Analysis of the Biomechanical Impact of Lower Limb Length Inequality in PEDiatrics (ABILMI-PED)

Biomechanical Analysis of the Impact of Lower Limb Length Discrepancy on Hip and Lumbar Spine Joints in Children

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.

Study Overview

• Status: Recruiting
• Conditions: Lower Limb Length Discrepancy (LLD) in Children
• Intervention / Treatment: Radiation: EOS Imaging System; Device: Force Platform (Bertec®, integrated into EOS cabin)

Detailed Description

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.

A temporary orthopedic compensation (shoe lift) will also be tested to assess its immediate biomechanical effect. Participants will be evaluated at baseline (two EOS acquisitions: with and without compensation) and at 2 years (without compensation).

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.

• Study Type: Observational
• Enrollment (Estimated): 100

Contacts and Locations

• Study Contact: Name: Thierry HAUMONT, MD, PhD; Phone Number: +33 4 27 85 57 88; Email: thierry.haumont@chu-lyon.fr
• Study Contact Backup: Name: Dimitri HERRERA-NATIVI; Email: dimitri.herrera-nativi01@chu-lyon.fr

Study Locations

• France
  • Bron, France, 69500
    • Recruiting
    • Hospices Civils de Lyon Service d'Orthopédie et de Traumatologie
    • Contact: Thierry HAUMONT, Pr; Phone Number: +33 04.27.85.57.88; Email: thierry.haumont@chu-lyon.fr
    • Principal Investigator: Thierry HAUMONT, Pr

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population will consist of approximately 100 pediatric patients (aged 10 to 15 years) presenting with an anatomical lower limb length discrepancy (LLD) greater than 5 mm, confirmed by clinical evaluation. Participants will be recruited consecutively during routine outpatient visits at the Pediatric Orthopedics Department of Hôpital Femme-Mère-Enfant (HFME), Hospices Civils de Lyon, Bron, France. This hospital is a tertiary referral center in pediatric orthopedics, receiving children from the Rhône-Alpes region and beyond.

All included patients will undergo EOS imaging as part of their standard clinical assessment for LLD, ensuring that the study is fully integrated within the regular care pathway. The cohort therefore represents a specialized clinical sample of children with LLD, rather than a general population or community-based sample.

Description

Inclusion Criteria:

• Children aged 10-15 years
• Anatomical LLD > 5 mm, clinically measured
• EOS imaging indicated by the pediatric orthopedic surgeon in routine care
• Ability to stand still for 30 seconds without assistance
• Covered by social security
• Parental consent and non-opposition obtained

Exclusion Criteria:

• - Functional or postural LLD without true anatomical discrepancy
• History of major pelvic or spinal surgery
• Severe neurological or orthopedic condition preventing standing (e.g. cerebral palsy, progressive myopathy)
• Fixed equinus deformity preventing plantar support
• Major lower limb deformity (severe genu varum/valgum)
• Contraindication or inability to undergo EOS imaging

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort

Intervention / Treatment

Children with lower limb length discrepancy (LLD); Pediatric patients aged 10-15 years with an anatomical LLD > 5 mm, evaluated in the routine pediatric orthopedic care pathway.

Radiation: 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.; Device: 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.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Asymmetry of Hip Joint Contact Forces (%) in Static Standing	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.	At baseline (Day 0, without compensation)

Collaborators and Investigators

• Sponsor: Hospices Civils de Lyon
• Investigators: Principal Investigator: Thierry HAUMONT, MD, Hospices Civils de Lyon

Study record dates

Study Major Dates

• Study Start (Actual): April 7, 2026
• Primary Completion (Estimated): June 7, 2029
• Study Completion (Estimated): June 7, 2029

Study Registration Dates

• First Submitted: November 19, 2025
• First Submitted That Met QC Criteria: November 19, 2025
• First Posted (Actual): November 28, 2025

Study Record Updates

• Last Update Posted (Actual): April 17, 2026
• Last Update Submitted That Met QC Criteria: April 14, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Biomechanics; Force platform; Pediatric orthopedics; limb length; EOS imaging; Lower limb length discrepancy (LLD)
• Additional Relevant MeSH Terms: Bone Diseases; Musculoskeletal Diseases; Pathological Conditions, Anatomical; Bone Diseases, Developmental; Pathological Conditions, Signs and Symptoms; Leg Length Inequality
• Other Study ID Numbers: 69HCL25_0746; 2025-A01923-46 (Other Identifier: ID-RCB)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No