• The Journal of Korean Academy of Prosthodontics
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• v.59 no.1
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• pp.27-35
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• 2021

Purpose: The purpose of this study is to compare the accuracy of digital scans of implants according to different shapes of scanbodies, and to compare the accuracy of library merging according to different oral exposure height. Materials and methods: A master model with a single tooth edentulous site was prepared. For the first experiment, three types of intraoral scanbodies were prepared, divided into three groups, and the following experiments were conducted for each group: An internal hex implant was placed. The master model with the scanbody connected was scanned with a model scanner, and a master reference file (control group) was created. 10 files (experimental group) were created by performing 10 consecutive scans with an intraoral scanner. After superimposing the control and experimental groups, the following values were calculated: 1) Distance deviation of a designated point on the scanbody 2) Angle deviation of the major axis of the scanbody. For the second experiment, the scanbody scan data were prepared in 6 different heights. Library files were merged with each of the scan data. The distance and angular deviation were calculated using the 7 mm scan data as control group. Results: In the first experiment, there were no significant differences between A and B (P=.278), B and C (P=.568), and C and A (P=.711) in the distance deviations. There were no significant differences between A and B (P=.568), B and C (P=.546), and C and A (P=.112) in the angular deviations. Also, the scanbody showed significantly higher library merging accuracy in the groups with high oral exposure height (P<.5). Conclusion: There were no significant differences in scan accuracy according to the different shapes of scanbodies, and the accuracy of library merging increased according to exposure height of the scanbody in the oral cavity.

• The Korean Journal of Nuclear Medicine Technology
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• v.25 no.1
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• pp.21-28
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• 2021

Purpose Brown fat, or brown adipose tissue (BAT), is involved in non-shivering thermogenesis and creates heat through glucose metabolism. BAT activation occurs stochastically by internal factors such as age, sex, and body mass index (BMI) and external factors such as temperature and environment. In this study, as a retrospective, electronic medical record (EMR) observation study, statistical analysis is conducted to confirm BAT activation and various factors. Materials and Methods From January 2018 to December 2019, EMR of patients who underwent PET/CT scan at the National Cancer Center for two years were collected, a total of 9155 patients were extracted, and 13442 case data including duplicate scan were targeted. After performing a univariable logistic regression analysis to determine whether BAT activation is affected by the environment (outdoor temperature) and the patient's condition (BMI, cancer type, sex, and age), A multivariable regression model that affects BAT activation was finally analyzed by selecting univariable factors with P<0.1. Results BAT activation occurred in 93 cases (0.7%). According to the results of univariable logistic regression analysis, the likelihood of BAT activation was increased in patients under 50 years old (P<0.001), in females (P<0.001), in lower outdoor temperature below 14.5℃ (P<0.001), in lower BMI (P<0.001) and in patients who had a injection before 12:30 PM (P<0.001). It decreased in higher BMI (P<0.001) and in patients diagnosed with lung cancer (P<0.05) In multivariable results, BAT activation was significantly increased in patients under 50 years (P<0.001), in females (P<0.001) and in lower outdoor temperature below 14.5℃ (P<0.001). It was significantly decreased in higher BMI (P<0.05). Conclusion A retrospective study of factors affecting BAT activation in patients who underwent PET/CT scan for 2 years at the National Cancer Center was conducted. The results confirmed that BAT was significantly activated in normal-weight women under 50 years old who underwent PET/CT scan in weather with an outdoor temperature of less than 14.5℃. Based on this result, the patient applied to the factor can be identified in advance, and it is thought that it will help to reduce BAT activation through several studies in the future.

• Journal of the Korean Orthopaedic Association
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• v.55 no.2
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• pp.135-142
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• 2020

Purpose: This paper presents the long term follow-up results of arthroscopic partial repair for massive irreparable rotator cuff tears using a biceps long head auto graft. Materials and Methods: Forty-one patients with massive irreparable rotator cuff tear, who underwent arthroscopic repair, were reviewed retrospectively. Patients who underwent arthroscopic partial repair using a biceps long head auto graft were assigned to group 1, and patients in group 2 underwent arthroscopic partial repair alone. Patients with a less than 50% partial tear of the long head biceps tendon were included in this study. The clinical scores were measured using a visual analogue pain scale (VAS) for pain, range of motion (ROM), The University of California, Los Angeles shoulder score (UCLA), American Shoulder and Elbow Surgeons Shoulder Score (ASES), and Korean Shoulder Scoring System (KSS) scores preoperatively and at the final follow-up. The acromiohumeral interval (AHI) was measured using plain radiographs taken preoperatively and at the final follow-up, and re-tear was evaluated using postoperative ultrasound or magnetic resonance imaging at the last follow-up. Results: The mean age of the patients was 62.1±12.7 years, and the mean follow-up period was 90.3±16.8 months. No significant differences in the VAS and ROM (forward flexion, external rotation, internal rotation) were found between the two groups (p=0.179, p=0.129, p=0.098, p=0.155, respectively). The UCLA (p=0.041), ASES (p=0.023), and KSS (p=0.019) scores showed functional improvements in group 1 compared to group 2. At the last follow-up, the measured AHI values were 9.46±0.41 mm and 6.86±0.64 mm in group 1 and 2, respectively (p=0.032). Re-tear was observed in six out of 21 cases (28.6%) in group 1 and nine out of 20 cases (45.0%) in group 2; the retear rate was significantly lower in group 1 than in group 2 (p=0.011). Conclusion: Arthroscopic partial repair for a massive irreparable rotator cuff tear using a biceps long head auto graft has significant clinical usefulness in functional recovery and decreases the re-tear rates after surgery than arthroscopic partial repair alone, showing favorable results after a long-term follow-up.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.42-50
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• 2021

Purpose: Periprosthetic fractures of a tumor prosthesis are rare but have difficulties in achieving sound fixation because of the poor bone quality, which increases the risk of loosening or re-fracture, even after bone union. A cortical strut onlay allograft was adopted for peri-prosthetic fractures after hip arthroplasty into the periprosthetic fracture of a tumor prosthesis, assuming that it would assist in firm fixation, shorten the time to union, and increase the bone stock, thereby, lower the chance of loosening and re-fracture. Materials and Methods: This study reviewed 27 patients (30 cases) of periprosthetic fracture of tumor prosthesis. Sixteen cases (allograft group) had augmentation with an onlay allograft, while 14 cases (conventional group) had internal fixation or conservative treatment. The following were assessed; mode of periprosthetic fracture, difference in the time to union between a strut cortical onlay allograft and without it, and survival of prosthesis, complication, and functional outcome between the two groups. Results: According to the unified classification system (UCS), 21 cases were type B (70.0%; B1, 14; B2, 1; B3, 6) and 9 cases were type C. The five-, 10-year survival of the 30 reconstructions by Kaplan-Meier plot was 84.5%±4.18% and 42.2%±7.83%, respectively. The average time to bone union of the entire cohort was 5.1 months (range, 2.0-11.2 months). The allograft group (3.5 months) showed a shorter period for union than the conventional group (7.2 months) (p<0.0001). All four cases of major complications occurred in the conventional group. Two cases with loosening and anterior angulation were treated with a change of prosthesis, and another with infection underwent amputation. The remaining case with loosening had conservative management. At the final follow-up, the average Musculosketal Tumor Society score of the allograft group (26.1) was better than that of the conventional group (20.9). Conclusion: Bone union in periprosthetic fractures of a tumor prosthesis can be achieved, but the minimization of complications is important. An onlay allograft facilitates firm fixation and increases the bone stock with a shortened time to union. This simple method can minimize the risk of loosening, joint contracture, and re-fracture.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.224-233
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• 2021

Purpose: The purpose of this study was to retrospectively evaluate the effect of 'Blocking Kirschner Wire (K-Wire) Technique', which has been developed to reduce protrusion of the lateral wall, in maintaining the level of reduction through clinical and radiological outcomes. Materials and Methods: Twenty-two patients with displaced intra-articular calcaneal fractures who used the blocking K-wire to maintain reduction (group A) and 44 patients that did not use blocking K-wire and were paired in 1:2 ratio with those Group A patients (group B), between January 2015 and December 2017 were enrolled in the study. All surgical procedures were performed via the extended sinus tarsi approach, and internal fixation using cannulated screws, Steinmann pins and K-wires was performed. American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot scale and postoperative recovery of exercise ability were compared for postoperative clinical outcomes. The radiological results were compared the Böhler angle, Gissane angle, calcaneal height and width, step off of posterior calcaneal joint, and the degree of protrusion of the lateral wall. Moreover, postoperative complications in both groups were compared. Results: There were no significant differences in the clinical outcomes of the two groups (p=0.924, p=0.961). The amount of Böhler angle, Gissane angle, calcaneal height and width, and step off of posterior calcaneal joint from the radiological results was not significantly different between the two groups (p=0.170, p=0.441, p=0.230, p=0.266, and p=0.400). However, the degree of protrusion of the lateral wall was 1.78 mm and 4.95 mm in group A and group B, respectively, and the difference between the two groups was significant (p=0.017). Although sural nerve entrapment and painful exostosis were more frequent in group B, they were occurred in a non-significant manner (p=0.293, p=0.655). Conclusion: Most of the clinical and radiological results as well as the complications were not significantly different between the two groups. However, the degree of protrusion of the calcaneus lateral wall in group A was promising. The 'Blocking K-Wires Technique' established by the authors may be an effective surgical option for maintaining the reduction of the lateral wall protrusion in displaced intraarticular calcaneal fractures.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.3
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• pp.305-313
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• 2021

Purpose. The purpose of this pilot study is to evaluate the reliability and validity of the Korean version of the oral health impact profile (OHIP-EDENT K) for edentulous patients. Materials and methods. The study was conducted on 12 patients who fabricated overdenture in the Department of Prosthodontics, Korea University, Guro Hospital. All subjects completed the Korean version of Oral Health Impact Profile (OHIP K) questionnaire. Shorten version of the OHIP called OHIP-14 K and OHIP-EDENT K were derived from the datasets. Cronbach's alpha was used to measure internal consistency of the summary scores for OHIP-EDENT K. The Spearman's correlation coefficient between the summary scores for OHIP-EDENT K and OHIP K was calculated to evaluate concurrent validity. Results. The reliability of the summary scores for OHIP-EDENT K was acceptable (α=.736). The Spearman's correlation coefficient of the summary scores for OHIP-EDENT K and OHIP K was 0.966, which was statistically significant (P<.001). OHIP-EDENT K exhibited less susceptibility to floor effects than OHIP-14 K and appeared to measure change as effectively as OHIP K. In order to prove the reliability, responsiveness and validity of OHIP-EDENT K, further studies with more samples are needed. Conclusion. The OHIP-EDENT K, a questionnaire on oral health-related QOL comprising 19 items, has measurement properties comparable with the full 49-item version. This modified shortened version can be an alternative questionnaire to full version of OHIP K and OHIP-14 K in edentulous patients.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.503-510
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• 2020

Purpose: Bipolar hemiarthroplasty is used as an alternative to open reduction and internal fixation for unstable intertrochanteric fractures in elderly patients. Recent advances in medical systems and technologies have resulted in increased survival rates after intertrochanteric fractures of the femur, requiring selection of the appropriate femoral stems considering the mid- to long-term duration of survival. Hemiarthroplasty was performed for unstable intertrochanteric fractures using a double tapered quadrilateral femoral stem (C2 stem), and the clinical and radiological results were evaluated as a five-year follow-up post-surgery. Materials and Methods: From January 2004 to December 2013, 43 patients (43 hips) who underwent hemiarthroplasty with a C2 stem were enrolled in this study. Their mean age was 78.6 years (range, 70-84 years), and the mean follow-up period was 85.4 months (range, 60-96 months). During the follow-up period, clinical parameters, such as the changes in pain, walking ability, and functional status, were examined. Radiologically, changes in the proximal femur, such as osteoporosis and bone resorption of cortical bone, were noted. Complications that occurred during the follow-up period, such as dislocation and prosthetic features, were also reviewed. Results: Initially, the pain was relieved postoperatively, but it increased four years after surgery. The walking ability was reduced by two steps in nine patients after 60 months, and the Harris hip score was reduced significantly postoperatively after two to three years. Radiologically, cortical osteoporosis occurred in 14 patients. Five patients developed cortical bone resorption. Four of them showed nonunion of the trochanteric fracture fragments, and three of them suffered reverse oblique fractures. Conclusion: Careful selection considering the general health condition and remaining lifespan of the patient would be necessary for primary hip hemiarthroplasty using a 3C type cementless femoral stem for unstable intertrochanteric fractures in elderly patients with osteoporosis.

• Journal of the Korean Orthopaedic Association
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• v.54 no.4
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• pp.317-326
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• 2019

Purpose: To compare and analyze the rate of prevention of two venous thromboembolism prophylaxis guidelines in patients with artificial joint arthroplasty and hip joint fracture. Proper prophylaxis for preventing thromboembolism in orthopedic surgery is significant because of this fetal complication. Materials and Methods: This study compared and retrospective analyzed the rate of prevention using the medical records and radiographs of patients who underwent orthopedic surgery from March 2009 to February 2011 according to the American College of Chest Physicians (ACCP) guidelines and from March 2012 to February 2014 according to the American Academy of Orthopedic Surgeons (AAOS) guidelines. Results: The guidelines for venous thromboembolism prophylaxis have been applied to patients with artificial joint replacement and hip joint fracture, the compliance rate of the ACCP guidelines was 56.0% before surgery, 67.0% after surgery with chemical prophylaxis, and 80.5% with mechanical prophylaxis. In addition, the compliance rate of the AAOS guidelines was 74.1% with chemical prophylaxis, and 88.3% with mechanical prophylaxis, which was higher than the ACCP guidelines. The compliance rates of mechanical and chemical prophylaxis before and after surgery of the ACCP guidelines, and the compliance rate of mechanical and chemical prophylaxis of the AAOS guidelines were compared and analyzed. The results revealed statistical significance (p<0.05) before and after total knee replacement arthroplasty and hip joint fracture internal fixation and total high risk orthopedic surgery. Conclusion: Raising the compliance rate of prophylaxis of venous thromboembolism in high risk orthopedic surgery is necessary and people should follow the guidelines for a unified direction depending on which situation they are in.

• Journal of the Korean Orthopaedic Association
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• v.52 no.1
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• pp.25-32
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• 2017

Purpose: The purpose of this study was to analyze the radiological and clinical outcomes in elderly patients with unstable intertrochanteric femur fractures in accordance with the length of intramedullary nail. Materials and Methods: Between August 2009 and December 2014, a total of 139 patients-older than 65 years of age with AO/OTA classification of 31-A2 unstable intertrochanteric femur fracture-who has been followed-up for at least 1 year after the treatment with internal fixation by using an intramedullary nail were enrolled for this retrospective control study. The subjects were classified into two groups according to the length of intramedullary nail: 106 patients in the short group (group I) and 33 patients in the long group (group II). For radiological assessments, the reduction state, time to union, and implant related complications were examined. The clinical outcomes were assessed by preoperative hemoglobin, operating time, intraoperative bleeding amount, blood transfusion rate, hospitalization period, and Charnley hip pain scoring system at the final follow-up. Results: The postoperative radiographs showed good or acceptable reduction in all cases. The mean time of radiologic bone union was 4.8 months, and there was no difference between the two groups. With respect to surgical time, the group II was found to take longer (57.87 minutes) than the group I (45.65 minutes) (p=0.003). The bleeding amount during surgery of the group II was greater (288.78 ml) than that of the group I (209.90 ml) (p=0.046). The clinical results at the final follow-up were found to be satisfactory in both groups. Conclusion: In cases of good reduction of the fracture from the treatment of unstable intertrochanteric femur fracture accompanying the posteromedial fragment in elderly patients, both groups-long and short intramedullary nails-showed satisfactory radiological and clinical outcomes.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.5A
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• pp.557-564
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• 2009

In recent years, there have been numerous explosion-related accidents due to military and terrorist activities. Such incidents caused not only damages to structures but also human casualties, especially in urban areas. To protect structures and save human lives against explosion accidents, better understanding of the explosion effect on structures is needed. In an explosion, the blast overpressure is applied to concrete structures as an impulsive load of extremely short duration with very high pressure and heat. Generally, concrete is known to have a relatively high blast resistance compared to other construction materials. However, information and test results related to the blast experiment of internal and external have been limited due to military and national security reasons. Therefore, in this paper, to evaluate blast effect on reinforced have concrete structure and its protective performance, blast tests are carried out with $1.0m{\times}1.0m{\times}150mm$ reinforce concrete slab structure at the Agency for Defence Development. The standoff blast distance is 1.5 m and the preliminary tests consists with TNT 9 lbs and TNT 35 lbs and the main tests used ANFO 35 lbs. It is the first ever blast experiment for nonmilitary purposes domestically. In this paper, based on the basic experiment procedure and measurement details for acquiring structural behavior data, the blast experimental measurement system and procedure are established details. The procedure of blast experiments are based on the established measurement system which consists of sensor, signal conditioner, DAQ system, software. It can be used as basic research references for related research areas, which include protective design and effective behavior measurements of structure under blast loading.