1.The Effects of Different Degrees of Leg Length Discrepancy on Vertical Ground Reaction Force in Children and Adults: Treatment Implications
Mohamed-Saaid F ; Sulaiman AR ; Munajat I ; Mohd EF ; Arifin WN ; Ghafar R
Malaysian Orthopaedic Journal 2023;17(No.3):66-72
Introduction: Previous studies on the degree of leg length
discrepancy that causes limb biomechanical problems did
not differentiate between adults and children. We conducted
this study to determine the effects of simulated leg length
discrepancy on vertical ground reaction force in children and
adults to enable decision-making for intervention in patients
with leg length discrepancy for different age groups or
heights.
Materials and methods: This cross-sectional study
involved male volunteers of children 150cm and adults with
170cm in height. Vertical ground reaction force was
measured using a gait analysis study. The first measurement
was taken without any leg length discrepancy as a baseline.
Subsequently, different amounts of leg length discrepancy
were simulated on the left leg with shoe lifts of 2, 3, and
4cm. The measurements were repeated on each volunteer
with similar shoe lifts on the right leg. Therefore, 14
volunteers provided simulations of 28 leg length
discrepancies for each group. The first and second peaks of
vertical ground reaction force were separately analysed. The
vertical GRF of a simulated leg length discrepancy was
compared with the baseline. Repeated measurement of
analysis of variance (ANOVA) within each group was done.
Results: In both groups, the second peak of vertical ground
reaction force in the longer leg reduced gradually as the shoe
lift increased sequentially from 2 to 3cm and then to 4cm. A
discrepancy of 3cm and above was statistically significant to
cause a reduction in the vertical GRF on the longer limb in
both height groups.
Conclusion: The degree of leg length discrepancy that
caused significant changes in second peak ground reaction
force in children with 150 and adults with 170cm height
population was similar at 3cm. Therefore, the cut-off point
for intervention for both groups are similar with additional
consideration of future growth in children.