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Background: Prosthetic alignment is used to optimize prosthetic functioning and comfort. Spatio-temporal and kinematic gait parameters are generally observed to guide this process. However, they have been shown to be influenced by compensations, which reduces their sensitivity to changes in alignment. Alternatively, the use of moments working at the base of the prosthetic socket, external socket reaction moments (ESRM), has been proposed to quantify prosthetic alignment.Research Question: To investigate if a predetermined kinetic alignment criterion, 0Nm averaged over the stance phase, can be used to fine-tune prosthetic alignment.Methods: 10 transtibial amputees were included in this intervention study. Firstly, their prostheses were aligned using conventional alignment procedures. Kinetic parameters and Socket Comfort Score (SCS) were measured in this initial alignment (IA) condition. Subsequently, the coronal plane ESRM during gait was presented to the prosthetist in real time using a Gait Real-time Analysis Interactive Lab. The prosthetist iteratively adapted the prosthetic alignment towards a predetermined average ESRM during the stance phase of 0 Nm. At the Final Alignment (FA), kinetic parameters and SCS were measured again and a paired sample t-test was performed to compare ESRMs and SCSs between alignments.Results: A significant (p < 0.001) change was found in the absolute coronal plane ESRM (mean ± SD) from IA (|0.104| ± 0.058 Nm/kg) to FA (|0.012| ± 0.015 Nm/kg). In addition a significant (p < 0.001) change of the external coronal adduction knee moments was observed from IA (-0,127 ± 0.079 Nm/kg) to FA (-0.055 ± 0.089 Nm/kg), however this change was more variable among participants. On average, no significant (p = 0.37) change in the SCS was observed.Significance: While this study shows the potential of quantifying and guiding alignment with the assistance of kinetic criteria, it also suggests that a sole reliance on the ESRM as a single alignment criterion might be too simple. [ABSTRACT FROM AUTHOR]

This investigation compared stance, swing, and double support times of a recent below-the-knee amputee (BKA) child's gait with the gait of normal children and with that of experienced BKA children. Kinematic data were collected for 11 normal children, 2 experienced BKA children, and a novice BKA child. Results indicated there were significant differences between the steps of prosthetic and nonprosthetic limbs and between normals and BKAs. Initially the gait of the novice BKA differed from that of experienced BKAs. After 94 days the gait of the novice BKA was not significantly different from that of the experienced BKAs. It was concluded that since the structure and function of the prosthetic limb is not the same as normal, (a) it may be appropriate for the BKA child to have an asymmetrical gait pattern, and (b) rehabilitation may be directed toward teaching the recent BKA child to walk more like experienced BKAs than like normal children. [ABSTRACT FROM AUTHOR]

Background: People with lower limb amputation may experience walking limitations on slopes because of missing musculoskeletal and neuromuscular systems. Elevated vacuum suspension could benefit transtibial amputee gait for slope walking, but research is lacking to inform clinical practice.Methods: Twelve people with unilateral transtibial amputation were fitted with the Unity elevated vacuum suspension system (Össur) and Pro-Flex XC foot. 3D motion analysis was performed for 7° incline, 7° decline, and level walking within a CAREN-Extended system virtual Park environment. Randomized and blinded walking trials were completed with the vacuum active or inactive.Results: Statistically significant differences (p < 0.05) were found between vacuum conditions when walking uphill or downhill for temporal spatial, kinematic, and kinetic gait parameters; however, effect sizes were small (r≤0.35). Prosthetic step length decreased for both vacuum conditions on downhill compared to uphill walking. Symmetry index was <10% for step length, step time, and stance time for both vacuum condition during downhill walking, indicating acceptable symmetry. During incline walking, step length was only symmetrical with active vacuum. Knee range of motion was not restricted, for both conditions.Conclusion: Active vacuum improved gait symmetry for incline walking, but the other differences between vacuum conditions were small and may not be clinically significant. Therefore, the Unity system approach for elevated vacuum suspension had a positive, but small, effect on walking and should maintain appropriate walking even with vacuum failure, until limb volume changes adversely affect socket fit (i.e., elevated vacuum helps control limb volume fluctuations over time). [ABSTRACT FROM AUTHOR]

Background: Daily ambulation with a prosthesis often involves turning to negotiate within the home and community environments, however how people with lower limb loss perform turns is infrequently studied. Administering a common clinical outcome measure to capture turn performance data provides a convenient means of assessing this ubiquitous activity.Research Question: What temporal-spatial parameters are exhibited by people with unilateral lower limb amputation while performing a 180˚ turn task?Methods: Forty community-ambulating subjects with unilateral lower limb amputation (20 transtibial amputees, 20 transfemoral amputees) performed the Component Timed-Up-and-Go (cTUG) test turning once in each direction, both toward the intact and toward the prosthetic limb. An instrumented walkway captured temporal-spatial parameters during performance of the 180˚ turn task of the cTUG, while a custom iPad application recorded time and number of steps to perform the turn. Comparisons between turn direction and level of amputation during the cTUG and temporal-spatial results were assessed.Results: People with lower limb amputation spent more time on their intact limb while turning than their prosthetic limb regardless of the position of the intact limb, and those with transfemoral amputation spent significantly more time over the intact limb than those with transtibial amputation. Additionally, subjects with transfemoral amputation performed the turn significantly faster when turning with an inner intact limb.Significance: Amputees use different movement strategies with altered temporal-spatial characteristics to turn depending on the direction of the turn and the level of amputation. Clinical use of the cTUG could provide evidence supporting prosthetic prescription practice and introduction of novel physical therapy interventions for individuals with lower limb amputation. [ABSTRACT FROM AUTHOR]

Background: Individuals with transfemoral amputation (TFA) have difficulty in descending ramps. Although individuals with TFA who descend ramps are speculated to have greater biomechanical demands, this has not been quantified.Research Question: How do individuals with TFA wearing a prosthetic knee without a stance control mechanism adapt their gait biomechanics to a slightly declined surface?Methods: We retrospectively analyzed data of level walking and ramp descent (5° decline) from six subjects with TFA who used a prosthesis without a stance control mechanism. Ground reaction force and joint moment, power, and kinematics were derived from three-dimensional motion capture, combined with force measurement. Kinematic and kinetic variables were compared during level walking and ramp descent using the paired tests.Results: Compared with level walking, ramp descent increased the maximum contralateral vertical ground reaction force by 16% of the body weight, on average (standard deviation: 20%). Ramp descent tended to induce smaller concentric hip power during late swing and greater hip eccentric power on the prosthetic-side during late stance. Greater biomechanical demands during ramp descent were indicated by increased maximum medial ground reaction force on both sides, and eccentric joint power of the contralateral ankle during stance.Significance: For individuals with TFA using a prosthetic knee without a stance control mechanism, descending a ramp can increase loading on the contralateral limb during the loading response; slower walking may alleviate the effect. Ramp descent can change prosthetic-side hip muscles' control of the swinging prosthetic limb, eccentric work on the contralateral ankle plantarflexors during stance, and mediolateral balance. All of these factors should be taken into consideration when individuals with TFA learn to descend a ramp. [ABSTRACT FROM AUTHOR]

Background: In product development for lower limb prosthetic devices, a set of special criteria needs to be met. Prosthetic devices have a direct impact on the rehabilitation process after an amputation with both perceived technological and psychological aspects playing an important role. However, available psychometric questionnaires fail to consider the important links between these two dimensions. In this article a probabilistic latent trait model is proposed with seven technical and psychological factors which measure satisfaction with the prosthesis. The results of a first study are used to determine the basic parameters of the statistical model. These distributions represent hypotheses about factor loadings between manifest items and latent factors of the proposed psychometric questionnaire.Methods: A study was conducted and analyzed to form hypotheses for the prior distributions of the questionnaire's measurement model. An expert agreement study conducted on 22 experts was used to determine the prior distribution of item-factor loadings in the model.Results: Model parameters that had to be specified as part of the measurement model were informed prior distributions on the item-factor loadings. For the current 70 items in the questionnaire, each factor loading was set to represent the certainty with which experts had assigned the items to their respective factors. Considering only the measurement model and not the structural model of the questionnaire, 70 out of 217 informed prior distributions on parameters were set.Conclusion: The use of preliminary studies to set prior distributions in latent trait models, while being a relatively new approach in psychological research, provides helpful information towards the design of a seven factor questionnaire that means to identify relations between technical and psychological factors in prosthetic product design and rehabilitation medicine. [ABSTRACT FROM AUTHOR]

Background: In transfemoral (TF) amputees, the forward propulsion of the prosthetic leg in swing has to be mainly carried out by hip muscles. With hip strength being the strongest predictor to ambulation ability, an active powered knee joint could have a positive influence, lowering hip loading and contributing to ambulation mobility. To assess this, gait of four TF amputees was measured for level walking, first while using a passive microprocessor-controlled prosthetic knee (P-MPK), subsequently while using an active powered microprocessor-controlled prosthetic knee (A-MPK). Furthermore, to assess long-term effects of the use of an A-MPK, a 4-weeks follow-up case study was performed.Methods: The kinetics and kinematics of the gait of four TF amputees were assessed while walking with subsequently the P-MPK and the A-MPK. For one amputee, a follow-up study was performed: he used the A-MPK for 4 weeks, his gait was measured weekly.Results: The range of motion of the knee was higher on both the prosthetic and the sound leg in the A-MPK compared to the P-MPK. Maximum hip torque (HT) during early stance increased for the prosthetic leg and decreased for the sound leg with the A-MPK compared to the P-MPK. During late stance, the maximum HT decreased for the prosthetic leg. The difference between prosthetic and sound leg for HT disappeared when using the A-MPK. Also, an increase in stance phase duration was observed. The follow-up study showed an increase in confidence with the A-MPK over time.Conclusions: Results suggested that, partially due to an induced knee flexion during stance, HT can be diminished when walking with the A-MPK compared to the P-MPK. The single case follow-up study showed positive trends indicating that an adaptation time is beneficial for the A-MPK. [ABSTRACT FROM AUTHOR]

This paper presents a review on design issues and solutions found in active lower limb prostheses. This review is based on a systematic literature search with a methodical search strategy. The search was carried out across four major technical databases and the retrieved records were screened for their relevance. A total of 21 different active prostheses, including 8 above-knee, 9 below-knee and 4 combined knee-ankle prostheses were identified. While an active prosthesis may help to restore the functional performance of an amputee, the requirements regarding the actuation unit as well as for the control system are high and the development becomes a challenging task. Regarding mechanical design and the actuation unit high force/torque delivery, high efficiency, low size and low weight are conflicting goals. The actuation principle and variable impedance actuators are discussed. The control system is paramount for a "natural functioning" of the prosthesis. The control system has to enable locomotion and should react to the amputee's intent. For this, multi-level control approaches are reviewed. [ABSTRACT FROM AUTHOR]

Background: Rehabilitation, which is essential for amputees with myoelectric hands, can improve the quality of daily life by remodeling the neuron network. In our study, we aim to develop a cerebral blood perfusion (CBF) single-photon emission computed tomography computer-aided (SPECT-CA) detection scheme to automatically locate the brain's activated regions after rehabilitation.Results: Five participants without forearms (three male, two female, mean age 51 ± 12.89 years, two missing the right side, and three missing the left side) were included in our study. In the clinical assessment, all of the participants received higher scores after training. The results of the SPM analysis indicated that CBF in the precentral gyrus, postcentral gyrus, frontal lobe, temporal lobe and cerebellum was significantly different among the five participants (P < 0.05). Moreover, SPECT-CA showed that the activated brain areas mainly included the precentral gyrus, postcentral gyrus, cerebellum and extensive cerebral cortex.Conclusion: Our study demonstrated that the CBF SPECT-CA method can detect the brain blood perfusion changes induced by rehabilitation with high sensitivity and accuracy. This method has great potential for locating the remodeled neuron regions of amputees with myoelectric hands after rehabilitation. [ABSTRACT FROM AUTHOR]

It is 8 a.m. on a December morning in Jaipur, Rajasthan, India. The day has just begun at Bhagawan Mahavir Vikalanga Sahayata Samithi (BMVSS), a nonprofit organization dedicated to fitting the disabled with artificial limbs (Figure 1). Slowly, patients from across India and neighboring countries gather in the center?s front yard. By the end of the day, more than 35 people will make a long journey back to their homes and communities outfitted with a new prosthetic leg or arm that will promise them a more active and functional future. The entire treatment is free. [ABSTRACT FROM PUBLISHER]

Background: Recovering from trips is challenging for transfemoral amputees, and attempts often result in falls. Better understanding of the effects of the sensory-motor deficits brought by amputation and the functional limitations of prosthetic devices could help guide therapy and fall prevention mechanisms in prostheses. However, how transfemoral amputees attempt to recover from trips on the sound and prosthesis sides throughout swing phase is poorly understood.Methods: We tripped eight able-bodied subjects and eight unilateral transfemoral amputees wearing their prescribed prostheses. The protocol consisted of six repetitions of 6 and 4 points throughout swing phase, respectively. We compared recovery strategies in able-bodied, sound side and prosthesis side limbs. The number of kinematic recovery strategies used, when they were used throughout swing phase, and kinematic characteristics (tripped limb joint angles, bilateral trochanter height and time from foot arrest to foot strike) of each strategy were compared across limb groups. Non-parametric statistical tests with corrections for post-hoc tests were used.Results: Amputees used the same recovery strategies as able-bodied subjects on both sound and prosthesis sides, although not all subjects used all strategies. Compared to able-bodied subjects, amputees used delayed-lowering strategies less often from 30-60 % of swing phase on the sound side, and from 45-60 % of swing phase on the prosthesis side. Within-strategy kinematic differences occurred across limbs; however, these differences were not consistent across all strategies. Amputee-specific recovery strategies-that are not used by control subjects-occurred following trips on both the sound and prosthesis sides in mid- to late swing.Conclusions: Collectively, these results suggest that sensory input from the distal tripped leg is not necessary to trigger able-bodied trip recovery strategies. In addition, the differences between sound and prosthesis side recoveries indicate that the ability of the support leg might be more critical than that of the tripped leg when determining the response to a trip. The outcomes of this study have implications for prosthesis control, suggesting that providing correct and intuitive real-time selection of typical able-bodied recovery strategies by a prosthetic device when it is the tripped and the support limb could better enable balance recovery and avoid falls. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the authors discuss various reports within the issue on topics including gait recognition and control of lower limb prosthetic, biomechanical analysis for assessment of the utility of active prostheses, and virtual reality rehabilitation.

The author presents the recommendations of a 27-expert panel on the impact of a paradigm shift on the amputee prosthetic care implemented by the U.S. Department of Veterans Affairs (VA). The panel is composed of academicians, clinicians and researchers from the VA and the U.S. Department of Defense (DOD), and veterans with limb loss from the Vietnam war, Operation Iraqi Freedom (OIF) and Operation Enduring Freedom (OEF). Further research into rehabilitation that will include psychological and social issues is emphasized.

The author presents his views on rehabilitation provided to U.S. service members who sustained limb loss during the Vietnam or Operation Iraqi Freedom/Operation Endurng Freedom (OIF/OEF). He cites the experience of Jonathan Pruden and Juan Arredondo who served in the OIF and OEF and Ned Foote who served in Vietnam. The support system that assisted Arredondo, Pruden and Foote is described.

Presents a study which hypothesized that the vacuum-assisted socket reduces the positive pressures during stance and increases the magnitude of the negative pressures on the limb during swing phase as compared to the normal total-surface weight-bearing socket. Reason for the challenge of achieving the proper fit of a prosthetic socket; Method used in the study; Results.

Background: In this paper, a novel functional near-infrared spectroscopy (fNIRS)-based brain-computer interface (BCI) framework for control of prosthetic legs and rehabilitation of patients suffering from locomotive disorders is presented.Methods: fNIRS signals are used to initiate and stop the gait cycle, while a nonlinear proportional derivative computed torque controller (PD-CTC) with gravity compensation is used to control the torques of hip and knee joints for minimization of position error. In the present study, the brain signals of walking intention and rest tasks were acquired from the left hemisphere's primary motor cortex for nine subjects. Thereafter, for removal of motion artifacts and physiological noises, the performances of six different filters (i.e. Kalman, Wiener, Gaussian, hemodynamic response filter (hrf), Band-pass, finite impulse response) were evaluated. Then, six different features were extracted from oxygenated hemoglobin signals, and their different combinations were used for classification. Also, the classification performances of five different classifiers (i.e. k-Nearest Neighbour, quadratic discriminant analysis, linear discriminant analysis (LDA), Naïve Bayes, support vector machine (SVM)) were tested.Results: The classification accuracies obtained from SVM using the hrf were significantly higher (p < 0.01) than those of the other classifier/ filter combinations. Those accuracies were 77.5, 72.5, 68.3, 74.2, 73.3, 80.8, 65, 76.7, and 86.7% for the nine subjects, respectively.Conclusion: The control commands generated using the classifiers initiated and stopped the gait cycle of the prosthetic leg, the knee and hip torques of which were controlled using the PD-CTC to minimize the position error. The proposed scheme can be effectively used for neurofeedback training and rehabilitation of lower-limb amputees and paralyzed patients. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study `The Influence of Limb Alignment on the Gait of Above-Knee Amputees,' by L. Yang, S.E. Solomonidis et al and reprinted from the 1991 issue of the `Journal of Biomechanics.'