[FG] Viehweger Heide Elke

Charcot-Marie-Tooth disease (CMT) stands as one of the most prevalent hereditary neurological disorders, also recognized as hereditary motor and sensory neuropathy (HMSN) [1]. It ranks as the most common inherited neuropathy. CMT displays genetic diversity, involving over 80 mutated genes with varying inheritance patterns [2]. 

The majority of CMT cases fall into the CMT1 group, characterized by a demyelinating pattern of nerve damage. Within this group, CMT1A comprises 70% of all CMT patients and is linked with a defect on chromosome 17 that affects the peripheral myelin protein. Conversely, CMT2 cases exhibit an axonal pattern of nerve damage [3]. 

Individuals with CMT typically experience progressive muscle atrophy and weakness, leading to foot deformities and less frequently, hand deformities. The progression of deformities varies based on genetic and phenotypic factors. The disease often manifests as a multiplanar foot deformity, with cavovarus being the most observed. This deformity entails hindfoot varus, a high arch (cavus), downward flexion of the first metatarsal, a forefoot that's pulled inward (adducted), and claw toes. It arises from an imbalance in muscle strength, where the peroneus longus muscle may be relatively strong compared to a weakened anterior tibial muscle, or where the posterior tibial muscle is strong while the peroneus brevis muscle is weak [4, 5]. 

Patients with cavovarus deformity experience varying degrees of sensory loss, muscle weakness, painful foot calluses, abnormal gait, and ankle instability [3-6]. Despite ongoing research, the full understanding of these deformities remains elusive, leading to a variety of treatment recommendations. Therefore, the aim of this project is, to investigate and characterize functional gait parameters in CMT patients to improve therapeutic management. 

To develop a sufficient therapeutic program (such as foot surgery and orthotics management), biomechanical knowledge on 1) the deviations from healthy function and 2) how the foot deformities influence dynamic function, are necessary.

1. Lisak RP., D.D.T., WILLIAM M. CARROLL, ROONGROJ BHIDAYASIRI, International Neurology – A Clinical Approach, ed. D.D.T. Lisak RP., WILLIAM M. CARROLL, ROONGROJ BHIDAYASIRI. 2009: Blackwell Publishing Ltd. 

2. Timmerman, V., A.V. Strickland, and S. Zuchner, Genetics of Charcot-Marie-Tooth (CMT) Disease within the Frame of the Human Genome Project Success. Genes (Basel), 2014. 5(1): p. 13-32. 

3. Newman, C.J., et al., The characteristics of gait in Charcot-Marie-Tooth disease types I and II. Gait Posture, 2007. 26(1): p. 120-7. 

4. Mann, R.A. and J. Missirian, Pathophysiology of Charcot-Marie-Tooth disease. Clin Orthop Relat Res, 1988(234): p. 221-8. 

5. Beals, T.C. and F. Nickisch, Charcot-Marie-Tooth disease and the cavovarus foot. Foot Ankle Clin, 2008. 13(2): p. 259-74, vi-vii. 

BASEC-ID: 2024-00652

Cerebral palsy is the first cause of disability with a prevalence of about 2.5 in 1000 children born in developed countries, that is about 250 children every year in Switzerland. The primary cause of cerebral palsy is a brain lesion occurring shortly before or after birth. The brain lesion is static and does not progress with time but secondary consequences, such as joint contractures and bony deformities develop during childhood and adolescence. A variety of surgical interventions and orthotics prescriptions may be performed to improve the biomechanical capacity of the musculoskeletal system once the deformities have developed.

However, ethical and practical difficulties to organise randomised controlled trials within the field of surgery have led to low or moderate level of evidence to support the interventions. In addition, different patients may respond markedly differently to the same treatment. In this context, the principles of evidence-based medicine are difficult to apply by clinicians when choosing the most appropriate treatment for a given child, or when discussing their rationale with the families.

Since the 90s, instrumented gait analysis has been utilised to inform the clinical decision-making process, plan the details of surgical interventions when these are deemed necessary, and evaluate the outcome of these interventions. Instrumented gait analysis provides quantitative and objective measures of the walking function. It generates a rich dataset composed of more than 50 scalar values describing the lower limb anatomy and functioning as well as more than 80 waveforms describing the walking pattern of the patients.

In this project, routine clinical data collected in two leading gait analysis centres at the UKBB (Basel) and at the HUG (Geneva) will be connected to the SPHN infrastructure. The objectives of the project are to ensure the SPHN | Swiss Personalized Health Network 2 | 4 interoperability of gait analysis data collected in different clinical centres in Switzerland and internationally, to determine the causal treatment effect of some of the most common orthopaedic treatments to improve walking in children with cerebral palsy, and to quantify the added value of multicentric observational datasets.

This project aims to lay the foundation for national, and international, gait analysis data interoperability as well as support evidence-based clinical decision-making in the field of neuro-orthopaedics for children with cerebral palsy. 

Cerebral palsy (CP) is a term addressing a group of disorders mostly affecting muscle tone, movement, and motor skills. It is caused by damage in the developing fetal or the child’s immature brain and leads to non-progressive spasticity, ataxia, or involuntary movements. CP is the most common pediatric disease and the leading cause of disability in children. The type of CP originates from the areas of the brain affected by the lesion.

Besides neurologic, gastrointestinal, respiratory, sleeping disorders, bone disease, oral health problems, impaired vision, hearing loss, genitourinary problems, drooling, or pain, orthopedic disorders are frequent complications associated with CP.

Regarding orthopaedic hip disorders in children with CP, hip subluxation is frequently seen, followed by hip luxation. The spasticity and muscle imbalance lead to an inward rotation, adduction, and flexion of the hip as well as a posterior pelvic tilt in CP patients. Consequently, it results in a migration of the femoral head that can lead to a subluxation of the hip. The severity of the hip subluxation correlates with greater Gross Motor Function Classification System (GMFCS) levels. Spastic muscle imbalance and the lack of weight-bearing in higher GMFCS levels lead furthermore to progressive structural changes around the hip joint.

The planned study aims to address the importance of early intervention in the prevention of hip subluxation and dislocation in CP patients. The study is going to elaborate on the influence of psoas, adductor and hamstring tenotomies in the prevention of hip dislocation and as a medium-term outcome. Following the surgery, the CP patients will be under hip surveillance with clinical examinations and AP pelvis radiographs according to the care pathways recommended by the American Academy for Cerebral Palsy. The Reimers Index, popliteal angle, hip extension as well as abduction will be monitored and evaluated. It intends to outline the factors influencing treatment outcomes, and it is warranted to refine the treatment protocols. Moreover, it is aimed to improve the support of well-located, pain-free hips, the prevention of hip dislocation and eventual bone operation and thus enhance the quality of life in children with CP. 

BASEC-ID: 2023-02374