Absorbent paper method for recording children foot progression angle
Because of its relation to the transverse plane rotation, the foot progression angle (FPA) remain an important gait parameter for the clinicians. FPA can be measured with electronic plantar pressure platform, but this mean requires an expensive equipment. The purpose of this study was to develop an inexpensive and easy-to-use technique to measure FPA in a daily orthopedic clinic, and examine its days-to-days reliability. Foot prints from children with “in-toeing” gait were collected with a standardized technique using water, an absorbent paper and a goniometer. Two trials per subject were analyzed in a period of two weeks. The relative reliability of the method was assessed with repeated measures one-way analysis of variance and calculation of intraclass correlation coefficient (ICC). Absolute disparity was determined by mean coefficient of variation (CV), limits of agreement (LOA) and standard error of measurement (SEM). Gait parameters have been collected from both sides from 13 patients. Statistical analyses revealed that ICC was excellent (0,83), CV was acceptable (23%), as well as SEM (2,32) and LOA [-3,63; 1,36] using this method. Used by the same observer, our method to measure FPA seems to be reliable and easy to implement in an outpatient department. A simpler technique to measure FPA, using absorbent paper, has already been published but their statistical method to confirm reliability and reproducibility remain incomplete. Our study is the first to validate the reproducibility of a simple and accessible method.
Steps to reproduce
1.1 Participants Thirteen in-toeing gait children (11 girls and 2 boys) with a mean age of 6 (ranging from 3 to 11 years) have been recruited based on idiopathic in-toeing gait and benefited from a complete clinical examination. Participants were excluded if they had previous surgery to the lower extremity, any neuromuscular or musculoskeletal disorder that directly affected gait. 1.2 Measurements of foot progression angle We performed a footprint recording during gait. Two measurements were made by the same examiner using described standardized techniques, with an intervening period of one week (Day 1 and Day 2 measurements). Thus, two trials per subjects were analyzed: Trial 1 and Trial 2. A 5m long and 1m wide walkway was created using Kraft® paper. Walkway was divided in 2 corridors (0.5m wide). Water was applied to the sole of both feet using a container disposed at the beginning of the walkway, and a wet carpet at the other side. Several walks were made with dry foot until the child became less self-conscious. The subjects were instructed to walk naturally down the walkway without looking his feet. The third footprint and the consecutive footprints were then evaluated. Only perfects representative sets of footprint were recorded. FPA was measured using a goniometer (graduated every 2°), a ruler and marker pens (3 different colors). FPA was obtained by drawing a line from the center of the heel to the center of the first inter metatarsal region, and then measuring the angle between this and the line of progression along the walkway. Negative values represent internal rotation of the lower limb during gait (in-toeing gait). Kraft® paper was marked by long parallel lines every millimeter which represented the line of progression. Subjects were asked to do 3 goings and comings (footprint was recorded with a different color of marker pen for each round). They had to soak their feet between each round. Thus, for one trial, we obtained about 20 footprints (10 rights and 10 lefts). The mean FPA of both right and left foot was calculated and compared to the mean FPA of the second trial 7 days later. The second trial was a blind test in comparison with the first trial. All statistical analysis was performed using the R software (version 3.4.0), results were considered significant with a p < 0,05.