IS UPPER LIMB MOTION INFLUENCED BY A STRUCTURAL LEG LENGTH DISCREPANCY IN ADOLESCENTS DURING GAIT?

Schmid S.¹, Angelico F.², Freslier M.³, Brunner R.^3,4, Romkes J.³

¹Bern University of Applied Sciences, Health Division, Bern, Switzerland, ²Zurich University of Applied Sciences, School of Health Professions, Winterthur, Switzerland, ³University of Basel Children's Hospital, Laboratory for Movement Analysis, Basel, Switzerland, ⁴University of Basel Children's Hospital, Orthopaedic Department, Basel, Switzerland

Background: Structural leg length discrepancy (LLD) is a relatively common problem found in 40-70% of the population. Complications of distinct LLDs (>30 mm) include functional limitations such as gait and balance problems and associated musculoskeletal disorders such as low back pain or stress fractures. Depending on the extent of an LLD, several compensatory mechanisms in the lower extremities and the trunk take place in order to maintain function and to optimize energy consumption during gait. However, studies describing the influence of a structural LLD on upper limb motion are lacking.

Purpose: To evaluate upper limb motion in LLD patients compared to healthy controls during gait.

Methods: Motion capture data from 14 adolescent patients with structural LLD and 15 age-matched healthy controls that were collected during barefoot walking at a self-selected speed were retrospectively analyzed. In particular, gait speed and kinematic parameters of the shoulder (flexion/extension and abduction/adduction) and elbow joints (flexion/extension) as well as the trunk segment (anterior/posterior tilt, lateral-flexion and axial rotation) were investigated using effect sizes and analyses of variance with Tukey HSD post hoc tests. In order to detect the clinical relevance of a difference, the results were considered in relation to a minimal clinically important difference of 5°.

Results: Gait speed in LLD patients was found to be no different from healthy controls. The shoulders in LLD patients on both sides were kept in a more extended position throughout the gait cycle (>+7°, d>1.28, p 0.007) and at initial contact in a more adducted position compared to healthy controls (>+5°, d>0.92, p 0.040). In addition, the patients’ elbow joints showed increased flexion motion (>+18°, d>2.11, p 0.001) and the trunk segment indicated a constant trunk lateral-flexion and axial rotation tendency towards the affected side.

Conclusion(s): Adolescents with structural LLD indicated clinically relevant compensatory mechanisms in sagittal and frontal plane shoulder motion. These mechanisms were assumed to have occurred for balance recovery after “stepping down” on the shorter leg as well as to align the arm swing in walking direction. Since gait speed showed no differences, a possible speed-dependency of the observed kinematic group differences in the current study can be excluded.

Implications: These findings contribute to the understanding of compensatory strategies induced by a structural LLD and might be considered in the planning of physiotherapy treatments and preventive interventions.

Funding acknowledgements: None

Topic: Human movement analysis

Ethics approval: This study was approved by the “Ethikkommission Nordwest- und Zentralschweiz”.

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