• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.7
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• pp.637-644
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• 2009

We have analyzed the biomechanical characteristics of cervical spine after total disc replacement using finite element analysis. A finite element model of C2-C7 spinal motion segment was developed and validated by other experimental studies. Two types of artificial discs, semi-constraint and un-constraint, were inserted at C6-C7 segments. Inferior plane of C7 vertebra was fixed and 1Nm of moment were applied on superior plane of C2 vertebra with 50N of compressive load along follower load direction. Mobility of the cervical spine in which each artificial disc inserted was higher than that of intact one in all loading conditions. Also, high mobility at the surgical level after total disc replacement could lead higher facet joint force and ligaments axial stresses. The results of present study could be used to evaluate surgical option and validate the biomechanical characteristics of the implant in total disc replacement in cervical spine.

• Journal of Computational Design and Engineering
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• v.1 no.1
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• pp.55-66
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• 2014

A knee joint's longevity depends on the proper integration of structural components in an axial alignment. If just one of the components is abnormally off-axis, the biomechanical system fails, resulting in arthritis. The complexity of various failures in the knee joint has led orthopedic surgeons to select total knee replacement as a primary treatment. In many cases, this means sacrificing much of an other-wise normal joint. Here, we review novel computational approaches to describe knee physiotherapy by introducing a new dimension of foot loading to the knee axis alignment producing an improved functional status of the patient. New physiotherapeutic applications are then possible by aligning foot loading with the functional axis of the knee joint during the treatment of patients with osteoarthritis.

• Journal of Korean Physical Therapy Science
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• v.24 no.2
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• pp.53-60
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• 2017

Purpose: This study aimed to investigate the effect of physiotherapy on the range of motion (ROM) of patients with hemophilic arthropathy after total knee replacement (TKR) during treadmill gait. Method: Nineteen patients (age range, 30-61 years) who received physiotherapy at the Korea Hemophilia Foundation (KHF) Clinic in Seoul between 2011 and 2013 after TKR were recruited. Protocol rehabilitation was performed (KHF Clinic, Department of Physiotherapy) with an average follow-up of 70 days (range, 6-141 days). Result: Physiotherapy after TKR improved the ROM parameters, including the post-operative average ROM. The post-operative and follow-up ROM also significantly increased. Conclusion: Patients with hemophilia require different physiotherapeutic techniques and need dedicated post-operative care in comparison with the general population.

• Journal of Korean Foot and Ankle Society
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• v.19 no.1
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• pp.1-6
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• 2015

Total ankle replacement has been performed for treatment of end stage arthritis of the ankle, hopefully being an alternative to ankle arthrodesis. However, due to its high failure rates, earlier versions of ankle replacements were not regarded as successful procedures. The latest design has shown increasingly positive results. Total joint replacement of the ankle itself is still regarded as a demanding procedure and much more challenging than that of the hip and knee in many aspects. Several studies, however, have pointed out that it is becoming the viable, accepted alternative for arthrodesis with advanced implants, appropriate patient selection, and proper training experience of procedures. Compared with arthrodesis, it shows equal or better outcomes in pain relief, range of motion, and patient's satisfaction. We are attempting to review its biomechanical characteristics, implant design, indications, complications, clinical outcomes, and survival rate.

• Journal of Korean Foot and Ankle Society
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• v.28 no.1
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• pp.1-7
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• 2024

Despite the advances in total ankle replacement (TAR), TAR has emerged as a promising alternative to ankle arthrodesis, particularly in severe ankle arthritis. Restoring ankle stability and alignment is the most important technical consideration and the goal of TAR. Hence, additional procedures, such as soft tissue balancing and osteotomies, are often critical parts of surgical planning. This article reviews the basics of joint balancing, offering suggestions on procedure selection for ligamentous balancing and varus and valgus malalignment in TARs.

• Proceedings of the Korean Geotechical Society Conference
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• 1987.06a
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• pp.51-80
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• 1987

In this studys a numerical analysis on the defomation of foundation layer was carried out by indroducing joint element. The method using the joust element between adj assent different materials has been originally developed for rock behavior(Goodman, et al. 1968) . The application of this method to the interface between the footing and soil layer proved satisfactory(Ghaboussi p et at. 1973). Authors tried to obtain the deformation of rrcompound foundation layerg", which vertically or horizontally or both consists of the natural(or intact) soft clay layer and the layer improved artificially in order to get high stiff-fness with replacement or chemical treatment to reduce the excessively detrimental settlemellt or lateral displacement in case of banking or building the civil structure on the soft layer. The joint conditions were classified into three categories : contacts sliding and separation. By coupling "JOINT" as a subroutine into multi-purpose code for the finite element method of the foundatlion daveloped by authors on the assumption that shearing and normal displacement can not be coupledl which terms pinon-dilatant" and by selecting modified Cam-clay modeIP the deformation analysis was performmed. The results using joint element were compared with those secured without introduction of joint element Nain results analized are as follows : 1. For the prediction of settlement and lateral desplacement, the result due to joint element was evaluated larger, which was regarded safe. 2. For the determination of ultimate bearing capacetyi the value using joint element appeared smaller by 20%, which was also safe.

• Biomedical Science Letters
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• v.28 no.1
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• pp.1-8
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• 2022

Total joint arthroplasty is a successful joint replacement treatment that improves joint function and overall quality of life and provides pain relief. However, the prevalence of periprosthetic joint infection (PJI) has become prevalent with the rise in the incidence of arthroplasty surgery. PJI occurs rarely following arthroplasty however presents with serious complications, including high morbidity. The identification of causative microorganisms is essential for the treatment of PJI. Managing PJI requires complex treatment strategies, including long-term antibacterial treatment, and significant medical costs can be incurred. The American Academy of Orthopedic Surgeons, the Centers for Disease Control and Prevention, and Surgical Care Improvement Project guidelines recommend that prophylactic antibiotics such as first-generation cephalosporins be infused completely 1 hour before surgical incision. However, these preventative antibiotics are very limited, therefore risk factors must be identified to diagnosis and treat patients effectively. Moreover, determining antimicrobial susceptibility during artificial joint surgery and choosing the most appropriate treatment strategy following an accurate diagnosis of microbial infections are essential. In the present review, we describe the management, including the etiology, diagnosis, and classification of PJI, and approaches to its diagnosis using the available novel molecular diagnostic methods.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.161-168
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• 1998

Increase of traffic volume in recent years results in deterioration of the bridge slab, which is directly subjected ot vehicle loads. Where extensive repair is necessary, replacement or enhancement of load carrying capacity using full depth precast concrete deck is often the most practical solution. Precast deck system has transverse joints between adjacent precast decks. Vertical shear forces occur when a vehicle wheel load is carried by precast decks and the joints are used to transfer the load to an adjacent deck. Effective load transfer between precast decks is critical for integral behavior. Finite element analysis and tests were run on the proposed femal-to-female type joint. 18 joint specimens were tested to investigate the effects of angle. D/H, and confining stress under static load. Results indicate joint with angle of 60$^{\circ}$ and D/H of 1/4 shows the improved load carrying capacity on crack. It is effective in protecting the cracking of joints to keep the joint in compression using confining stress.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1058-1070
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• 2007

Internal and external railway management corporations are using the periodic replacement criteria of rail by accumulated passing tonnage and wear to maintain rails for servicing. However, internal the periodic replacement criteria of continuous welded rail(CWR) by accumulated passing tonnage is the one(50kg/m-5 million gross tonnage, 60kg/m-6 million gross tonnage) presented in Japan before. It was estimated with the fatigue life about 50kg N rail joints applied diesel train load but it wasn't applied to current conditions of track; elimination of rail joint, using the concrete slab track and operation of light train load and effect of welding, manufacturing technique, grinding of rail. Therefore, in this study, it was investigated the types of damage and cause in welded rails and examined standards and information resources. Also, this study presents preliminary data to revise the periodic replacement criteria of CWR by current accumulated passing tonnage in bending test of laid welded rail and a survey of track maintenance history of Seoul metro.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.365-366
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• 2002

The sliding wear behavior of ultra high molecular weight polyethylene (UHMWPE) was examined on a novel low temperature degradation-free zirconia/alumina composite material and conventional alumina and zirconia ceramics used for femoral head in total hip joint replacement. The wear of UHMWPE pins against these ceramic disks was evaluated by performing linear reciprocal sliding and repeat pass rotational sliding tests for one million cycles in bovine serum. The weight loss of polyethylene against the novel low temperature degradation-free zirconia/alumina composite disks was much less than those against conventional ceramics for all tests. The mean weight loss of the polyethylene pins was more io the linear reciprocal sliding test than in the repeal pass rotational sliding lest for all kinds of disk materials. Neither the coherent transfer film nor the surface damage was observed on the surface of the novel zirconia/alumina composite disks during the test. The observed r,'stilts indicated that the wear of the polyethylene was closely related to contacting materials and kinematic motions. In conclusion, the novel zirconia/alumina composite leads the least wear of polyethylene among the tested ceramics and demonstrates the potential as lhe alternative materials for femoral head in total hip joint replacement.