'Travels' impairments predict gross motor function and participation of school-aged children with achondroplasia

Abstract

Background and Objective(s): Achondroplasia is the most common form of short-limbed dwarfism. Children with achondroplasia experience significant gross motor delays, proposed to be related to several lower limb impairments, summarized by the acronym 'TRAVELS': (1) Trident pelvis, (2) Rhizomelic shortening of femur, (3) Acetabular angle reduction, (4) Varus knee, (5) Expanded metaphysis, (6) Long fibula and (7) Short toes. Although previous literature has referred to the potential impact of some TRAVELS impairments on gross motor function, no research has formally evaluated the relationship between these factors. The aim of this study was to determine whether shorter lower limb lengths (TRAVELS impairments) are related to gross motor limitations or participation restrictions in children with achondroplasia. Study Design: Population-based, cross-sectional cohort. Study Participants & Setting: All Queensland children with achondroplasia aged 4-12 years were invited to participate (n=16) and 87.5% were recruited (n=14, 10 male, mean=6y 9mo, SD=2y 7mo). Data was collected at the Children's Health Queensland Hospital and Health Service. Materials/Methods: Children were assessed for four clinical TRAVELS impairments (1. thigh length, 2. foot length, 3. toe lengths and iv. tibia-fibula length ratio); gross motor ability (Timed Up and Go (TUG), Timed Up and Down Stairs (TUDS), Forward Reach Test (FRT)); and participation (Functional Independence Measure for Children (WeeFIMII ™)). Statistical analysis included Pearson's correlations to examine whether associations were present between anthropometric measurements and motor function and participation. In addition, linear regressions were conducted for the four dependent variables of FRT, TUG, TUDS and WeeFIM-II™ to examine (1) the contribution of each anthropometric measurement, and (2) the interrelationships between FRT, TUG, TUDS and WeeFIM-II™. Results: All children (100%) demonstrated TRAVELS impairments, motor limitations and participation restrictions. Severity of limb shortening was moderately to strongly associated with severity of motor limitations on the TUG (all r>0.65, p<0.05) and TUDS (all r> -0.56, p<0.05) and participation restrictions on the WeeFIM-II™ Mobility Subscale (all r>0.68, p<0.01). Shorter foot and second and third toe lengths were associated with shorter FRT distance (all r>0.57, p<0.05). There were no relationships with fibula-tibia length ratio. Greater participation restrictions (WeeFIM-II™ Functional Mobility) were associated with greater motor impairments on all measures (TUG, TUDS and FRT; all r>±0.70, p<0.01). Conclusions/Significance: Shorter lower limb lengths (TRAVELS impairments) predicted greater motor limitations and greater participation restrictions in this population-based sample of children with achondroplasia. Clinicians may use this prognostic information to identify children who may require closer surveillance or intervention.L618469766 <br />