• 대한골관절종양학회지
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• 제1권1호
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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.

• Journal of information and communication convergence engineering
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• 제2권2호
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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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1183-1184
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• 2012

• 대한기계학회논문집A
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• 제24권2호
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• pp.329-337
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• 2000

An investigation has been performed to develop an analysis tool based on a nonlinear beam theory, which can be used to predict the long-term behavior of an artificial hip joint. The nonlinear behav ior of the femur arise from the coupled dependence of the bone density and the mechanical properties on each other. The beam theory together with its numerical algorithm is developed to take into account the nonlinear bone remodeling process of the femur that is long enough to be assumed as a beam. A piecewise linear curve for the bone remodeling rate is used in the bone remodeling theory and the surface area density of bone is modeled as the third order polynomial function of bone density. At each section of the beam, a constant curvature is assumed and the longitudinal strains are also assumed to vary linearly across the section. The Newton-Rhapson iteration method is used to solve the nonlinear equations for each cross section of the bone and a backward method is used to march along the time. The density and the remodeling signal ar, calculated along with time for the various time steps, and the developed beam theory has been verified by comparing with the results of finite element analysis of a remodeling bone with an artificial hip joint of titanium prosthesis subjected to uni-axial loads and pure bending moment. It is concluded that the developed beam theory can be used to predict the long-term behavior of the femur and thus to design the artificial hip prosthesis.

• 대한치과보철학회지
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• 제34권3호
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• pp.501-532
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• 1996

This study investigated the effects of cantilever length, location and load condition on stress distribution developed in the implants, prostheses and supporting tissues. The osseointegrated prostheses with two 10mm Branemark implants at 2nd premolar and 1st molar sites with cantilever extensions at 1st premolar, 2nd and 3rd molar sites were constructed. Under 100N, 200N of vertical and $45^{\circ}$ oblique loads at the cantilever pontics, stress distribution patterns and displacement were analyzed with three dimensional finite element method. The results were as follows : 1. The stress was concentrated at the joint of the cantilever pontic and implant superstructure, the neck of implant and the ridge crest near the cantilever But there was little load transfer to the lower supporting tissues of implants. 2. The implant near the cantilever was displaced inferiorly while the implant far from the cantilever was displaced superiorly. In horizontal direction the implants were displaced to the direction where the loads were applied, except the apexes of the implants. 3. In case of anterior cantilever, the stress and displacement were higher than the prosthesis connected with natural tooth. 4. The stress developed in the posterior cantilevered type was higher than in the anterior cantilevered type. The greastest stress was concentrated at the ridge crest near the posterior cantilever. 5. The longer the cantilever, the more the stress was developed and was concentrated at the joint of the cantilever pontic and implant superstructure. 6. Under oblique load, the stress was concentrated at the necks of implants and the ridge crests, but decreased at the joint of the cantilever pontic and implant superstructure than under vertical load.

• 구강회복응용과학지
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• 제19권2호
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• pp.125-137
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• 2003

The use of screw-retaind prosthesis on an osseointegrated implant is a popular treatment modality offering relative ease in the removal of the restoration. One of the complications associated with this modality is the loosening of the abutment and coping screws. Loosening of the screws results in patient dissatisfaction, frustration to the dentist and, if left untreated, component fracture. There are several factors which contribute to the loosening of implant components which can be controlled by the restorative dentist and lab technician. This article offers pratical solutions to minimize this clinical problem and describes the factors involved in maintaining a stable screw joint assembly. To avoid joint failure, adherence to specific clinical, as well as mechanical, parameters is critical. With respect to hardware, optimal tolerance and fit, minimal rotational play, best physical properties, a predictable interface, and optimal torque application are mandatory. In the clinical arena, optimal implant distribution; load in line with implant axis; optimal number, diameter, and length of implants; elimination of cantilevers; optimal prosthesis fit; and occlusal load control are equally important.

• 대한골관절종양학회지
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• 제13권1호
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• pp.31-36
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• 2007

목적: 악성 골종양 환자에서 사지구제술 후 결손부위의 재건방법 중 체외 방사선 조사를 이용한 재활용 자가골 이식술이 한 방법으로 시행되고 있다. 그러나 관절주위에서 발생한 종양의 수술시 관절 내 절제술 및 재활용 자가 관절이식술 시행 후 발생하는 관절의 불안정성, 진행되는 관절염 등의 단점이 있다. 이러한 단점을 보완하기 위해 생각되어진 관절외 절제술 및 체외 방사선 조사를 이용한 재활용 전 자가 관절 이식술을 시행하여 그 결과를 알아보고자 하였다. 대상 및 방법: 1997년 6월부터 2006년 2월까지 슬관절 주위의 악성 골종양으로 진단받고, 동일한 수술을 시행한 5례를 대상으로 하였다. 추시 중 합병증과 재발의 유무를 확인하기 위해 주기적 진찰 및 검사를 시행하였다. 추시 기간은 최단 93개월에서 최고 105개월로 평균 100개월이었으며, 평균 나이는 21.6세였다. 결과: 단순 방사선상 골 유합기간은 평균 15.6개월(9~40개월)이었으며, Enneking 기준의 기능적 평가결과 평균 71.6%(66.6~80%)였으며 재발은 1례도 없었다. 합병증은 골단부 붕괴 3례, 관절 불안정성 5례가 발생하였고, 전례에서 종양 대치물로 관절 치환술을 시행하였다. 결론: 슬관절 주위에 원발성 골종양이 발생한 경우 체외 방사선 조사를 이용한 재활용 전자가 관절이식술은 관절 불안정성을 일으켜 영구적인 관절 기능을 유지하지 못하므로 종양 대치물의 사용이 적절할 것으로 생각된다.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 2000년도 Proceedings of 2000 International Nano Crystals/Ceramics Forum and International Symposium on Intermaterials
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• pp.165-177
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• 2000

Ceramic on ceramic total hip prostheses are developed to apply to young patients because lifetime of polyethylene joint prostheses is limited by loosening due to biological response. As mating faces of all-ceramic joint must be highly conformed to reduce stress concentration, wear properties of flat surfaces are investigated in this study. Through wear tests at 2 MPa of contact pressure and 36 mm/s of sliding velocity, alumina and silicon carbide keep low wear rate, high hardness and smooth surface. Soft surface film was detected after the test in bovine serum. This suggests that boundary lubrication is effective to reduce wear in all-ceramic joint.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제35권6호
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• pp.412-420
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• 2013

The literature on alloplastic total temporomandibular joint (TMJ) replacement is encouraging, with acceptable improvement of treatment outcomes in terms of both pain level and jaw function. This is a case report on patients who suffered from degenerative joint disease and ankylosis after mandibular condyle fracture or prior TMJ surgery and were treated by TMJ replacement with condyle prosthesis. We obtained good results from the procedures, including total TMJ replacement.

• 대한골관절종양학회지
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• 제5권1호
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• pp.9-16
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• 1999

A new method of limb sparing by resection, extracorporeal irradiation and reimplantation has several theoretical advantages. This method preserves the mobility of a joint and avoids the problem of loosening or breakage of tumor prosthesis. This study involved using extracorporeal irradiated autogenous joint transplantation for reconstruction after en bloc resection, and observed the periods of functional union and histological changes in irradiated tissue of the knee joint. This study also aimed to clarify whether the degeneration of articular cartilage is induced in rabbits by a single 50Gy dose of irradiation at the knee joint. Twenty New Zealand rabbits about three kilograms were randomized into two groups of 10 rabbits each. In group 1, as control, we resected the knee joint followed by reimplantation without irradiation. Group 2 received extracorporeal irradiation on the resected knee joint followed by reimplantation. Following are the results of these observations. The osteotomy site showed external callus formation in the roentgenographic finding eight weeks after reimplantation. There was marked degenerative changes in the collagen fiber of the irradiated anterior cruciate ligament and meniscus during the fourth week, but new blood-vessel formation was observed in the vicinity. There was degenerative changes in the collagen fiber of articular cartilage treated extracorporeal irradiation at four and eight weeks in the scanning electron micrographic findings. These findings was in contrast to those of subchondral bone which showed decreased cellularity and empty lacuna at four and eight weeks. Autoradiography demonstrated active [$^3H$]uridine incorporation by irradiated chondrocyte at eight weeks after reimplantation. These results indicate that when destruction of the articular cartilage and soft tissue of the knee joint is not severe, extracorporeal irradiation and reimplantation can be used with several advantage in maintaining movement of the joint while avoiding problems of tumor prosthesis and rejection, and therefore extracorporeal irradiated autogenous joint transplantation can be used as a limb-sparing procedure for temporary biological spacer in the childhood bone tumor around the knee.