Previous studies have shown major deficits in gait for individuals with peripheral arterial disease before and after the onset of pain. However, these studies did not have subjects ambulate at similar velocities and potential exists that the differences in joint powers may have been due to differences in walking velocity. The purpose of this study was to examine the joint moments and powers of peripheral arterial disease limbs for subjects walking at similar self-selected walking velocities as healthy controls prior to onset of any symptoms. Results revealed peripheral arterial disease patients have reduced peak hip power absorption in midstance (p=0.017), reduced peak knee power absorption in early and late stance (p=0.037 and p=0.020 respectively), and reduced peak ankle power generation in late stance (p=0.021). This study reveals that the gait of patients with peripheral arterial disease walking prior to the onset of any leg symptoms is characterized by failure of specific and identifiable muscle groups needed to perform normal walking and that these gait deficits are independent of reduced gait velocity.

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Abstract-The purpose of this study was to determine the relationship between stride-to-stride fluctuations and prosthesis preference. Thirteen individuals with unilateral, transtibial amputation consented to participate. Individuals walked on a treadmill for 3 min with their prescribed and an alternate prosthesis. Stride-to-stride fluctuations were quantified with the largest Lyapunov exponent (LyE) of each joint flexion/extension time series. The change in the LyE was calculated for each major lower-limb joint for both conditions. Participants indicated preference between the prostheses on a continuous visual analog scale. The change in the LyE was correlated with the degree of preference between the two prostheses at the prosthetic ankle. The change in the LyE of the prosthetic ankle was strongly related to the degree of preference (r = 0.629, p = 0.02). Thus, stride-to-stride fluctuations, quantified by the LyE, are strongly related to the patient's perception of the prosthesis. As a result, the LyE is the first objective measure to detect changes in gait that relate to the patient's perception of the prosthesis. The LyE should be further examined as a potentially effective prescriptive and outcome measure in prosthetic rehabilitation.

The amputation and subsequent prosthetic rehabilitation of a lower leg affects gait. Dynamical systems theory would predict the use of a prosthetic device should alter the functional attractor dynamics to which the system self-organizes. Therefore, the purpose of this study was to compare the largest Lyapunov exponent (a nonlinear tool for assessing attractor dynamics) for amputee gait compared to healthy non-amputee individuals. Fourteen unilateral, transtibial amputees and fourteen healthy, non-amputee individuals ambulated on a treadmill at preferred, self-selected walking speed. Our results showed that the sound hip (p=0.013), sound knee (p=0.05), and prosthetic ankle (p=0.023) have significantly greater largest Lyapunov exponents than healthy non-amputees. Furthermore, the prosthetic ankle has a significantly greater (p=0.0.17) largest Lyapunov exponent than the sound leg ankle. These findings indicate attractor states for amputee gait with increased divergence. The increased attractor divergence seems to coincide with decreased ability for motor control between the natural rhythms of the individual and those of the prosthetic device. Future work should consider the impact of different prostheses and rehabilitation on the attractor dynamics.

Background-Multiple sclerosis is a progressive neurological disease that results in a high incident of gait disturbance. Exploring the frequency content of the ground reaction forces generated during walking may provide additional insights to gait in patients with multiple sclerosis that could lead to specific tools for differential diagnosis. The purpose of this study was to investigate differences in the frequency content of these forces in an effort to contribute to improved clinical management of this disease.

Twenty-four individuals with transtibial amputation were recruited to a randomized, crossover design study to examine stride-to-stride fluctuations of lower limb joint flexion/extension time series using the largest Lyapunov exponent (λ). Each individual wore a “more appropriate” and a “less appropriate” prosthesis design based on the subject's previous functional classification for a three week adaptation period. Results showed decreased λ for the sound ankle compared to the prosthetic ankle (F1,23 = 13.897, p = 0.001) and a decreased λ for the “more appropriate” prosthesis (F1,23 = 4.849, p = 0.038). There was also a significant effect for the time point in the adaptation period (F2,46 = 3.164, p = 0.050). Through the adaptation period, a freezing and subsequent freeing of dynamic degrees of freedom was seen as the λ at the ankle decreased at the midpoint of the adaptation period compared to the initial prosthesis fitting (p = 0.032), but then increased at the end compared to the midpoint (p = 0.042). No differences were seen between the initial fitting and the end of the adaptation for λ (p = 0.577). It is concluded that the λ may be a feasible clinical tool for measuring prosthesis functionality and adaptation to a new prosthesis is a process through which the motor control develops mastery of redundant degrees of freedom present in the system.

Materials N/A Methods The guideline is based upon the best available evidence as it relates to socket design, interface, and suspension of definitive transtibial prostheses. Where possible, recommendations are drawn from systematic review and meta-analysis. Where this standard is unavailable, alternate academic literature has been used to support individual recommendations. Results Recommendation 1: The static and dynamic pressure distribution of the residual limb within the socket are essential considerations in patient comfort, function and well-being. Recommendation 2: Total surface bearing sockets are indicated to decrease fitting times and enable higher activity levels. Recommendation 3: Compared to traditional foam-based interfaces, viscoelastic interface liners are indicated to decrease dependence on walking aides, improve suspension, improve load distribution, decrease pain and increase comfort. Recommendation 4: Among modern suspension options, vacuum assisted suspension (VAS) sockets permits the least amount of pistoning within the socket, followed by suction suspension and then pin-lock suspension. The traditional suspension options of supracondylar, cuff and sleeve suspension provide comparatively compromised suspension. Recommendation 5: VAS sockets are indicated to decrease daily limb volume changes of the limb in the socket while facilitating more favorable pressure distribution during gait. Recommendation 6: VAS sockets require both awareness and compliance on the part of the end user and are not universally indicated. Conclusions These clinical practice guidelines summarize the available evidence related to the socket design, interface, and suspension of definitive transitibial prostheses. The noted clinical practice guidelines are meant to serve on as “guides.” They may not apply to all patients and clinical situations.

Background:While rehabilitation professionals are historically trained to place emphasis on the restoration of mobility following lower limb amputation, changes in healthcare dynamics are placing an increased emphasis on the limb loss patient’s quality of life and general satisfaction. Thus, the relationship between these constructs and mobility in the patient with lower limb loss warrants further investigation.Objectives:To determine the relationship between mobility of the patient with lower limb loss and both (1) general satisfaction and (2) quality of life.Study design:Retrospective chart analysis.Methods:A retrospective chart review of the Prosthetic Limb Users Survey of Mobility and the Prosthesis Evaluation Questionnaire—Well-Being subsection. Pearson correlations were used to test relationships.Results:Data from 509 patients with a lower limb prosthesis were included. Mobility was found to be positively correlated with quality of life (r = 0.511, p < 0.001, 95% confidence interval (0.443, 0.569)) and general satisfaction (r = 0.475, p < 0.001, 95% confidence interval (0.403, 0.542)), as well as their arithmetic mean (i.e. Prosthesis Evaluation Questionnaire—Well-Being) (r = 0.533, p < 0.001, 95% confidence interval (0.466, 0.592)).Conclusion:This study provides evidence of a strong positive correlation between mobility and both quality of life and general satisfaction. Thus, in the holistic care of a patient with lower limb loss, maximizing mobility would correlate with greater quality of life and general satisfaction.Clinical relevanceThere is growing emphasis on the quality of life and general satisfaction experienced by patients undergoing prosthetic rehabilitation. The results of this study underscore the importance of providing prosthetic rehabilitation that maximizes the patient’s mobility, noting that these individuals also report greater quality of life and general satisfaction.