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For lower limb amputees, trans-femoral prostheses play an important role not only in regaining the gait ability of amputees, but also daily life activities. In recent years, the use of robotic technology has led to the development of robotic prostheses that provide better safety and comfortness in practicing normal walking. However, since daily activities other than walking rely heavily on the function of the sound leg, it is important not to put excessive burden on the sound leg in a mid-back posture and sit-to-stand motion. Therefore, in this study, in order to reduce the burden on the sound leg while using a prosthesis, we developed a new robotic prosthesis that maintains flexion posture at arbitrary knee angle in circumstances where the burden on the sound leg increases during daily life. Moreover, we proposed a model of daily activities based on finite state machine that represents not only walking, but also all daily activities such as sit-to-stand motion. Finally, we conducted experiments by a user of trans-femoral prosthesis and showed the effectiveness of maintaining flexion posture.

This study establishes the existing relation between gait asymmetry of an amputee that wears passive transfemoral prosthesis and the appearance of the hip pathologies in healthy and amputated limbs. This purpose is achieved through an integrated assessment of the results obtained out of kinematic and dynamic analysis of the amputee gait throughout the videographic techniques and the use of clinical trials such as radiography and densitometry, as the most important aspect related to design assessment and functionality of the transfemoral prosthesis. The result of the spatiotemporal variables measurement performed on healthy and amputee patients established a significant difference between gait patterns of healthy and amputee patients, and between healthy and amputated limbs of the amputee. Dynamic inverse analysis (DIA) and implementation of finite element method demonstrated that patients with such gait asymmetry have dynamic imbalance related to the degenerative hip diseases. Performed clinical trials showed the prevalence of osteoporosis in amputated limb of 7 patients, an 87.5% of studied cases, which highlights the influence of mechanical stimulus on bone remodeling and the presence of osteoarthritis in both limbs. [ABSTRACT FROM AUTHOR]

[Purpose] It is difficult to identify by visual observation whether alignment abnormalities in trans-femoral prostheses in the frontal plane are attributable to the adduction angle or the abnormal alignment of the positions of the medial and lateral sides of the socket in relation to the foot. Therefore, we focused on the trajectory of the center of plantar pressure during walking, and we proposed a method for differentiating these two alignment abnormalities. [Subjects and Methods] We recruited 4 trans-femoral unilateral amputees. Bench alignment was achieved initially. We compared the amplitude of the trajectory of the center of plantar pressure when walking under 2 conditions: 1) when changing the adduction angle and 2) when changing the positional relationship between the socket and the foot. [Results] It was not possible to distinguish between the 2 types of malalignment on the prosthesis side. There was a significant difference when changing the positional relationship on the contralateral side. Thereby, the plantar pressure of the contralateral side could be used to distinguish between the 2 types of malalignment. [Conclusion] The results of this study suggested that trans-femoral prosthesis malalignment could be evaluated through the plantar pressure of the contralateral side in amputees.