experiment, the optimization design of sub region was verified. Results The designed insole could reduce the peak pressure of high arch foot by 52.8% in static standing state and 18.43% in gait condition. Conclusions This method can be used to design customized insoles, such as functional insoles for patients with diabetes and high arch feet, by providing better decompression function. The research findings provide references for conservative treatment of foot diseases with decompression needs.
ABSTRACT
Background: A flexible flatfoot is considered to be a variation of a normal foot. Any deviation from the anatomical plantigrade foot is a deformed foot. Some of the deformities of the foot are: Flat Foot. The normal concavity due to the medial longitudinal arch is absent. High Arch Foot - A normal foot has a medial longitudinal arch which is higher. Materials and Methods: A total population of 625, in age ranging from 5 year to 9 years in Kanchipuram district was chosen. Each individual was made to sit and the foot was brought in contact with the Foot Impression gaining Kit on white sheets in standing posture. Results: The flat feet and high arch feet evaluation was obtained by means of foot prints and the plantar arch index was established. The mean values of plantar arch index within the age group were stable and ranges from 0.72 to 0.73. With plantar arch indices greater than 1.15 was regarded as flatfeet and less than 0.10 was regarded as High arch feet. Discussion: In normal feet with presence of an arch, the stress will be distributed in an even manner so that the person will not experience any kind of pain. Under an abnormal condition that occurs due to lack of stretching of muscles, bones and tendons, there will be absence of arch among these people. In this condition, all the weight will be concentrated in smaller area on the feet and generates a lot more pain than normal. This condition might occur in both children and adults. In some people both feet will be flat and in some only one foot will be flat. Conclusion: Flat foot is highly prevalent in the ages between 5-9. The average values for plantar arch indices are stable and ranges from 0.72 to 0.73 in our sample regarded as Normal foot. Plantar arch index > 1.15 is regarded as Flat foot. Plantar arch index < 0.10 is regarded as High arch foot.