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Richard R Neptune - One of the best experts on this subject based on the ideXlab platform.
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hip recovery strategy used by below knee Amputees following mediolateral foot perturbations
Journal of Biomechanics, 2018Co-Authors: Sarah E Miller, Ava D Segal, Glenn K Klute, Richard R NeptuneAbstract:Abstract Lower-limb Amputees have a higher risk of falling compared to non-Amputees. Proper regulation of whole-body angular momentum is necessary to prevent falls, particularly in the frontal plane where individuals are most unstable. However, the balance recovery mechanisms used by lower-limb Amputees when recovering from a perturbation are not well-understood. This study sought to understand the balance recovery mechanisms used by lower-limb Amputees in response to mediolateral foot perturbations by examining changes to frontal plane whole-body angular momentum and hip joint work. These metrics provide a quantitative measure of frontal plane dynamic balance and associated joint contributions required to maintain balance during gait. Nine Amputees and 11 non-Amputees participated in this study where an unexpected medial or lateral foot placement perturbation occurred immediately prior to heel strike on the residual, sound or non-Amputee limbs. Lateral perturbations of all limbs resulted in a reduced range of whole-body angular momentum and increased positive frontal plane hip work in the first half of single limb support. Medial perturbations for all limbs resulted in increased range of whole-body angular momentum and decreased positive frontal plane hip work, also in the first half of single limb support. These results suggest that medial foot placement perturbations are particularly challenging and that hip strategies play an important role in balance recovery. Thus, rehabilitation interventions that focus on hip muscles that regulate mediolateral balance, particularly the hip abductors, and the use of prostheses with active ankle control, may reduce the risk of falls.
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optimization of prosthetic foot stiffness to reduce metabolic cost and intact knee loading during below knee Amputee walking a theoretical study
Journal of Biomechanical Engineering-transactions of The Asme, 2012Co-Authors: Nicholas P Fey, Glenn K Klute, Richard R NeptuneAbstract:Unilateral below-knee Amputees develop abnormal gait characteristics that include bilateral asymmetries and an elevated metabolic cost relative to non-Amputees. In addition, long-term prosthesis use has been linked to an increased prevalence of joint pain and osteoarthritis in the intact leg knee. To improve Amputee mobility, prosthetic feet that utilize elastic energy storage and return (ESAR) have been designed, which perform important biomechanical functions such as providing body support and forward propulsion. However, the prescription of appropriate design characteristics (e.g., stiffness) is not well-defined since its influence on foot function and important in vivo biomechanical quantities such as metabolic cost and joint loading remain unclear. The design of feet that improve these quantities could provide considerable advancements in Amputee care. Therefore, the purpose of this study was to couple design optimization with dynamic simulations of Amputee walking to identify the optimal foot stiffness that minimizes metabolic cost and intact knee joint loading. A musculoskeletal model and distributed stiffness ESAR prosthetic foot model were developed to generate muscle-actuated forward dynamics simulations of Amputee walking. Dynamic optimization was used to solve for the optimal muscle excitation patterns and foot stiffness profile that produced simulations that tracked experimental Amputee walking data while minimizing metabolic cost and intact leg internal knee contact forces. Muscle and foot function were evaluated by calculating their contributions to the important walking subtasks of body support, forward propulsion and leg swing. The analyses showed that altering a nominal prosthetic foot stiffness distribution by stiffening the toe and mid-foot while making the ankle and heel less stiff improved ESAR foot performance by offloading the intact knee during early to mid-stance of the intact leg and reducing metabolic cost. The optimal design also provided moderate braking and body support during the first half of residual leg stance, while increasing the prosthesis contributions to forward propulsion and body support during the second half of residual leg stance. Future work will be directed at experimentally validating these results, which have important implications for future designs of prosthetic feet that could significantly improve Amputee care.
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muscle and prosthesis contributions to Amputee walking mechanics a modeling study
Journal of Biomechanics, 2012Co-Authors: Anne K. Silverman, Richard R NeptuneAbstract:Unilateral, below-knee Amputees have altered gait mechanics, which can significantly affect their mobility. Below-knee Amputees lose the functional use of the ankle muscles, which are critical during walking to provide body support, forward propulsion, leg-swing initiation and mediolateral balance. Thus, either muscles must compensate or the prosthesis must provide the functional tasks normally provided by the ankle muscles. Three-dimensional (3D) forward dynamics simulations of Amputee and non-Amputee walking were generated to identify muscle and prosthesis contributions to Amputee walking mechanics, including the subtasks of body support, forward propulsion, leg-swing initiation and mediolateral balance. Results showed that the prosthesis provided body support in the absence of the ankle muscles. The prosthesis contributed to braking from early to mid-stance and propulsion in late stance. The prosthesis also functioned like the uniarticular soleus muscle by transferring energy from the residual leg to the trunk to provide trunk propulsion. The residual-leg vasti and rectus femoris reduced their contributions to braking in early stance, which mitigated braking from the prosthesis during this period. The prosthesis did not replace the function of the gastrocnemius, which normally generates energy to the leg to initiate swing. As a result, lower overall energy was delivered to the residual leg. The prosthesis also acted to accelerate the body laterally in the absence of the ankle muscles. These results provide further insight into muscle and prosthesis function in below-knee Amputee walking and can help guide rehabilitation methods and device designs to improve Amputee mobility.
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the effects of prosthetic ankle dorsiflexion and energy return on below knee Amputee leg loading
Clinical Biomechanics, 2011Co-Authors: Jessica D. Ventura, Glenn K Klute, Richard R NeptuneAbstract:Abstract Background Prosthetic devices are intended to return lower limb Amputees to their pre-amputation functional status. However, prosthetic devices designed for unilateral below-knee Amputees have yet to completely restore the biomechanical functions normally provided by the ankle muscles, leading to gait asymmetries and increased reliance on their intact leg. In an effort to improve Amputee gait, energy storage and return feet have been developed that store mechanical energy in elastic structures in early to mid-stance and return it in late stance. However, little is known regarding how ankle compliance and the level of energy return influences walking mechanics. The purpose of this study was to identify the influence of prosthetic ankle dorsiflexion and energy storage and return on leg loading during steady-state walking. Methods Compliant ankles with different stiffness levels were attached to a Seattle Lightfoot2 in different orientations (forward- and reverse-facing). Findings The ankles decreased residual leg vertical ground reaction forces in late stance, increased residual leg propulsive ground reaction force impulses and increased residual leg knee joint extensor moments. The reverse-facing ankles increased residual leg vertical ground reaction forces in early stance, and the compliant forward-facing ankle increased residual leg braking impulses. In contrast to previous studies, increased energy storage and return from compliant ankles did not decrease hip joint powers or the intact leg vertical ground reaction forces. Interpretation These results provide insight into the relationships between ankle dorsiflexion, energy storage and return, and leg loading, which may lead to more effective prosthetic devices to improve Amputee gait.
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Differences in whole-body angular momentum between below-knee Amputees and non-Amputees across walking speeds
Journal of Biomechanics, 2011Co-Authors: Anne K. Silverman, Richard R NeptuneAbstract:Unilateral, below-knee Amputees have an increased risk of falling compared to non-Amputees. The regulation of whole-body angular momentum is important for preventing falls, but little is known about how Amputees regulate angular momentum during walking. This study analyzed three-dimensional, whole-body angular momentum at four walking speeds in 12 Amputees and 10 non-Amputees. The range of angular momentum in all planes significantly decreased with increasing walking speed for both groups. However, the range of frontal-plane angular momentum was greater in Amputees compared to non-Amputees at the first three walking speeds. This range was correlated with a reduced second vertical ground reaction force peak in both the intact and residual legs. In the sagittal plane, the Amputee range of angular momentum in the first half of the residual leg gait cycle was significantly larger than in the non-Amputees at the three highest speeds. In the second half of the gait cycle, the range of sagittal-plane angular momentum was significantly smaller in Amputees compared to the non-Amputees at all speeds. Correlation analyses suggested that the greater range of angular momentum in the first half of the Amputee gait cycle is associated with reduced residual leg braking and that the smaller range of angular momentum in the second half of the gait cycle is associated with reduced residual leg propulsion. Thus, reducing residual leg braking appears to be a compensatory mechanism to help regulate sagittal-plane angular momentum over the gait cycle, but may lead to an increased risk of falling.
Glenn K Klute - One of the best experts on this subject based on the ideXlab platform.
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hip recovery strategy used by below knee Amputees following mediolateral foot perturbations
Journal of Biomechanics, 2018Co-Authors: Sarah E Miller, Ava D Segal, Glenn K Klute, Richard R NeptuneAbstract:Abstract Lower-limb Amputees have a higher risk of falling compared to non-Amputees. Proper regulation of whole-body angular momentum is necessary to prevent falls, particularly in the frontal plane where individuals are most unstable. However, the balance recovery mechanisms used by lower-limb Amputees when recovering from a perturbation are not well-understood. This study sought to understand the balance recovery mechanisms used by lower-limb Amputees in response to mediolateral foot perturbations by examining changes to frontal plane whole-body angular momentum and hip joint work. These metrics provide a quantitative measure of frontal plane dynamic balance and associated joint contributions required to maintain balance during gait. Nine Amputees and 11 non-Amputees participated in this study where an unexpected medial or lateral foot placement perturbation occurred immediately prior to heel strike on the residual, sound or non-Amputee limbs. Lateral perturbations of all limbs resulted in a reduced range of whole-body angular momentum and increased positive frontal plane hip work in the first half of single limb support. Medial perturbations for all limbs resulted in increased range of whole-body angular momentum and decreased positive frontal plane hip work, also in the first half of single limb support. These results suggest that medial foot placement perturbations are particularly challenging and that hip strategies play an important role in balance recovery. Thus, rehabilitation interventions that focus on hip muscles that regulate mediolateral balance, particularly the hip abductors, and the use of prostheses with active ankle control, may reduce the risk of falls.
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lower limb Amputee recovery response to an imposed error in mediolateral foot placement
Journal of Biomechanics, 2014Co-Authors: Ava D Segal, Glenn K KluteAbstract:Despite walking with a wider step width, Amputees remain 20% more likely to fall than non-Amputees. Since mediolateral (ML) balance is critical for ambulation and contingent on ML foot placement, we used a ML disturbance to perturb walking balance and explore the influence of prosthetic foot stiffness on balance recovery. Ten transtibial Amputees were fit with two commonly prescribed prosthetic feet with differing stiffness characteristics; 12 non-Amputees also participated. A perturbation device that released an air burst just before heel strike imposed a repeatable medial or lateral disturbance in foot placement. After a medial disturbance, the first recovery step width was narrowed (p<0.0001) for the prosthetic limb (−103%), the sound limb (−51%) and non-Amputees (−41%) and more than twice as variable. The ML inclination angle remained reduced (−109%) for the prosthetic limb, while the sound limb and non-Amputees approached undisturbed levels (p<0.0004). Amputees required five steps to return to undisturbed step width after a prosthetic medial disturbance versus two steps for the sound limb and for non-Amputees. After a lateral disturbance, the first recovery step was widened for the prosthetic limb (+82%), sound limb (+75%), and wider than non-Amputees (+51%; p<0.0001), with all participants requiring three steps to return to undisturbed step width. Amputees also exhibited a similar upper torso response compared to the non-Amputees for both disturbances. Prosthetic feet with different stiffness properties did not have a significant effect. In conclusion, Amputee balance was particularly challenged by medial disturbances to the prosthetic limb implying a need for improved interventions that address these balance deficits.
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optimization of prosthetic foot stiffness to reduce metabolic cost and intact knee loading during below knee Amputee walking a theoretical study
Journal of Biomechanical Engineering-transactions of The Asme, 2012Co-Authors: Nicholas P Fey, Glenn K Klute, Richard R NeptuneAbstract:Unilateral below-knee Amputees develop abnormal gait characteristics that include bilateral asymmetries and an elevated metabolic cost relative to non-Amputees. In addition, long-term prosthesis use has been linked to an increased prevalence of joint pain and osteoarthritis in the intact leg knee. To improve Amputee mobility, prosthetic feet that utilize elastic energy storage and return (ESAR) have been designed, which perform important biomechanical functions such as providing body support and forward propulsion. However, the prescription of appropriate design characteristics (e.g., stiffness) is not well-defined since its influence on foot function and important in vivo biomechanical quantities such as metabolic cost and joint loading remain unclear. The design of feet that improve these quantities could provide considerable advancements in Amputee care. Therefore, the purpose of this study was to couple design optimization with dynamic simulations of Amputee walking to identify the optimal foot stiffness that minimizes metabolic cost and intact knee joint loading. A musculoskeletal model and distributed stiffness ESAR prosthetic foot model were developed to generate muscle-actuated forward dynamics simulations of Amputee walking. Dynamic optimization was used to solve for the optimal muscle excitation patterns and foot stiffness profile that produced simulations that tracked experimental Amputee walking data while minimizing metabolic cost and intact leg internal knee contact forces. Muscle and foot function were evaluated by calculating their contributions to the important walking subtasks of body support, forward propulsion and leg swing. The analyses showed that altering a nominal prosthetic foot stiffness distribution by stiffening the toe and mid-foot while making the ankle and heel less stiff improved ESAR foot performance by offloading the intact knee during early to mid-stance of the intact leg and reducing metabolic cost. The optimal design also provided moderate braking and body support during the first half of residual leg stance, while increasing the prosthesis contributions to forward propulsion and body support during the second half of residual leg stance. Future work will be directed at experimentally validating these results, which have important implications for future designs of prosthetic feet that could significantly improve Amputee care.
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the effects of a controlled energy storage and return prototype prosthetic foot on transtibial Amputee ambulation
Human Movement Science, 2012Co-Authors: Ava D Segal, Glenn K Klute, Michael S. Orendurff, Karl E Zelik, David C Morgenroth, Michael E Hahn, Peter G Adamczyk, Steven H Collins, Arthur D Kuo, Joseph M. CzernieckiAbstract:The lack of functional ankle musculature in lower limb Amputees contributes to the reduced prosthetic ankle push-off, compensations at other joints and more energetically costly gait commonly observed in comparison to non-Amputees. A variety of energy storing and return prosthetic feet have been developed to address these issues but have not been shown to sufficiently improve Amputee biomechanics and energetic cost, perhaps because the timing and magnitude of energy return is not controlled. The goal of this study was to examine how a prototype microprocessor-controlled prosthetic foot designed to store some of the energy during loading and return it during push-off affects Amputee gait. Unilateral transtibial Amputees wore the Controlled Energy Storage and Return prosthetic foot (CESR), a conventional foot (CONV), and their previously prescribed foot (PRES) in random order. Three-dimensional gait analysis and net oxygen consumption were collected as participants walked at constant speed. The CESR foot demonstrated increased energy storage during early stance, increased prosthetic foot peak push-off power and work, increased prosthetic limb center of mass (COM) push-off work and decreased intact limb COM collision work compared to CONV and PRES. The biological contribution of the positive COM work for CESR was reduced compared to CONV and PRES. However, the net metabolic cost for CESR did not change compared to CONV and increased compared to PRES, which may partially reflect the greater weight, lack of individualized size and stiffness and relatively less familiarity for CESR and CONV. Controlled energy storage and return enhanced prosthetic push-off, but requires further design modifications to improve Amputee walking economy.
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the effects of prosthetic ankle dorsiflexion and energy return on below knee Amputee leg loading
Clinical Biomechanics, 2011Co-Authors: Jessica D. Ventura, Glenn K Klute, Richard R NeptuneAbstract:Abstract Background Prosthetic devices are intended to return lower limb Amputees to their pre-amputation functional status. However, prosthetic devices designed for unilateral below-knee Amputees have yet to completely restore the biomechanical functions normally provided by the ankle muscles, leading to gait asymmetries and increased reliance on their intact leg. In an effort to improve Amputee gait, energy storage and return feet have been developed that store mechanical energy in elastic structures in early to mid-stance and return it in late stance. However, little is known regarding how ankle compliance and the level of energy return influences walking mechanics. The purpose of this study was to identify the influence of prosthetic ankle dorsiflexion and energy storage and return on leg loading during steady-state walking. Methods Compliant ankles with different stiffness levels were attached to a Seattle Lightfoot2 in different orientations (forward- and reverse-facing). Findings The ankles decreased residual leg vertical ground reaction forces in late stance, increased residual leg propulsive ground reaction force impulses and increased residual leg knee joint extensor moments. The reverse-facing ankles increased residual leg vertical ground reaction forces in early stance, and the compliant forward-facing ankle increased residual leg braking impulses. In contrast to previous studies, increased energy storage and return from compliant ankles did not decrease hip joint powers or the intact leg vertical ground reaction forces. Interpretation These results provide insight into the relationships between ankle dorsiflexion, energy storage and return, and leg loading, which may lead to more effective prosthetic devices to improve Amputee gait.
Joseph M. Czerniecki - One of the best experts on this subject based on the ideXlab platform.
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transfemoral Amputee intact limb loading and compensatory gait mechanics during down slope ambulation and the effect of prosthetic knee mechanisms
Clinical Biomechanics, 2018Co-Authors: David C Morgenroth, Michelle Roland, Alison L Pruziner, Joseph M. CzernieckiAbstract:Abstract Background Intact limb knee osteoarthritis is a prevalent secondary disability in transfemoral Amputees. Walking down a ramp may increase this risk due to excessive limb loading. We sought to determine whether intact limb loading differed between transfemoral Amputees and controls during down slope ambulation, and the compensatory strategies transfemoral Amputees used to modify intact limb loading. Secondarily, we sought to determine the effect of prosthetic knee type. Methods Five unilateral transfemoral Amputees and five non-Amputee controls walked down a ramp and the following outcome measures were compared between Amputees and controls and across prosthetic knee type (C-leg versus Power Knee): step length, walking speed, leading limb ground reaction forces, and trailing and leading limb ankle and knee energy absorption. Linear mixed effects regression was used to test for association between gait variables and limb. Findings There were no significant differences in intact limb loading between Amputees and controls or between prosthetic knee types. Transfemoral Amputees walked slower (C-leg - control = −0.29 m/s; P = 0.008, Power Knee – control = −0.38 m/s; P Interpretation Intact limb loading in transfemoral Amputees is equivalent to controls during down ramp ambulation, in spite of reduced prosthetic trailing limb energy absorption. The primary compensatory strategies include a reduced ambulation speed and intact limb step length, which reduces center of mass velocity at heel contact.
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the development and validation of a novel outcome measure to quantify mobility in the dysvascular lower extremity Amputee the Amputee single item mobility measure
Clinical Rehabilitation, 2016Co-Authors: Daniel C Norvell, Rhonda M. Williams, Aaron P Turner, Joseph M. CzernieckiAbstract:Objective:This study describes the development and psychometric evaluation of a novel patient-reported single-item mobility measure.Design:Prospective cohort study.Setting:Four Veteran’s Administration Medical Centers.Subjects:Individuals undergoing their first major unilateral lower extremity amputation; 198 met inclusion criteria; of these, 113 (57%) enrolled.Interventions:None.Main measures:The Amputee Single Item Mobility Measure, a single item measure with scores ranging from 0 to 6, was developed by an expert panel, and concurrently administered with the Locomotor Capabilities Index-5 (LCI-5) and other outcome measures at six weeks, four months, and 12 months post-amputation. Criterion and construct validity, responsiveness, and floor/ceiling effects were evaluated. Responsiveness was assessed using the standardized response mean.Results:The overall mean 12-month Amputee Single Item Mobility Measure score was 3.39 ±1.4. Scores for transmetatarsal, transtibial, and transfemoral Amputees were 4.2 (±1....
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the effects of a controlled energy storage and return prototype prosthetic foot on transtibial Amputee ambulation
Human Movement Science, 2012Co-Authors: Ava D Segal, Glenn K Klute, Michael S. Orendurff, Karl E Zelik, David C Morgenroth, Michael E Hahn, Peter G Adamczyk, Steven H Collins, Arthur D Kuo, Joseph M. CzernieckiAbstract:The lack of functional ankle musculature in lower limb Amputees contributes to the reduced prosthetic ankle push-off, compensations at other joints and more energetically costly gait commonly observed in comparison to non-Amputees. A variety of energy storing and return prosthetic feet have been developed to address these issues but have not been shown to sufficiently improve Amputee biomechanics and energetic cost, perhaps because the timing and magnitude of energy return is not controlled. The goal of this study was to examine how a prototype microprocessor-controlled prosthetic foot designed to store some of the energy during loading and return it during push-off affects Amputee gait. Unilateral transtibial Amputees wore the Controlled Energy Storage and Return prosthetic foot (CESR), a conventional foot (CONV), and their previously prescribed foot (PRES) in random order. Three-dimensional gait analysis and net oxygen consumption were collected as participants walked at constant speed. The CESR foot demonstrated increased energy storage during early stance, increased prosthetic foot peak push-off power and work, increased prosthetic limb center of mass (COM) push-off work and decreased intact limb COM collision work compared to CONV and PRES. The biological contribution of the positive COM work for CESR was reduced compared to CONV and PRES. However, the net metabolic cost for CESR did not change compared to CONV and increased compared to PRES, which may partially reflect the greater weight, lack of individualized size and stiffness and relatively less familiarity for CESR and CONV. Controlled energy storage and return enhanced prosthetic push-off, but requires further design modifications to improve Amputee walking economy.
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Comparison of transtibial Amputee and non-Amputee biomechanics during a common turning task.
Gait & Posture, 2011Co-Authors: Ava D Segal, Michael S. Orendurff, Joseph M. Czerniecki, Jason A. Schoen, Glenn K KluteAbstract:The biomechanics of Amputee turning gait has been minimally studied, in spite of its integral relationship with the more complex gait required for household or community ambulation. This study compares the biomechanics of unilateral transtibial Amputees and non-Amputees completing a common turning task. Full body gait analysis was completed for subjects walking at comparable self-selected speeds around a 1m radius circular path. Peak internal and external rotation moments of the hip, knee and ankle, mediolateral ground reaction impulse (ML GRI), peak effective limb length, and stride length were compared across conditions (non-Amputee, Amputee prosthetic limb, Amputee sound limb). Amputees showed decreased internal rotation moments at the prosthetic limb hip and knee compared to non-Amputees, perhaps as a protective mechanism to minimize stress on the residual limb. There was also an increase in Amputee sound limb hip external rotation moment in early stance compared to non-Amputees, which may be a compensation for the decrease in prosthetic limb internal rotation moment during late stance of the prior step. ML GRI was decreased for the Amputee inside limb compared to non-Amputee, possibly to minimize the body's acceleration in the direction of the turn. Amputees also exhibited a shorter inside limb stride length compared to non-Amputees. Both decreased ML GRI and stride length indicate a COM that is more centered over the base of support, which may minimize the risk of falling. Finally, a longer effective limb length was found for the Amputee inside limb turning, possibly due to excessive trunk shift.
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kinematic and kinetic comparisons of transfemoral Amputee gait using c leg and mauch sns prosthetic knees
Journal of Rehabilitation Research and Development, 2006Co-Authors: Ava D Segal, Glenn K Klute, Michael S. Orendurff, Martin L Mcdowell, Janice A Pecoraro, Jane B Shofer, Joseph M. CzernieckiAbstract:INTRODUCTION Lower-limb Amputees must relearn basic ambulatory skills to successfully function within the community. The two primary concerns for lower-limb Amputees are comfort and mobility [1]. Despite continuous advances in prosthetic technology, 55 percent of Amputees report they are unable to use their prosthesis to the extent they desire [2]. Most transfemoral (TF) Amputees wear a noncomputerized prosthetic knee that incorporates friction, pneumatic, or hydraulic swing phase control. These devices are thought to be limited because the resistance setting that controls the rate of knee extension during swing remains constant and is therefore only optimal at specific walking speeds, which results in nonoptimal kinematics at a complete range of speeds. In addition, these non-adaptive, mechanically passive devices do not incorporate adaptive stance phase control, which requires the Amputee Abbreviations: %BW = percent body weight, CWS = controlled walking speed, OHS = opposite heel strike, SD = standard deviation, SSWS = self-selected walking speed, TF = transfemoral, VGRF = vertical ground reaction force. to lock the knee mechanism in full extension during stance to avoid buckling. These limitations result in gait asymmetries [3-4], such as increased prosthetic swing phase knee flexion and decreased prosthetic stance phase knee flexion, which may contribute to such problems as increased metabolic cost [5] and secondary disability [6-8]. Therefore, further developments in prosthetic technology are needed to normalize Amputee ambulation and minimize gait asymmetries. Past research has suggested that many challenges associated with TF-Amputee ambulation are caused by gait asymmetries associated with stance phase kinetics [3-4,6]. For example, previous research demonstrated that Amputee subjects had decreased loading on the prosthetic limb with increased loading on the intact limb compared with control subjects [9]. The higher forces on the intact limb may result from the lack of damping of the prosthetic knee during stance because of a decrease in prosthetic knee flexion, which causes excessive rise of the center of mass over the prosthetic limb [4-5]. The high forces shown to occur at the intact limb are thought to lead to pain and joint degeneration, which explains why TF Amputees have a higher incidence of degenerative arthritis in their intact limbs compared with non-disabled subjects [6-8]. Specifically, coronal knee moments have been shown to be a major determinant of the load distribution during walking, with a significant correlation between external knee-adduction moment and bone distribution between the proximal-medial and proximallateral plateaus [10]. Sagittal-plane moments have also been shown to play a role in determining the overall compressive load on the knee joint. Therefore, both coronal and sagittal-plane knee moments are relevant measures when the relationship between loading and knee osteoarthritis is studied [10]. In a recent study of transtibial Amputees, researchers measured coronal knee moments and found an increase in abduction moment of 56 percent compared with the prosthetic limb and 10 percent compared with the control group [11]. Despite the high occurrence of osteoarthritis in the intact limb of TF Amputees, few studies have examined coronal knee moments [12]. In addition to the inability to use normal stance phase knee flexion to maintain stability and avoid inadvertent knee buckling [3], TF Amputees have another common asymmetry: increased hip extensor activity for assisting stabilization of the knee. The increased hip power output may help compensate for the lack of ankle power generated by the prosthetic foot [13]. Mechanical power measurements, defined as the product of the joint moment of force and the angular velocity, are important measures of muscle function during concentric and eccentric phases of gait [14]. Therefore, increased power measurements may result in increased fatigue and secondary disability. …
John G Buckley - One of the best experts on this subject based on the ideXlab platform.
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chronic low back pain in traumatic lower limb Amputees
Clinical Rehabilitation, 2005Co-Authors: J Kulkarni, W J Gaine, John G Buckley, J J Rankine, Judith E AdamsAbstract:Objective: To ascertain the prevalence of back pain amongst traumatic lower limb Amputees attending a regional rehabilitation centre and to determine the possible causes of back pain.Design: All traumatic lower limb Amputees given a semi-structured questionnaire to complete and a comparative subgroup of Amputees with back pain and without back pain underwent physical examination, gait analysis, magnetic resonance scanning (MRI) and gait/standing stability analysis.Setting: A subregional Amputee rehabilitation centre.Results: Transfemoral Amputees were more likely to suffer from back pain (81%) than transtibial Amputees (62%) (p≤0.05) and of those suffering from severe back pain, 89% and 81% also suffered from severe pain in the phantom limb and severe stump pain respectively. In two comparative subgroups of Amputees there was no significant difference between back pain and pain-free groups except those with pain were more likely to have a body mass index (BMI) ratio above 50% of the recommended ratio. No ...
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biomechanical adaptations of transtibial Amputee sprinting in athletes using dedicated prostheses
Clinical Biomechanics, 2000Co-Authors: John G BuckleyAbstract:Objective. To determine the biomechanical adaptations of the prosthetic and sound limbs in two of the world’s best transtibial Amputee athletes whilst sprinting. Design. Case study design, repeated measures. Background. Using dedicated sprint prostheses transtibial Amputees have run the 100 m in a little over 11 s. Lower-limb biomechanics when using such prostheses have not previously been investigated. Methods. Moments, muscle powers and the mechanical work done at the joints of the prosthetic and sound limbs were calculated as subjects performed repeated maximal sprint trials using a Sprint Flex or Cheetah prosthesis. Results. An increased hip extension moment on the prosthetic limb, with an accompanying increase in the amount of concentric work done, was the most notable adaptation in Subject 1 using either prosthesis. In Subject 2, an increased extension moment at the residual knee, and an accompanying increase in the amount of total work done, was the most notable adaptation using either prosthesis. This later adaptation was also evident in Subject 1 when using his Sprint Flex prosthesis. Conclusions. Increased hip work on the prosthetic limb has previously been shown to be the major compensatory mechanism that allow transtibial Amputees to run. The increased work found at the residual knee, suggests that the two Amputee sprinters used an additional compensatory mechanism. Relevance These findings provide an insight into the biomechanical adaptations that allow a transtibial Amputee to attain the speeds achieved when sprinting. ” 2000 Elsevier Science Ltd. All rights reserved.
Ava D Segal - One of the best experts on this subject based on the ideXlab platform.
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hip recovery strategy used by below knee Amputees following mediolateral foot perturbations
Journal of Biomechanics, 2018Co-Authors: Sarah E Miller, Ava D Segal, Glenn K Klute, Richard R NeptuneAbstract:Abstract Lower-limb Amputees have a higher risk of falling compared to non-Amputees. Proper regulation of whole-body angular momentum is necessary to prevent falls, particularly in the frontal plane where individuals are most unstable. However, the balance recovery mechanisms used by lower-limb Amputees when recovering from a perturbation are not well-understood. This study sought to understand the balance recovery mechanisms used by lower-limb Amputees in response to mediolateral foot perturbations by examining changes to frontal plane whole-body angular momentum and hip joint work. These metrics provide a quantitative measure of frontal plane dynamic balance and associated joint contributions required to maintain balance during gait. Nine Amputees and 11 non-Amputees participated in this study where an unexpected medial or lateral foot placement perturbation occurred immediately prior to heel strike on the residual, sound or non-Amputee limbs. Lateral perturbations of all limbs resulted in a reduced range of whole-body angular momentum and increased positive frontal plane hip work in the first half of single limb support. Medial perturbations for all limbs resulted in increased range of whole-body angular momentum and decreased positive frontal plane hip work, also in the first half of single limb support. These results suggest that medial foot placement perturbations are particularly challenging and that hip strategies play an important role in balance recovery. Thus, rehabilitation interventions that focus on hip muscles that regulate mediolateral balance, particularly the hip abductors, and the use of prostheses with active ankle control, may reduce the risk of falls.
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lower limb Amputee recovery response to an imposed error in mediolateral foot placement
Journal of Biomechanics, 2014Co-Authors: Ava D Segal, Glenn K KluteAbstract:Despite walking with a wider step width, Amputees remain 20% more likely to fall than non-Amputees. Since mediolateral (ML) balance is critical for ambulation and contingent on ML foot placement, we used a ML disturbance to perturb walking balance and explore the influence of prosthetic foot stiffness on balance recovery. Ten transtibial Amputees were fit with two commonly prescribed prosthetic feet with differing stiffness characteristics; 12 non-Amputees also participated. A perturbation device that released an air burst just before heel strike imposed a repeatable medial or lateral disturbance in foot placement. After a medial disturbance, the first recovery step width was narrowed (p<0.0001) for the prosthetic limb (−103%), the sound limb (−51%) and non-Amputees (−41%) and more than twice as variable. The ML inclination angle remained reduced (−109%) for the prosthetic limb, while the sound limb and non-Amputees approached undisturbed levels (p<0.0004). Amputees required five steps to return to undisturbed step width after a prosthetic medial disturbance versus two steps for the sound limb and for non-Amputees. After a lateral disturbance, the first recovery step was widened for the prosthetic limb (+82%), sound limb (+75%), and wider than non-Amputees (+51%; p<0.0001), with all participants requiring three steps to return to undisturbed step width. Amputees also exhibited a similar upper torso response compared to the non-Amputees for both disturbances. Prosthetic feet with different stiffness properties did not have a significant effect. In conclusion, Amputee balance was particularly challenged by medial disturbances to the prosthetic limb implying a need for improved interventions that address these balance deficits.
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the effects of a controlled energy storage and return prototype prosthetic foot on transtibial Amputee ambulation
Human Movement Science, 2012Co-Authors: Ava D Segal, Glenn K Klute, Michael S. Orendurff, Karl E Zelik, David C Morgenroth, Michael E Hahn, Peter G Adamczyk, Steven H Collins, Arthur D Kuo, Joseph M. CzernieckiAbstract:The lack of functional ankle musculature in lower limb Amputees contributes to the reduced prosthetic ankle push-off, compensations at other joints and more energetically costly gait commonly observed in comparison to non-Amputees. A variety of energy storing and return prosthetic feet have been developed to address these issues but have not been shown to sufficiently improve Amputee biomechanics and energetic cost, perhaps because the timing and magnitude of energy return is not controlled. The goal of this study was to examine how a prototype microprocessor-controlled prosthetic foot designed to store some of the energy during loading and return it during push-off affects Amputee gait. Unilateral transtibial Amputees wore the Controlled Energy Storage and Return prosthetic foot (CESR), a conventional foot (CONV), and their previously prescribed foot (PRES) in random order. Three-dimensional gait analysis and net oxygen consumption were collected as participants walked at constant speed. The CESR foot demonstrated increased energy storage during early stance, increased prosthetic foot peak push-off power and work, increased prosthetic limb center of mass (COM) push-off work and decreased intact limb COM collision work compared to CONV and PRES. The biological contribution of the positive COM work for CESR was reduced compared to CONV and PRES. However, the net metabolic cost for CESR did not change compared to CONV and increased compared to PRES, which may partially reflect the greater weight, lack of individualized size and stiffness and relatively less familiarity for CESR and CONV. Controlled energy storage and return enhanced prosthetic push-off, but requires further design modifications to improve Amputee walking economy.
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Comparison of transtibial Amputee and non-Amputee biomechanics during a common turning task.
Gait & Posture, 2011Co-Authors: Ava D Segal, Michael S. Orendurff, Joseph M. Czerniecki, Jason A. Schoen, Glenn K KluteAbstract:The biomechanics of Amputee turning gait has been minimally studied, in spite of its integral relationship with the more complex gait required for household or community ambulation. This study compares the biomechanics of unilateral transtibial Amputees and non-Amputees completing a common turning task. Full body gait analysis was completed for subjects walking at comparable self-selected speeds around a 1m radius circular path. Peak internal and external rotation moments of the hip, knee and ankle, mediolateral ground reaction impulse (ML GRI), peak effective limb length, and stride length were compared across conditions (non-Amputee, Amputee prosthetic limb, Amputee sound limb). Amputees showed decreased internal rotation moments at the prosthetic limb hip and knee compared to non-Amputees, perhaps as a protective mechanism to minimize stress on the residual limb. There was also an increase in Amputee sound limb hip external rotation moment in early stance compared to non-Amputees, which may be a compensation for the decrease in prosthetic limb internal rotation moment during late stance of the prior step. ML GRI was decreased for the Amputee inside limb compared to non-Amputee, possibly to minimize the body's acceleration in the direction of the turn. Amputees also exhibited a shorter inside limb stride length compared to non-Amputees. Both decreased ML GRI and stride length indicate a COM that is more centered over the base of support, which may minimize the risk of falling. Finally, a longer effective limb length was found for the Amputee inside limb turning, possibly due to excessive trunk shift.
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Compensatory mechanisms of transtibial Amputees during circular turning
Gait & Posture, 2011Co-Authors: Jessica D. Ventura, Ava D Segal, Glenn K Klute, Richard R NeptuneAbstract:A B S T R A C T Turning plays a prominent role in daily living activities and requires the modulation of the ground reaction forces to accelerate the body’s center-of-mass along the path of the turn. With the ankle plantarflexors being prominent contributors to the propulsive ground reaction forces, it is not clear how transtibial Amputees perform turning tasks without these important muscles. The purpose of this study was to identify the compensatory mechanisms used by transtibial Amputees during a simple turning task by analyzing the radial and anterior–posterior ground reaction impulses and sagittal, transverse and coronal joint work of the residual and intact legs. These quantities were analyzed with the residual leg on both the inside and outside of the turn and compared to non-Amputees. The analysis showed that Amputees and non-Amputees use different joint strategies to turn. Amputees rely primarily on sagittal plane hip joint work to turn while non-Amputees rely primarily on ankle work in the sagittal plane and hip joint work in the coronal plane. Differences in strategies are most likely due to the minimal power output provided by the passive prosthetic feet used by Amputees and perhaps a desire to minimize the risk of falling. Understanding these differences in turning strategies will aid in developing effective rehabilitation therapies and prosthetic devices that improve Amputee mobility.