• Clinics in Shoulder and Elbow
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• 제19권4호
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• pp.216-222
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• 2016

Background: We investigated the effectiveness of fibular strut allograft augmentation of proximal humerus fractures to prevent varus deformity in patients over the age of 65 years with insufficient medial support. Methods: We analyzed the clinical and radiological outcomes of locking plate fixation with adjunct fibular strut allograft augmentation in 21 patients with proximal humeral fractures. The inclusion criteria were age (65-year-old or older); presence of severe medial comminution; inadequate medial support; and those who could participate in at least a one year follow-up. The average age was 76.4 years. We analyzed each patient's Constant score, our indicator of clinical outcome. As radiological parameters, we analyzed time-to-bone union; restoration of the medial hinge; difference between the immediately postoperative and the last follow-up humeral neck-shaft angles;; and anatomical reduction status, which was assessed using the Paavolainen method. Results: A successful bone union was achieved in all patients at an average of 11.4 weeks. We found that the average Constant score was 74.2, showing a satisfactory outcome. The average difference in the humeral neck-shaft angles between the immediately postoperative time-point and at the final follow-up was $3.09^{\circ}$. According to the Paavolainen method, the anatomical reduction was rated excellent. The medial hinge was restored in 14 of 21 patients. Although we did not find evidence for osteonecrosis, we found that a single patient had a postoperative complication of screw cut-out. Conclusions: Fibular strut allografting as an adjunct treatment of proximal humeral fractures may reduce varus deformity in patients with severe medial comminution.

• 대한기계학회논문집
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• 제13권1호
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• pp.9-19
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• 1989

본 논문에서는 복합 적층판의 이론적 충격 응답을 통한 충격 응력 및 충격파 전파를 해석하기 위하여 이질, 이방성 판에 전단 변형을 고려한 Whitney와 Pagano의 이론에 기초를 두고 정적 접촉법칙과 연계한 동적 유한요소해석(FEA)을 하여, 이 중 충격 접촉력에 관하여는 각각 [0。/45。/0。/-45。/0。]$_{2s}$와 [90。/45。/90。/-45。/90。]$_{2s}$의 두 적층 형태를 가지는 흑연/에폭시와 유리/ 에폭시 복합 재료에 대한 강구에 의한 충격 해석을 하여, Yang의 식에 의한 최대 접촉력과 비교 검토하였고, 다음 변형율 파형을 파동 전파(wave propagation) 이론에 의해 비교 검토하므로써 본 이론해석의 타당성을 입증하였고, 재료 및 적층 형태에 따른 충격 응답, 충격 응력 및 충격파 전파 특성에 대하여 연구하였다.하였다.

• Journal of Korean Neurosurgical Society
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• 제30권11호
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• pp.1336-1339
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• 2001

Mesenchymal chondrosarcoma is a rare tumor occurring in both bone and soft tissues and exhibits characteristic of a malignant nature. The authors experienced a case of mesenchymal chondrosarcoma occurring in a 23-year-old woman which had invaded the cervical spine. The patient presented with severe both shoulder pain, left upper extremity weakness(Grade IV) and paresthesia at admission. Radiologic studies of the cervial spine showed an aggressive osteolysis of C4 vertebral body, pedicle and lamina with compression of the spinal cord posteriorly on C3, C4, C5 levels. The tumor was totally removed by a combined anterior and posterior approach. The removed vertebral body was replaced with autogenous bone and stabilized by Codman locking plate symtem. The pathological examination showed characteristic of mesenchymal chondrosarcoma.previous symptoms well improved postoperatively. The authors present a case of mesenchymal chondrosarcoma with review of literature.

• Structural Engineering and Mechanics
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• 제57권3호
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• pp.473-506
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• 2016

The aim of this work is the development of a 2D quadrilateral isoparametric finite element model, based on a layerwise approach, for the bending analysis of sandwich plates. The face sheets and the core are modeled individually using, respectively, the first order shear deformation theory and the third-order plate theory. The displacement continuity condition at the interfaces 'face sheets-core' is satisfied. The assumed natural strains method is introduced to avoid an eventual shear locking phenomenon. The developed element is a four-nodded isoparametric element with fifty two degrees-of-freedom (52 DOF). Each face sheet has only two rotational DOF per node and the core has nine DOF per node: six rotational degrees and three translation components which are common for the all sandwich layers. The performance of the proposed element model is assessed by six examples, considering symmetric/unsymmetric composite sandwich plates with different aspect ratios, loadings and boundary conditions. The numerical results obtained are compared with the analytical solutions and the numerical results obtained by other authors. The results indicate that the proposed element model is promising in terms of the accuracy and the convergence speed for both thin and thick plates.

• 전산구조공학
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• 제11권4호
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• pp.155-168
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• 1998

보강된 판 및 쉘구조의 안정성 및 후좌굴을 포함하는 기하학적 비선형 해석을 수행하기 위하여, total Lagrangian formulation에 근거한 연속체의 증분평형방정식으로부터 변형된 쉘요소인 유한요소이론을 제시하였다. 쉘구조의 곡률이 불연속적으로 변하거나 쉘부재들이 유한한 각도로 만나는 보강된 판 및 쉘구조의 비선형 해석이 가능하도록 주부재와 보강재 간의 연결점에 대한 일반적인 변환관계를 제시하였으며 좌굴해석 및 기하학적 비선형해석의 경우에 해의 정확성 및 수렴성을 개선시키기 위하여 접선강도행렬 산정시 회전각의 2차항을 포함시켰다. 또한, shear locking 현상을 극복하기 위하여 감차적분을 적용하였고 쉘구조의 좌굴해석에서는 power method를 적용하여 해석의 효율을 높였으며, 후좌굴해석에서는 변위 및 하중증분법을 적절히 결합시켜 보강된 쉘구조의 후좌굴 거동추적이 용이하였다. 또한, 입력자료를 손쉽게 준비하고 좌굴모드 및 후좌굴거동을 효율적으로 분석하기 위하여 전, 후 처리 프로그램을 개발하였고 다양한 해석예제를 통하여 다른 문헌의 해석결과를 비교함으로써 본 연구에서 개발된 유한요소 해석프로그램의 타당성 및 정확성을 입증하였다.

• Structural Engineering and Mechanics
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• 제23권5호
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• pp.487-504
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• 2006

Several new versatile two-dimensional p-version finite elements are developed. The element matrices are integrated analytically to guarantee the accuracy and monotonic convergence of the predicted solutions of the proposed p-version elements. The analysis results show that the convergence rate of the present elements is very fast with respect to the number of additional Fourier or polynomial terms in shape functions, and their solutions are much more accurate than those of the linear finite elements for the same number of degrees of freedom. Additionally, the new p-version plate elements without the reduced integration can overcome the shear locking problem over the conventional h-version elements. Using the proposed p-version elements with fast convergent characteristic, the elasto-plastic impact of the structure attached with the absorber is simulated. Good agreement between the simulated and experimental results verifies the present p-version finite elements for the analyses of structural dynamic responses and the structural elasto-plastic impact. Further, using the elasto-plastic impact model and the p-version finite element method, the absorber of the T structure on the Qiantang River is designed for its collision protection.

• 한국임상수의학회지
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• 제36권4호
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• pp.229-232
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• 2019

Total Hip Replacement in a patient with chronic coxofemoral joint dislocation is a challenging problem because chronic coxofemoral joint dislocation causes severe morphological changes. These challenging factors make surgery more difficult and increase the possibility of postoperative complications including cup implant dislocation and prosthetic joint luxation. All patients were diagnosed having at least 2 months of coxofemoral joint dislocation. On physical examination, crepitus was noted in the coxofemoral joint. Radiographs revealed hip joint dislocation with mild to severe degenerative changes. Total hip replacement was planned for all patients. Dorsal acetabular rim deficiency in 3 cases was augmented using a locking plate and polymethylmethacrylate bone cement. All cases have shown difficulty in prosthetic joint reduction. Pectineus and rectus femoris muscle origin were released in all cases. At 12 months follow up, all patients showed satisfactory ambulation. The issues on perioperative prosthetic joint reduction and luxation due to chronic coxofemoral joint luxation with muscle contracture and dorsal acetabular rim deficiency can be resolved by muscle releasing and dorsal acetabular rim augmentation.

• Clinics in Shoulder and Elbow
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• 제25권1호
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• pp.68-72
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• 2022

Proximal humerus fractures are the third most common fractures, totaling 4% to 5% of all fractures. Here, we present the case of a 39-year-old man with a dislocated four-part fracture of the proximal humerus with a huge bony Bankart lesion. Preoperatively, the bony Bankart lesion of the glenoid was not visualized on computed tomography scans or magnetic resonance imaging because the fracture of the proximal humerus was comminuted, displaced, and complex. It was planned for only the humerus fracture to be treated by open reduction and internal fixation using a locking plate. However, a fractured fragment remained under the scapula after reduction of the dislocated humeral head. This was mistaken for a dislocated bone fragment of the greater tuberosity and repositioning was attempted. After failure, visual confirmation showed that the bone fragment was a piece of the glenoid. After reduction and fixation of this glenoid part with suture anchors, we acquired a well-reduced fluoroscopic image. Given this case of complex proximal humerus fracture, a glenoid fracture such as a bony Bankart lesion should be considered preoperatively and intraoperatively in such cases.

• Clinics in Shoulder and Elbow
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• 제24권3호
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• pp.183-188
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• 2021

We report a case of a 69-year-old right-dominant man who had an open Monteggia-like lesion of the right elbow (Gustilo-Andersen IIIA) with severe proximal ulna bone loss associated with an ipsilateral ulnar shaft fracture due to a motorcycle accident. The patient underwent two-stage surgery. Wound debridement and bridging external fixation were performed at first. Three months later, a frozen massive osteochondral ulnar allograft was implanted and fixed with a locking compression plate. A superficial wound infection appeared 5 weeks after the second surgery. Superficial wound debridement, negative pressure therapy, and antibiotics were administered for 3 months, achieving infection healing. At 3 years post-surgery, the elbow range of motion was satisfactory with a Disabilities of the Arm, Shoulder and Hand (DASH) score of 16.7. Radiographs and computed tomography scans showed good allograft-bone integration without allograft reabsorption or hardware loosening. Although not complication-free, massive ulna osteochondral allograft implantation can be considered a valid option in cases of open Monteggia-like lesions associated with ulnar shaft fracture and severe bone loss in active patients, whenever osteosynthesis or joint replacement is not a proper solution. This type of bone stock restoration allows for future surgery, if needed.

• Journal of Trauma and Injury
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• 제37권1호
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• pp.89-96
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• 2024

The indications for total hip replacement are increasing and not limited to osteoarthritis. Total hip replacement may also be done for trauma and pathological fractures in patients otherwise physiologically fit and active. This trend has led to an inevitable rise in complications such as periprosthetic femoral fracture. Periprosthetic femoral fracture can be challenging due to poor bone quality, osteoporosis, and stress fractures. We present a case of periprosthetic femoral fracture in a 71-year-old woman with some components of an atypical femoral fracture. The fracture was internally fixed but was subsequently complicated by infection, implant failure needing revision, and later stress fracture. She was on a bisphosphonate after her index total hip replacement surgery for an impending pathological left proximal femur fracture, and this may have caused the later stress fracture. Unfortunately, she then experienced implant breakage (nonunion), which was treated with a biplanar locking plate and bone grafting. The patient finally regained her premorbid mobility 13 months after the last surgery and progressed satisfactorily towards bony union.