Chippaux-Smirak Index Research Articles

Does obesity influence foot structure in prepubescent children?

This study examines the relationship between obesity and foot structure in prepubescent children. Field-based, experimental data on BMI (body mass index) and foot structure were collected for 431 consenting children from 18 randomly selected primary schools. Of the 431 participants, 62 obese (BMI>95th percentile) and 62 non-obese (10th percentile<BMI>90th percentile) children (age = 8.5+/-0.5 y) were selected. Height and weight were measured to calculate BMI. Static weight-bearing footprints for the right and left foot of each subject were then taken using a pedograph to calculate the Footprint Angle and the Chippaux-Smirak Index as representative measures of the surface area of the foot in contact with the ground. A significant difference was found between the Footprint Angle of the obese and non-obese subjects for both the left (t = 3.663; P<0.001) and right (t = 3.742; P<0.001) feet whereby obese subjects displayed a reduced angle. Chippaux-Smirak Index scores were also significantly different for both the left (t = -6.362; P<0.001) and right (t=-5.675; P<0.001) feet between the two subject groups where a greater score for the obese subjects was evident. A decreased footprint angle and an increased Chippaux-Smirak Index are characteristic of structural foot changes that have been associated with compromised foot function. Excess body mass appears to have a significant effect on the foot structure of prepubescent children whereby young obese children display structural foot characteristics which may develop into problematic symptoms if excessive weight gain continues. Further investigation into possible consequences, particularly any effects on foot function, is warranted.

Comparison of footprint parameters calculated from static and dynamic footprints

In attempting to establish relationships between ‘foot-type’ and pathology, many researchers have chosen to use parameters calculated from static footprints to define study groups. In this study the ability of such static information to reflect the dynamic foot was investigated by comparing values for three parameters (Stahelis Arch Index, Chippaux-Smirak Index, Footprint Angle) calculated from static and dynamic prints. Three static and three dynamic footprints were obtained for 20 subjects. Reliability of the electronic data collection technique ( P<0.001) was good for all three parameters, while linear parameters displayed greater between-print reliability ( P<0.001) than the angular. Parameters calculated from dynamic prints were found to differ significantly ( P<0.05) from those calculated from static prints, although good correlation’s between the two states ( P<0.001) indicate a general dynamic increase of 28%. Further, the Stahelis arch and Chippaux-Smirak indices, both claiming to measure the same condition, correlated very well with each other ( P<0.001). Continued investigation of footprint parameters appears warranted.

Ultrasonic cleaning equipment

An ink pad and paper, pressure-sensitive platforms, and photography have previously been used to collect footprint data used in clinical assessment. Digital scanners have been widely used more recently to collect such data. The purpose of this study was to evaluate the intra- and interrater reliability of a flatbed digital image scanning technology to capture footprint data.This study used a repeated-measures design on 32 (16 male 16 female) healthy subjects. The following measured indices of footprint were recorded from 2-dimensional images of the plantar surface of the foot recorded with an Associate Platinum (Foot Levelers Inc, Roanoke, VA) digital foot scanner: Staheli index, Chippaux-Smirak index, arch angle, and arch index. Intraclass correlation coefficient (ICC) values were calculated to evaluate intrarater, interday, and interclinician reliability.The ICC values for intrarater reliability were greater than or equal to .817, indicating an excellent level of reproducibility in assessing the collected images. Analyses of variance revealed that there were no significant differences between raters for each index (P > .05). The ICC values also indicated excellent reliability (.881-.971) between days and clinicians in all but one of the indices of footprint, arch angle (.689), with good reliability between clinicians. The full-factorial analysis of variance model did not reveal any interaction effects (P > .05), which indicated that indices of footprint were not changing across days and clinicians.Scanning technology used in this study demonstrated good intra- and interrater reliability measurements of footprint indices, as demonstrated by high ICC values.