Stair ascent kinematics and kinetics with a powered lower leg system following transtibial amputation

Center for the Intrepid, Department of Orthopaedics and Rehabilitation, Brooke Army Medical Center, Ft. Sam Houston, TX 78234, USA.
Gait & posture (Impact Factor: 2.75). 05/2012; 36(2):291-5. DOI: 10.1016/j.gaitpost.2012.03.013
Source: PubMed


During stair ascent (STA) persons with transtibial amputation (TTA) typically adopt a hip strategy to compensate for the limited ankle motion and joint power that is characteristic of conventional energy storing and returning (ESR) prosthetic feet. The purpose of this investigation was to determine if providing ankle power via a powered prosthetic device (BiOM) normalized STA kinematics and kinetics. Eleven individuals with TTA participated in two STA gait analysis sessions: (1) using an ESR foot, and (2) using the BiOM. Eleven height and weight matched able-bodied controls (CONT) were also assessed. Lower extremity peak kinematic and kinetic values were calculated at a self-selected and controlled cadence (80 steps/min). Increased prosthetic limb peak ankle plantarflexion and push-up power were observed while using the BiOM as compared to ESR. Peak ankle power was not significantly different between BiOM and CONT indicating normalization of ankle power generation. However, peak ankle plantarflexion was significantly lower than CONT. Limb asymmetries including greater prosthetic limb hip flexion and power during stance, and decreased prosthetic limb knee power during stance were observed in the BiOM and ESR conditions. The results suggest that the BiOM successfully increased ankle motion and restored ankle power during STA. These differences did not, however, reduce the use of a hip strategy while ascending stairs. Additional device specific training may be necessary to utilize the full benefits of the device.

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    • "These devices aim to restore natural gait by performing positive net work at the ankle joint over the gait cycle and have shown promising results in reducing metabolic costs and increasing preferred walking velocity during level-ground walking (Herr and Grabowski, 2012). However, these prostheses are not explicitly designed for stair walking (Eilenberg et al., 2010), and individuals with TTA have similar kinematics and kinetics when walking with both powered and passive prostheses on stairs (Aldridge et al., 2012). In addition, the influence of powered prostheses relative to passive prostheses on maintaining dynamic balance is unknown. "
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    ABSTRACT: Individuals with a unilateral transtibial amputation have a greater risk of falling compared to able-bodied individuals, and falling on stairs can lead to serious injuries. Individuals with transtibial amputations have lost ankle plantarflexor muscle function, which is critical for regulating whole-body angular momentum to maintain dynamic balance. Recently, powered prostheses have been designed to provide active ankle power generation with the goal of restoring biological ankle function. However, the effects of using a powered prosthesis on the regulation of whole-body angular momentum are unknown. The purpose of this study was to use angular momentum to evaluate dynamic balance in individuals with a transtibial amputation using powered and passive prostheses relative to able-bodied individuals during stair ascent and descent. Ground reaction forces, external moment arms, and joint powers were also investigated to interpret the angular momentum results. A key result was that individuals with an amputation had a larger range of sagittal-plane angular momentum during prosthetic limb stance compared to able-bodied individuals during stair ascent. There were no significant differences in the frontal, transverse, or sagittal-plane ranges of angular momentum or maximum magnitude of the angular momentum vector between the passive and powered prostheses during stair ascent or descent. These results indicate that individuals with an amputation have altered angular momentum trajectories during stair walking compared to able-bodied individuals, which may contribute to an increased fall risk. The results also suggest that a powered prosthesis provides no distinct advantage over a passive prosthesis in maintaining dynamic balance during stair walking.
    Journal of Biomechanics 08/2014; 47(13). DOI:10.1016/j.jbiomech.2014.08.001 · 2.75 Impact Factor
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    • "However , investigations into LLA function during challenging motor tasks similar to stepping gait, such as stair negotiation and obstacle crossing, have outlined specific biomechanical adaptations which may also be adopted during LLA stepping gait. For example, during stair descent, transtibial amputees (TTA) maintain the affected lead limb in an extended position in an attempt to reduce the demands on the knee extensor musculature, avoiding potential limb buckling, whilst during stair ascent intact trail limb ankle plantarflexion and knee extension during stance aids the elevation of the COM in preparation for affected limb stance (Aldridge et al., 2012; Alimusaj et al., 2009; Jones et al., 2006; Powers et al., 1997; Ramstrand and Nilsson, 2009; Schmalz et al., 2007; Vanicek et al., 2010; Winter and Sienko, 1988). When "
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    ABSTRACT: Background: Negotiating a raised surface during continuous gait is an important activity of daily living and is a potentially hazardous task with regards to trips, falls and fall-related injury. However, it is not known how recent transtibial amputees adapt to performing stepping gait tasks in the 6-month period following discharge from rehabilitation. Methods: Recent transtibial amputees performed continuous gait trials, stepping onto and from a raised surface walkway representing the height of a street kerb, whilst kinematic and kinetic data were recorded at one, three and six months post-discharge from rehabilitation. Findings: Walking speed increased when stepping down (p=0.04) and was invariant across the study period when stepping up. At one month post-discharge, participants displayed an affected lead limb preference (90.8%) when stepping down and an intact lead limb preference (70.0%) when stepping up, although these lead limb preferences diminished over time. Participants spent more time in stance on the intact limb compared to the affected limb in both stepping down (trail limb) (p=0.01) and stepping up (lead and trail limbs) (p=0.05). Participants displayed significantly greater joint mobility and power bursts in the intact trail limb when stepping down and in the intact lead limb when stepping up. Interpretation: Transtibial amputees prefer to exploit intact limb function to a greater extent, although over time, the means by which this occurs changes which affects the initial lead limb preferences. The results from the current study enable future evidence-based therapeutic and prosthetic interventions to be designed that improve transtibial amputee stepping gait.
    Clinical biomechanics (Bristol, Avon) 06/2014; 29(7). DOI:10.1016/j.clinbiomech.2014.05.012 · 1.97 Impact Factor
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    • "Load patterns in this study were similar to those observed in the gait analysis literature for corresponding tasks, points and anatomical planes, both in healthy subjects (Protopapadaki et al., 2007; Beaulieu et al,. 2008) and in individuals with transtibial amputation (Sanderson and Martin, 1997; Powers et al., 1998; Schmalz et al., 2007; Alimusaj et al., 2009; Vanicek et al., 2010; Aldridge et al., 2012; Sinistski et al., 2012; Rueda et al., 2013). Fig. 5. Same selection of plots of Fig. 4 "
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    ABSTRACT: External load at the tibia during activities of daily living provides baseline measures for the improvement of the design of the bone–implant interface for relevant internal and external prostheses. A motion analysis system was used together with an established protocol with skin markers to estimate three-dimensional forces and moments acting on ten equidistant points along the tibial shaft. Twenty young and able-bodied volunteers were analysed while performing three repetitions of the following tasks: level walking at three different speeds, in a straight-line and with sudden changes of direction to the right and to the left, stair ascending and descending, squatting, rising from a chair and sitting down. Moment and force patterns were normalised to the percentage of body weight per height and body weight, respectively, and then averaged over all subjects for each point, about the three tibial anatomical axes, and for each task. Load patterns were found to be consistent over subjects, but different among the anatomical axes, tasks and points. Generally, moments were higher in the medio/lateral axis and influenced by walking speed. In all five walking tasks and in ascending stairs with alternating feet, the more proximal the point was the smaller the mean moment was. For the remaining tasks the opposite trend was observed. The overall largest value was observed in the medio/lateral direction at the ankle centre in level walking at high speed (9.1% body weight * height on average), nearly three times larger than that of the anterior/posterior axis (2.9) during level walking with a sidestep turn. The present results should be of value also for in-vitro mechanical tests and finite element models.
    Journal of Biomechanics 03/2014; 47(5):2014. DOI:10.1016/j.jbiomech.2014.01.045 · 2.75 Impact Factor
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