• Journal of Korean Physical Therapy Science
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• v.12 no.4
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• pp.89-97
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• 2005

Objective: The purpose of this study was to access quality of life and evaluate pre and post surgery management for persons with lower limb amputations. Method: This study was designed as a telephone survey. The subjects were patients who underwent their lower limb amputation between January 1994, and February 2005 at Asan Medical Center in seoul. sixty one of 203 subjects had granted consent and were studied. Results: The major cause of below knee amputations was vascular disease. Traumatic injuries were more common among subjects with above knee amputations. 93.4% of subjects were in use of prosthesis and 70.1 days were required to fit the prosthesis. 68.4% of subjects were able to ambulate with single point cane or without assistive devices. 80.3% of subjects complained phantom pain. Most subjects expressed the unsatisfactory result regarding the functional usage of prosthesis and education from hospital. Conclusion: Pre and post surgery rehabilitation program will benefit to promote better functional status and quality of life for persons with lower limb amputations.

• Journal of information and communication convergence engineering
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• v.2 no.2
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• pp.110-115
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• 2004

The prosthesis of current commercialized apparatus has considerable problems, requiring improvement. Especially, LLP(Lower Limb Prosthesis)-related problems have improved, but it cannot provide normal walking because, mainly, the gait control of the LLP does not fit with patient's gait manner. To solve this problem, HCI((Human Computer Interaction) that adapts and controls LLP postures according to patient's gait manner more effectively is studied in this research. The proposed control technique has 2 steps： 1) the multilayer neural network forecasts angles of gait of LLP by using the angle of normal side of lower limbs； and 2) the adaptive neural controller manages the postures of the LLP based on the predicted joint angles. According to the experiment data, the prediction error of hip angles was 0.32［deg.］, and the predicted error of knee angles was 0.12［deg.] for the estimated posture angles for the LLP. The performance data was obtained by applying the reference inputs of the LLP controller while walking. Accordingly, the control performance of the hip prosthesis improved by 80% due to the control postures of the LLP using the reference input when comparing with LQR controller.

• The Journal of the Korean bone and joint tumor society
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• v.1 no.1
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• pp.23-29
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• 1995

Recently limb-salvage operation is widely used for the treatment of malignant bone tumor. But distal leg is out of range of limb-salvage operation due to its technical problem. We report satisfactory limb-salvage operation with tumor prosthesis in 3 cases of osteosarcoma of the distal tibia and fibula. Two cases involved in the tibia and 1 case in the fibula. Average age at operation was 23 years. Neoadjuvant and adjuvant chemotherapy were performed in all 3 cases. We used custom made tumor prosthesis which is designed by Seoul National University Orthopaedic Department. Overall Functional Evaluations by Enneking rating system were good in all 3 cases. All cases are CDF(continuosly disease free since the surgical procedure) state at mean follow-up 2 year and 9 months. In conclusion limb-salvage with tumor prosthesis is useful treatment modality for malignant bone tumor of distal tibia and fibula. Good functional results and few complications suggests limb salvage of distal lower leg may be replaceable with B-K amputation.

• International Journal of Control, Automation, and Systems
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• v.3 no.2
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• pp.152-158
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• 2005

Commercial lower limb prostheses or orthotics help patients achieve a normal life. However, patients who use such aids need prolonged training to achieve a normal gait, and their fatigability increases. To improve patient comfort, this study proposed a method of predicting gait angle using neural networks and EMG signals. Experimental results using our method show that the absolute average error of the estimated gait angles is $0.25^{\circ}$. This performance data used reference input from a controller for the lower limb orthotic or prosthesis controllers while the patients were walking.

• Physical Therapy Korea
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• v.8 no.3
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• pp.1-10
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• 2001

The purpose of this study was to compare the static pressure, dynamic pressure, dynamic pressure-time integral, relative impulse, and contact time between the sound lower limb and amputated lower limb in trans-tibial amputee subjects using Parotec system. Seventeen trans-tibial amputee subjects wearing endoskeletal trans-tibial prosthesis voluntarily participated in this study. The results were as follows: 1) In static standing condition, there were significantly higher static pressure in sound lower limb insole sensor of 10, 14, 15, 18, 19, 23, and 24 and in amputated lower limb insole sensor of 9, 12, and 16 (p<.05). 2) In dynamic gait condition, there were significantly higher dynamic pressure in sound lower limb insole sensor of 2, 18, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, 14, 15, and 16 (p<.05). 3) In dynamic gait condition, there were significantly higher pressure-time integral in sound lower limb insole sensor of 2, 4, 18, 19, 20, 21, 23, and 24 and in amputated lower limb insole sensor of 5, 11, 12, and 15 (p<.05). 4) In dynamic gait condition, there were significantly higher relative impulse in sound lower limb insole sensor of 18, 19, 20, 22, 23, and 24 and in amputated lower limb insole sensor of 5, 9, 10, 11, 12, and 15 (p<.05). 5) In dynamic gait condition, there was significantly higher percentage of contact time in push off phase of sound lower limb and in support phase of amputated lower limb (p<.05). These results suggest that trans-tibial amputee subjects had characteristics of shortened push off phase due to unutilized forefoot and of lengthened support phase with higher pressure in the midfoot.

• The Journal of Korea Robotics Society
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• v.19 no.2
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• pp.159-168
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• 2024

Lower limb amputees are increasing due to various reasons. It is difficult for lower limb amputees to walk without an assistive device such as a prosthetic leg. In this paper, an electronically controlled knee-type prosthetic leg with a 4-bar linkage structure for lower limb amputees was developed. The knee-type prosthetic leg has a 4-bar linkage structure and assists walking by using an integrated drive module. The torque is 90 Nm, the rotation speed is up to 120 deg, and it weight 1.9 kg, so it is lighter than a commercial prosthetic leg, so it can be used for a long time because there is less fatigue when walking. An integrated control board was developed by applying various sensors and microprocessor. The motor drive and encoder are built into the integrated drive module. The integrated control board and integrated drive module communicate using CAN. When a lower limb amputee wears a knee-type prosthetic leg and walks, it shows a shape similar to the swing phase graph of a normal people, and it is possible to walk naturally while walking.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.267-271
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• 1997

In this study, swing phase dynamic simulation of above-knee prosthesis is performed. The prosthesis consists of a single axis knee mechanism and pneumatic cylinder. The numerical modelling of the prosthesis is analyzed in two dimensions. The governing equation of thermodynamical pneumatic cylinder model is applied to construct the control of lower limb during swing phase. Knee flexion angle with respect to the orifice diameter of the pneumatic cylinder is produced. This analysis will be very useful to the design of pneumatic cylinder in prosthesis.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.10 no.4
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• pp.305-313
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• 2016

Movements of the lower limb are important for normal walking and smooth oscillation of the center of gravity. The ankle rotations such as dorsi-flexion, plantar-flexion, inversion and eversion allows the foot to accommodate to ground during level ground walking. Current below knee (B/K) prostheses are used for replacing amputated ankle, and make it possible for amputees to walk again. However, most of amputees with B/K prostheses often experience a loss of terrain adaptability as well as stability because of limited ankle rotation. This study is focused on the development of multi-rotational prosthetic foot for lower limb amputee. Our prosthesis is possible for amputees to easily walk in level ground by rotating ankle joint in sagittal plane and adapt to the abnormal terrain with ankle rotation in coronal plane. The resistance of ankle joint in the direction of dorsi/plantar-flexion can be manually regulated by hydraulic damper with controllable nozzle. Furthermore, double layered rubber induce the prosthesis adapt to irregular ground by tilting itself in direction of eversion and inversion. The experimental results highlights the potential that our prosthesis induce a normal gait for below knee amputee.

• Journal of the Institute of Convergence Signal Processing
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• v.25 no.2
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• pp.77-85
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• 2024

The suspension device that connects the prosthetic leg and the residual limb allows lower limb amputees to wear prosthetic limbs, and is the most sensitive part when using prosthetic limbs as it is always in contact with the residual limb not only while walking but also in everyday life. In this paper, using the principles of attraction and repulsion of permanent magnets, we developed a magnetic lock suspension device that can fix the amputees and prosthetic legs of lower limb amputees by changing the polarity of the magnet. The operation method of the magnetic lock is that when neodymium magnets are placed on the left and right as NNSS based on a non-magnetic brass core, the magnetic force flows outward beyond the brass core using the adsorption member as a medium to generate bonding force. When rotated 90 degrees, the magnet moves to NSNS. The principle is that as the position moves, the magnetic force flows inward and cancels out.Based on this, we conducted a bonding test using tensile strength and a short-term comparative evaluation of the prosthesis with the shuttle lock suspension system, which was a comparison group, to verify reliability and evaluate satisfaction with the prototype. As a result, the tensile strength exceeding the appropriate bonding strength was confirmed, and the magnetic lock showed higher satisfaction than the shuttle lock. In the future, we plan to conduct long-term ADL clinical trials for commercialization and develop a product that can be distributed to actual amputees.

• The Journal of the Korean bone and joint tumor society
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• v.6 no.4
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• pp.152-162
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• 2000

Purpose : To verify radiological changes of limb salvage operation using tumor prosthesis. Materials and Methods : Sixty-nine cases which used tumor prosthesis were reviewed. They have been followed up for average four years and nine months. We evaluated radiographs by ISOLS(International Symposium On Limb Salvage) radiological implants evaluation system immediate postoperatively, at postoperative 1 year and last follow-up. After converting 'excellent, good, fair, poor' to '4, 3, 2, 1' for stastical analysis, data were analyzed according to the use of cement, anatomical sites, diagnosis implant designs and age (<20 year vs. ${\geq}$20 year) using t-test and ANOVA. Results : The outcomes of cemented type prostheses were superior in remodelling and interface but inferior in anchorage. The scores of proximal femur and distal tibia were worse in bone remodelling. Osteosarcoma group had lower scores in anchorage and implant articular problem. There were no significant differences according to four different implant designs and age. Conclusion : In the intermediate term follow-up radiological evaluation, cemented type prosthesis were better in the aspects of bony resorption and osteolysis, and cementless one in anchorage. Distal femur and proximal tibia have higher scores in bony resorption, and osteosarcoma was worse tumor entity in anchorage and articular problem, and chemotherapy may be the cause.