Biomechanical Model for Evaluation of Pediatric Upper Extremity Joint Dynamics During Wheelchair Mobility

Pediatric manual wheelchair users (MWU) require high joint demands on their upper extremity (UE) during wheelchair mobility, leading them to be at risk of developing pain and pathology. Studies have examined UE biomechanics during wheelchair mobility in the adult population; however, current methods for evaluating UE joint dynamics of pediatric MWU are limited. An inverse dynamics model is proposed to characterize three-dimensional UE joint kinematics and kinetics during pediatric wheelchair mobility using a SmartWheel instrumented handrim system. The bilateral model comprises thorax, clavicle, scapula, upper arm, forearm, and hand segments and includes the sternoclavicular, acromioclavicular, glenohumeral, elbow and wrist joints. A single 17 year-old male with a C7 spinal cord injury (SCI) was evaluated while propelling his wheelchair across a 15-meter walkway. The subject exhibited wrist extension angles up to 60°, large elbow ranges of motion and peak glenohumeral joint forces up to 10% body weight. Statistically significant asymmetry of the wrist, elbow, glenohumeral and acromioclavicular joints was detected by the model. As demonstrated, the custom bilateral UE pediatric model may provide considerable quantitative insight into UE joint dynamics to improve wheelchair prescription, training, rehabilitation and long-term care of children with orthopedic disabilities. Further research is warranted to evaluate pediatric wheelchair mobility in a larger population of children with SCI to investigate correlations to pain, function and transitional changes to adulthood

Upper Extremity Biomechanics of Children with Spinal Cord Injury during Wheelchair Mobility

While much work is being done evaluating the upper extremity joint dynamics of adult manual wheelchair propulsion, limited work has examined the pediatric population of manual wheelchair users. Our group used a custom pediatric biomechanical model to characterize the upper extremity joint dynamics of 12 children and adolescents with spinal cord injury (SCI) during wheelchair propulsion. Results show that loading appears to agree with that of adult manual wheelchair users, with the highest loading primarily seen at the glenohumeral joint. This is concerning due to the increased time of wheelchair use in the pediatric population and the impact of this loading during developmental years. This research may assist clinicians with improved mobility assessment methods, wheelchair prescription, training, and long-term care of children with orthopaedic disabilities

Biomechanics of Pediatric Manual Wheelchair Mobility

Currently, there is limited research of the biomechanics of pediatric manual wheelchair mobility. Specifically, the biomechanics of functional tasks and their relationship to joint pain and health is not well understood. To contribute to this knowledge gap, a quantitative rehabilitation approach was applied for characterizing upper extremity biomechanics of manual wheelchair mobility in children and adolescents during propulsion, starting, and stopping tasks. A Vicon motion analysis system captured movement, while a SmartWheel simultaneously collected three-dimensional forces and moments occurring at the handrim. A custom pediatric inverse dynamics model was used to evaluate three-dimensional upper extremity joint motions, forces, and moments of 14 children with spinal cord injury (SCI) during the functional tasks. Additionally, pain and health-related quality of life outcomes were assessed. This research found that joint demands are significantly different amongst functional tasks, with greatest demands placed on the shoulder during the starting task. Propulsion was significantly different from starting and stopping at all joints. We identified multiple stroke patterns used by the children, some of which are not standard in adults. One subject reported average daily pain, which was minimal. Lower than normal physical health and higher than normal mental health was found in this population. It can be concluded that functional tasks should be considered in addition to propulsion for rehabilitation and SCI treatment planning. This research provides wheelchair users and clinicians with a comprehensive, biomechanical, mobility assessment approach for wheelchair prescription, training, and long-term care of children with SCI

Use of a Dynamic Balance System to Quantify Postural Steadiness and Stability of Individuals with Lower-Limb Amputation: A Pilot Study

Introduction Despite rehabilitation and gait training, the gait of individuals with lower-limb amputation is often asymmetric and falls and/or fear of falling are common. Clinical assessments of balance and stability include the Berg BalanceScale and the Dynamic Gait Index. Biomechanical assessments, conducted largely in research laboratories, are more objective, quantitative, and may provide greater resolution. These biomechanical measures include postural sway during both unilateral and bilateral standing tasks and the dynamic postural response to applied or volitional perturbations. The objective of this study was to investigate the utility of a dynamic balance system, a relatively new clinical tool incorporating dual force plates similar to that used in research laboratories, to assess the postural steadiness and stability of a small, diverse population of persons with lower-limb amputation. The specific aim was to investigate whether differences in balance of persons with amputation due to changes in prosthetic componentry were reflected in the resultant data. Materials and Methods Dynamic balance testing was conducted using the Bertec Balance Advantage–Dynamic CDP system on five adult subjects with varying levels of lower-limb amputation. Trials were conducted in both the subjects\u27 current prosthesis and alternative prosthetic componentry after a 1-week acclimation period. Specific tasks included limits of stability, weight-bearing squats, and unilateral stance. Results Subjects had difficulty shifting their weight during the limits of stability task; both the maximum excursion and anteroposterior directional control varied with prosthetic componentry. Load sharing also varied with prosthetic componentry. Load sharing became more asymmetric as knee flexion increased during the weight-bearing bilateral squat tasks, with less weight supported on the prosthetic limb. Finally, the metrics for the unilateral stance task varied with prosthetic componentry. Conclusions The dynamic balance system tasks and related metrics demonstrated the potential to discern differences in balance in persons with amputation due to changes in prosthetic componentry. Further study is needed to investigate these parameters, their correlation with clinical measures of balance, and the effects of both prosthetic componentry and alignment

Evaluation of Pediatric Manual Wheelchair Mobility Using Advanced Biomechanical Methods

There is minimal research of upper extremity joint dynamics during pediatric wheelchair mobility despite the large number of children using manual wheelchairs. Special concern arises with the pediatric population, particularly in regard to the longer duration of wheelchair use, joint integrity, participation and community integration, and transitional care into adulthood. This study seeks to provide evaluation methods for characterizing the biomechanics of wheelchair use by children with spinal cord injury (SCI). Twelve subjects with SCI underwent motion analysis while they propelled their wheelchair at a self-selected speed and propulsion pattern. Upper extremity joint kinematics, forces, and moments were computed using inverse dynamics methods with our custom model. The glenohumeral joint displayed the largest average range of motion (ROM) at 47.1° in the sagittal plane and the largest average superiorly and anteriorly directed joint forces of 6.1% BW and 6.5% BW, respectively. The largest joint moments were 1.4% body weight times height (BW × H) of elbow flexion and 1.2% BW × H of glenohumeral joint extension. Pediatric manual wheelchair users demonstrating these high joint demands may be at risk for pain and upper limb injuries. These evaluation methods may be a useful tool for clinicians and therapists for pediatric wheelchair prescription and training

The Influence of Age at Pediatric-Onset Spinal Cord Injury and Years of Wheelchair Use on Shoulder Complex Joint Dynamics During Manual Wheelchair Propulsion

Objective To assess the association of age at pediatric-onset spinal cord injury (SCI) and years of manual wheelchair use with shoulder dynamics. Design Upper extremity kinematics and hand-rim kinetics were obtained during manual wheelchair propulsion. An inverse dynamics model computed three-dimensional acromioclavicular, sternoclavicular, and glenohumeral joint dynamics. Linear mixed effects models evaluated the association of age at injury onset and years of wheelchair use with shoulder dynamics. Setting Motion laboratory within a children\u27s hospital. Participants Seventeen manual wheelchair users (N=17; 6 female, 11 male; mean age: 17.2 years, mean age at SCI onset: 11.5 years) with pediatric-onset SCI (levels: C4-T11) and International Standards for Neurological Classification of SCI grades: A (11), B (3), C (2), and N/A (2). Interventions Not applicable. Main Outcome Measures Acromioclavicular, sternoclavicular, and glenohumeral angles and ranges of motion, and glenohumeral forces and moments. Results We observed a decrease in maximum acromioclavicular upward rotation (ß [95% confidence interval {CI}]=3.02 [0.15,5.89], P=.039) and an increase in acromioclavicular downward/upward rotation range of motion (ß [95% CI]=0.44 [0.08,0.80], P=.016) with increasing age at SCI onset. We found interactions between age at onset and years of use for maximum glenohumeral abduction (ß [95% CI]=0.16 [0.03,0.29], P=.017), acromioclavicular downward/upward rotation range of motion (ß [95% CI]=-0.05 [-0.09,-0.01], P=.008), minimum acromioclavicular upward rotation (ß [95% CI]=-0.34 [-0.64,-0.04], P=.026). A decrease in glenohumeral internal rotation moment (ß [95% CI]=-0.09 [-0.17,-0.009], P=.029) with increasing years of use was found. Conclusions Age at injury and the years of wheelchair use are associated with shoulder complex biomechanics during wheelchair propulsion. These results are noteworthy, as both age at SCI onset and years of wheelchair use are considered important factors in the incidence of shoulder pain. These results suggest that investigations of biomechanical changes over the lifespan are critical

Longitudinal Evaluation of Variability of Stroke Patterns and Shoulder Forces in Pediatric SCI Wheelchair Users

Research Objectives To investigate changes in propulsive stroke patterns, glenohumeral joint forces, and pain in pediatric manual wheelchair users with respect to age to better understand risk for injury and contribute to training and rehabilitation. Design Longitudinal, prospective. Setting Motion Analysis Lab at Shriners Hospitals for Children-Chicago. Participants Three pediatric manual wheelchair users with spinal cord injury (SCI). Mean subject age for the first and second visit: 14.8 years (2.5 years) and 16.3 years (2.7 years), respectively. Bony level of SCI ranged from sixth cervical to ninth thoracic vertebra. Interventions Not applicable. Main Outcome Measures Propulsive stroke patterns and glenohumeral joint forces. Results There was significant variation in the stroke patterns, both within and between visits for all subjects. Additionally, patterns not represented by any of the four adult classifications were observed [1]. Further variation was seen in GH joint forces, as determined by our pediatric biomechanical model [1]. The average superior GH joint forces and the average lateral joint forces, both correlated with shoulder pathology [2], increased between visits, changing from 6.79 %BW to 8.53 %BW and from 5.70 %BW to 7.71 %BW, respectively. All other GH forces did not follow similar trends among subjects. Also, subjects with similar weight, time since injury, SCI level, and age differed in their joint forces and stroke patterns. The average reported pain on the Visual Analog Scale (VAS) [3] decreased from 6.67 (9.42) to 3.33 (4.71); however, one subject reported no change in pain. Conclusions While limited by the population size, the increased joint forces and fluctuating stroke patterns demonstrate the variability between these pediatric users. The variation in joint forces potentially resulting from the varied stroke patterns may be important in preventing overuse injuries and pain