A Biomechanical Simulation of Musculoskeletal Kinematics During Ambulation

The purpose of this study was to validate a 3D musculoskeletal model in OpenSim and assess OpenSim’s ability to determine muscle-length variation during ambulation. An 18 camera motion capture system was used to analyze 20 healthy individuals between the ages of 18 and 35. Following data collection, the data was processed through OpenSim and Visual3D. The kinematic output processed through the OpenSim model was then compared to the kinematic output of the validated Visual3D model to validate the OpenSim model. Muscle fiber length data obtained from the same experimental data was compared to control data to assess OpenSim’s muscle analysis functions. Spatiotemporal parameters including walking speed, left and right cadence, and stride length were also compared between the processed output from OpenSim and Visual3D. The mean maximum, minimum, and range of kinematics and muscle length data were calculated from the experimental and control data for comparison. Paired t test statistical analysis was performed in comparing the right and left limb kinematics between OpenSim and Visual3D. One sample t test statistical analysis was performed in comparing the muscle-length output from the experimental and control data. Both statistical tests were conducted at a 95% confidence interval. The paired t test statistical analysis concluded varying results of significant similarities and differences at each joint during stance and swing phase between both sets of data. The one sample t test also resulted in varying results of significant similarities and differences for muscles in stance and swing phase between both sets of data. OpenSim has variability in calculating inverse kinematics. Differences in the software compared to Visual3D support this claim. OpenSim’s ability to calculate muscle-length changes sets it apart from Visual3D. The difference in anatomical modeling in OpenSim and Visual3D attributes to their difference in kinematic output. OpenSim’s multitude of functions allows it to analyze different biomechanical aspects of human motion analysis. OpenSim’s ability to determine inverse kinematics and muscle-length variation during gait can ultimately help physicians, biomedical engineers and clinicians to further assess motion analysis and properly prescribe restorative surgeries and therapies

Survey of transfemoral amputee experience and priorities for the user-centered design of powered robotic transfemoral prostheses

BACKGROUND: Transfemoral amputees experience a complex host of physical, psychological, and social challenges, compounded by the functional limitations of current transfemoral prostheses. However, the specific relationships between human factors and prosthesis design and performance characteristics have not yet been adequately investigated. The present study aims to address this knowledge gap. METHODS: A comprehensive single-cohort survey of 114 unilateral transfemoral amputees addressed a broad range of demographic and clinical characteristics, functional autonomy, satisfaction and attitudes towards their current prostheses, and design priorities for an ideal transfemoral prosthesis, including the possibility of active assistance from a robotic knee unit. The survey was custom-developed based on several standard questionnaires used to assess motor abilities and autonomy in activities of daily living, prosthesis satisfaction, and quality of life in lower-limb amputees. Survey data were analyzed to compare the experience (including autonomy and satisfaction) and design priorities of users of transfemoral prostheses with versus without microprocessor-controlled knee units (MPKs and NMPKs, respectively), with a subsequent analyses of cross-category correlation, principal component analysis (PCA), cost-sensitivity segmentation, and unsupervised K-means clustering applied within the most cost-sensitive participants, to identify functional groupings of users with respect to their design priorities. RESULTS: The cohort featured predominantly younger (< 50 years) traumatic male amputees with respect to the general transfemoral amputee population, with pronounced differences in age distribution and amputation etiology (traumatic vs. non-traumatic) between MPK and NMPK groups. These differences were further reflected in user experience, with MPK users reporting significantly greater overall functional autonomy, satisfaction, and sense of prosthesis ownership than those with NMPKs, in conjunction with a decreased incidence of instability and falls. Across all participants, the leading functional priorities for an ideal transfemoral prosthesis were overall stability, adaptability to variable walking velocity, and lifestyle-related functionality, while the highest-prioritized general characteristics were reliability, comfort, and weight, with highly variable prioritization of cost according to reimbursement status. PCA and user clustering analyses revealed the possibility for functionally relevant groupings of prosthesis features and users, based on their differential prioritization of these features—with implications towards prosthesis design tradeoffs. CONCLUSIONS: This study’s findings support the understanding that when appropriately prescribed according to patient characteristics and needs in the context of a proactive rehabilitation program, advanced transfemoral prostheses promote patient mobility, autonomy, and overall health. Survey data indicate overall stability, modularity, and versatility as key design priorities for the continued development of transfemoral prosthesis technology. Finally, observed associations between prosthesis type, user experience, and attitudes concerning prosthesis ownership suggest both that prosthesis characteristics influence device acceptance and functional outcomes, and that psychosocial factors should be specifically and proactively addressed during the rehabilitation process. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12984-021-00944-x

An Insight into the acceptable use and assessment of lower-limb running prostheses in disability sport.

Sports technology can be any product or system used to facilitate, train or influence an athlete’s performance. The role of prostheses used for disability sport was initially to help facilitate exercise and then ultimately, competition. In able-bodied sport, controversy has occasionally been caused through the adoption or introduction of sports technology. However, scant attention has been paid to sport with a disability with respect to such concerns. This research project provides a novel contribution to knowledge by investigating the use of lower-limb running prostheses in competition by trans-tibial amputees. A novel study using a mixed method approach has investigated the nature, use and assessment of lower-limb running prostheses. It has proposed that the unchecked introduction of such technology has affected the sport negatively. From this, the study conducted a stakeholder assessment of the sport and provided a proposed series of guidelines for lower-limb prostheses technology inclusion. Finally, the recommendation was made that a proactive approach to such technologies’ inclusion in the future should be implemented. These guidelines were further developed by assessing symmetrical and nonsymmetrical lower-limb function and proposed that single and double lowerlimb amputees should be separated in competition in the future. To this end, it was proposed that lower-limb symmetry, stiffness and energy return were important means of monitoring prosthesis performance. Ultimately, a dynamic technique which assesses these qualities was proposed as an assessment strategy for further development in the future

Eccentric cycling rehabilitation after anterior cruciate ligament reconstruction: a randomised controlled trial of strength and biomechanical outcomes

After anterior cruciate ligament reconstruction (ACL-R), persistent strength and biomechanical deviations remain. Reducing these by training may reduce risk of re-injury or osteoarthritis for these patients. A cross-sectional study investigated biomechanics of ACL-R male patients long-term (~5 years) post surgery. Fifteen ACL-R and fifteen healthy controls were tested in walking and running using motion capture. Devi- ations were found, primarily between-limbs, and also between groups. Largest deviations were lower knee angles and moments in the affected limb during running. However, these were not found during walking; thus, differences were highlighted by the higher-intensity task. During running, knee abduction moment was lower (more valgus) for the affected compared to unaffected and control limbs. The larger effects in moment show greater clinical potential than knee valgus angle. The ACL-R patients had lower impact foot strike during running than controls. The above results indicate chronic, clinical changes in joint loading. A randomised controlled intervention trial evaluated progressive eccentric cycling for ACL-R males, compared to concentric controls. This is one of the first trials of eccentric vs. concentric training for ACL-R, matched by rating of perceived exertion. Twenty-six adult males, 12 weeks post hamstring-graft ACL-R trained three times/week for 8 weeks under supervision. During training the eccentric group limb powers absorbed were higher than those produced by the concentric group, with a lower heart rate. For both groups, pain scores were low, and one of the patient-reported outcomes (IKDC) improved. Hamstring strength increased in the eccentric group by 15%, but this was not seen in the concentric group. For both groups, 60°/s quadriceps strength increased by a similar amount, approximately 28%. Biomechanically, eccentric training was more effective than matched concen- tric training at resolving knee (P=0.022, walk) and hip (P =0.010, run) flexion angle deviations in the affected limb. In both groups, knee extension moments increased, reducing asymmetries. Large knee abduction moment deviations at baseline were not reduced by either programme (P >0.05). At follow-up (~6 months), both groups showed similar return-to-sports progress; several patients passed using one criterion (IKDC), and none passed using a stricter four-criteria method (Univ. Delaware). Thus it can be concluded that for adult ACL-R males, eccentric cycle training is clinically acceptable, with similar or in some cases better outcomes than concentric cycle training. It improves patient-reported outcomes, strength recovery, biomechanical deviations, and return-to-sports measures

Assessment and exercise for Freezing of Gait in Parkinson’s Disease

Parkinson&#39;s disease (PD) is a neurodegenerative disorder characterized through multiple motor- and non-motor symptoms. Gait disorders and balance deficits are very common in people with PD and often cannot be fully alleviated by standard therapy. The mentioned deficits not only lower the quality of life but also increase the risk for falls. Especially people with PD who experience Freezing of Gait (FOG), an episodic gait disturbance, are at risk and need individualized therapy options. Therefore, exercise and physical therapy have become increasingly important in the rehabilitation of PD. This work aims to investigate the validity and reliability for assessment methods for FOG and check their potential as outcome measures for clinical trials. Furthermore, it explores feasibility and treatment options of the Split-belt treadmill (SBT) as a tool modulate gait asymmetry in people with PD as well as the short-term effects on gait. Study 1 focused on the validity of the German version of the New Freezing of Gait-Questionnaire. It found that the translated version was a valid instrument to assess the severity of FOG in the German-speaking PD population. Study 2 investigated the within-session reliability of the assessment of anticipatory postural adjustment in PD+FOG and found a high variability in the reliability scores, depending on the outcome of interest. Study 3 summarized the current literature on SBT walking in people with PD and showed that people with PD can successfully adapt their gait to the split belts. The final study investigated the short-term effects of one SBT training session and found that SBT with changing conditions was most useful to improve gait adaptation in PD+FOG. This thesis provides some important findings regarding the assessment of FOG and highlights opportunities for suitable outcome measures for clinical studies in this field. Furthermore, it highlights the potential of SBT training for the rehabilitation of PD by showing that it is feasible, safe and above all has positive effects on gait adaptation in people with PD. Those findings give important implications for the selection of outcome measure and the design of training interventions for PD+FOG in future studies

In-clinic Functional Measurement and Analysis of Knee Osteoarthritis Patients Undergoing Total Knee Replacement

Prevalence of osteoarthritis is increasing as individuals are remaining active later in life. Since the knee is one of the most commonly affected joints and is involved in almost all daily activities, functional impairment has a substantial impact on overall health. Despite this increase, there currently exists no disease modifying drugs or treatments. Mild cases are managed with physiotherapeutic exercises and common anti-inflammatories but surgical intervention is required for more severe disease progression. Total knee replacement as a treatment for osteoarthritis is a highly successful surgery that is effective at restoring knee function and reducing pain but still requires further refinement. Over 70,000 of these surgeries are performed annually in Canada with 99% for the treatment of degenerative arthritis. Despite improvements to surgical technique and implant designs, studies report up to 20% of patients remain dissatisfied with their knee replacement up to the point of not undergoing the surgery again if it were an option. A singular cause for this dissatisfaction has not been pinpointed but strong influencers are pain, low functional improvement, and unmet expectations. Early detection of functional problems permits further intervention through targeted physiotherapy or additional surgeries before problems escalate and cause patient dissatisfaction or implant revision. Current methods of patient evaluation rely on self-reported measures, which suffer from ceiling and floor effects often masking inter-patient differences. These measures are also influenced from patient expectations and what a patient reports they can\u27\u27 do, is not always representative of their true functional ability. Wearable sensors permit objective functional measurement of the knee as a supplement to patient-reported measures. Instrumented performance tests can measure patient function and compare to similar recoveries to highlight deficiencies or positive recovery traits. This thesis outlines the development of such a wearable system for in-clinic measurement and the extraction of functional parameters to predict future outcomes and give surgeons the earliest indications for intervention. This information can also help surgeons realistically adjust patient expectations for recovery, even before undergoing surgery. It is expected that these individualized assessments to set expectations before surgical intervention will help address the persistently high patient dissatisfaction

New Insights into the Landing Phase of Reactive Stepping: Predictors of Control, Muscle Recruitment, Movement Restraints and Two-Step Responses

Preventing falls and fall-related injuries are public health challenges of the upmost importance for Canadians, particularly for older adults. Due to the severe consequences that can accompany a fall (e.g., traumatic brain injuries, hip fractures), studying age-related changes in balance control is an important avenue towards informing more effective fall-prevention interventions. As tripping is a common cause of falling in older adults, many researchers have studied reactive stepping after a simulated trip. While the majority of studies have focused on recovery at foot-contact (FC), researchers have begun to focus on the landing phase (or restabilisation phase), which occurs after the point of FC of the reactive step. This thesis adds to the burgeoning insights in this important area by addressing the following four general objectives: i) determine which individual characteristics are predictive of center of mass (COM) displacement during the reactive stepping and landing phases in young and older adults (Study 1); ii) determine how lower-limb muscle recruitment patterns during the landing phase compare to earlier phases of the reactive stepping response, as well as how lower-limb electromyography signals relate to each other during the landing phase (Study 2); iii) determine if wide stepping and restricted arm movement influence balance control during the landing phase (Study 3); and, iv) to quantify balance control after FC when participants responded with two reactive steps (Study 4). Reactive stepping was evoked via a tether-release paradigm. In Study 1, it was found that for both young and older adults, regression models driven by specific tether-release metrics were stronger predictors of COM movement during the stepping and landing phases compared to general metrics, calculated separately from the tether-release trials (e.g., response time, range-of-motion, etc.). For Study 2, which quantified lower-limb electromyography (EMG), the peak timing and magnitude were generally slower (more variable) and smallest from the point of the maximum COM after FC to the end of the trial. The muscles which exhibited their highest peak magnitude during the landing phase were the biceps femoris of the step-leg, which was correlated with the peak medial gastrocnemius magnitude during landing, and the rectus femoris and tibialis anterior of the support-leg. Peak magnitudes suggest that the step-leg biceps femoris and medial gastrocnemius and support-leg rectus femoris (in continuation from the swing phase) and tibialis anterior are important during landing, while the step-leg rectus femoris and tibialis anterior are important in the swing phase. Regarding the investigation of wide stepping and restricted arm movement in Study 3, wide stepping resulted in the largest medio-lateral (ML) and anterior-posterior (AP) body movement after FC, regardless of age group. Second, despite limited AP influence, restricted arm movement resulted in larger ML body movement after FC, compared to the preferred stepping condition. During Study 4, analyses of the first step revealed that during the two-step condition peak AP COM displacement after FC was increased, while peak ML COM displacement was decreased, for both loading conditions. With asymmetrical loading, first step lengths were larger during the one-step condition, while first step width was reduced over both stepping tasks with asymmetrical loading. During two-steps, peak AP extrapolated COM (xCOM) displacement after FC was larger in the second vs. the first step with asymmetrical loading, yet the first step resulted in greater ML xCOM displacement vs. the second step, regardless of loading. Interestingly, first step width was narrower than the second with asymmetrical loading. As hypothesized, peak xCOM displacement between the first and second steps was correlated. As a whole, the results of these studies provide novel insights into the landing phase of reactive stepping. A consistent theme pertains to the potential ability of pro-actively training effective reactive stepping responses. The findings suggest that researchers and clinicians should consider task specificity if training reactive stepping responses. Furthermore, focus should be placed on the muscles which were their most active (and correlated) during landing, (i.e., the biceps femoris and medial gastrocnemius of the step-leg). The large stability margin observed during wide stepping suggests it can be a positive strategy for increased ML stability. Incorporating the arms into training would also be positive, as ML COM control decreased when the arms were restricted. Finally, multi-step balance control should not be inferred using single-step responses, as differences in COM\xCOM displacement existed between stepping tasks and step number. Further, xCOM correlations between the first and second step did not improve when the one-step responses were used for the first step metrics. To further enhance the evidence base in this area, future work could focus on characterizing landing phase control during more dynamic activities such as tripping during gait, ideally with participants who represent high-fall risk groups

Watch your step! Towards predicting osteoarthritis onset based on side-to-side imbalances

Osteoarthritis (OA) is a debilitating disease characterized by the erosion of articular cartilage at the extremity of bones. OA contributes to economic burdens, pain, and abnormal locomotion to accommodate for loss of protective cartilage. Since there is no cure for OA, mitigating disease onset can relieve the lives of millions of people who are at higher risk of OA such as females and overweight people.The progressive disappearance of protective cartilage leads to bone-on-bone contact at the joints, which is aggravated by higher-than-normal joint contact forces. Although OA can affect any joint, the primary weight-bearing joints of the lower body, i.e. hip, knee, and ankle, suffer the most impairment. Thus, investigating walking behavior can aid in detecting abnormal locomotion that may lead to OA.The objectives of this study were (1) to investigate a simple mechanical model’s ability to accurately reproduce measured gait kinetics and (2) to propose and evaluate novel parameters to supplement current noninvasive clinical tools for gait analysis.For a total of forty healthy subjects, kinematic and kinetic parameters were optimized for 300 consecutive steps to fit experimental vertical ground reaction force data measured during treadmill walking. Using an existing inverted spring-loaded pendulum with a spring-loaded ankle, we assessed the variations in leg and ankle stiffnesses during gait. We quantified bilateral lower limb symmetry, gait regularity, and gait variability based on the optimized stiffness values, which highlighted gait disparities between males and females, and between different body mass index categories.Our results confirmed that all subjects exhibited a certain amount of side-to-side asymmetry, irregularity, and variability in their leg and ankle stiffnesses during walking. Furthermore, large inter-subject variability indicated that our simple model could detect idiosyncratic gait patterns and therefore estimate potential imbalances in gait patterns. Future studies to test these walking assessments with accelerations as input parameters, which are easier to measure in a clinical setting, can improve current screenings for OA