• Clinics in Shoulder and Elbow
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• 제11권2호
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• pp.143-149
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• 2008

목적: 근위 상완골 골절에서 잠김 압박 금속판과 비잠김 금속판 고정의 방사선학적 임상적 추시 결과를 비교 분석하고자 하였다. 대상 및 방법: 2003년부터 2007년 까지 본원에서 근위 상완골 골절로 입원하였던 87명의 환자중 금속판 고정술을 시행 받았던 환자 20명을 대상으로 하였으며 20명의 환자는 잠김 압박 금속판 고정을 시행하였던 환자 10명, 비잠김 금속판 고정을 시행하였던 환자 10명의 두 군으로 나뉘었다. 각각의 환자군은 수술 직후와 수술 후 6개월 뒤 방사선 사진상 상완골의 경간각, 골유합까지 소요된 시간, 합병증의 빈도 그리고 마지막 추시 당시의 Constant score를 측정하여 서로 비교 분석 하였다. 결과: 상완골의 경각간 및 골유합, Constant score에 대해서 두 군은 유의한 차이를 보이지 않았으나 비잠김 금속판을 사용한 군에서 나사 풀림 현상이 3례에서 발견되었다. 결론: 추시 결과상 잠김 압박 금속판의 사용이 비잠김 금속판에 비하여 임상적, 방사선학적으로 유의한 차이는 없었으나 근위 상완골 골절의 치료에서 나사 풀림 현상 등의 합병증이 적은 잠김 압박 금속판을 사용하는 것이 더 효과적일 것으로 사료된다.

• Structural Engineering and Mechanics
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• 제50권2호
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• pp.181-199
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• 2014

Locking phenomenon is a mesh problem and can be staved off with mesh refinement. If the studier is not preferred going to the solution with increasing mesh size or the computer memory can stack over flow than using higher order plate finite element or using integration techniques is a solution for this problem. The purpose of this paper is to show the shear locking phenomenon can be avoided by increase low order finite element mesh size of the plates and to study shear locking-free analysis of thick plates using Mindlin's theory by using higher order displacement shape function and to determine the effects of various parameters such as the thickness/span ratio, mesh size on the linear responses of thick plates subjected to uniformly distributed loads. A computer program using finite element method is coded in C++ to analyze the plates clamped or simply supported along all four edges. In the analysis, 4-, 8- and 17-noded quadrilateral finite elements are used. It is concluded that 17-noded finite element converges to exact results much faster than 8-noded finite element, and that it is better to use 17-noded finite element for shear-locking free analysis of plates.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집A
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• pp.680-685
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• 2001

In this paper, RKPM is extended for solving moderately thick and thin structures. General Timoshenko beam and Mindlin plate theory are used far formulation. Shear locking is the main difficulty in analysis of these kinds of structures. Shear relaxation factor, which is formulated using the difference between bending and shear strain energy, is introduced to overcome shear locking. Analysis results obtained reveal that RKPM using introduced method is free of locking and very effectively applicable to deeply as well as shallowly beams and plates.

• Clinics in Shoulder and Elbow
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• 제17권1호
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• pp.2-9
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• 2014

Background: Indirect reduction technique offers a valid option in the treatment of proximal humerus fracture. The purpose of this study is to evaluate the functional outcome and the complication rate after indirect reduction and internal fixation of unstable proximal humeral fractures with use of a locking plate. Methods: Twenty four patients with acute proximal humerus fracture were managed with indirect reduction and internal fixation with a locking plate. The mean follow-up period was 15.5 months. Results: The anatomical reduction of the medial cortex buttress was seen in 16 patients (66%) of the Group A and the non-anatomical reduction was seen in 8 patients (33%) of the Group B. Mean union time was $3.2{\pm}1.9$ months; it was $2.2{\pm}0.6$ months in the Group A and $5.3{\pm}2.2$ months in the Group B (p < 0.05). In our series, there were 6 cases of complications and these include 2 cases of varus malunion, 2 cases of shoulder stiffness, 1 case of heterotrophic ossification, 2 cases of screw perforation and 1 case of impingement. Conclusions: We conclude from our studies that indirect reduction and internal fixation using locking plate for acute proximal humerus fracture can give good results with bony union and predictable good overall functional outcome. If the medial cortex buttress is well maintained, a better anatomical reduction would be achieved, the union would be prompted, the pain would be further reduced and the range of the motion would be recovered more promptly.

• Clinics in Shoulder and Elbow
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• 제20권4호
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• pp.236-239
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• 2017

After dual plating with a locking compression plate for comminuted intraarticular fractures of the distal humerus, the incidence of ulnar nerve injury after surgery has been reported to be up to 38%. This can be reduced by an anterior transposition of the ulnar nerve but some surgeons believe that extensive handling of the nerve with transposition can increase the risk of an ulnar nerve dysfunction. This paper reports ulnar nerve injuries caused by the incomplete insertion of a screw head in dual plating without an anterior ulnar nerve transposition for AO/OTA type C2 distal humerus fractures. When an anatomical locking plate is applied to a distal humeral fracture, locking screws around the ulnar nerve should be inserted fully without protrusion of the screw because an incompletely inserted screw can cause irritation or injury to the ulnar nerve because the screw head in the locking system usually has a slightly sharp edge because screw head has threads. If the change in insertion angle and resulting protruded head of the screw are unavoidable for firm fixation of fracture, the anterior transposition of the ulnar nerve is recommended over a soft tissue shield.

• Clinics in Shoulder and Elbow
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• 제17권3호
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• pp.114-119
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• 2014

Background: To evaluate clinical and radiological outcome using AO hook locking plate in acute acromioclavicular joint injuries. Methods: This study was based on patients with Rockwood type 3 or 5 acromioclavicular joint injuries who received surgery with AO hook locking plate from June 2008 until June 2009. Among the 22 patients, 19 of them were male and 3 were female, the mean age was $44.4{\pm}15.57$ years (20-72 years) and follow-up period was $15.5{\pm}3.90$ months (12-23 months). Preoperatively, postoperatively, and at the final follow-up after the plate removal, both coracoclavicular distances were measured from the anteroposterior radiograph. Also, the Shoulder Rating Scale of the University of California at Los Angeles scores (UCLA scores), the American Shoulder and Elbow Surgeons scores (ASES scores), Constant scores, and the Korean Shoulder Society scores (KSS scores) were measured at the final followup to evaluate the function of the shoulder joint. Results: At the time of injury, the mean coracoclavicular distance of the injured side was $17.69{\pm}4.23mm$ (9.57-27.82 mm) and the unaffected side was $7.55{\pm}2.20mm$ (3.24-13.05 mm). The mean coracoclavicular distance measured postoperatively and at the final follow-up was $6.87{\pm}2.34mm$ (4.07-14.13 mm) and $8.47{\pm}2.96mm$ (4.37-17.48 mm), respectively. The mean UCLA, ASES, Constant, and KSS scores measured in the final follow-up were $33.5{\pm}1.30$ (31-35), $90.8{\pm}8.36$ (72-100), $78.6{\pm}8.80$ (62-100), and $94.4{\pm}5.08$ (84-100) each. Conclusions: From this short-term research, the surgical treatment using AO hook locking plates in acute acromioclavicular joint injuries is clinically and radiographically satisfying and considered as a useful treatment method.

• 대한견주관절학회:학술대회논문집
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• 대한견주관절학회 2006년도 제14차 학술대회
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• pp.63-63
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• 2006

• 전산구조공학
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• 제1권2호
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• pp.83-90
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• 1988

본 연구에서는 평판 구조물의 해석을 위한 개선된 유한요소를 제시하였다. 이 요소는 Mindlin 평판이론에 의하여 수식화되었으며, 'Heterosis'평판요소의 변위장에 비적합변위형을 추가함으로써 유도되었다. 본 연구에서 제시한 평판요소는 요소의 강체운동과 관련된 Zero Eigenvalue만을 갖고 있으므로 Spurious Zero Energy Mode를 보이지 않는다. 대표적인 문제에 대한 수치해석을 해 본 결과 본 연구에서 제시한 평판요소는 우수한 수렴도를 보여 주었으며, 아주 얇은 평판문제에서도 요소의 형상에 관계없이 Shear Locking현상을 극복하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제7권2호
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• pp.324-345
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• 2015

A new procedure for determining properties of thick plate finite elements, based on the modified Mindlin theory for moderately thick plate, is presented. Bending deflection is used as a potential function for the definition of total (bending and shear) deflection and angles of cross-section rotations. As a result of the introduced interdependence among displacements, the shear locking problem, present and solved in known finite element formulations, is avoided. Natural vibration analysis of rectangular plate, utilizing the proposed four-node quadrilateral finite element, shows higher accuracy than the sophisticated finite elements incorporated in some commercial software. In addition, the relation between thick and thin finite element properties is established, and compared with those in relevant literature.

• Clinics in Shoulder and Elbow
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• 제19권3호
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• pp.149-154
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• 2016

Background: The purpose of this study is to compare clinical and radiological outcomes between trans-acromial fixation with Kirschner's wire (K-wire) and AO locking hook plate fixation for acute acromioclavicular (AC) joint dislocation. Methods: This study included 61 patients who underwent either closed reduction and trans-acromial fixation with K-wire (group A, 23 patients) or open reduction and internal fixation with AO locking hook plate (group B, 38 patients). Pain on a visual analogue scale (VAS) score, the University of California Los Angeles (UCLA) shoulder score, the American Shoulder and Elbow Surgeons (ASES) score, and active range of motion (ROM) were used in the functional evaluation. For radiological evaluation, coracoclavicular distance (CCD) was measured on both clavicular anteroposterior view and compared between groups. Results: At one-year follow-up, no significant differences in VAS pain score, UCLA shoulder score, ASES score, and active ROM were observed between groups, despite five cases (22.7%, 5/23) of complication in group A. The side-to-side difference between normal and affected CCD was $2.4{\pm}2.2mm$ in group A and $0.2{\pm}0.7mm$ in group B. This difference showed a statistical significance between groups (p<0.001). Conclusions: For the treatment of acute AC joint dislocation, the K-wire trans-acromial fixation group showed a significantly greater CCD than the AO locking hook plate group. In addition, during the follow-up period, much higher incidence of complication related to implant was observed in the trans-acromial fixation group. Although clinical outcomes between groups were not significantly different, these results should be interpreted carefully.