• Journal of Korean Foot and Ankle Society
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• v.10 no.1
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• pp.11-17
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• 2006

Purpose: To evaluate the clinical results of resection of os subfibulare and lateral ligament reattachment or modified Brostrom procedure in patients with symptomatic os subfibulare. Materials and Methods: This is a retrospective study on fourteen patients (14 ankles) who have symptoms associated with os subfibulare. Between August 1999 and July 2004, they underwent 4 resection of os subfibulare and lateral ligament reattachment for ankle pain due to os subfibulare or 10 resection of os subfibulare and modified Brostrom procedure available for ankle instability due to os subfibulare. Follow-up period is averaged for 17.6 months (12-24 months). Clinical results were graded according to the AOFAS clinical rating system. Results: Clinical results were rated as good in 4 ankles after resection of os subfibulare and lateral ligament reattachment, excellent in 5, good in 4, and fair in 1 ankle after the resection of os subfibulare and modified Brostrom procedure. In the last follow up period, 1 case of anterolateral ankle instability, 1 case of ankle pain and 1 case of inversion limitation were present postoperatively, but all symptoms were improved progressively. Conclusion: Resection of os subfibulare and modified Brostrom procedure is a good surgical technique for chronic ankle instability due to os subfibulare. But if just the ankle pain is present, resection of os subfibulare and lateral ligament reattachment is a sufficient procedure.

• Advances in materials Research
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• v.11 no.1
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• pp.59-73
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• 2022

In the construction industry, thin-walled frame elements with very slender open cross-sections and low torsional stiffness are often subjected to a complex loading condition where axial, bending, shear and torsional stresses are present simultaneously. Hence, these often fail in instability even before the yield capacity is reached. One of the most common instability conditions associated with thin-walled structures is Lateral Torsional Buckling (LTB). In this study, a first order Generalized Beam Theory (GBT) formulation and numerical analysis of cold-formed steel lipped channel beams (C80×40×10×1, C90×40×10×1, C100×40×10×1, C80×40×10×1.6, C90×40×10×1.6 and C100×40×10×1.6) subjected to uniform moment is carried out to predict pure Lateral Torsional Buckling (LTB). These results are compared with the Finite Element Analysis of the beams modelled with shell elements using ABAQUS and analytical results based on Euler's buckling formula. The mode wise deformed shape and modal participation factors are obtained for comparison of the responses along with the effect of varying the length of the beam from 2.5 m to 10 m. The deformed shapes of the beam for different modes and GBTUL plots are analyzed for comparative conclusions.

• Steel and Composite Structures
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• v.6 no.3
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• pp.203-219
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• 2006

One of the most promising ways through which a steel moment frame may attain high energy dissipating capability is to trim off a portion of the beam flanges near the column face. This type of moment connection, known as Reduced Beam Section (RBS) connection, has notable superiority in comparison with other moment connection types. As the result of the advantages of RBS moment connection, it has widely being used in practice. In spite of the good hysteretic behaviour, an RBS beam suffers from an undesirable drawback, which is local and lateral instability of the beam. The instability in the RBS beam reduces beam load-carrying capacity. This paper aims to investigate key issues influencing cyclic behaviour of RBS beams. To this end, a numerical analysis was conducted on a series of steel subassemblies with various geometric properties. The obtained results together with the existing experimental data are used to study the instability of RBS beams. A new slenderness concept is presented to control an RBS beam for combined local and lateral instability. This concept is in good agreement with the numerical and experimental results. Finally, a model is developed for the prediction of the magnitude of moment degradation owing to the instability of an RBS beam.

• Journal of Korean Foot and Ankle Society
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• v.25 no.1
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• pp.6-9
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• 2021

The term chronic lateral ankle instability (CLAI) embraces a spectrum of conditions that involve functional and mechanical instability, both in athletes and lower-demand patients. The hallmarks of CLAI are recurrent sprains, persistent pain, and repeated episodes of the ankle giving way. CLAI is the main complication of acute ankle sprains, which can cause discomfort in daily and sports activity. Approximately 10% to 30% of patients with acute ligament ruptures will develop chronic instability over the course of a year from the index injury. An accurate diagnostic approach and successful treatment plan should be established based on a comprehensive understanding of the concept of functional and mechanical instability. Unfortunately, the optimal modality for the management of CLAI is unclear. Even after conservative treatment or surgical intervention, it could result in degenerative changes to the ankle joint in the long term. Thus far, the incidence of ligamentous posttraumatic ankle osteoarthritis was reported to be 13% to 78%. The mean latency time between injury and osteoarthritis was at least 10 to 34.3 years. CLAI is an important pathological condition that can cause discomfort or dysfunction in daily activity in the short term, resulting in joint destruction in the long term. Therefore, it is important to understand the various complications that can occur when CLAI is not treated properly.

• Korean Journal of Applied Biomechanics
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• v.32 no.1
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• pp.9-16
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• 2022

Objective: The purpose of this study was to investigate how the chronic ankle instability affects postural control during forward jump landing. Method: 20 women with chronic ankle instability (age: 21.7 ± 1.6 yrs, height: 162.1 ± 3.7 cm, weight: 52.2 ± 5.8 kg) and 20 healthy adult women (age: 21.8 ± 1.6 yrs, height: 161.9 ± 4.4 cm, weight: 52.9 ± 7.2 kg) participated in this study. For the forward jump participants were instructed to stand on two legs at a distance of 40% of their body height from the center of force plate. Participants were jump forward over a 15 cm hurdle to the force plate and land on their non-dominant or affected leg. Kinetic and kinematic data were obtained using 8 motion capture cameras and 1 force plates and joint angle, vertical ground reaction force and center of pressure. All statistical analyses were using SPSS 25.0 program. The differences in variables between the two groups were compared through an independent sample t-test, and the significance level was to p < .05. Results: In the hip and knee joint angle, the CAI group showed a smaller flexion angle than the control group, and the knee joint valgus angle was significantly larger. In the case of ankle joint, the CAI group showed a large inversion angle at all events. In the kinetic variables, the vGRF was significantly greater in the CAI group than control group at IC and mGRF. In COP Y, the CAI group showed a lateral shifted center of pressure. Conclusion: Our results indicated that chronic ankle instability decreases the flexion angle of the hip and knee joint, increases the valgus angle of the knee joint, and increases the inversion angle of the ankle joint during landing. In addition, an increase in the maximum vertical ground reaction force and a lateral shifted center of pressure were observed. This suggests that chronic ankle instability increases the risk of non-contact knee injury as well as the risk of lateral ankle sprain during forward jump landing.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.145-152
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• 2007

The dynamic behaviors of counterflow non-premixed flame have been investigated experimentally to study effects of heat losses on edge flame oscillation, which result from the advancing and retreating edge flame motion of outer flame edge at low strain rate flame. For low strain rate flame, lateral conduction heat loss in addition to radiation heat loss could be more remarkable than the others. Oscillatory instabilities appear at fuel Lewis number greater than unity. But excessive lateral conduction heat loss causes edge flame instability even at fuel Lewis number less than unity. The dramatic change of burner diameters in which flame length is an indicator of lateral conduction heat loss was applied to examine the onset condition of edge flame oscillation and flame oscillation modes. Especially, extinction behaviors quite different from the previous study were observed.

• Journal of the Korean Arthroscopy Society
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• v.5 no.2
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• pp.135-139
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• 2001

Purpose : Repair of the posterior capsule tear at the time of the operation for the chronic postero-lateral or postero-medial rotary instability has not been reported. We describe the arthroscopic repair of the posterior capsule tear using the posterior trans-septal portal. Method : After conducting basic arthroscopic examination of the knee, postero-medial and postero-lateral portals are secure to make the posterior trans-septal portal, through which the postero-medial and postero-lateral capsule tears are repaired using the suture hook under the arthroscopic guidance. Conclusion : When arthroscopic reconstruction of PCL insufficiency or postero-lateral rotaty instability that accompanies postero-medial or postero-lateral capsular tears. rising the posterior traits-septal portal could ensure better visualization of the capsule and a subsequent more accurate repair of the capsule. Since it significantly lessened instability, it could contribute to an achievement of successful clinical results.

• Annals of Clinical Neurophysiology
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• v.20 no.1
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• pp.31-35
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• 2018

Background: Although postural instability is one of the major symptoms of Parkinson's disease (PD), dopaminergic treatment is ineffective for treating postural instability. Recent reports have shown that somatosensory deficit is associated with postural instability, and that somatosensory input improved postural instability. The purpose of this study is to evaluate the effects of lateral wedges for quiet standing postural control in people with PD. Methods: Twenty-two patients who were diagnosed with PD were enrolled in this study. The participants stood on a force plate under two conditions (wedge and no wedge) with or without having their eyes open or closed. The center of pressure (COP) range and velocity were analyzed using a two-way repeated-measures analysis of variance. Results: The range and velocity of COP in the anterioposterior and mediolateral (ML) directions were significantly improved after the patients stood on the lateral wedge with their eyes closed (p < 0.05). The range in ML direction and velocity in both directions of COP were significantly decreased when their eyes were open (p < 0.05). Conclusions: Regardless of vision, standing on lateral wedges improved postural sway in people with PD.

• Journal of Korean Foot and Ankle Society
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• v.5 no.1
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• pp.5-12
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• 2001

Purpose: To find out the priority of which procedure has had a better outcome both clinically and radiographically between the two groups, one is treated by primary repair and the other by modified Brostr$\ddot{o}$m's procedure, by comparing the postoperative ankle joint stability and the patient's degree of satisfaction. Material and methods: 16 cases were taken into consideration whose number of severed ligaments were at least two or more of the lateral collateral ligaments of the ankle, and also were confirmed intraoperatively. Among them, 8 cases were treated with primary repair and the other 8 cases were treated with primary repair and the other 8 cases by modified Brostr$\ddot{o}$m's procedure. Results: There was no distinguishable difference for the patient's degree of satisfaction between the two procedures above mentioned. In 3 cases treated with primary repair, functional instability was observed. In case of postoperative ankle joint stability, 7 of 8 cases treated by modified Brostr$\ddot{o}$m's procedure has revealed increased joint stability. And 3 of 8 cases which were treated by primary repair have showed postoperative residual instability. Conclusion: Actually, the severed ligament can not maintain its normal strength though several months has elapsed, and possible residual instability could be remained. Therefore, it can be expected that modified Brostr$\ddot{o}$m's procedure also would be a .good method in obtaining suitable ankle joint stability as well as subtalar joint stability because of its reinforcement using extensor retinaculum.

• Journal of Korean Foot and Ankle Society
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• v.25 no.3
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• pp.117-125
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• 2021

Purpose: The aim of this study was to evaluate biological ligament healing quantitatively after suture-tape augmentation for chronic lateral ankle instability. Materials and Methods: Thirty-two patients underwent magnetic resonance imaging (MRI) at a minimum of 2 years after lateral ligament augmentation using suture-tape. Signal/noise ratios (SNRs) and widths of anterior talofibular ligaments (ATFLs) were measured on preoperative and postoperative MRI by three researchers. ATFL biological healing degrees were analyzed using changes in SNRs and widths of ATFLs and by comparing these metrics with those of normal contralateral ankles. Clinical evaluations were performed using foot and ankle outcome scores (FAOSs), Foot and Ankle Ability Measure (FAAM) scores, and ankle stress radiographs. Results: Mean FAOS and FAAM scores improved significantly from 62.4 to 93.6 and 58.3 to 92.3, respectively, at final follow-up (p<0.001). Mean SNRs and ATFL widths improved insignificantly from 8.49 to 8.21 and 2.07 to 2.15 mm, respectively, at final follow-up (p=0.424, p=0.718). Significant differences in mean SNRs and ATFL widths were found between ipsilateral and contralateral sides (p<0.001, p=0.002). Spearman's correlation analysis revealed no significant association between clinical outcomes and degrees of biological healing of ATFLs based on MRI findings. Conclusion: Despite improvements in clinical outcome measures, the effects of suture-tape augmentation for chronic lateral ankle instability on biological ligament healing were insignificant. In addition, no significant correlation was found between clinical outcomes and degrees of biological healing of ATFLs.