Search Results (225)

The physiological changes and alterations in gait following amputation may increase the risk of fractures. However, there is insufficient research on fracture risk in amputees. Therefore, this study intended to analyze whether the risk of new fractures increases after traumatic amputations. This population-based, retrospective cohort study used data from the Korean National Health Insurance System database. The study included 19,586 participants who had undergone an amputation and 76,645 matched controls. The incidence of any fracture and site-specific fractures (vertebral, hip, and others) according to amputation site(s) and severity of disability due to amputation were evaluated using Cox proportional hazard regression analysis. During the mean follow-up of 4.2 years, amputees had a higher incidence rate (IR) of any fracture (adjusted HR [aHR] 1.47, 95% CI 1.36–1.60), vertebral fracture (aHR 1.63, 95% CI 1.44–1.85), hip fracture (aHR 1.85, 95% CI 1.39–2.46), and other fracture (aHR 1.34, 95% CI 1.20–1.49) compared to that of controls. In the presence of disability, the risks were further increased and were highest among amputees with severe disabilities. All fracture risks were higher in amputees than they were in controls, regardless of lower limb or upper limb amputation. This cohort study demonstrated that traumatic amputees experienced higher incidence of all fractures than did individuals without amputations, and this risk increases with severity of disability. This finding underscores the importance of early screening and lifestyle interventions to address fracture risk in traumatic amputees. Full article

Bionic prosthetic hands hold the potential to replicate the functionality of human hands. The use of bionic limbs can assist amputees in performing everyday activities. This article systematically reviews the research progress on bionic prostheses, with a focus on control mechanisms, sensory feedback integration, and mechanical design innovations. It emphasizes the use of bioelectrical signals, such as electromyography (EMG), for prosthetic control and discusses the application of machine learning algorithms to enhance the accuracy of gesture recognition. Additionally, the paper explores advancements in sensory feedback technologies, including tactile, visual, and auditory modalities, which enhance user interaction by providing essential environmental feedback. The mechanical design of prosthetic hands is also examined, with particular attention to achieving a balance between dexterity, weight, and durability. Our contribution consists of compiling current research trends and identifying key areas for future development, including the enhancement of control system integration and improving the aesthetic and functional resemblance of prostheses to natural limbs. This work aims to inform and inspire ongoing research that seeks to refine the utility and accessibility of prosthetic hands for amputees, emphasizing user-centric innovations. Full article

The amputation of a limb in quadrupeds can overload the remaining limbs, especially the contralateral one. The compensatory effort is especially high if it is a forelimb. It is, therefore, important to objectively know the changes in weight redistribution that occur in the animal while walking and standing still. With this objective, static (postural) and dynamic kinetic examinations were carried out on five French bulldogs with an amputated forelimb and five intact French bulldogs. For this examination, force and pressure platforms were used. The results were statistically compared using the student t-test. The parameters derived from the ground reaction forces were significantly higher in the amputee group. Surprisingly, postural examination showed that amputated dogs reached the same stability as healthy ones. Tripedal support in dogs does not objectively imply a loss of balance in quantitative terms; although the increase in force used by the remaining limb, as well as its altered cranial disposition during the support phase, may potentially predispose the animal to additional injuries in the future due to an overuse of different musculoskeletal units. Full article

People use their hands for intricate tasks like playing musical instruments, employing myriad touch sensations to inform motor control. In contrast, current prosthetic hands lack comprehensive haptic feedback and exhibit rudimentary multitasking functionality. Limited research has explored the potential of upper limb amputees to feel, perceive, and respond to multiple channels of simultaneously activated haptic feedback to concurrently control the individual fingers of dexterous prosthetic hands. This study introduces a novel control architecture for three amputees and nine additional subjects to concurrently control individual fingers of an artificial hand using two channels of context-specific haptic feedback. Artificial neural networks (ANNs) recognize subjects’ electromyogram (EMG) patterns governing the artificial hand controller. ANNs also classify the directions objects slip across tactile sensors on the robotic fingertips, which are encoded via the vibration frequency of wearable vibrotactile actuators. Subjects implement control strategies with each finger simultaneously to prevent or permit slip as desired, achieving a 94.49% ± 8.79% overall success rate. Although no statistically significant difference exists between amputees’ and non-amputees’ success rates, amputees require more time to respond to simultaneous haptic feedback signals, suggesting a higher cognitive load. Nevertheless, amputees can accurately interpret multiple channels of nuanced haptic feedback to concurrently control individual robotic fingers, addressing the challenge of multitasking with dexterous prosthetic hands. Full article

Background: Patients with peripheral artery disease (PAD) have 40–70% higher three-year mortality after lower limb amputation compared to non-amputees. In this study, we examined the consequences of delayed treatment for patients with PAD during the coronavirus disease 2019 (COVID-19) pandemic. Methods: This study employed a retrospective single-centre cohort design at a large tertiary care hospital. We compared amputees with PAD during the initial COVID-19 outbreak period in 2020 with a control group of amputees from 2019 after a three-year follow-up. Results: In total, 134 amputees with PAD were included due to unsuccessful revascularization (n = 84 in 2020 vs. n = 50 in 2019). Patients in 2020 were significantly younger than those in 2019 (p = 0.01) and mostly admitted with advanced stages of PAD (p < 0.03). The proportion of major limb amputations increased significantly in 2020 (p = 0.03). Non-COVID-19-related deaths among patients in 2020 were more than twice as many as those in 2019, and long-term mortality in 2020 was 49% compared to 39% in 2019 (p = 0.04). Diabetes and renal insufficiency had a significantly negative impact on the survival of amputees with PAD (p < 0.01). Conclusions: Delayed treatment in patients with PAD leads to high long-term mortality risk after amputation, especially in PAD patients with diabetes and renal insufficiency. Therefore, in future pandemics, continuously monitoring patients with PAD will be crucial to prevent delayed treatment and severe short-term and long-term consequences. Full article

Prosthetic socket manufacturing is experiencing a revolutionary shift towards using digital methods, such as 3D scanning and 3D printing. However, using digital methods requires the clinician to transfer their skills from making sockets by hand to making sockets with a computer. This shift in practice may change the socket geometry and fit; however, to what extent is unknown. Thus, the aim of this study was to explore the feasibility of analyzing geometric and clinical differences between digitally- and manually-designed sockets. Nine adult inpatients with below-knee amputation were recruited. Two sockets were 3D printed for each participant from 3D socket models that were developed from: (1) 3D scanning a manually-modified hand-casted positive mold of the residuum; and (2) a digitally-modified 3D scan of the residuum. Manual and digital procedures were compared for three measures: final socket geometry, the Socket Comfort Score, and a patient experience survey. Feasibility data were collected to measure protocol implementation fidelity to inform a future larger study. These data revealed that 89% of participants followed the intended protocol, no participants dropped out, and only one adverse event was report. As no significant geometric differences were found and participants experienced similar comfort scores between manually- and digitally-designed sockets, study feasibility was determined to be successful. Thus, a randomized control trial study will be conducted to draw statistically relevant conclusions from these outcome measures that may provide meaningful information for improving digital design procedures. Full article

Background and Objectives: mortality and morbidity due to cardiovascular causes are frequently experienced in amputees. Research on the effects of chronic exercise on biomarkers and cardiac damage indicators in these individuals is limited. The aim of this study was to investigate the effects of a core training program on brain natriuretic-related peptide, as well as hematological and biochemical parameters in amputee soccer players. Materials and Methods: The participants were randomly allocated to the following two groups: a core exercise group (CEG) and a control group (CG). While the CG continued routine soccer training, the CEG group was included in a core exercise program different from this group. During the study, routine hemogram parameters of the participants, various biochemical markers, and the concentration of brain natriuretic-related peptide (NT-pro-BNP) were analyzed. Results: after the training period, notable improvements in various hematological parameters were observed in both groups. In the CEG, there were significant enhancements in red blood cell count (RBC), hematocrit (HCT), mean corpuscular hemoglobin concentration (MCHC), and mean corpuscular hemoglobin (MCH) values. Similarly, the CG also showed substantial improvements in RBC, HCT, mean corpuscular volume (MCV), MCHC, MCH, red cell distribution width-standard deviation (RDW-SD), platelet-to-lymphocyte ratio (PLCR), mean platelet volume (MPV), and platelet distribution width (PDW). Moreover, in the CEG, serum triglycerides (TG) and maximal oxygen uptake (MaxVO₂) exhibited significant increases. Conversely, TG levels decreased in the CG, while high-density lipoprotein (HDL), low-density lipoprotein (LDL), and MaxVO₂ levels demonstrated substantial elevations. Notably, the N-terminal pro-brain natriuretic peptide (BNP) levels did not undergo significant changes in either the CEG or the CG following the core exercise program (p > 0.05). However, in the CEG, a meaningful positive correlation was observed between NT-pro-BNP and creatine kinase (CK) levels before and after the core exercise program. Conclusions: the findings emphasized the potential benefits of core training in enhancing specific physiological aspects, such as erythrocyte-related parameters and lipid metabolism, as well as aerobic capacity. Furthermore, the observed correlation between NT-pro-BNP and CK levels in the CEG provides intriguing insights into the unique physiological adaptations of amputee athletes. Full article

The demand for affordable prostheses, particularly in low- and middle-income countries (LMICs), is significant. Currently, the majority of prosthetic sockets are manufactured using monolithic thermoplastic polymers such as PP (polypropylene), which lack durability, strength, and exhibit creep. Alternatively, they are reinforced with consumptive thermoset resin and expensive composite fillers such as carbon, glass, or Kevlar fibres. However, there are unmet needs that amputees face in obtaining affordable prosthetic sockets, demanding a solution. This study utilises self-reinforced PET (polyethylene terephthalate), an affordable and sustainable composite material, to produce custom-made sockets. Advancing the development of a unique socket manufacturing technique employing a reusable vacuum bag and a purpose-built curing oven, we tested fabricated sockets for maximum strength. Subsequently, a prosthetic device was created and assessed for its performance during ambulation. The mechanical and structural strength of PET materials for sockets reached a maximum strength of 132 MPa and 5686 N. Findings indicate that the material has the potential to serve as a viable substitute for manufacturing functional sockets. Additionally, TOPSIS analysis was conducted to compare the performance index of sockets, considering decision criteria such as material cost, socket weight, and strength. The results showed that PET sockets outperformed other materials in affordability, durability, and strength. The methodology successfully fabricated complex-shaped patient sockets in under two hours. Additionally, walking tests demonstrated that amputees could perform daily activities without interruptions. This research makes significant progress towards realising affordable prostheses for LMICs, aiming to provide patient-specific affordable prostheses tailored for LMICs. Full article

Pattern recognition in myoelectric control that relies on the myoelectric activity associated with arm motions is an effective control method applied to myoelectric prostheses. Individuals with transhumeral amputation face significant challenges in effectively controlling their prosthetics, as muscle activation varies with changes in arm positions, leading to a notable decrease in the accuracy of motion pattern recognition and consequently resulting in a high rejection rate of prosthetic devices. Therefore, to achieve high accuracy and arm position stability in upper-arm motion recognition, we propose a Deep Adversarial Inception Domain Adaptation (DAIDA) based on the Inception feature module to enhance the generalization ability of the model. Surface electromyography (sEMG) signals were collected from 10 healthy subjects and two transhumeral amputees while performing hand, wrist, and elbow motions at three arm positions. The recognition performance of different feature modules was compared, and ultimately, accurate recognition of upper-arm motions was achieved using the Inception C module with a recognition accuracy of 90.70% ± 9.27%. Subsequently, validation was performed using data from different arm positions as source and target domains, and the results showed that compared to the direct use of a convolutional neural network (CNN), the recognition accuracy on untrained arm positions increased by 75.71% (p < 0.05), with a recognition accuracy of 91.25% ± 6.59%. Similarly, in testing scenarios involving multiple arm positions, there was a significant improvement in recognition accuracy, with recognition accuracy exceeding 90% for both healthy subjects and transhumeral amputees. Full article

Lower limb amputation affects several parameters of a patient’s life. Family caregivers providing care for these patients experience multiple feelings and needs; knowing caregivers’ needs is essential to prepare them for this new role, as well as the health planning of this type of care. This scoping review aimed to identify and map the needs of family caregivers of people with lower limb amputations. This scoping review was conducted in accordance with the JBI methodological framework and the PRISMA-ScR reporting guidelines. A bibliographical search was carried out on the needs of family caregivers of lower limb amputees in 15 databases. Two independent reviewers extracted data using a data extraction tool developed for this scoping review. Eight studies were included in the present review (n = 6 quantitative studies; n = 2 reviews). Results indicate that family caregivers of people with lower limb amputations may experience an extensive range of needs, as follows: (i) mental health and psychological support, (ii) physical health, (iii) health and well-being, (iv) supportive care, (v) social support, and (vi) educational/informational support. The needs identified in this review can help to develop interventions and programs that provide better support during the situational transition process. Full article

Adults who have had an amputation face barriers to having an active lifestyle which attenuates cardiorespiratory fitness. Prior studies in amputees typically involve treadmill walking or arm ergometry, yet physiological responses to bilateral leg cycling are less understood. This study assessed the hemodynamic and metabolic responses to moderate and vigorous cycle ergometry in men who have had a transtibial amputation (TTA). Five men who had had a unilateral TTA (age = 39 ± 15 yr) and six controls (CONs) without an amputation (age = 31 ± 11 yr) performed two 20 min bouts of cycling differing in intensity. Cardiac output (CO), stroke volume (SV), and oxygen consumption (VO₂) were measured during moderate intensity continuous exercise (MICE) and high intensity interval exercise (HIIE) using thoracic impedance and indirect calorimetry. In response to MICE and HIIE, the HR and VO₂ levels were similar (p > 0.05) between groups. Stroke volume and CO were higher (p < 0.05) in the CONs, which was attributed to their higher body mass. In men with TTAs, HIIE elicited a peak HR = 88%HRmax and substantial blood lactate accumulation, representing vigorous exercise intensity. No adverse events were exhibited in the men with TTAs. The men with TTAs show similar responses to MICE and HIIE versus the CONs. Full article

Lower limb knee–ankle prostheses can effectively assist above-knee amputees in completing their basic daily activities. This study explored methods for estimating the joint kinematics of intelligent lower limb prostheses to better adapt them to the walking requirements of amputees. A method of estimating the knee and ankle joint trajectories under different speeds and slopes was raised. The joints of a prosthetic need to have a movement trajectory similar to that of the joints of healthy individuals, taking into account the person’s motion intentions and complying with the law of movement. In this study, a prosthetic kinematics estimation method was studied to realize continuous speed and slope adaptation through key points. The iterative Douglas–Peucker algorithm automatically found the key points of the kinematic trajectory curve, and an invariant basis function-fitting model with key points constraints was constructed. Finally, the radial basis function neural network was used to estimate the adaptive task function of the parts affected by the speed and slope, resulting in an overall kinematics estimation model. Our experiments verified the effectiveness of the proposed method, which accurately estimated the kinematic trajectory; the knee and ankle joint estimation errors were greatly reduced compared to those obtained with previous methods, facilitating further research on individual algorithms. Full article

Background and Objectives: Medical registries evolved from a basic epidemiological data set to further applications allowing deriving decision making. Revision rates after non-traumatic amputation are high and dramatically impact the following rehabilitation of the amputee. Risk scores for revision surgery after non-traumatic lower limb amputation are still missing. The main objective was to create an amputation registry allowing us to determine risk factors for revision surgery after non-traumatic lower-limb amputation and to develop a score for an early detection and decision-making tool for the therapeutic course of patients at risk for non-traumatic lower limb amputation and/or revision surgery. Materials and Methods: Retrospective data analysis was of patients with major amputations lower limbs in a four-year interval at a University Hospital of maximum care. Medical records of 164 patients analysed demographics, comorbidities, and amputation-related factors. Descriptive statistics analysed demographics, prevalence of amputation level and comorbidities of non-traumatic lower limb amputees with and without revision surgery. Correlation analysis identified parameters determining revision surgery. Results: In 4 years, 199 major amputations were performed; 88% were amputated for non-traumatic reasons. A total of 27% of the non-traumatic cohort needed revision surgery. Peripheral vascular disease (PVD) (72%), atherosclerosis (69%), diabetes (42%), arterial hypertension (38%), overweight (BMI > 25), initial gangrene (47%), sepsis (19%), age > 68.2 years and nicotine abuse (17%) were set as relevant within this study and given a non-traumatic amputation score. Correlation analysis revealed delayed wound healing (confidence interval: 64.1% (47.18%; 78.8%)), a hospital length of stay before amputation of longer than 32 days (confidence interval: 32.3 (23.2; 41.3)), and a BKA amputation level (confidence interval: 74.4% (58%; 87%)) as risk factors for revision surgery after non-traumatic amputation. A combined score including all parameters was drafted to identify non-traumatic amputees at risk for revision surgery. Conclusions: Our results describe novel scoring systems for risk assessment for non-traumatic amputations and for revision surgery at non-traumatic amputations. It may be used after further prospective evaluation as an early-warning system for amputated limbs at risk of revision. Full article

The prognostic nutritional index (PNI) is a new marker used to assess a patient’s nutritional and immune status. It is calculated using serum albumin levels and total lymphocyte count. The aim of this study was to investigate the relationship between PNI and amputation in patients with diabetic foot ulcer (DFU). Patients with DFU were enrolled in this retrospective study. In our study, a total of 386 patient data, of 110 (28.5%) amputated and 276 (71.5%) non-amputated patients, were statistically analyzed. PNI values were significantly lower in the amputated patient group than in the non-amputee patient group (p < 0.001). According to the ROC analysis results, PNI was significant in the prediction of amputation at an excellent level (AUC = 0.937 (0.911–0.963), p < 0.001). The optimal cut-off point for PNI was found to be 39,005. There was classification success for this cut-off point: sensitivity was calculated as 82.7% (74.1–89) and specificity as 93.1% (89.3–95.7). In the multivariate model, the odds ratio (OR) (95% CI) was calculated as 81.8 (38.5–173.7) for PNI. The PNI was associated with an increase in amputation rate in patients with DFU. By using PNI, patients can be directed to advanced centers and have access to early and appropriate interventions. Full article

Objective: To train a machine-learning (ML) algorithm to classify stumbling in transfemoral amputee gait. Methods: Three subjects completed gait trials in which they were induced to stumble via three different means. Several iterations of ML algorithms were developed to ultimately classify whether individual steps were stumbles or normal gait using leave-one-out methodology. Data cleaning and hyperparameter tuning were applied. Results: One hundred thirty individual stumbles were marked and collected during the trials. Single-layer networks including Long-Short Term Memory (LSTM), Simple Recurrent Neural Network (SimpleRNN), and Gradient Recurrent Unit (GRU) were evaluated at 76% accuracy (LSTM and GRU). A four-layer LSTM achieved an 88.7% classic accuracy, with 66.9% step-specific accuracy. Conclusion: This initial trial demonstrated the ML capabilities of the gathered dataset. Though further data collection and exploration would likely improve results, the initial findings demonstrate that three forms of induced stumble can be learned with some accuracy. Significance: Other datasets and studies, such as that of Chereshnev et al. with HuGaDB, demonstrate the cataloging of human gait activities and classifying them for activity prediction. This study suggests that the integration of stumble data with such datasets would allow a knee prosthesis to detect stumbles and adapt to gait activities with some accuracy without depending on state-based recognition. Full article