• The Korean Journal of Health Service Management
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• v.9 no.4
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• pp.131-144
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• 2015

Objectives : This study investigated the health care utilization patterns and length of stay (LOS) determinants of fracture patients with workers' compensation insurance (WCI) and national health insurance (NHI). Methods : The discharge summary data of 4,394 WCI fracture patients were compared to 28,874 NHI patients. Health care utilization characteristics were compared with a logistic regression analysis, and the LOS determinants were identified with linear regression analysis. Results : The average LOS of the WCI fracture patients was 2.4 times higher than that of the NHI patients. WCI patients used more small or medium sized hospitals, and were more frequently admitted through the emergency room. Females, older patients and patients admitted through emergency room had a significant positive impact on LOS. Conclusions : Healthcare utilization by the WCI fracture patients may include medically unnecessary hospital stays. Therefore, policy makers need to respond appropriately to the inefficient use of health resources by WCI patients.

• Journal of Veterinary Clinics
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• v.35 no.3
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• pp.83-87
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• 2018

The aim of this study was to evaluate the biomechanical behavior of xenogenic bone plate system (equine bone) using a three-dimensional finite element ulna fracture model. The model was used to calculate the Von Mises stress (VMS) and stress distribution in fracture healing periods with metallic bone plate and xenogenic bone plate systems, which are installed while the canine patient is standing. Bone healing rate (BHR) (0%) and maximum VMS of the xenogenic plate was similar to the yield strength of equine bone (125 MPa). VMS at the ulna and fracture zones were higher with the xenogenic bone plate than with the metallic bone plate at BHRs of 0% and 1%. Stress distributions in fracture zone were higher with the xenogenic bone plate than the metallic bone plate. This study results indicate that the xenogenic bone plate may be considered more beneficial for callus formation and bone healing than the metallic bon plate. Xeonogenic bone plate and screw applied in clinical treatment of canines may provide reduced stress shielding of fractures during healing.

• Journal of Korean Foot and Ankle Society
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• v.18 no.3
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• pp.124-128
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• 2014

Purpose: The purpose of this study was to assess the treatment outcomes and prognosis of Lisfranc joint fracture and dislocation according to the mechanism of injury and treatment method. Materials and Methods: Twenty six patients with Lisfranc fracture-dislocation who had been treated surgically were included in this retrospective study. The patients were divided into two groups according to mechanism of injury: direct crushing injury (16 patients) and indirect rotational or compressive injury (10 patients). The patients were also divided into three groups according to the surgical methods. The parameters used were radiographic evaluation, patients' subjective satisfaction levels, length of hospital stay, and the American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score. Statistical analysis was performed. Results: The mean postoperative AOFAS midfoot score was 78.7. The mean length of stay was 39.6 days. Statistically significant differences in subjective satisfaction, AOFAS midfoot score, and length of hospital stay were observed between the two groups (p<0.05). However, no significance differences were observed between the three groups who were divided according to the different surgical methods (p>0.05). Conclusion: Mechanism of trauma and the severity of soft-tissue injury were significant prognostic factors affecting the surgical outcomes of Lisfranc joint fracture and dislocation.

• Transactions of Materials Processing
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• v.21 no.4
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• pp.258-264
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• 2012

The forming failure of AZ31 alloy sheet during deep drawing processes was predicted by the FEM and ductile fracture criteria. Uniaxial tensile tests of round-notched specimens and FE simulations were performed to calculate the critical damage values for three ductile fracture criteria. The critical damage values for each criterion were expressed as a function of strain rate at various temperatures. In order to determine the best criterion for failure prediction, Erichsen cupping test under isothermal conditions at $250^{\circ}C$ were conducted. Based on the plastic deformation histories obtained from the FE analysis of the Erichsen cupping tests and the critical damage value curves, the initiation time and location of fracture were predicted under bi-axial tension deformation. The results indicate that the Cockcroft-Latham criterion had good agreement with the experimental data. In addition, the FE analysis combined with the criterion was applied to another deep drawing process using an irregular shaped blank and these additional results were verified with experimental tests.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.1975-1988
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• 2024

It is important to maintain cladding integrity in spent nuclear fuel management. This study proposes a numerical analysis method to evaluate the fracture resistance of irradiated zirconium alloy cladding under pinch load known to cause Mode-III failure. The mechanical behavior and fracture of the cladding under pinch loading can be evaluated by a Ring Compression Test (RCT). To simulate the fracture of hydride precipitates, zirconium matrix, and Zr/hydride interfaces under the stress field generated by RCT, a micro-structure crack propagation simulation method based on Continuum Damage Mechanics (CDM) has been proposed. Our RCT simulation model was constructed from microscopic images of irradiated cladding. In this study, we developed an automated process to generate a pixel-based finite element model by separating the hydride precipitates, zirconium matrix, and interfaces using an image segmentation method. The appropriate element size was selected to ensure the efficiency and accuracy of a crack propagation simulation. The load-displacement curves and strain energies from RCT were compared and analyzed with the simulation results of different element sizes. The finalized RCT simulation model can be used to establish the failure criterion of fuel rods under pinch loading. The advantages and limitations of the proposed method are fully discussed here.

• Archives of Plastic Surgery
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• v.35 no.5
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• pp.560-564
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• 2008

Purpose: Because of traffic accidents and many criminal violences, the incidence of facial trauma has been increasing not only in adults but also in children. We planed this study to introduce our experience about pediatric blow out fracture and provide more information. Methods: We made retrospective study in 76 children with blow out fracture from January 2001 to September 2005 by retrospective chart review including detailed preoperative and postoperative evaluations, age, sex, cause, symptom and sign, and their post-operative complications. Results: Among our patients, 69 were male and 7 were female. The ages ranged from 7 to 18 years, which shows the greatest incidence of blow out fracture. Physical violence(46%) was the most common cause in this group and was followed by vehicle accident(28%), and fall down accident(17%). Left side(64%) showed slightly more incidence than right side(36%), but there were no statistical importance. Ecchymosis(88%) was the most common symptom and followed by periorbital swelling(68%) and diplopia(30%). 30 patients was diagnosed with another facial bone fracture and nasal bone(51%) was the most common associated facial bone fracture. Fourty four Patients(60%) got an orbital wall reconstruction in 7 days after trauma. After the operation, only 3 patients(4%) suffered from diplopia postoperative 3 month, and resolved in 4 years. Conclusion: The incidence of blow out fracture in children has been increasing every year, and violence has become more important etiology of pediatric blow out fracture and public and private education institutions were the most common place that blow out fracture originated. Accurate diagnosis and careful treatment plans are important in pediatric blow out fracture.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.39 no.5
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• pp.217-223
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• 2013

Objectives: Buccal fracture of the mandibular proximal bone segment during bilateral sagittal split ramus osteotomy (SSRO) reduces the postoperative stability. The primary aim of this study is to evaluate the effect of this type of fracture on bone healing and postoperative stability after mandibular setback surgery. Materials and Methods: Ten patients who experienced buccal fracture during SSRO for mandibular setback movement were evaluated. We measured the amount of bone generation on a computed tomography scan, using an image analysis program, and compared the buccal fracture side to the opposite side in each patient. To investigate the effect on postoperative stability, we measured the postoperative relapse in lateral cephalograms, immediately following and six months after the surgery. The control group consisted of ten randomly-selected patients having a similar amount of set-back without buccal fracture. Results: Less bone generation was observed on the buccal fracture side compared with the opposite side (P<0.05). However, there was no significant difference in anterior-posterior postoperative relapse between the group with buccal fracture and the control group. The increased mandibular plane angle and anterior facial height after the surgery in the group with buccal fracture manifested as a postoperative clockwise rotation of the mandible. Conclusion: Bone generation was delayed compared to the opposite side. However, postoperative stability in the anterior-posterior direction could be maintained with rigid fixation.

• The Journal of Advanced Prosthodontics
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• v.10 no.2
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• pp.155-162
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• 2018

PURPOSE. The aim of this study was to compare the fracture of implant component behavior of external and internal type of implants to suggest directions for successful implant treatment. MATERIALS AND METHODS. Data were collected from the clinical records of all patients who received WARANTEC implants at Seoul National University Dental Hospital from February 2002 to January 2014 for 12 years. Total number of implants was 1,289 and an average of 3.2 implants was installed per patient. Information about abutment connection type, implant locations, platform sizes was collected with presence of implant component fractures and their managements. SPSS statistics software (version 24.0, IBM) was used for the statistical analysis. RESULTS. Overall fracture was significantly more frequent in internal type. The most frequently fractured component was abutment in internal type implants, and screw fracture occurred most frequently in external type. Analyzing by fractured components, screw fracture was the most frequent in the maxillary anterior region and the most abutment fracture occurred in the maxillary posterior region and screw fractures occurred more frequently in NP (narrow platform) and abutment fractures occurred more frequently in RP (regular platform). CONCLUSION. In external type, screw fracture occurred most frequently, especially in the maxillary anterior region, and in internal type, abutment fracture occurred frequently in the posterior region. placement of an external type implant rather than an internal type is recommended for the posterior region where abutment fractures frequently occur.

• Archives of Plastic Surgery
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• v.32 no.1
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• pp.49-54
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• 2005

Evaluations and treatments of nasal bone fracture have been mainly focused on aesthetic aspect, but nose has an important role as an airway. The purpose of this study was evaluation of nasal bone fractures in the view of nasal obstruction and its improvement after reduction. Acoustic rhinometry was applied to the 77 nasal bone fractured patients who received closed reduction from August 2002 to July 2003 and received closed reduction. This was tested twice, before and 6 days after reduction, for all 77 patients and additional acoustic rhinometry was also possible in 26 patients after 6 months. The analysis of acoustic rhinometry were based on data of minimal cross-sectional area(MCA) according to fracture sites(one side, both side and tip) and septal displacement. Mean MCA for all cases before reduction was $0.43{\pm}0.21cm^2$, which was 19% decrease compared to normal adult data($0.53{\pm}0.12cm^2$). Depending on fracture sites the MCA were $0.45{\pm}0.16cm^2$ for one side fracture, $0.35{\pm}0.18cm^2$ for both side fracture, and $0.42{\pm}0.25cm^2$ for tip fracture. The patients with septal displacement showed more severe obstruction than ones without septal displacement, $0.26{\pm}0.26cm^2$ and $0.46{\pm}0.10cm^2$, respectively. The MCA was improved up to $0.50{\pm}0.22cm^2$ after reduction and showed slight decrease after 6 month($0.48{\pm}0.23cm^2$). Based on the results of this study, nasal bone fracture really caused airway obstruction(19% decrease). Both side fracture showed more profound decrease than one side fracture and septal displacement was an important parameter which causes nasal obstruction. Closed reduction improved MCA by 14% right after reduction, and 11% after 6 month follow up.

• The Journal of Advanced Prosthodontics
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• v.5 no.2
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• pp.92-97
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• 2013

PURPOSE. All-ceramic crowns are subject to fracture during function. To minimize this common clinical complication, zirconium oxide has been used as the framework for all-ceramic crowns. The aim of this study was to compare the fracture strengths of two computer-aided design/computer-aided manufacturing (CAD/CAM) zirconia crown systems: Lava and Digident. MATERIALS AND METHODS. Twenty Lava CAD/CAM zirconia crowns and twenty Digident CAD/CAM zirconia crowns were fabricated. A metal die was also duplicated from the original prepared tooth for fracture testing. A universal testing machine was used to determine the fracture strength of the crowns. RESULTS. The mean fracture strengths were as follows: $54.9{\pm}15.6$ N for the Lava CAD/CAM zirconia crowns and $87.0{\pm}16.0$ N for the Digident CAD/CAM zirconia crowns. The difference between the mean fracture strengths of the Lava and Digident crowns was statistically significant (P<.001). Lava CAD/CAM zirconia crowns showed a complete fracture of both the veneering porcelain and the core whereas the Digident CAD/CAM zirconia crowns showed fracture only of the veneering porcelain. CONCLUSION. The fracture strengths of CAD/CAM zirconia crowns differ depending on the compatibility of the core material and the veneering porcelain.