T.T.T. Yam1, S.S.M. Fong2, W.W.N. Tsang1
1The Open University of Hong Kong, Department of Physiotherapy, School of Nursing and Health Studies, Hong Kong, Hong Kong, 2University of Hong Kong, School of Public Health, Hong Kong, Hong Kong
Background: The medial longitudinal arch (MLA) is usually developed to adult-like structure at the age of 4-5 in typically developing children. Pes planus (flatfoot) is a medical condition where the MLA comes into complete or near complete contact with the ground. This is especially common in school-aged children with a prevalence rate of up to 59%. This may progress to symptomatic pes planus which affects greatly in daily activities. Developmental coordination disorder (DCD) is a neurodevelopmental condition that exhibit motor deficits which greatly affects normal activities. With a greater chance of being overweight/obese in children with DCD, it is questionable if there are any associations between excessive body weight and pes planus.
Purpose: This study compared the foot posture and body composition measures of children with and without DCD.
Methods: This was a cross-sectional study which recruited one hundred and nineteen children. Screening was performed by a physiotherapist where fifty-nine were categorized to the DCD group (mean age ± standard deviation = 8.07 ± 1.10 years; 45 males and 14 females) and sixty-two to the typically developing (TD) group (mean age ± standard deviation = 7.97 ± 1.05; 39 males and 21 females). Participants were instructed to wear loose clothing without metal parts. Each underwent a full-body dual-energy X-ray absorptiometry (DXA) scan. Subsequently, each participant, standing upright in barefoot, was assessed by a physiotherapist using the foot posture index (FPI-6). The primary outcomes included FPI-6 scores and DXA-derived body composition measures of the lower limbs.
Results: It revealed a significantly higher FPI-6 total score in the DCD group (Left total score: p = 0.021; Right total score: p = 0.016) when compared to the TD group. The FPI-6 sub-scores for both sides were significantly higher in the DCD group with measures including i) talar head palpation (Left: p = 0.044; Right: p = 0.040); and ii) abduction/adduction of forefoot on rearfoot (Left: p = 0.018; Right: p = 0.010). For the DXA-derived outcomes, the DCD group had a significantly higher total fat mass and total fat percent (p = 0.030 and p = 0.037, respectively). Linear regression showed that total fat percent (t = -2.213, p = 0.031) was a significant predictor of FPI-6 right total score and accounted for 7.9% of the variance (adjusted 6.3%).
Conclusion(s): Children with DCD were relatively more like to exhibit pes planus compared to TD children. They also illustrated a significantly higher total fat mass and total fat percent. Further analysis showed pes planus was partially explained by total fat percent.
Implications: This study provides a glimpse of how body composition measures could possibly influence the foot posture of children with DCD. This may foreshadow an increased emphasis on interventions that are targeted to reduce body weight and body fat.
Funding, acknowledgements: No funding was provided for this study.
Keywords: Developmental coordination disorder, Pes Planus, Dual-Energy X-ray Absorptiometry
Topic: Paediatrics
Did this work require ethics approval? Yes
Institution: The University of Hong Kong
Committee: Human Research Ethics Committee
Ethics number: EA1512037
All authors, affiliations and abstracts have been published as submitted.
