• Archives of Reconstructive Microsurgery
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• v.10 no.1
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• pp.18-22
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• 2001

Purpose : The purpose of this study was to evaluate stress fracture of vascularized fibular grafts(VFG) by analyzing factors associated with stress fracture and the treatment results. Materials and Methods : From June 1985 to May 1998, 7 patients with stress fractures in the 38 patients with long bone defect who had vascularized fibular graft were evaluated with clinical and radiologic methods including grafted fibular length and hypertrophic index of de Boer. The average age of the patients was 35 years(range, $14{\sim}60$ years). The mean follow-up period was 20 months(range, $16{\sim}32$ months). Results: 7(18.4%) stress fractures occurred in 38 patients. Characteristics of the fractures were (1) all occurred at lower extremity of male patients treated with VFG for long bone defected caused by infected nonunion; (2) all occurred 10 months at the average(range, $4{\sim}17$ months) after VFG; and (3) the length and hypertrophic index of grafted fibula had no influence on the incidence of stress fracture. Union was obtained in 3 patients by conservative treatment. 4 patients obtained union by internal fixation; one at immediately onset of fracture; and three after failure of conservative treatment who had fracture around the knee joint. Conclusion : Stress fracture may occur during the first one year after vascularized fibular graft and more attention must be paid for prevention of it, especially in the cases of infected nonunion. Stress fracture around the knee joint was expected to lead to a good result of early union by operative treatment.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.03b
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• pp.3-12
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• 1994

Based on the shear failure mechanism, hydraulic fracturing criteria are extended to three dimensional stress state. According to the situation of the directions of borehole and major principal stress axes, three equations can be derived for three dimensional hydraulic fracturing problems. By comparing these equations, a single criterion is selected for hydraulic fracturing pressure in cohesive soils. The criterion is a function of maximum principal stress, minimum principal stress and soil parameters in UU conditions. The equation indicates that with any increase in maximim principal stress, hydraulic fracturing pressure decreases. In order to prove the integrity of the criteria, laboratory tests are performed on compacted cubical specimens using true a triaxial apparatus. The shape and direction of fractures are determined by injecting colored water after fracture initiation. It is found that the direction of fractures are perpendicular to the o1 plane.

• Geomechanics and Engineering
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• v.32 no.4
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• pp.375-385
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• 2023

There are many joint fissures distributed in the engineering rock mass. In the process of geological history, the underground rock mass undergoes strong geological processes, and undergoes complex geological processes such as fracture breeding, expansion, recementation, and re-expansion. In this paper, the damage-stick-slip process (DSSP), an analysis model used for rock mass failure slip, was established to examine the master control and time-dependent mechanical properties of the new and primary fractures of a multi-fractured rock mass under the action of stress loading. The experimental system for the recemented multi-fractured rock mass was developed to validate the above theory. First, a rock mass failure test was conducted. Then, the failure stress state was kept constant, and the fractured rock mass was grouted and cemented. A secondary loading was applied until the grouted mass reached the intended strength to investigate the bearing capacity of the recemented multi-fractured rock mass, and an acoustic emission (AE) system was used to monitor AE events and the update of damage energy. The results show that the initial fracture angle and direction had a significant effect on the re-failure process of the cement rock mass; Compared with the monitoring results of the acoustic emission (AE) measurements, the master control surface, key blocks and other control factors in the multi-fractured rock mass were obtained; The triangular shaped block in rock mass plays an important role in the stress and displacement change of multi-fracture rock mass and the long fissure and the fractures with close fracture tip are easier to activate, and the position where the longer fractures intersect with the smaller fractures is easier to generate new fractures. The results are of great significance to a multi-block structure, which affects the safety of underground coal mining.

• Geomechanics and Engineering
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• v.6 no.2
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• pp.153-172
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• 2014

In order to investigate the effect of different perforation angles (the angle between the perforation direction and the maximum horizontal principal stress) on the fracture initiation and propagation during hydraulic fracturing of highly deviated well in oil & gas saturated formation, laboratory experiments of the hydraulic fracturing had been carried out on the basis of non-dimensional similar criteria by using 400^3 $mm^3$ cement cubes. A plane fracture can be produced when the perforations are placed in the direction of the maximum horizontal principal stress. When the perforation angle is $45^{\circ}$, the fractures firstly initiate from the perforations at the upper side of the wellbore, and then turn to the maximum horizontal principal stress direction. When the well deviation angle and perforation angle are both between $45^{\circ}$ and $90^{\circ}$, the fractures hardly initiate from the perforations at the lower side of the wellbore. Well azimuth (the angle between the wellbore axis and the maximum horizontal principal stress) has a little influence on the fracture geometries; however it mainly increases the fracture roughness, fracture continuity and the number of secondary fractures, and also increases the fracture initiation and propagation pressure. Oriented perforating technology should be applied in highly deviated well to obtain a single plane fracture. If the well deviation angle is smaller, the fractures may link up.

• 한국석유지질학회:학술대회논문집
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• autumn
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• pp.6-22
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• 2001

A study of the fracture systems in outcrops of southern onshore Vietnam revealed two kinds of fracture groups according to their origin: cooling fractures and deformation related fractures. Cooling of magma introduced extensive fractures in the batholiths with wide spacing and narrow aperture. They are found widespread in all magmatic bodies, but result in poor reservoir quality due to low bulk porosity and narrow aperture. Cooling fractures are often reactivated during later stress regimes. Deformation related fractures, especially 'fault damage zones' and 'hanging wall deformation' is thought to form the most important reservoir type in the fractured basement rock. The porosity formed by intense fracturing and fault breccia along minor fault zones is thought to be the producing zones in the producing fields of Cuu Long basin. They are found along major faults and widespread in hanging wall blocks.

• Journal of Korean Foot and Ankle Society
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• v.16 no.1
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• pp.70-72
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• 2012

Stress fractures of the proximal phalanx of the great toe are rare. This fractures have been associated with halux valgus deformity in most reports. We performed open reduction and internal fixation with distal chevron osteotomy for the stress fracture of the proximal phalanx of the great toe in a basketball player with hallux valgus, and obtained successful bony union and rapid return to sports.

• Journal of Trauma and Injury
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• v.36 no.4
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• pp.376-384
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• 2023

Purpose: The Armed Forces Trauma Center of Korea was established in April 2022. This study was conducted to report our 1-year experience of treating soldiers with open fractures of the lower extremity. Methods: In this case series, we reviewed the medical records of 51 Korean soldiers with open fractures of the lower extremity between April 2022 and March 2023 at a trauma center. We analyzed patients with Gustilo-Anderson type II and III fractures and reported the duration of transportation, injury mechanisms, injured sites, and associated injuries. We also presented laboratory findings, surgery types, intensive care unit stays, hospital stays, rehabilitation results, and reasons for psychiatric consultation. Additionally, we described patients' mode of transport. Results: This study enrolled nine male patients who were between 21 and 26 years old. Six patients had type II and three had type III fractures. Transport from the accident scene to the emergency room ranged from 75 to 455 minutes, and from the emergency room to the operating room ranged from 35 to 200 minutes. Injury mechanisms included gunshot wounds, landmine explosions, grenade explosions, and entrapment by ship mooring ropes. One case had serious associated injuries (inhalation burn, open facial bone fractures, and hemopneumothorax). No cases with serious blood loss or coagulopathies were found, but most cases had a significant elevation of creatinine kinase. Two patients underwent vascular reconstruction, whereas four patients received flap surgery. After rehabilitation, six patients could walk, one patient could move their joints actively, and two patients performed active assistive movement. Eight patients were referred to the psychiatry department due to suicidal attempts and posttraumatic stress disorder. Conclusions: This study provides insights into how to improve treatment for patients with military trauma, as well as medical services such as the transport system, by revising treatment protocols and systematizing treatment.

• Journal of Trauma and Injury
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• v.37 no.1
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• pp.89-96
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• 2024

The indications for total hip replacement are increasing and not limited to osteoarthritis. Total hip replacement may also be done for trauma and pathological fractures in patients otherwise physiologically fit and active. This trend has led to an inevitable rise in complications such as periprosthetic femoral fracture. Periprosthetic femoral fracture can be challenging due to poor bone quality, osteoporosis, and stress fractures. We present a case of periprosthetic femoral fracture in a 71-year-old woman with some components of an atypical femoral fracture. The fracture was internally fixed but was subsequently complicated by infection, implant failure needing revision, and later stress fracture. She was on a bisphosphonate after her index total hip replacement surgery for an impending pathological left proximal femur fracture, and this may have caused the later stress fracture. Unfortunately, she then experienced implant breakage (nonunion), which was treated with a biplanar locking plate and bone grafting. The patient finally regained her premorbid mobility 13 months after the last surgery and progressed satisfactorily towards bony union.

• Clinical Pain
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• v.19 no.2
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• pp.138-141
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• 2020

Clay-shoveler's fractures are rare stress-type avulsion fractures of the spinous processes especially in sports. There have been two case reports that discussed clay-shoveler's fractures in golf. A 36-year-old beginner golfer presented with a pain in the back after practicing golf swing. No fractures were detected using cervical radiography; however, computed tomography (CT) and magnetic resonance imaging (MRI) revealed T2~T3 spinous process fractures. The patient was treated conservatively and his pain subsided. The mechanism of injury is speculated to that of clay-shoveler's fractures. Therefore, if a golfer suffers persistent pain in the cervicothoracic region, clay-shoveler's fracture is one possibility to consider.

• Journal of Acupuncture Research
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• v.39 no.1
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• pp.64-69
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• 2022

The risk of stress fractures is associated with rheumatoid arthritis (RA), which can aggravate bone loss. We report the case of a patient who was on long-term medication for RA presenting with lower extremity pain on the left and swelling without trauma. Magnetic resonance imaging and plain radiographs at the previous hospital showed no signs of fracture, but radiographs performed later, revealed a stress fracture of the left distal tibia. The stress fracture may have occurred due to multiple reasons such as long-term use of methotrexate and glucocorticoids, active RA, postmenopausal state, and immobility. Suspicion of a stress fracture should not be ruled out especially in RA patients with persistent pain, even if the radiographical findings are normal. Additional imaging and follow-ups are essential. The patient's pain was relieved with Korean medicine treatments, which suggests their potential application for stress fractures in RA patients.