Lower extremity joint contracture according to ambulatory status in children with Duchenne muscular dystrophy

Perks of Rehabilitation in Improving Motor Function in a Nine-Year-Old Male With Duchenne Muscular Dystrophy: A Case Report

Duchenne muscular dystrophy (DMD) is a progressive disorder. It is the most typical X-linked muscular dystrophy in children. It primarily affects males and is characterized by motor delays, muscle weakness, respiratory impairment, and loss of ambulation. A case study of a nine-year-old male diagnosed with DMD is presented. The patient had difficulty walking since the age of four and had a proximal lower extremity weakness on both sides previously with a reduced range of motion (ROM). For the last 15 days, the patient is unable to walk and has hypotonia in both lower limbs. The diagnostic Gowers sign was positive. Balance and mobility were affected. Treatment of this patient is focused mostly on maintaining the range of motion (ROM), respiratory training, and balance.

Orthopedic Interventions for Foot Deformities in Non-Ambulant People with Duchenne Muscular Dystrophy: A Retrospective Study on Indications, Post-Operative and Long-Term Outcomes

Background: Progressive equinovarus deformities are common in people with Duchenne Muscular Dystrophy (DMD); they may provoke pain, pressure spots, cause problems with wearing footwear, and may lead to an unstable sitting position. Objective: Explore indications and compare complications and long-term outcomes after soft tissue and osseous interventions in people with DMD. Methods: Retrospective, monocenter, longitudinal study. Data on indications, equinus and varus deformity before and after surgery, wound healing problems, pain, edema, and long-term outcomes were collected from medical files. Soft tissue interventions were compared with osseous interventions. Results: From a series of 18 patients, data on 32 surgical interventions and 169 follow-up visits were analyzed. ‘Footrest placement’ was the most frequent surgical indication, followed by pain. Osseous interventions were performed in older patients with rigid deformities. Directly after surgery remaining deformities were reported after soft tissue interventions (18 %), no remaining deformities were reported after osseous interventions. Pain and edema were frequently present, especially after osseous surgery. Longitudinal follow-up showed that surgical interventions could lead to a neutral foot for a for more than 3 years on average years. Relapses of foot deformity occurred, especially the recurrence of varus deformity after osseous interventions. Conclusions: Surgical interventions can successfully lead to a neutral foot position for for more than 3 years on average. Soft tissue interventions appear to be superior to osseous corrections, considering the varus recurrence period and complications, and may be considered when feet are still (partly) correctable. Pain management and edema prevention should be anticipated before surgery. Future research on patient reported outcomes as well as evaluating the outcome of the initial indication is needed to further identify benefits.

Management of arthrofibrosis in neuromuscular disorders: a review

Arthrofibrosis, or rigid contracture of major articular joints, is a significant morbidity of many neurodegenerative disorders. The pathogenesis depends on the mechanism and severity of the precipitating neuromuscular disorder. Most neuromuscular disorders, whether spastic or hypotonic, culminate in decreased joint range of motion. Limited range of motion precipitates a cascade of pathophysiological changes in the muscle-tendon unit, the joint capsule, and the articular cartilage. Resulting joint contractures limit functional mobility, posing both physical and psychosocial burdens to patients, economic burdens on the healthcare system, and lost productivity to society. This article reviews the pathophysiology of arthrofibrosis in the setting of neuromuscular disorders. We describe current non-surgical and surgical interventions for treating arthrofibrosis of commonly affected joints. In addition, we preview several promising modalities under development to ameliorate arthrofibrosis non-surgically and discuss limitations in the field of arthrofibrosis secondary to neuromuscular disorders.

Pain characteristics among individuals with Duchenne muscular dystrophy according to their clinical stage

Background

Assessment of pain is not routine, standardized, or well-understood in individuals with Duchenne muscular dystrophy (DMD), even though pain is a common problem reported by more than half of the patients with DMD. Previous studies in this area included multiple neuromuscular diseases with highly variable phenotypes. Therefore, our aim was to specifically focus on DMD and evaluate the comprehensive pain characteristics according to the disease stages, from ambulatory to late non-ambulatory.

Methods

This cross-sectional study was conducted in an out-patient pediatric rehabilitation clinic including 148 male participants with confirmed DMD (14.5 ± 5.3 years of age). Face-to-face interviews were conducted using a structured questionnaire concerning the pain frequency, duration, intensity, location, aggravating/relieving factors, pain interference (Brief Pain Inventory), pain phenotype (PainDETECT Questionnaire), and functional ability (DMD Functional Ability Self-Assessment Tool). Pain characteristics were analyzed according to the clinical stage: ambulatory (Amb), early non-ambulatory (ENA), and late non-ambulatory (LNA).

Results

Of the 148 participants who completed the assessment, 66 (44.6%) reported pain during the previous 4 weeks. There were no differences in the pain duration or intensity among the three groups. Pain location (Amb: calf, ENA: knee, LNA: lumbosacral region), aggravating factor (Amb: ambulation, ENA: transfer, LNA: sitting), and relieving factor (Amb: rest and massage, ENA and LNA: positional change) differed according to the clinical stage. Individuals in the LNA stage reported an increase in the frequency of pain and number of pain sites. The effect of pain on mood was also found to be greater in the LNA group than in the other clinical stages.

Conclusion

There is a change in the pain characteristics, including the location, aggravating/relieving factors, pain frequency, and pain interference, with the progress of the disease in patients with DMD. Thus, clinicians could more efficiently and critically assess and manage the patients’ pain based on these findings.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05504-5.

Longitudinal Alterations in Gait Features in Growing Children With Duchenne Muscular Dystrophy

Prolonging ambulation is an important treatment goal in children with Duchenne muscular dystrophy (DMD). Three-dimensional gait analysis (3DGA) could provide sensitive parameters to study the efficacy of clinical trials aiming to preserve ambulation. However, quantitative descriptions of the natural history of gait features in DMD are first required. The overall goal was to provide a full delineation of the progressive gait pathology in children with DMD, covering the entire period of ambulation, by performing a so-called mixed cross-sectional longitudinal study. Firstly, to make our results comparable with previous literature, we aimed to cross-sectionally compare 31 predefined gait features between children with DMD and a typically developing (TD) database (1). Secondly, we aimed to explore the longitudinal changes in the 31 predefined gait features in growing boys with DMD using follow-up 3DGA sessions (2). 3DGA-sessions (n = 124) at self-selected speed were collected in 27 boys with DMD (baseline age: 4.6–15 years). They were repeatedly measured over a varying follow-up period (range: 6 months–5 years). The TD group consisted of 27 children (age: 5.4–15.6 years). Per measurement session, the spatiotemporal parameters, and the kinematic and kinetic waveforms were averaged over the selected gait cycles. From the averaged waveforms, discrete gait features (e.g., maxima and minima) were extracted. Mann-Whitney U tests were performed to cross-sectionally analyze the differences between DMD at baseline and TD (1). Linear mixed effect models were performed to assess the changes in gait features in the same group of children with DMD from both a longitudinal (i.e., increasing time) as well as a cross-sectional perspective (i.e., increasing baseline age) (2). At baseline, the boys with DMD differed from the TD children in 17 gait features. Additionally, 21 gait features evolved longitudinally when following-up the same boys with DMD and 25 gait features presented a significant cross-sectional baseline age-effect. The current study quantitatively described the longitudinal alterations in gait features in boys with DMD, thereby providing detailed insight into how DMD gait deteriorates. Additionally, our results highlight that gait features extracted from 3DGA are promising outcome measures for future clinical trials to quantify the efficacy of novel therapeutic strategies.

Development of Contractures in DMD in Relation to MRI-Determined Muscle Quality and Ambulatory Function

BACKGROUND

Joint contractures are common in boys and men with Duchenne muscular dystrophy (DMD), and management of contractures is an important part of care. The optimal methods to prevent and treat contractures are controversial, and the natural history of contracture development is understudied in glucocorticoid treated individuals at joints beyond the ankle.

OBJECTIVE

To describe the development of contractures over time in a large cohort of individuals with DMD in relation to ambulatory ability, functional performance, and muscle quality measured using magnetic resonance imaging (MRI) and spectroscopy (MRS).

METHODS

In this longitudinal study, range of motion (ROM) was measured annually at the hip, knee, and ankle, and at the elbow, forearm, and wrist at a subset of visits. Ambulatory function (10 meter walk/run and 6 minute walk test) and MR-determined muscle quality (transverse relaxation time (T2) and fat fraction) were measured at each visit.

RESULTS

In 178 boys with DMD, contracture prevalence and severity increased with age. Among ambulatory participants, more severe contractures (defined as greater loss of ROM) were significantly associated with worse ambulatory function, and across all participants, more severe contractures significantly associated with higher MRI T2 or MRS FF (ρ: 0.40-0.61 in the lower extremity; 0.20-0.47 in the upper extremity). Agonist/antagonist differences in MRI T2 were not strong predictors of ROM.

CONCLUSIONS

Contracture severity increases with disease progression (increasing age and muscle involvement and decreasing functional ability), but is only moderately predicted by muscle fatty infiltration and MRI T2, suggesting that other changes in the muscle, tendon, or joint contribute meaningfully to contracture formation in DMD.

Knee Strength and Ankle Range of Motion Impacts on Timed Function Tests in Duchenne Muscular Dystrophy: In the Era of Glucocorticoids

BACKGROUND

Duchenne Muscular Dystrophy (DMD) is a neuromuscular disorder that presents in childhood and is characterized by slowly progressive proximal weakness and lower extremity contractures that limit ambulatory ability [1, 2]. Contractures develop in the ankles, knees, and hips due to muscle imbalances, fibrotic changes, loss of strength, and static positioning [2, 5]. Currently, standards of care guidelines emphasize the importance of maintaining good musculoskeletal alignment through stretching, bracing, and glucocorticoid (GC) therapy to preserve strength and function.

METHODS

This is a retrospective analysis of prospectively collected data through the CINRG Duchenne Natural history study (DNHS). The objectives of this analysis are to understand the progression of ankle contractures for individuals with DMD and to investigate the relationship between progressive lower limb contractures, knee strength, and Timed Function Tests.A collection of TFTs including supine to stand (STS), 10 meter walk test (10MWT), and timed stair climbing (4SC) have been used to monitor disease progression and are predictive of loss of ambulation in these patients [4]. Multiple factors contribute to loss of ambulation, including progressive loss of strength and contracture development that leads to changing biomechanical demands for ambulation. A better understanding of the changes in strength and range of motion (ROM) that contribute to loss of function is important in a more individualized rehabilitation management plan. In this longitudinal study, we measured strength using quantitative muscle testing (QMT) with the CINRG Quantitative Measurement System (CQMS)), ROM was measuresed with a goniometer and TFTs were measured using a standard stopwatch and methodology.

RESULTS

We enrolled 440 participants; mean baseline age was 8.9 (2.1, 28.0) years with 1321 observations used for analysis. GC use was stratified based on duration on drug with 18.7%at <  6 months or naïve; 4.3%<1 year; 58.0%1 <  10 years; and 19.3%between 10-25 years of GC use. Ankle ROM was better for those on GC compared to GC naive but did not significantly influence long-term progression rates. QMT, ROM, age and GCs contribute to speed of TFTs. Knee extension (KE) strength and Dorsiflexion (DF) ROM are significant predictors of speed for all TFTs (p <  0.001). Of the variables used in this analysis, KE strength is the primary predictor of walking speed, estimating that every pound increase in KE results in a 0.042 m/s improvement in 10MWT, and a smaller similar increase of 0.009 m/s with every degree of ankle DF ROM.

CONCLUSION

GC use provides an improvement in strength and ROM but does not affect rate of change. Knee strength has a greater influence on speed of TFTs than DF ROM, although both are statistically significant predictors of speed. Results show that retaining knee strength [1, 2], along with joint flexibility, may be important factors in the ability to perform walking, climbing and supine to stand activities.

Complexity of skeletal muscle degeneration: multi-systems pathophysiology and organ crosstalk in dystrophinopathy

Duchenne muscular dystrophy is a highly progressive muscle wasting disorder due to primary abnormalities in one of the largest genes in the human genome, the DMD gene, which encodes various tissue-specific isoforms of the protein dystrophin. Although dystrophinopathies are classified as primary neuromuscular disorders, the body-wide abnormalities that are associated with this disorder and the occurrence of organ crosstalk suggest that a multi-systems pathophysiological view should be taken for a better overall understanding of the complex aetiology of X-linked muscular dystrophy. This article reviews the molecular and cellular effects of deficiency in dystrophin isoforms in relation to voluntary striated muscles, the cardio-respiratory system, the kidney, the liver, the gastrointestinal tract, the nervous system and the immune system. Based on the establishment of comprehensive biomarker signatures of X-linked muscular dystrophy using large-scale screening of both patient specimens and genetic animal models, this article also discusses the potential usefulness of novel disease markers for more inclusive approaches to differential diagnosis, prognosis and therapy monitoring that also take into account multi-systems aspects of dystrophinopathy. Current therapeutic approaches to combat muscular dystrophy are summarised.

Passive stiffness of fibrotic skeletal muscle in mdx mice relates to collagen architecture

KEY POINTS

The amount of fibrotic material in dystrophic mouse muscles relates to contractile function, but not passive function. Collagen fibres in skeletal muscle are associated with increased passive muscle stiffness in fibrotic muscles. The alignment of collagen is independently associated with passive stiffness in dystrophic skeletal muscles. These outcomes demonstrate that collagen architecture rather than collagen content should be a target of anti-fibrotic therapies to treat muscle stiffness.

ABSTRACT

Fibrosis is prominent in many skeletal muscle pathologies including dystrophies, neurological disorders, cachexia, chronic kidney disease, sarcopenia and metabolic disorders. Fibrosis in muscle is associated with decreased contractile forces and increased passive stiffness that limits joint mobility leading to contractures. However, the assumption that more fibrotic material is directly related to decreased function has not held true. Here we utilize novel measurement of extracellular matrix (ECM) and collagen architecture to relate ECM form to muscle function. We used mdx mice, a model for Duchenne muscular dystrophy that becomes fibrotic, and wildtype mice. In this model, extensor digitorum longus (EDL) muscle was significantly stiffer, but with similar total collagen, while the soleus muscle did not change stiffness, but increased collagen. The stiffness of the EDL was associated with increased collagen crosslinking as determined by collagen solubility. Measurement of ECM alignment using polarized light microscopy showed a robust relationship between stiffness and alignment for wildtype muscle that broke down in mdx muscles. Direct visualization of large collagen fibres with second harmonic generation imaging revealed their relative abundance in stiff muscles. Collagen fibre alignment was linked to stiffness across all muscles investigated and the most significant factor in a multiple linear regression-based model of muscle stiffness from ECM parameters. This work establishes novel characteristics of skeletal muscle ECM architecture and provides evidence for a mechanical function of collagen fibres in muscle. This finding suggests that anti-fibrotic strategies to enhance muscle function and excessive stiffness should target large collagen fibres and their alignment rather than total collagen.

Potential cross-talk between muscle and tendon in Duchenne muscular dystrophy

PURPOSE

To describe potential signaling (cross-talk) between dystrophic skeletal muscle and tendon in Duchenne muscular dystrophy.

MATERIALS AND METHODS

Review of Duchenne muscular dystrophy and associated literature relevant to muscle-tendon cross-talk.

RESULTS AND CONCLUSIONS

Duchenne muscular dystrophy results from the absence of the protein dystrophin and the associated dystrophin - glycoprotein complex, which are thought to provide both structural support and signaling functions for the muscle fiber. In addition, there are other potential signal pathways that could represent cross-talk between muscle and tendon, particularly at the myotendinous junction. Duchenne muscular dystrophy is characterized by multiple pathophysiologic mechanisms. Herein, we explore three of these: (1) the extracellular matrix, fibrosis, and fat deposition; (2) satellite cells; and (3) tensegrity. A key signaling protein that emerged in each was transforming growth factor - beta one (TGF-β1).].

Establishing a telerehabilitation program for patients with Duchenne muscular dystrophy in the COVID-19 pandemic

Background

Duchenne muscular dystrophy is a genetic disease characterized by gradual loss of motor function, respiratory failure and cardiomyopathy. During the time of the global coronavirus pandemic, maintenance of social distancing and self-isolation might complicate regular multidisciplinary care of patients with Duchenne muscular dystrophy but on the other hand may lead to new medical care telehealth solutions. The aim of the study was to investigate patients’ situation regarding rehabilitation in the pandemic, to establish an online rehabilitation program and motor assessment and to determine the needs of telerehabilitation in this group.

Methods

The project involved 69 boys with Duchenne muscular dystrophy. The rehabilitation program was presented during online workshops for patients and caregivers. The same program was recorded on video and published in the internet. The online motor assessment tool consisted of six motor tests, caregivers were asked to perform the tasks and share a photograph of the patient’s posture using a designed app.

Results

In the nonambulant group the emphasis was placed on chest physiotherapy, stretching of upper extremities, positioning and wheelchair ergonomics. The program for the ambulant group focused on lower extremities stretching and full body exercises. Response rate for the workshops for ambulant patients was 29.7%, and only 9.0% for nonambulant patients. Videos showing exercises were displayed 132 times within a month.

Conclusion

With the physiotherapist guidance (online communication or video) patients with caregivers’ help can continue home based rehabilitation. Online videos/instructions/video guidelines are more acceptable by parents/caregivers of patients with Duchenne muscular dystrophy than live workshops.

Muscle weakness has a limited effect on motor control of gait in Duchenne muscular dystrophy

Aim

Our aim was to determine if synergy weights and activations are altered in Duchenne muscular dystrophy (DMD) and if these alterations could be linked to muscle weakness.

Methods

In 22 children with DMD and 22 typical developing (TD) children of a similar age, surface electromyography (sEMG) of the gluteus medius, rectus femoris (REF), medial hamstrings, tibialis anterior, and medial gastrocnemius (GAS) were recorded during gait. Muscle weakness was assessed with maximal voluntary isometric contractions (MVIC). Synergies were calculated with non-negative matrix factorization. The number of synergies explaining ≥90% of the variance in the sEMG signals (N90), were extracted and grouped with k-means cluster analysis. We verified differences in weights with a Mann-Whitney U test. Statistical non-parametric mapping (Hotelling's T² test and two-tailed t-test) was used to assess group differences in synergy activations. We used Spearman’s rank correlation coefficients and canonical correlation analysis to assess if weakness was related to modifications in weights and activations, respectively.

Results

For both groups, average N90 was three. In synergy one, characterized by activity at the beginning of stance, the DMDs showed an increased REF weight (p = 0.001) and decreased GAS weight (p = 0.007). Synergy activations were similar, with only a small difference detected in mid-swing in the combined activations (p<0.001). Weakness was not associated with these differences.

Conclusion

Despite the apparent weakness in DMD, synergy weights and activations were similar between the two groups. Our findings are in line with previous research suggesting non-neural alterations have limited influence on muscle synergies.

Benefits of powered standing wheelchair devices for adolescents with Duchenne muscular dystrophy in the first year of use

AIM

Poorer physical and mental health often accompany loss of walking in Duchenne muscular dystrophy. This study assessed the impacts of powered wheelchair standing device (PWSD) use on muscle and joint pain, joint angles when standing and mental health in adolescents with Duchenne muscular dystrophy.

METHODS

Fourteen adolescents and parents participated in a stepped wedge design study over 12 months. During a baseline and intervention period, adolescents described pain and mental health, and parents reported their child's mental health. Video data were collected to measure hip, knee and ankle joint angles in the preferred standing position.

RESULTS

Compared with baseline and adjusting for covariates, standing wheelchair use was associated with no change in muscle or joint pain or videoed joint angles in standing. Child-reported Strengths and Difficulties total scores decreased (coefficient -3.1, 95% confidence interval -4.6, -1.5); and parent-reported Personal Adjustment and Role Skills Scale total scores increased (coefficient 7.9, 95% confidence interval 3.3-12.5).

CONCLUSIONS

PWSD use was associated with maintenance of musculoskeletal status and advantages to mental health. Long-term observations are necessary to improve understanding of how to support wellbeing in adolescents with Duchenne muscular dystrophy.

Magnetic Resonance Imaging Studies in Duchenne Muscular Dystrophy: Linking Findings to the Physical Therapy Clinic

Duchenne muscular dystrophy (DMD) is a muscle degenerative disorder that manifests in early childhood and results in progressive muscle weakness. Physical therapists have long been an important component of the multidisciplinary team caring for people with DMD, providing expertise in areas of disease assessment, contracture management, assistive device prescription, and exercise prescription. Over the last decade, magnetic resonance imaging of muscles in people with DMD has led to an improved understanding of the muscle pathology underlying the clinical manifestations of DMD. Findings from magnetic resonance imaging (MRI) studies in DMD, paired with the clinical expertise of physical therapists, can help guide research that leads to improved physical therapist care for this unique patient population. The 2 main goals of this perspective article are to (1) summarize muscle pathology and disease progression findings from qualitative and quantitative muscle MRI studies in DMD and (2) link MRI findings of muscle pathology to the clinical manifestations observed by physical therapists with discussion of any potential implications of MRI findings on physical therapy management.

Comparison of motor proficiency and functional ambulation in Duchenne muscular dystrophy with healthy peers

AIMS

The study was aimed to investigate the difference between boys with Duchenne muscular dystrophy (DMD) and healthy peers in terms of gross and fine motor proficiency, and determine the relationship between motor proficiency and ambulation.

METHODS

A total of 24 boys with DMD and 22 healthy peers were evaluated. Demographics and physical characteristics were recorded. The Bruininks Oseretsky Test of Motor Proficiency-Short Form (BOTMP-SF) was administered to evaluate gross and fine motor proficiency in both groups. The 6-minute walk test (6MWT) was performed to evaluate functional walking capacity and North Star Ambulatory Assessment (NSAA) was used to determine ambulatory status of boys with DMD.

RESULTS

The gross motor proficiency score was significantly lower in boys with DMD (p = 0.001). No difference was found between the groups in terms of fine motor proficiency (p = 0.962). The gross motor function of BOTMP-SF was significantly related to 6MWT distance (r = 0.696, p = 0.001) and NSAA (r = 0.738, p = 0.001). No relationship was found between BOTMP-SF fine motor proficiency and 6MWT distance (r = 0.210, p = 0.361), and NSAA (r = -0.020, p = 0.928). There were significant correlations between running speed and agility with 6MWT distance (r = 0.585, p = 0.005) and NSAA (r = 0.650, p = 0.056).

CONCLUSIONS

Boys with DMD were more affected in aspects of gross motor proficiency than healthy peers, while fine motor proficiency were found same. The gross motor proficiency was found more related to the level of ambulation.

Conference report on contractures in musculoskeletal and neurological conditions

Limb contractures are debilitating complications associated with various muscle and nervous system disorders. This report summarizes presentations at a conference at the Shirley Ryan AbilityLab in Chicago, Illinois, on April 19-20, 2018, involving researchers and physicians from diverse disciplines who convened to discuss current clinical and preclinical understanding of contractures in Duchenne muscular dystrophy, stroke, cerebral palsy, and other conditions. Presenters described changes in muscle architecture, activation, extracellular matrix, satellite cells, and muscle fiber sarcomeric structure that accompany or predispose muscles to contracture. Participants identified ongoing and future research directions that may lead to understanding of the intersecting factors that trigger contractures. These include additional studies of changes in muscle, tendon, joint, and neuronal tissues during contracture development with imaging, molecular, and physiologic approaches. Participants identified the requirement for improved biomarkers and outcome measures to identify patients likely to develop contractures and to accurately measure efficacy of treatments currently available and under development.