Elsevier

Clinical Biomechanics

Volume 27, Issue 7, August 2012, Pages 744-747
Clinical Biomechanics

Brief report
Symmetry of foot alignment and ankle flexibility in paediatric Charcot–Marie–Tooth disease

https://doi.org/10.1016/j.clinbiomech.2012.02.006Get rights and content

Abstract

Background

Charcot–Marie–Tooth disease is the most common inherited nerve disorder and typically presents with pes cavus foot deformity and ankle equinus during childhood. Level in the variation of symmetry of musculoskeletal lower limb involvement across the clinical population is unknown, despite early reports describing gross asymmetry.

Methods

We measured foot alignment and ankle flexibility of the left and right limbs using accurate and reliable standardised paediatric outcome measures in 172 patients aged 3–20 years with a variety of disease subtypes recruited from the United States, United Kingdom, Italy and Australia.

Findings

While a large range of differences existed between left and right feet for a small proportion of children, there was no overall significant difference between limbs.

Interpretation

There are two important implications of these findings. Children with Charcot–Marie–Tooth disease generally exhibit symmetrical foot alignment and ankle flexibility between limbs. As such, analysing one limb only for biomechanical-related research is appropriate and satisfies the independence requirements for statistical analysis. However, because there are large differences between feet for a small proportion of children, an individualised limb-focused approach to clinical care is required.

Introduction

Charcot–Marie–Tooth disease (CMT), a group of genetically-based nerve disorders, affects ~ 1 in 2500 people and is among the most common inherited neurological disorders (Skre, 1974). It is characterised by demyelination and/or axonal loss of the peripheral nerves. As a result there is progressive weakness of the distal, and to a lesser extent proximal, limb musculature, hand, foot and ankle deformities, impairment of motor function, and sensory loss.

During childhood, CMT usually presents with lower limb muscle imbalance and ankle contracture associated with a painful cavus (high-arched) foot deformity which becomes increasingly severe and rigid as the disease progresses (Burns et al., 2005). Foot alignment and ankle flexibility are thought to be generally symmetrical; however, cases of asymmetry are reported and are considered more severe. Indeed the original description by Charcot and Marie in 1886 shows gross foot and ankle asymmetry (Fig. 1) (Charcot and Marie, 1886). Retrospective chart reviews have previously identified a small proportion of children (4 of 52) with one cavovarus and one planovalgus foot (Wines et al., 2005), and a small proportion of adults (5 of 61) with pes cavus and ankle contracture asymmetry (Bienfait et al., 2006). However, these studies are limited by their retrospective design and unclear methods of foot and ankle assessment.

The aim of this study was to prospectively evaluate the frequency and extent of symmetrical foot and ankle involvement between limbs of children with CMT using reliable and validated outcome measures.

Section snippets

Methods

This study was conducted as part of the Inherited Neuropathies Consortium and included leading paediatric tertiary healthcare institutions of Detroit, London, Milan, Philadelphia, Rochester and Sydney. Ethics approval from all institutions for all studies, and written informed assent/consent from all children and their families were obtained.

Objective measurements of left and right foot alignment and ankle flexibility were obtained from all children using highly reliable and validated

Results

During a 14-month prospective period, 172 patients aged 3–20 years were recruited. Patient profile was: 90 female (52%); mean age, 10.8 years (SD 4.2); mean height, 1.44 m (SD 0.22); mean weight, 42.5 kg (SD 18.9). The sample comprised a broad range of CMT subtypes. Lower limb symptoms reported by the children included foot pain in 66 (38%), leg cramps in 68 (40%), ankle instability during walking in 84 (49%), daily trips/falls in 82 (48%), and sensory symptoms in 54 (31%). Foot drop was evident in

Discussion

There are two important implications of these findings. Children with CMT generally exhibit symmetrical foot alignment and ankle flexibility between limbs. As such, analysing one limb only for biomechanical-related research (e.g. dominant foot, worst foot, or randomly selected foot) is appropriate and satisfies the independence requirements for statistical analysis (Menz, 2005). However, because there are large differences between feet for a small proportion of children, an individualised

Conclusion

Despite early classical reports showing gross foot and ankle asymmetry (Fig. 1), most children with CMT typically have symmetrical foot alignment and ankle flexibility, as shown in Fig. 3.

Conflict of interest statement and funding

The authors have no conflicts of interest to declare related to this study. This research was supported by grants from the NHMRC (National Health and Medical Research Council of Australia, #1007569), NIH (National Institutes of Neurological Disorders and Stroke and Office of Rare Diseases, #U54NS065712), Charcot Marie Tooth Association (CMTA), Muscular Dystrophy Association (MDA) and CMT Association of Australia (CMTAA).

Acknowledgments

We are grateful for the assistance of site co-investigators: Allan Glanzman, PT (Children's Hospital of Philadelphia, PA, USA), Polly Swingle, PT; Agnes Patzko, MD; Sindhu Ramchandren, MD (Wayne State University Detroit, MI, USA), Isabella Moroni, MD; Emanuela Pagliano, MD (IRCCS Foundation Carlo Besta Neurological Institute, Milan, Italy); Andy Hiscock, PT (UCL Institute of Child Health and Great Ormond Street Hospital, London, UK), Monique Ryan, MD; Eppie Yiu, MD (Royal Children's Hospital,

References (16)

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