Technology Efficacy in Active Prosthetic Knees for Transfemoral Amputees: A Quantitative Evaluation

Several studies have presented technological ensembles of active knee systems for transfemoral prosthesis. Other studies have examined the amputees’ gait performance while wearing a specific active prosthesis. This paper combined both insights, that is, a technical examination of the components used, with an evaluation of how these improved the gait of respective users. This study aims to offer a quantitative understanding of the potential enhancement derived from strategic integration of core elements in developing an effective device. The study systematically discussed the current technology in active transfemoral prosthesis with respect to its functional walking performance amongst above-knee amputee users, to evaluate the system’s efficacy in producing close-to-normal user performance. The performances of its actuator, sensory system, and control technique that are incorporated in each reported system were evaluated separately and numerical comparisons were conducted based on the percentage of amputees’ gait deviation from normal gait profile points. The results identified particular components that contributed closest to normal gait parameters. However, the conclusion is limitedly extendable due to the small number of studies. Thus, more clinical validation of the active prosthetic knee technology is needed to better understand the extent of contribution of each component to the most functional development

Potential Optimal Gait Performance of Mauch S-N-S Prosthetic Knee Configurations as Predicted by Dynamic Modeling

Patients with prosthetic legs routinely suffer from abnormal gait patterns which can cause health issues and eventually lower the quality of their lives. Despite the half-century advance in the technology of prosthetic knees, from the purely mechanical to microprocessor controlled systems, patient testing suggests that very little progress has been made in the quality of the kinetics and kinematics of amputee gait. Moreover, the cost of microprocessor controlled prosthetic knees may be 10 times more than the purely mechanical knees. While prosthetic knees have become more complex and expensive, it is not proven that the prosthetic knee is a central factor limiting amputee patient gait. The goal of this project is to determine the degree to which the Mauch S-N-S prosthetic knee limits the ability of a subject to achieve a close to normal gait pattern. In this research, we developed dynamic models of the Mauch S-N-S prosthetic knee based on gait-like motion tests of a Mauch knee cylinder and used the dynamic models in computational simulations to determine the best achievable gait, on the basis of obtaining near-to-normal gait kinematics and kinetics. Idealized assumptions were made for patient performance capability and characteristics of the other prosthetic leg components, to obtain the desired focus on knee capabilities and limitations. The results indicate that even with this relatively old technology prosthetic knee, subjects have the potential to walk much more normally than the patient-test data indicates. An extension of the study showed the significant interaction of the prosthetic knee and ankle with respect to achieving optimal gait. The methodology of this study can be applied to evaluation other knees, prosthetic components and prosthetic systems combining these component

Mechanisms and component design of prosthetic knees : a review from a biomechanical function perspective

Prosthetic knees are state-of-the-art medical devices that use mechanical mechanisms and components to simulate the normal biological knee function for individuals with transfemoral amputation. A large variety of complicated mechanical mechanisms and components have been employed; however, they lack clear relevance to the walking biomechanics of users in the design process. This article aims to bridge this knowledge gap by providing a review of prosthetic knees from a biomechanical perspective and includes stance stability, early-stance flexion and swing resistance, which directly relate the mechanical mechanisms to the perceived walking performance, i.e., fall avoidance, shock absorption, and gait symmetry. The prescription criteria and selection of prosthetic knees depend on the interaction between the user and prosthesis, which includes five functional levels from K0 to K4. Misunderstood functions and the improper adjustment of knee prostheses may lead to reduced stability, restricted stance flexion, and unnatural gait for users. Our review identifies current commercial and recent studied prosthetic knees to provide a new paradigm for prosthetic knee analysis and facilitates the standardization and optimization of prosthetic knee design. This may also enable the design of functional mechanisms and components tailored to regaining lost functions of a specific person, hence providing individualized product design