• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.1
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• pp.39-45
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• 2009

Purpose: We intended to classify the pattern and to seek the cause of fractures and/or dislocations related to middle and high school Taekwondo athletes in competition and try to get the ways for preventing them. Materials and Methods: We studied 50 fractures and dislocations of the athletes in competition, which were surveyed in 2005-2007 national middle and high school Taekwondo tournament annually. We analyzed the type and the cause of the injury, performed survey at postinjury l year in 32 cases, sought proper treatments and methods for prevention. Results: The 26 cases (52%) of foot fracture, 15 cases (30%) of hand fracture and 9 cases (18%) of forearm fracture are occurred in this study. The 9 cases (28%) of satisfaction in treatment, 15 cases (47%) of average and 8 cases (25%) of dissatisfaction are surveyed in the 32 cases. The causes of dissatisfaction are lack of rest (7 cases), excessive training (5 cases), immoderate participation of match (6 cases) and the others. The athletes were returned to the match before complete recovery in 21 cases (67%). Conclusion: The causes of fractures and dislocations in middle and high school Taekwondo athletes were stroke on upper and lower extremities and high-speed hyperflexion injury that was occurred during spraining of great toe on the floor. We consider that the athletes need the development of effective protector, improvement of equipment in stadium and enough rest and education.

• Archives of Reconstructive Microsurgery
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• v.10 no.2
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• pp.75-80
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• 2001

Purpose : We have evaluated the morbidity of donor site after transfer of free fibular osseous and osteocutaneous flap to defect site of bone and soft tissue due to chronic osteomyelitis of long tubular bone, open fracture with bony defect, bone or soft tissue tumor and congenital anomaly. Materials and methods : The 54 cases of 79 cases to be carried out from May, 1982 to May, 2001 which could be followed up were reviewed. There were forty nine in male and five in female. The mean age was 35(4 to 66)years old and mean follow up period is 21.3 month(12 to 72). We have retrospectively analyzed the various postoperative complications such as compartment syndrome, donor site infection, skin defect, hypesthesia, hammer toes, ankle instability and activity of daily living by help of questionnaire, telephone, physical examination, follow up x-ray study and chart. Results : In the total 54 cases the medication period for pain control after operation were classified into three groups under 2 weeks(49 cases), from 2 weeks to 6 weeks(3 cases) and over 6 weeks(2 cases). The postoperative morbidity were occurred in total 12 cases(compartment syndrome: 0, infection : 2, skin defect: 1, hypesthesia: 5, hammer toe: 2 ankle pain: 2 discomfort in activity of daily living: 0), and also the morbidity rates of donor site were 23.5% in osseous flap and 21.6% in osteocutaneous flap were occurred. There was no statistical significonce in morbidity between osseous and osteocutaneous free fibular flap transfer(P>0.05). Discussion : In general the morbidity of free fibular flap transfer was relatively high but it did not have any effect on daily activity of living. We think that the meticulous operation technique, detailed wound care and early range of motion exercise will reduce the morbidity of donor site of flap.

• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2331-2338
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• 1994

Experimental conditions of the optical shadow methods of caustics for measurement of the stress intensity factor and the J-integral in various materials(polycarbonate, PMMA, Al 5586D) are investigated. The necessary experimental requirements toe determine accurate values of the stress intensity factors and the J-integrals are described. The ratio of $r_o$ (radius of initial curve) to $r_p$ (plastic zone size) is selected as a parameter to verify the experimental limitation of the method of caustics in determination of fracture parameters. In this study, transmission caustics method was used for compact tension specimens made of polycarbonate and PMMA. while reflection caustics method was applied to c-shaped tension specimen made of Al 5586D. The appropriate ranges of $r_o/r_p$ tp determine accurate values of stress intensity factors were found to be 1.5~1.8. Existing experimental results have been obtained mainly by changing $r_p$ with different loads in $r_o/r_p$. However, in this study we could obtain varying $K_{caus}/K_{th}$ over the wide range of $r_o/r_p$ at fixed load conditions with newly designed optical arrangement. Thus, we could find the range in which theoretical and experimental results agree well each other by changing $r_o$ values only. In Al 5586D specimen, experimental caustics were located inside of the plastic zone, and $K_{caus}/K_{th}$ were found to be not unity in this range. It is found that $J_{caus}/J_{th}=1{\;}with{\;}r_o/t{\geq}0.8$ and the experimental plastic zone includes the contours of caustics.

• Journal of Welding and Joining
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• v.23 no.3
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• pp.68-75
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• 2005

The fatigue life of welded joints is associated with crack initiation and propagation life. Theses cannot be easily separated, since the definition of crack initiation is vague due to the initiation of multiple cracks that are distributed randomly along the weld toes. In this paper a method involving a notch strain and fracture mechanical approach, which considers the characteristics of welded joints, e.g. welding residual stress and statistical characteristics of multiple cracks, is proposed, in an attempt to reasonably estimate these fatigue lives. The fatigue crack initiation life was evaluated statistically, e.g. the probability of failure occurrence in 2.3, 50 and $97.7\%$, in which the cyclic response of the local stress/strain hi the vicinity of the weld toes and notch factors derived by the irregular shape of the weld bead are taken into account. The fatigue crack propagation life was simulated by using Monte-Carlo method in consideration of the Ad-factor and the mechanical behavior of mutual interaction/coalescence between two adjacent cracks. The estimated total fatigue life, $(N_T)_{P50\%}$, as a sum of crack initiation and propagation life under the probability of failure occurrence in $50\%$ showed a good agreement with the experimental results. The developed technique for fatigue lift estimation enables to provide a quantitative proportion of crack initiation and propagation life in the total fatigue life due to the nominal stress range, ${\Delta}S$.

• Archives of Reconstructive Microsurgery
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• v.16 no.2
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• pp.93-99
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• 2007

Purpose: To report the clinical results and efficacies of one stage reverse lateral supramalleolar adipofascial flap for soft tissue reconstruction of the foot and ankle joint. Material and Methods: We performed 5 cases of one stage reverse lateral supramalleolar adipofascial flap from Jan 2005 to Sept 2005. All patients were males and mean age was 50(36~59) years old. The causes of soft tissue defects were 1 diabetic foot, 2 crushing injuries of the foot, 1 open fracture of the calcaneus, and 1 chronic osteomyelitis of the medial cuneiform bone. Average size of the flap was 3.6(3~4)${\times}$4.6(4~6) cm. All flaps were harvested as adipofascial flap and were performed with the split-thickness skin grafts (STSG) above the flaps simultaneously. Results: All flap survived completely and good taking of STSG on the flap was achieved in all cases. There were no venous congestion and marginal necrosis of the flap. In diabetic foot case, wound was healed at 4 weeks after surgery due to wound infection. There was no contracture on the grafted sites. Ankle and toe motion were not restricted at last follow up. All patients did not have difficulty in wearing shoes. Conclusion: The reverse lateral supramalleolar adipofascial flap and STSG offers a valuable option for repair of exposure of the tendon and bone around the ankle and foot. Also one stage procedure with STSG can give more advantages than second stage with FTSG, such as good and fast take-up, early ambulation and physical therapy, and good functional result.

• Clinics in Shoulder and Elbow
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• v.26 no.3
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• pp.287-295
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• 2023

Background: Posterolateral rotatory instability (PLRI) is a common mechanism of recurrent elbow instability. While the essential lesion is a deficiency in the lateral ulnar collateral ligament (LUCL), there are often associated concomitant bony lesions, such as an Osborne-Cotterill lesions (posterior capitellar fractures) and marginal radial head fractures, that compromise stability. Currently, there is no standard treatment for posterior capitellar deficiency associated with recurrent PLRI. Methods: We conducted a retrospective review of five patients with recurrent PLRI of the elbow associated with a posterior capitellar impaction fracture engaging with the radial head during normal range of motion. The patients were treated surgically with LUCL reconstruction or repair and off-label reconstruction of the capitellar joint surface using a small metal prosthesis designed for metatarsal head resurfacing (HemiCAP toe classic). Results: Five patients (three adolescent males, two adult females) were treated between 2007 and 2018. At a median follow-up of 5 years, all patients had complete relief of their symptomatic instability. No patients had pain at rest, but two patients had mild pain (visual analog scale 1-3) during physical activity. Three patients rated their elbow as normal, one as almost normal, and one as greatly improved. On short-term radiographic follow-up there were no signs of implant loosening. None of the patients needed reoperation. Conclusions: Recurrent PLRI of the elbow associated with an engaging posterior capitellar lesion can be treated successfully by LUCL reconstruction and repair and filling of the capitellar defect with a metal prosthesis. This treatment option has excellent clinical results in the short-medium term. Level of evidence: IV.

• The Journal of Engineering Geology
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• v.30 no.3
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• pp.289-302
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• 2020

To determine the shallow subsurface structure and sliding surface of land creeping in 2016 at Hadong-gun, Gyeongsangnam-do, geophysical surveys (electric resistivity, and refraction seismic methods, borehole televiewer) and slope stability analysis were conducted. The subsurface structure delineated with borehole lithologies and seismic velocity structures provided the information that the sediment layer on the top of the slope was rather as thick as 20 m and the underlying weathered rock (anorthosite) was thinner than 1 m. Based on the tension cracks observed during the geological mapping, televiewer scanning was performed at the borehole BH-2 and detected the intensive fracture zones at the ground-water level, associated with the slip weak zones mapped in dipole-dipole electrical resistivity section. Downslope sliding and slightly upward pushing at the apex of high resistive bedrock explains the curved slip plane of the land creeping. Such a convex structure might play a role of natural toe abutment for preventing the downward development of slip weak zones. In slope stability analysis, the safety factors of the slip weak zone are calculated with varying the groundwater levels for dry and rainy seasons and the downslope is founded to be unstable with safety factor of 0.89 due to fully saturated material in rainy season.