Previous
orthopaedic research has indicated a greater prevalence of lower extremity
malalignment in obese children during static posture. The purpose of this study
is to determine if obese children demonstrate similar dynamic joint
malalignment during gait. METHODS: Forty children were classified as obese
(age: 10.8±1.4
y; BMI: 24.3±2.7) or non-obese (age: 10.4±1.6
y; BMI: 17.2±1.4). 3-dimensional
motion analysis was conducted for five successful trials of barefoot walking at
a self-selected pace. Group differences in peak joint displacement and amount
of joint motion throughout the gait cycle (calculated as the integrated
displacement curve) were analysed using ANOVAs. RESULTS: Non-obese children had
greater peak knee (p=0.013) and hip extension (p=0.023) during gait; however,
there were no group differences in amount of sagittal plane motion at any
joint. Obese children had greater peak hip adduction (p=0.001), and also spent
more time in hip adduction (p=0.003) than non-obese children. Obese children
had greater peak externally rotated toe progression (p=0.004), and spent more
time in this toe-out position (p=0.012). Obese children had greater peak hip
internal rotation (p=0.002), and spent more time in hip internal rotation
(p=0.004). CONCLUSIONS: Non-obese children showed greater mobility in the
sagittal plane, particularly at the hip and knee. Frontal and transverse plane
differences suggest that obese children function in a more genu valgum position
than non-obese children. Static measures of genu valgum have been previously
associated with pediatric obesity; the findings of this study indicate that
there are also dynamic implications of such lower extremity malalignment in
obese children. Genu valgum presents a greater risk of osteoarthritis for obese
children and should be considered when prescribing weight bearing exercise to
this cohort.