• The Journal of Korea Robotics Society
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• v.14 no.4
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• pp.237-244
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• 2019

This paper suggests novel types of joint mechanisms composed of elastic strings and rigid bodies. All of the human hinge joints have the articular capsule and a pair of collateral ligaments. These fibrous tissues make the joint compliant and stable. The proposed mechanism closely imitates the human hinge joint structure by using the concept of tensegrity. The resultant mechanism has several characteristics shown commonly from both the tensegrity structure and the human joint such as compliance, stability, lightweight, and non-contact between rigid bodies. In addition, the role and feature of the human hinge joints vary according to the origins of a pair of collateral ligaments. Likewise, the locations of two strings corresponding to a pair of collateral ligaments produce different function and motion of the proposed mechanism. It would be one of the advantages obtained from the proposed mechanism. How to make a joint mechanism with different features is also suggested in this paper.

• Proceedings of the KSME Conference
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• 2008.11a
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• pp.1471-1472
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• 2008

To analyze biomechanical effects of various types of menisectomy in the knee joint, the contact area and pressure distribution of intact the knee joint and the operated by various menisectomies were studied by using finite element method their results are compared with each other. In this study, the femur, the tibia, the articular cartilage and the menisci were three dimensionally reconstructed using MR Images of healthy knee joint in full extension of 26 years old male. Also, three dimensional finite element model of the knee joint was constructed including the models of ligaments and tendons on the reconstructed three dimensional model. Bones were considered to be rigid, articular cartilage and menisci were considered as homogeneous, isotropic and linearly elastic materials and ligaments and tendons were modeled as hyperelastic materials. Based on the results, the effects of various types of menisectomy on the knee joints are clearly elucidated.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.14 no.2
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• pp.16-24
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• 2008

Anatomy: Advanced knowledges of cellular and molecular biology led to the development of therapies of rheumatoid arthritis(RA). Rheumatoid arthritis (RA) is a chronic, recurrent, systemic inflammatory disease and results in major deformity or dysfunction of joints. Etiology: Rheumatoid arthritis is now concevied as autoimmune disease. There have been many trials to define the immunological changes in rheumatoid arthritis. But now pathogenesis and significance of immunoglobulin complement and rheumatoid factor are not full accepted. Syndrome: Joints are characteristically involved with early inflammatory changes in the synovial membrane, peripheral portions of the articular cartilage, and lation tissue(pannus) forms, covers, and erodes the articular cartilage, bone and ligaments within the jiont capsule. Inflammatory changes also occur in tendon sheaths(tenosynovitis), and if subjected to a lot of friction, the tendons may fray or rupture. Extra-articular pathological changes sometimes occur, these include rheumatoid nodules, atrophy and fibrosis of muscles, and mild cardiac changes. Treatment: Tumor necrosis factor(TNF) inhibitor for the treatment of rheumatoid arthritis(RA) induces not only significant improvement of symptoms and signs of RA but also substantial inhibition of progressive joint damage.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.533-539
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• 2009

In this study, the femur, the tibia, the articular cartilage and the menisci are three dimensionally reconstructed using MR images of healthy knee joint in full extension of 26-year-old male. Three dimensional finite element model of the knee joint is fabricated on the reconstructed model. Also, the FE models of ligaments and tendons are attached on the biologically suitable position of the FE model. Bones, articular cartilages and menisci are considered as homogeneous, isotropic and linear elastic materials, and ligaments and tendons are modeled as truss element and nonlinear elastic springs. The numerical results show the contact pressure and the von Mises stress distribution in the soft tissues such as articular cartilages and menisci which can be regarded as important parameters to estimate the failure of the tissues and the pain of the patients.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.6
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• pp.354-359
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• 2023

The temporomandibular joint is a unique structure composed of the joint capsule, articular disc, mandibular condyles, glenoid fossa of the temporal bone, surrounding ligaments, and associated muscles. The condyle is one of the major components of a functional temporomandibular joint. Reconstruction of large mandibular defects involving the condyle is a surgical challenge for oral and maxillofacial surgeons. To restore large mandibular defects, there are different options for free flap method such as fibula, scapula, and iliac crest. Currently, the vascularized fibula free flap is the gold standard for reconstruction of complex mandibular defects involving the condyle. In the present report, neocondyle regeneration after mandible reconstruction including the condyle head with fibula free flap was evaluated. In this report, two patients were evaluated periodically, and remodeling of the distal end of the free fibula was observed in both cases after condylectomy or mandibulectomy. With preservation of the articular disc, trapezoidal shaping of the neocondyle, and elastic guidance of occlusion, neocondyle bone regeneration occured without ankylosis. Preservation of the articular disc and maintenance of proper occlusion are critical factors in regeneration of the neocondyle after mandible reconstruction.

• Journal of Korean Foot and Ankle Society
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• v.14 no.1
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• pp.53-57
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• 2010

Purpose: This study was designed to evaluate the clinical and radiographical results of anatomical reconstruction by Chen method for chronic lateral ankle instability. Materials and Methods: Fifteen patients with chronic lateral ankle instability who had undergone anatomical reconstruction of anterior talofibular and calcaneofibular ligaments by Chen method were evaluated retrospectively. Average age of the patients was 31.3 years, and average follow-up period was 15.5 months. Preoperative and postoperative radiographs including varus stress view and magnetic resonance imaging (MRI) were analyzed. The clinical evaluation was performed according to the American Orthopaedic Foot and Ankle Society (AOFAS) scale. Results: Radiographically average talar tilt angle was $15.3^{\circ}$ preoperatively, and the difference with contralateral normal side was $10.1^{\circ}$. At last follow up, talar tile angle and the difference with contralateral side improved to $5.9^{\circ}$ and $1.3^{\circ}$ respectively. AOFAS scale was 66.6 preoperatively and 87.3 postoperatively. In MRI findings, four patients had associated intra-articular lesion such as articular cartilage defect, synovitis and osteoarthritis. The talar tilt angle improvement and AOFAS scale of patients without intra-articular lesion was better than those of four patients with intra-articular lesions. Surgical wound pain occurred in six patients and sural neuropathy in three patients. Conclusion: The anatomical reconstruction by Chen method was an easy and effective procedure for symptomatic chronic lateral ankle instability. Careful operative technique may prevent the surgical wound pain and sural neuropathy.

• Journal of Mechanical Science and Technology
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• v.18 no.2
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• pp.211-220
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• 2004

It is well known that the geometry of the articular surface has a major role in determining the position of articular contact and the lines of action for the contact forces. The contact force calculation of the knee joint under the effect of sliding and rolling is one of the most challenging issues in this field. We present a 3-D human knee joint model including sliding and rolling motions and major ligaments to calculate the lateral and medial condyle contact forces from the recovered total internal reaction force using inverse dynamic contact modeling and the Least-Square method. As results, it is believed that the patella, muscles and tendon affect a lot for the internal reaction forces at the initial heel contact stage. With increasing flexion angles during gait, the decreasing contact area is progressively shifted to the posterior direction on the tibia plateau. In addition, the medial side contact force is larger than the lateral side contact force in the knee joint during normal human walking. The total internal forces of the knee joint are reasonable compared to previous studies.

• Journal of Yeungnam Medical Science
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• v.37 no.3
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• pp.149-158
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• 2020

Mesenchymal stem cells (MSCs) are emerging as an attractive option for osteoarthritis (OA) of the knee joint, due to their marked disease-modifying ability and chondrogenic potential. MSCs can be isolated from various organ tissues, such as bone marrow, adipose tissue, synovium, umbilical cord blood, and articular cartilage with similar phenotypic characteristics but different proliferation and differentiation potentials. They can be differentiated into a variety of connective tissues such as bone, adipose tissue, cartilage, intervertebral discs, ligaments, and muscles. Although several studies have reported on the clinical efficacy of MSCs in knee OA, the results lack consistency. Furthermore, there is no consensus regarding the proper cell dosage and application method to achieve the optimal effect of stem cells. Therefore, the purpose of this study is to review the characteristics of various type of stem cells in knee OA, especially MSCs. Moreover, we summarize the clinical issues faced during the application of MSCs.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.21 no.2
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• pp.209-214
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• 1999

Chronic recurrent TMJ dislocation results in difficulty of mastication, speaking, and swallowing due to the limitation of the mandibular movement. Etiologic factors are considered as the looseness of the capsule and ligaments, the decrease of the articular eminence, condylar morphologic change, muscular disharmony near by TMJ, and the decrease of the vertical length of the mandibular ramus. Treatment approach has been suggested that surgical methods are selected for the correction of the etiologic factors when conservative treatments are not effective. Many surgical methods have been reported such as eminectomy, eminence augmentation, condylotomy, and zygomatic arch down fracture technique. We performed the eminence augmentation through interpositional bone graft in chronic recurrent TMJ dislocation. This method leads to favorable postoperative result without recurrence and complication, so we report the case with related references.

• Advances in biomechanics and applications
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• v.1 no.3
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• pp.169-185
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• 2014

Computational multibody models of the elbow can provide a versatile tool to study joint mechanics, cartilage loading, ligament function and the effects of joint trauma and orthopaedic repair. An efficiently developed computational model can assist surgeons and other investigators in the design and evaluation of treatments for elbow injuries, and contribute to improvements in patient care. The purpose of this study was to develop an anatomically correct elbow joint model and validate the model against experimental data. The elbow model was constrained by multiple bundles of non-linear ligaments, three-dimensional deformable contacts between articulating geometries, and applied external loads. The developed anatomical computational models of the joint can then be incorporated into neuro-musculoskeletal models within a multibody framework. In the approach presented here, volume images of two cadaver elbows were generated by computed tomography (CT) and one elbow by magnetic resonance imaging (MRI) to construct the three-dimensional bone geometries for the model. The ligaments and triceps tendon were represented with non-linear spring-damper elements as a function of stiffness, ligament length and ligament zero-load length. Articular cartilage was represented as uniform thickness solids that allowed prediction of compliant contact forces. As a final step, the subject specific model was validated by comparing predicted kinematics and triceps tendon forces to experimentally obtained data of the identically loaded cadaver elbow. The maximum root mean square (RMS) error between the predicted and measured kinematics during the complete testing cycle was 4.9 mm medial-lateral translational of the radius relative to the humerus (for Specimen 2 in this study) and 5.30 internal-external rotation of the radius relative to the humerus (for Specimen 3 in this study). The maximum RMS error for triceps tendon force was 7.6 N (for Specimen 3).