• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.4
• /
• pp.52-72
• /
• 2002

• Proceedings of the IEEK Conference
• /
• 2002.06e
• /
• pp.281-284
• /
• 2002

대부분의 보조기 및 의족은 기계식이 주류이며 환자가 착용시 정상보행은 부드럽지 못하고 원활한 보행을 위해서는 장기간 동안 훈련이 요구된다. 따라서 대퇴의족에서 발생하는 이러한 문제점을 개선하기 위해 본 연구에서는 대퇴절단자(transfermoral amputee)의 보행을 정상보행에 일치하는 보행 능력을 복원하기 위해 근전도 신호와 인공신경망을 이용하여 적응 PID제어기를 설계하였고 그 제어 결과를 제시하였다.

• Journal of the Korean Society for Precision Engineering
• /
• v.29 no.2
• /
• pp.239-244
• /
• 2012

The prevalence of knee osteoarthritis was higher people with lower limb amputation. This was identified that transfemoral amputees have a greater external knee adduction moment than ablebodied subjects by biomechanical studies. Therefore, they need rehabilitative intervention for prevention and reduction of knee osteoarthritis. The purpose of this study was to determine the effect of lateral wedge insole used in the treatment of knee osteoarthritis. This study was participated in fourteen unilateral transfemoral amputees and we were analyzed the difference gait variables between without lateral wedge insole and with $5^{\circ}$ and $10^{\circ}$ lateral wedge insole during gait. Our results showed that step length ratio was more symmetrical and, hip adduction and ankle inversion angle were more close to normal value, and knee adduction moment was decreased as the wedge angle increases. We proposed that these data would be utilized conservative treatment of knee osteoarthritis in lower limb amputees.

• Journal of the Korean Society for Precision Engineering
• /
• v.31 no.10
• /
• pp.913-922
• /
• 2014

This paper describes design of a robotic above-knee prosthetic leg which is powered by electrical motors. As a special feature, the robotic prosthetic leg has enough D.O.F.s. For mimicking the human leg, the robotic prosthetic leg is composed of five joints. Three of them are called 'active joint' which is driven by electrical motors. They are placed at the knee-pitch-axis, the ankle-pitch-axis, and the an! kle-roll-axis. Every 'active joint' has enough torque capacity to overcome ground reaction forces for walking and is backlashless for accurate motion generation and high-performance balance control. Other two joints are called 'passive joint' which is activating by torsion spring. They are placed at the toe part and designed by Crank-rocker mechanism using kinematic design approach. In order to verify working performance of the robotic prosthetic leg, we designed a gait trajectory through motion capture technique and experimentally applied it to the robot.

• Clinical and Experimental Pediatrics
• /
• v.45 no.11
• /
• pp.1397-1402
• /
• 2002

Purpose : One of the major complication of arterial catheterization is the thrombosis of the iliac or femoral arteries. Tissue loss following femoral artery catheterization is rare. However longterm sequelae such as impaired limb growth and future impairment of vascular access, are also important in pediatric cardiac patients. But standard methods to treat thrombotic complication of arterial catheterization in infants and children is not established. The present study was performed to assess the efficacy of intraarterial catheter-directed urokinase infusion in infants and children with limb ischemia due to arterial thrombosis after cardiac catheterization. Methods : From January 1994 to August 2002, 12 patients with thrombotic femoral artery occlusion after arterial catheterization were treated with catheter-directed urokinase infusion in Dong-A University Hospital. Retrospective analysis of the medical records and angiograms was conducted. Results : The incidence of femoral artery thrombosis after retrograde arterial catheterization, which had not responded to systemic infusion of heparin and/or urokinase, was 2.8 percent. The doses of urokinase were 1,000-4,400 unit/kg/hr and duration of infusion was $50.6{\pm}29.2$ hours(18-110 hours). Clot resolution was complete in all patients who started to receive the intraarterial urokinase infusion within four days after catheterization. Only partial thrombolysis was seen in two patients who were treated with intraarterial urokinase on the 12th and 19th days after thrombus formation. Balloon angioplasty was done for these two patients with partial success. Bleeding complications were seen in two cases. Conclusion : Early use of catheter-directed intraarterial infusion of urokinase is safe and effective in thrombolysis of femoral artery occlusion after cardiac catheterization in infants and children.

• Journal of IKEEE
• /
• v.26 no.2
• /
• pp.249-256
• /
• 2022

The prosthetic leg is a device that performs walking instead of a amputated lower limb, and require a change in locomotion mode by providing the user's intention to respond to a discontinuous locomotion environment. Research has been conducted to detect the users' intentions through biomechanical features inside the socket that directly contacts the cut site in demand for natural locomotion mode changes without external control equipment. However, there is still a need for a sensor system that is suitable for the internal environment of the main body and socket of the cut site. Accordingly, this paper proposed a film-type sensor system that is suitable for the main body characteristics of the cut site, is not affected by the temperature and humidity conditions inside the socket, and is easy to manufacture in various sizes. The proposed sensor is manufactured base on Velostat film and takes into account the pressure measurement characteristics that vary with size. Through the experiment, the change in the internal pressure of the socket due to the intentional posture performance of the wearer was measured, and the possibility of detecting the intention to change the locomotion mode was confirmed.

• Korean Journal of Applied Biomechanics
• /
• v.23 no.1
• /
• pp.77-83
• /
• 2013

The purpose of this study was to compare kinematic variables and stiffnesses of ankle joints between normal person and transfemoral amputee gait in order to develop or fit prosthetic leg. Twenty subjects (ten normal persons and ten transfemoral amputees) participated in this experiment, and walked three trials at a self-selected pace. The gait motions were captured with Vicon system and variables were calculated with Visual-3D. The velocity, stride length, stride width, cycle time, double limb support time and right swing time of gaits were statistically significant. Because coefficients of variability of normal persons on velocity, double limb support time and swing time were greater than transfemoral amputees, normal persons controlled these gait variables effectively. The stiffnesses of ankle joints were not statistically significant, but patterns of stiffnesses of ankle joints during three rockers were absolutely different. The negative correlations between stiffnesses of ankle joints and cycle time and swing time were presented. These differences suggest that developing and fitting prosthetic leg were demanded. Further studies should develop fitting program and simulator of prosthetic leg.

• Journal of Biomedical Engineering Research
• /
• v.19 no.4
• /
• pp.403-416
• /
• 1998

Socket pressure distributions with gait analysis of a trnsfemoral and a transtibial prostheses were measured in order to assess an optimal socket fitting and function. Ankle joint was aligned by the neutral and the dorsi/plantar flexed positions. Compared to dorsi and plantar flexed positions of ankle joint, cadence and walking speed increased with the neutral ankle joint alignment. Other gait parameters were close to the normative data with the neutral ankle joint alignment. For the transfemoral amputee, dorsiflexed alignment of the ankle joint created high pressure on the lateral aspect of the socket, on the other hand, plantarflexed alignment resulted in increased pressure on the medial aspect of the socket. For the transtibial amputee, dorsiflexed alignment of the ankle resulted in high pressure on the antero-lateral aspect of the socket during mid-stance, but apltarflexion of the ankle joint showed slight increases in pressure at the same location in the socket. The present study clearly demonstarted that malalignment of a prosthesis results in localized increasesing pressure within the socket. Proper slignment of the prosthesis is required in order to acquire an appropriate socket-limb interface as well as the proper gait.

• Journal of Chest Surgery
• /
• v.30 no.7
• /
• pp.733-738
• /
• 1997

Sequential bilateral lung transplantation may result in a variety of perioperative and postoperative complications, showing high perioperative morbidity and mortality rates. This research was performed to investigate the hemodynamic changes in adult mongrel dogs after bilateral reimplantation, two methods preferred for avoiding or minimizing graft rejection. The anterior portion of the pulmonary artery and the left atrium proximal to the superior and the inferior pulmonary veins were resected out and then re-anastomosed one hour later to prevent torsion or stenosis of the anastomotic site and the formation of a thrombosis in the left atrium. An everted suture technique was employed for the left atrium; An hour after the division, however, the main bronchus was tightly anastomose by interrupted sutures of No. 4-0 prolene in a telescope method. A modified I-C solution mixed with PGEI was infused into the cut portion of the pulmonary artery at the rate of 15 mllkglmin and at a pressure of 40 cmH20 for a total dosage of 70 mlfkg in order to preserve the transected lung. Topical cooling using wet gauzes soaked with cold I-C solution was performed for one hour to prevent ischemic lung injury. The above procedures are considered to be beneficial for achieving a satisfactory outcome for bilateral lung reimplantation.

• The Journal of the Korean bone and joint tumor society
• /
• v.10 no.1
• /
• pp.1-12
• /
• 2004

Purpose: The current study was performed to analyze the oncological and functional results, and the patient, the limb and the prosthesis survival of osteosarcoma around the knee in children according to the treatment options. Materials and Methods: From 1982 to 2002, 63 patients with osteosarcoma around the knee underwent surgical treatments before 16 years of age. Surgical treatment options were amputation, endoprosthetic replacement, and implantation of low heat-treated autogenous bone graft after wide resection of tumor. The mean age of patients was 11.5 years (4.4~16), and the mean follow-up period was 6.1 years (2.1~16.8). All patients had neoadjuvant and adjuvant chemotherapy. All endoprosthses were extendible types. Anatomical locations of osteosarcoma were distal femur in 40 patients, and proximal tibia in 23 patients. As regard to Enneking stage, 4 patients had stage $II_A$, 50 patients had stage $II_B$, and 9 patients had stage III tumors. Results: The 5 year survival rate of stage $II_B$ patients was 72.7% in amputation, 83.7% in endoprosthesis, and 100% in low heat-treated autogenous bone graft. The 5 year survival rate of salvaged limb was 84.4% in endoprosthesis, and 80% in low heat-treated autogenous bone graft. The survival rate of prosthesis was 92.7% at 5 years, 67.4% at 10 years in endoprosthesis, and 75% at 5 years in low heat-treated autogenous bone graft. Mean functional outcome scores were 8.7 points in amputation, 20.6 points in endoprosthesis, and 16 points in low heat-treated autogenous bone graft. Distant metastasis occurred 15.8% in amputation, 27% in endoprosthesis and local recurrence occurred 8.1% in endoprosthesis, 14.3% in low heat-treated autogenous bone graft. Major complications happened 26.3% in amputation, 35.1% in endoprosthesis, and 28.6% in low heat-treated autogenous bone graft. Conclusion: Limb salvage procedure had functionally better results than amputation in children with osteosarcoma around the knee. Reconstruction with endoprosthesis after resection of tumor had good results in children as adults. In certain circumstances as too small bone for endoprosthesis or minimal bony destruction or too skeletally immature patient, low heat-treated autogenous bone graft may be a good treatment option. Low heat-treated autogenous bone graft may be considered as not only a substitute for endoprosthesis but also a temporary method before endoprosthesis.