Aim: The absence of dystrophin in patients with Duchenne Muscular Dystrophy (DMD) causes muscle fiber necrosis and fibrosis and eventually muscle weakness and contractures. This study aimed to investigate the timing and extent of lower limb contracture development and to examine how contractures, muscle strength, and kinematic (e.g., limb position or joint movement) deviations relate to longitudinal changes in gait spatiotemporal parameters. Methods: Seventy-five ambulatory boys with DMD participated in this prospective longitudinal study of contractures, isometric muscle strength, and gait analysis. Nonlinear mixed modeling (NLMIXED) exponential growth curve models were developed to investigate the effects of contractures, muscle strength, and kinematic deviations on longitudinal changes in gait spatiotemporal parameters. Results: Ankle plantar flexion contractures were present as early as 4 years of age. Hip flexion contractures, assessed by the Thomas test, and knee flexion contractures, assessed by knee extension in supine, developed around 13 years of age and did not exceed ten degrees. Over time, gait speed, stride length, and cadence decreased. Statistically significant covariates for gait speed included hip flexor contracture (limitation in hip extension), hip extensor and ankle plantar flexor strength, and pelvic tilt Gait Variable Score (GVS). Plantar flexor strength was a significant covariate for stride length, while pelvic obliquity GVS significantly correlated with cadence. Conclusion: Subtle changes in hip extensor and ankle plantar flexor strength, along with pelvic range of motion during gait, are indicators of DMD disease progression. Gait analysis, including easily accessible measures of gait speed and normalized stride length, may provide a more sensitive indicator of DMD disease progression than manual assessments of contractures and muscle strength.

BACKGROUND:Severe spastic wrist contractures secondary to cerebral palsy (CP) or alike can have significant implications for patient hand function, hygiene, skin breakdown, and cosmesis. When these contractures become rigid, soft tissue procedures alone are unable to obtain or maintain the desired correction. In these patients' wrist arthrodesis is an option-enabling the hand to be stabilized in a more functional position for hygiene, dressing, and general cosmesis, though are patients satisfied?METHODS:All children who had undergone a wrist arthrodesis for the management of a severe wrist contracture at Shriners Hospital, Portland between January 2016 and January 2021 were identified (n=23). A chart review was undertaken to obtain data-demographic, operative, clinical, and radiographic. All patients were then contacted to participate in 2 patient-reported outcome questionnaires (74% response agreement), a numerical rating scale (NRS), based on the visual analog scale (VAS) and the disability analog scale (DAS). Results were assessed with the aid of descriptive statistics, means and percentages with the primary focus of determining overall patient satisfaction with the procedure.RESULTS:Twenty-three patients were included in the review, and 74% took part in the prospective survey. Included were 10 patients with hemiplegia, 4 with triplegia, 7 with quadriplegia, 1 with a diagnosis of Rhett syndrome, and 1 with a history of traumatic brain injury. All patients achieved radiologic union by a mean of 8 weeks, and 87% obtained a neutral postoperative wrist alignment. The NRS showed 88% of patients were highly satisfied with their results; specifically, 82% had an improved appearance, 53% improved function, 71% improved daily cares, and 65% improved hygiene. The postoperative DAS score averaged 4.7 of 12 indicating mild disability. When looking at how a patient's diagnostic subtype affected outcome results, patients with triplegia reported less improvement and greater disability on the NRS and DAS, averaging 9.5 (severe disability on the DAS). The GMFCS classification had less correlation with outcomes.CONCLUSION:Wrist arthrodesis is a good option for the management of pediatric spastic wrist contractures, with limited complications and an overall high patient/carer satisfaction rate.LEVEL OF EVIDENCE:Level IV-case series.

BACKGROUND:Though the primary goal for limb length discrepancy (LLD) management is to equalize the leg lengths, symmetry between corresponding long bones is usually not achieved, leading to knee height asymmetry (KHA). To date, there is minimal information on what effect KHA has on gait biomechanics and joint loading. Thus, the purpose of this study is to determine the impact of KHA on gait biomechanics. METHODS:Seventeen subjects with KHA after limb equalizing surgery and 10 healthy controls were enrolled. Subjects participated in 3D gait analysis collected using self-selected speed. Lower extremity kinematics, kinetics, work generated/absorbed, and total work were calculated. Standing lower limb x-rays and scanograms were used to measure LLD and calculate the tibia-to-femur (TF) ratio for each limb. Two sample t tests were used to compare differences in standing LLD, TF ratio, and work between groups. Bivariate correlation using Pearson correlation coefficients was conducted between TF ratio and total mechanical work, as well as between knee height asymmetry indices and total work asymmetry (α=0.05). RESULTS:Among participants, there were no differences between LLD; however, there were differences between TF ratio and knee height asymmetry. We found a nonsignificant relationship between TF ratio and total mechanical work for individual lower extremities. Therefore, the length of individual bones (TF ratio) relative to each other within the individual lower extremity was not associated with the amount of work produced. However, when a difference exists between sides (asymmetry, ie, TF ratio asymmetry), there were associated differences in work (work asymmetry) produced between sides (r=0.54, P =0.003). In other words, greater knee height asymmetry between limbs resulted in more asymmetrical mechanical work during walking. CONCLUSIONS:These findings may have implications for the management of LLD. Asymmetrical total mechanical work could lead to atypical joint loading during gait. Surgeons may want to consider prioritizing achieving knee height symmetry as a postoperative goal when correcting limb length discrepancy. LEVEL OF EVIDENCE:Level III, Case Control Study.

Abstract Introduction To describe the development and implementation of learning health system (LHS) infrastructure for a pediatric specialty care health system to support LHS research in pediatric rehabilitation settings. Methods An existing pediatric common data model (eg, PEDSnet) of standardized medical terminologies for research was expanded and leveraged for this stud, and applied to SHOnet, a clinical research data resource consisting of deidentified data extracted from the electronic health record (EHR) from the Shriners Hospitals for Children speacialty pediatric health care system. We mapped EHR data for laboratory, procedures, drugs, and conditions to standardized vocabularies including ICD‐10, CPT, RxNorm, and LOINC to the common data model using an established extraction‐transformation‐loading process. Rigorous quality checks were conducted to ensure a high degree of data conformance, completeness, and plausibility. SHOnet data elements from all sources are de‐identified and the server is managed by the SHC Information Systems Department. SHOnet data are refreshed monthly and data elements are continually expanded based on new research endeavors. Interventions Not applicable. Results The Shriners Health Outcomes Network (SHOnet) includes data for over 10 000 distinct observational data elements based on over two million patient encounters between 2011 and present. Conclusion The systematic process to develop SHOnet is replicable and flexible for other pediatric rehabilitation research settings interested in building out their LHS capabilities. Challenges and facilitators may arise for building such LHS infrastructure for rehabilitation in areas of (a) data capture, curation, query, and governance, (b) generating knowledge from data, and (c) dissemination and implementation of new institutional knowledge. Further research studies are needed to evaluate these data resources for scalable system‐learning endeavors. SHOnet is an exemplar of an LHS for rehabilitation and specialty care settings. The success of an LHS is dependent on engagement of multiple stakeholders, shared governance, effective knowledge translation, and deep commitment to long‐term strategies for engaging clinicians, administration, and families in leveraging knowledge to improve clinical outcomes.

BACKGROUND:Duchenne Muscular Dystrophy (DMD) is an X-linked muscle disorder caused by a mutation or deletion in the dystrophin gene. In boys with DMD, muscle weakness progresses in a proximal to distal pattern, leading to gait abnormalities at all joints, in all planes of motion. Longitudinal studies are imperative to quantify changes in gait function due to DMD and are of particular importance when examining the efficacy of treatment interventions. RESEARCH QUESTION:The purpose of this study was to examine the sensitivity of the Gait Deviation Index (GDI) and Movement Analysis Profile (Gait Profile Score (GPS) and Gait Variable Score (GVS)) to quantify the longitudinal ambulatory decline in boys with DMD. A secondary aim was to quantify the effect of corticosteroid (CS) treatment. METHODS:The gait patterns of 75 boys were assessed longitudinally, 11 were steroid naïve (SN), and 64 received CS treatment. Joint kinematics were collected using either a VICON 612 or a Motion Analysis Corporation 3-D system. Representative trials were used to compute the GDI, GPS and the nine GVS for each boy for each visit. RESULTS:At baseline, GVS for the boys with DMD revealed abnormalities in all lower extremity joints and in all planes of movement compared to TD peers. GDI and GPS indices verified that the overall quality of gait in boys with DMD decreases at a significant rate with age. Boys who were steroid naïve changed at a rate 3 times greater than boys on CS in coronal plane hip motion. SIGNIFICANCE:The gait indices of GDI and GPS are able to identify changes in the quality of gait patterns in boys with DMD. Although boys on steroids had greater gait deviations than boys who were SN at baseline, the rate of decline in gait quality was slower in boys on CS.

Background: Postoperative urinary retention (POUR) is a surgical complication more prevalent in children with neurodisability and associated with an increase length of hospitalization. Risk factors include pre-existing bladder dysfunction, type and duration of surgery, anesthesia medications, postoperative opioid pain management, and patient demographics. The purpose of this investigation was (1) to determine the frequency of POUR following hip/lower limb orthopaedic procedures in which epidural analgesia was used for pain management; (2) to explore factors influencing postoperative bladder management. Methods: A retrospective analysis of clinical data was performed in an orthopaedic specialty care health care system. A health outcomes network was queried for patients with a diagnoses of cerebral palsy (ICD-9/10 codes) who had one of 57 unique CPT procedure codes corresponding to hip osteotomies or tenotomies from 2011 to 2019. All surgical observations included in analysis required a discrete data element and the confirmation of a secondary proxy. The database was also queried for postoperative medications received and patient demographics of interest. Results: A total of 704 surgical procedures met inclusion criteria resulting in a patient population with a mean age of 11 years, 58% male, 53% Caucasian, and 55% classified as quadriplegia [51% Gross Motor Function Classification System (GMFCS) levels IV/V]. Three hundred and thirty-five procedures (48%) involved epidural anesthesia. Sixty-five patients required intermittent catheterization (9.2%) postoperatively following foley catheter removal, of which 23 (3.3%) required recatheterization. The rate of recatheterization was similar regardless of anesthesia mode; 1.8% for general and 1.4% for epidural and was associated with a greater number of pain medications. Epidural anesthesia resulted in significantly longer periods of catheterization. For the total group the time to urinary catheter removal differed significantly among cerebral palsy subtypes, GMFCS Level, race, and ethnicity. Factors identified as significant predictors of the length of catheterization were epidural analgesia, number of pain medications, and osteotomy. Conclusions: The number of postoperative pain medications utilized was more predictive of POUR than the mode of analgesia delivery; however, epidural analgesia and the type of surgical procedure did significantly impact the length of catheterization. Level of Evidence: Level III.

BACKGROUND:Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder, that is characterized by progressive muscle degeneration and loss of ambulation between 7-13 years of age. Novel pharmacological agents targeting the genetic defects and disease mechanisms are becoming available; however, corticosteroid (CS) therapy remains the standard of care.OBJECTIVE:The purpose of this longitudinal study was to elucidate the effect of CS therapy on the rate of muscle strength and gross motor skill decline in boys with DMD and assess the sensitivity of selected outcome measures.METHODS:Eighty-four ambulatory boys with DMD (49-180 months), 70 on CS, 14 corticosteroid naïve (NCS), participated in this 8-year multi-site study. Outcomes included; isokinetic dynamometry, the Standing (STD) and Walking/Running/jumping (WRJ) dimensions of the Gross Motor Function Measure (GMFM), and Timed Function Tests (TFTs). Nonlinear mixed modeling procedures determined the rate of change with age and the influence of steroids.RESULTS:Despite CS therapy the rate of decline in strength with age was significant in all muscle groups assessed. CS therapy significantly slowed decline in knee extensor strength, as the NCS group declined at 3x the rate of the CS group. Concurrently, WRJ skills declined in the NCS group at twice the rate of the CS group. 4-stair climb and 10 meter walk/run performance was superior in the boys on CS therapy.CONCLUSION:CS therapy slowed the rate of muscle strength decline and afforded longer retention of select gross motor skills in boys on CS compared to boys who were NCS. Isokinetic dynamometry, Walk/Run/Jump skills, and select TFTs may prove informative in assessing the efficacy of new therapeutics in ambulatory boys with DMD.

BACKGROUND:In boys with DMD, muscle weakness progresses in a proximal to distal pattern, leading to compensatory gait strategies, including hyperlordosis and equinus, that increase energy cost and accelerate the loss of walking capacity.RESEARCH QUESTION:The purpose of this study was to determine the changes in the energy cost of walking that occur with disease progression and to determine the optimal normalization scheme for the longitudinal assessment of the energy cost of walking in boys with DMD.METHODS:Energy cost was assessed with the COSMED K4b2. Three normalization schemes were examined: gross energy cost (EC), net non-dimensional oxygen cost (NNcost) and speed-matched control energy cost (SMC-EC). Nonlinear mixed modeling procedures determined the rate of change with age. Linear regression was used to asses the relationship between each normalization scheme and age and body height.RESULTS:74 boys with DMD were assessed for the energy cost of walking. Velocity decreased at a significant rate (-.00245/month, p = .03) across time; (Fig. 2), while gross EC (.003248/month, p = 0.0026), NNcost (.006155/month, p < 0.0001) and SMC-EC (.001690/month, p = 0.03) all increased significantly. Age and height were significantly associated with NNcost and SMC-EC. The sensitivity of NNcost and SMC-EC to age over time were similar, while SMC-EC was less sensitive to changes in height over time than NNcost.SIGNIFICANCE:In contrast to able-bodied peers, boys with DMD decrease their velocity while all walking energy cost measures increased over time. Both SMC-EC and NNcost proved appropriate normalization schemes for boys with DMD. Compared to gross EC, both NNcost and SMC-EC were less sensitive to changes in age over time, while SMC-EC was less sensitive to changes in height than NNcost. Therefore, both NNCost and SMC-EC are suggested normalization schemes for the longitudinal assessment of energy cost in boys with DMD.

Purpose Pharmacologic doses of corticosteroid (CS) have been shown to ameliorate the progression of Duchenne muscular dystrophy (DMD) preserving strength, pulmonary function and ambulation as well as reducing the incidence of scoliosis. However, there are serious side effects of CS, which may impact dose tolerance. The purpose of this study was to compare the magnitude of positive CS effects on patients in our clinic to those reported in the literature. Methods We retrospectively reviewed medical records and radiographs of 142 DMD patients who were seen between 1st January 1991 and 31st December 2017. Results In total, 101 boys met study inclusion criteria. Of these 32 were steroid naïve, 37 took the recommended dose (standard of care, SOC) of Prednisone or Deflazacort, and 32 took a lower dose (LD). Following initiation of CS, both treatment groups showed an increase in weight velocity and decrease in linear growth velocity. Although there was a trend to later loss of ambulation (LOA) in the SOC group relative to the naïve group by one year, this was not significant, however, a small subgroup of boys on Deflazacort showed a 3.4 year later LOA than the naïve group. The incidence of scoliosis was reduced from 69% in the naïve, to 41% in the LD and 47% in the SOC group. Conclusions Although there was a reduction in the incidence of scoliosis, it was not as robust as seen elsewhere. Many published studies have inadequate data on scoliosis probably due to the lack of inclusion of orthopaedists in the study group. Level of evidence IV

ABSTRACTIntroductionNatural history studies for Duchenne muscular dystrophy (DMD) have not included measures of community ambulation.MethodsStep activity (SA) monitors quantified community ambulation in 42 boys (ages 4–16 years) with DMD with serial enrollment up to 5 years by using a repeated‐measures mixed model. Additionally, data were compared with 10‐meter walk/run (10mWR) speed to determine validity and sensitivity.ResultsThere were significant declines in average strides/day and percent strides at moderate, high and pediatric high rates as a function of age (P < 0.05). Significant correlations for 10mWR versus high and low stride rates were found at baseline (P < 0.05). SA outcomes were sensitive to change over 1 year, but the direction and parameter differed by age group (younger vs. older). Changes in strides/day and percentages of high frequency and low frequency strides correlated significantly with changes in 10mWR speed (P < 0.05).DiscussionCommunity ambulation data provide valid and sensitive real‐world measures that may inform clinical trials. Muscle Nerve 57: 401–406, 2018

Duchenne muscular dystrophy (DMD) is an X-linked genetic neuromuscular disorder characterized by progressive proximal to distal muscle weakness. The success of randomized clinical trials for novel therapeutics depends on outcome measurements that are sensitive to change. As the development of motor skills may lead to functional improvements in young boys with DMD, their inclusion may potentially confound clinical trials. Three-dimensional gait analysis is an under-utilized approach that can quantify joint moments and powers, which reflect functional muscle strength. In this study, gait kinetics, kinematics, spatial-temporal parameters, and timed functional tests were quantified over a one-year period for 21 boys between 4 and 8 years old who were enrolled in a multisite natural history study. At baseline, hip moments and powers were inadequate. Between the two visits, 12 boys began a corticosteroid regimen (mean duration 10.8 ± 2.4 months) while 9 boys remained steroid-naïve. Significant between-group differences favoring steroid use were found for primary kinetic outcomes (peak hip extensor moments (p = .007), duration of hip extensor moments (p = .007), peak hip power generation (p = .028)), and spatial-temporal parameters (walking speed (p = .016) and cadence (p = .021)). Significant between-group differences were not found for kinematics or timed functional tests with the exception of the 10 m walk test (p = .03), which improves in typically developing children within this age range. These results indicate that hip joint kinetics can be used to identify weakness in young boys with DMD and are sensitive to corticosteroid intervention. Inclusion of gait analysis may enhance detection of a treatment effect in clinical trials particularly for young boys with more preserved muscle function.

The aim of this study was to determine whether prednisone and deflazacort play a different role in child behavior and perceived health related psychosocial quality of life in ambulant boys with Duchenne Muscular Dystrophy. As part of a prospective natural-history study, parents of sixty-seven ambulant boys with DMD (27 taking prednisone, 15 taking deflazacort, 25 were steroid naïve) completed the Child Behavior Checklist (CBCL) for assessment of behavioral, emotional and social problems and both parents and boys with DMD completed the PedsQL™4.0 generic core scale short form. Boys with DMD had higher rates of general behavioral problems than age-matched peers. No significant differences were found among the groups for any of the CBCL syndrome scales raw scores, including internalizing and externalizing behaviors; however, on average boys taking deflazacort demonstrated more withdrawn behaviors than those taking prednisone, while on average the boys taking prednisone demonstrated more aggressive behaviors than boys taking deflazacort. Age, internalizing and externalizing behaviors accounted for 39 and 48% of the variance in psychosocial quality of life for both parents and boys with DMD, respectively. Overall, the use of steroids was not associated with more behavioral problems in boys with DMD. As behavior played a significant role in psychosocial quality of life, comprehensive assessment and treatment of behavioral problems is crucial in this population.

Background: In the absence of a curative treatment for Duchenne Muscular Dystrophy (DMD), corticosteroid therapy (prednisone, deflazacort) has been adopted as the standard of care, as it slows the progression of muscle weakness and enables longer retention of functional mobility. The ongoing development of novel pharmacological agents that target the genetic defect underlying DMD offer hope for a significant alteration in disease progression; however, substantiation of therapeutic efficacy has proved challenging. Identifying functional outcomes sensitive to the early, subtle changes in muscle function has confounded clinical trials. Additionally, the alterations in disease progression secondary to corticosteroid therapy are not well described making it difficult to ascertain the benefits of novel agents, often taken concurrently with corticosteroids. Objective: The purpose of this study was to examine outcome responsiveness to corticosteroid therapy and age at the onset of a natural history study of ambulatory boys with DMD. Methods: Eighty-five ambulatory boys with DMD (mean age 93 mo, range 49 to 180 mo) were recruited into this study. Fifty participants were on corticosteroid therapy, while 33 were corticosteroid naïve at the baseline assessment. Within each treatment group boys were divided in two age groups, 4 to 7 years and 8 and greater years of age. The Biodex System 3 Pro isokinetic dynamometer was used to assess muscle strength. Motor skills were assessed using the upper two dimensions (standing/walking, running & jumping) of the Gross Motor Function Measure (GMFM 88) and Timed Motor Tests (TMTs) (10-meter run, sit to stand, supine to stand, climb 4-stairs). Two way analysis of variance and Pearson correlations were used for analysis. Results: A main effect for age was seen in select lower extremity muscle groups (hip flexors, knee extensors and ankle dorsiflexors), standing dimension skills, and all TMTs with significantly greater weakness and loss of motor skill ability seen in the older age group regardless of treatment group. Interaction effects were seen for the walking, running, and jumping dimension of the GMFM with the naïve boys scoring higher in the younger group and boys on corticosteroid therapy scoring higher in the older group. The TMT of climb 4-stairs demonstrated a significant treatment effect with the boys on corticosteroid therapy climbing stairs faster than those who were naïve, regardless of age. Examination of individual items within the upper level GMFM dimensions revealed select motor skills are more informative of disease progression than others; indicating their potential to be sensitive indicators of alterations in disease progression and intervention efficacy. Analysis of the relationship between muscle group strength and motor skill performance revealed differences in use patterns in the corticosteroid versus naïve boys. Conclusion: Significant muscle weakness is apparent in young boys with DMD regardless of corticosteroid treatment; however, older boys on corticosteroid therapy tend to have greater retention of muscle strength and motor skill ability than those who are naive. Quantification of muscle strength via isokinetic dynamometry is feasible and sensitive to the variable rates of disease progression in lower extremity muscle groups, but possibly most informative are the subtle changes in the performance characteristics of select motor skills. Further analysis of longitudinal data from this study will explore the influence of corticosteroid therapy on muscle strength and further clarify its impact on motor performance.

Congenital unilateral absence of the hand (amelia) completely deprives individuals of sensorimotor experiences with their absent effector. The consequences of such deprivation on motor planning abilities are poorly understood. Fourteen patients and matched controls performed two grip selection tasks: 1) overt grip selection (OGS), in which they used their intact hand to grasp a three-dimensional object that appeared in different orientations using the most natural (under-or over-hand) precision grip, and 2) prospective grip selection (PGS), in which they selected the most natural grip for either the intact or absent hand without moving. For the intact hand, we evaluated planning accuracy by comparing concordance between grip preferences expressed in PGS vs. OGS. For the absent hand, we compared PGS responses with OGS responses for the intact hand that had been phase shifted by 180°, thereby accounting for mirror symmetrical biomechanical constraints of the two limbs. Like controls, amelic individuals displayed a consistent preference for less awkward grips in both OGS and PGS. Unexpectedly, however, they were slower and less accurate for PGS based on either the intact or the absent hand. We conclude that direct sensorimotor experience with both hands may be important for the typical development or refinement of effector-specific internal representations of either limb.

For ambulatory children with cerebral palsy, the assessment of walking energy efficiency is utilized to determine functional changes following surgical, pharmacologic, or orthotic interventions. While the assessment of energy efficiency is considered a useful outcome tool, minimal information exists about the changes in energy efficiency over one year in children with cerebral palsy at different gross motor function classification system (GMFCS) levels and whether the patterns of change are similar to their able-bodied peers. The purpose of this study was to determine whether energy efficiency variables change similarly over one year in children with cerebral palsy by GMFCS level and whether they differ from their age-matched peers. Forty-five able-bodied children and 34 children with cerebral palsy, GMFCS levels I-III participated in the study. Energy efficiency variables were measured at baseline and at 12 months using a Cosmed K4b2. All subjects walked at their self-selected velocity for testing around a 33 m track. Baseline velocity and net non-dimensional cost (NNcost) differed by GMFCS level and between the able-bodied peers and all GMFCS levels. Children in GMFCS level III had the highest cost and the slowest velocity. When controlling for age and baseline values, significant differences in the magnitude of change were seen in velocity between children in GMFCS level III and children in GMFCS level I and II and their able-bodied peers. In comparison to their able-bodied peers, all GMFCS levels had an increase in NNcost over one year when controlling for age and baseline NNcost, with the difference in magnitude increasing by GMFCS level. Consistent with the literature, children with cerebral palsy had an increase in NNcost over one year in comparison to their able-bodied peers, which increased with GMFCS level. This finding demonstrates that when evaluating the change in walking energy efficiency with maturation and therapeutic intervention, comparisons should be made by GMFCS level.

Corticosteroids have recently been shown to reduce expected loss of muscle strength in patients with Duchenne muscular dystrophy and extend the time they can walk. We evaluated 43 boys with the condition to determine whether taking corticosteroids is associated with differences in gait pattern, gross motor skills, energy efficiency, and timed motor performance. We used the gait deviation index to quantify the degree of gait pathology and a single measure of gait quality. There were minimal differences in gait pattern, gross motor skills, energy efficiency, or timed motor performance in boys who took corticosteroids compared with those who did not. Clustering by gait deviation index, however, revealed subtle differences between groups in gait patterns, gross motor skills, and energy efficiency. We conclude that, in boys with Duchenne muscular dystrophy, gait pattern deviations are related to function, which can provide further insight into the understanding of disease progression and treatment options to enhance function and maintain ambulation.