Analysis of the Biomechanical Impact of Lower Limb Length Inequality in PEDiatrics

Condition(s) studied

Investigational drug(s) / intervention(s)

EOS Imaging System: Low-dose biplanar radiographs of the whole body in standing position (EOS Imaging System). At baseline, two EOS acquisitions will be performed in static standing position : one without compensation (natural position) and one with temporary orthopedic compensation (shoe lift under the shorter limb). At 24 months, one EOS acquisition will be performed without compensation. Each acquisition lasts a few seconds, with radiation exposure 5 to 10 times lower than conventional radiographs.

Force Platform (Bertec®, integrated into EOS cabin): Ground reaction force (GRF) measurements obtained from a force platform integrated in the EOS cabin. The platform records weight distribution and center of pressure during static standing posture. Measurements are fully synchronized with EOS acquisitions, without additional time or discomfort for participants. At baseline, GRF measurements will be collected in two conditions (with and without orthopedic compensation). At 24 months, GRF measurements will be collected in the non-compensated condition.

Study summary

Lower limb length discrepancy (LLD) is a frequent condition in pediatric orthopedics. Even moderate discrepancies can induce pelvic obliquity and compensatory scoliosis, modifying the distribution of joint loads at the hips and lumbar spine. These biomechanical imbalances are suspected to contribute to early degenerative conditions such as osteoarthritis or chronic low back pain.

The aim of this study is to quantify the biomechanical impact of LLD in children aged 10 to 15 years, using a combination of low dose biplanar EOS imaging (EOS Imaging System) and synchronized ground reaction force (GRF) measurements from integrated force platforms. These data will be used in musculoskeletal models developed in collaboration with the Biomechanics and Impact Mechanics Laboratory (LBMC, Laboratoire de Biomécanique et Mécanique des Chocs), enabling the estimation of hip joint and lumbar intervertebral disc loads.

This is the first pediatric study integrating EOS imaging, force platforms, and personalized musculoskeletal modeling to explore the mechanical consequences of LLD. The findings are expected to improve clinical reasoning and guide early therapeutic strategies.

Eligibility

Primary outcome measure(s)

• Asymmetry of Hip Joint Contact Forces (%) in Static Standing — At baseline (Day 0, without compensation)
  Hip joint contact force asymmetry index (%): calculated as AI (%) = 100 × (F\_long - F\_short) / \[(F\_long + F\_short)/2\], where F\_long and F\_short are side-specific resultant hip joint contact forces (estimated by musculoskeletal modeling from EOS imaging and ground reaction force data). Units: percent (%).Higher values indicate greater asymmetry.

Trial sites (1)

More Hospices Civils de Lyon trials in France