Eureka! A reliable, home-made water volumetry device

Abstract

Background Water displacement is considered to be the gold standard for measuring foot volume; however, it is time-consuming and infrequently used in clinical practice. The objectives of this study were to determine whether a home-made water displacement device is a reliable and time-efficient method for determining foot volume. Methods Thirty participants with no foot pathologies were enrolled and had their foot volume measured in two home-made water volumetry devices (Preski and PreskiLite). The participants' foot volumes were measured on two occasions on each of two different days. Results All measurements were achieved in less than 90 seconds. Within-day reliability was high (intraclass correlation [ICC]=0.997–0.999) with the minimal detectable change (MDC) at the 90% confidence level (MDC90) of less than 25 ml for both devices. Mean differences in volume displaced between days were small (range 0.6– -5.4 mls). For between-day measures on the same leg, the mean coefficient of variation ranged from 0.65–1 with associated ICCs of 0.989–0.997. The MDC90 for between-day measures was 46 ml for the PreskiLite and 23 ml for the Preski. The difference in volume displaced between right and left legs was less than the MDC90 for both devices. Conclusions A novel, home-made water volumetry device provides reliable measures of foot volume both within and between days. Measurements taken on the contralateral leg provide an adequate control. These portable devices provide rapid measurements and only one measurement is needed per day.