• Journal of Yeungnam Medical Science
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• v.37 no.1
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• pp.40-46
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• 2020

Background: Postoperative pain occurring after hip arthroplasty has become common since the expanded use of cementless femoral stems. The characteristic pain develop in the anterolateral thigh area. This study aimed to predict anterior thigh pain based on the measurements of postoperative anteroposterior (AP) and lateral (Lat) radiographs of the hip joint. Methods: The present study included 26 patients (29 hips) who underwent total hip replacement or bipolar hemiarthroplasty between March 2010 and May 2016, whose complete clinical information was available. AP and Lat radiographs of the affected hip were taken on the day of surgery and 1 and 6 months postoperatively. Patients with improper radiographs were excluded. The distance from the femoral stem to the nearest cortical bone in the distal region of the stem was measured. The patient group with a visual analog scale (VAS) score of ≥6 points was designated as patients with anterior thigh pain. Results: Sex, age, weight, height, body mass index, and bone mineral density in the lumbar spine and femur did not have a significant effect on postoperative VAS scores (p>0.05). Presence of contact between the femoral stem and cortical bone was associated with postoperative anterior thigh pain. Conclusion: Hip AP and Lat radiographs are usually taken to confirm fixation and alignment of the femoral stem after hip arthroplasty. The measurement method introduced in this study can be utilized for predicting anterior thigh pain after hip arthroplasty.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.263-266
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• 1997

Three dimensional numerical model based on the finite element method(FEM) were developed to predict the mechanical behavior of hip implants. The purpose of this study is to investigate the stress distribution of two types of cementless total hip replacement femoral component -a straight stem and a curved stem, and to compare their effect on the stress shielding between two types by three dimensional finite element method. The authors analyzed von Mises stress in the cortex & stem and compared the stress between the straight and the curved stem. In comparison of stresses between two different design of femoral stem, there was 25% more decrease of stress in straight stem than curved stem in the medial cortex at proximal region. The straight stem had consistently much lower stresses than the curved stem throughout the whole medial cortex with maximum 70% reduction of stress. However, there was little change in stress between nature and 2 implanted femur throughout the lateral cortex. Stress of femoral stem was much higher in the straight stem than the curved stem up to 60%. The straight stem had more chance of stress shielding and a risk of fatigue fracture of the stem compared with the curved stem in noncement hip arthroplasty. In design of femoral stem still we have to consider to develop design to distribute more even stress on the proximal medial cortex.

• Biomaterials and Biomechanics in Bioengineering
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• v.3 no.2
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• pp.85-104
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• 2016

Stability and loosening of implanted femoral stems in Total Hip Replacement have been well established as barriers to the primary concerns of osseointegration and long term implant survival. In-vitro experiments and finite element modeling have for years been used as a primary tool to assess the bone stem interface with variable methodologies leading to a wide range of micromotion, interference fit and stress shielding values in the literature. The current study aims to provide a comprehensive review of currently utilized methodologies for in-vitro mechanical testing as well as finite element modeling of both micromotion and interference of implanted femoral stems. A total of 12 studies detailed in 33 articles were selected for inclusion. Experimental values of micromotion ranged from 12 to $182{\mu}m$ while finite element analysis reported a wider range from 2.74 to $1,277{\mu}m$. Only two studies were found that modeled bone/implant contact with consideration for interference fit. In studies evaluating stem micromotion in THA, the reference surface at the bone/stem interface should be well defined. Additionally, the amount of penetration considered should be disclosed and associated with bone density and roughness.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.81-92
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• 1996

The cementless fixation of bone ingrowth by porous coatings on artificial hip joint prostheses are replacing polymethylmethacrylate(PMMA) bone cement fixations. However, the major interests in the field of porous metal coating are environmental corrosivity accelerated by metal ion release, deterioration in the mechanical property of the coating, and the mechanical failure of the coatings as well as the substrate. Therefore, the selection of right materials for coatings and the development of porous coating techniques must be accomplished. Because of the existing problems in Ti and Ti alloys which are used extensively, this study is focused on the plasma spraying technique for coating on super stainless steel substrate. In order to determine the optimum conditions which satisfy the requirement for the porous coatings, under the plasma spraying, we selected the experimental parameters which extensively influenced on the characteristics of the coating through the pre-examination. Spray distance has been selected among 120, 160, and 200mm and primary gas flow rate among 70, 100, and 130 SCFH. Current and secondary gas($H_2$) flow rate was fixed at 400A, and 15 SCFH respectively. To understand the characteristics of the coatings, surface morphology, cross-sectional micro-structure, surface roughness, residual stress, and corrosion resistance were elucidated and the best conditions for the bone ingrowth improvement on artificial hip joint prostheses were found.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.3
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• pp.260-267
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• 2021

The purpose of this study was to experimentally investigate the effects of curing methods on the compressive strength and tensile behavior of alkali-activated slag-based fiber-reinforced composite with a water-to-binder ratio of 15%. Three kinds of mixtures according to the curing conditions were prepared and compressive strength and tension tests were performed. Test results showed that the compressive strength and the first cracking strength of composites decreased when high temperature curing and air curing were adopted, while tensile strain capacity of composites increased. It was also observed that crack spacing and crack width of composites decreased by applying high temperature and air curing.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.06a
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• pp.126-127
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• 2020

Recently, as interest in environmental issues increases, minimizing carbon dioxide generated during cement manufacturing is a problem to be solved. In order to solve such a problem, it is required to use an industrial by-product of recycled aggregate, blast furnace slag, and circulating fluidized bed boiler fly ash to replace it on the basis of geopolymer(=cementless). This study examines the characteristics of eco-friendly artificial stone according to the mixing ratio of geopolymer-based recycled aggregate. As a result of the experiment, when the addition rate of the alkali stimulant was 15% and the mixing ratio of the circulating aggregate was 70%, the flexural strength and compressive strength were the highest. Density and water absorption decreased as density of circulating aggregates increased and water absorption increased. However, when the mixing ratio of the circulating aggregate exceeded 70%, the flexural strength and compressive strength decreased. Therefore, in order to obtain strengths meeting the KS standards, the mixing ratio of recycled aggregate was set to 70%, and artificial stone was manufactured using industrial by-products.

• Hip & pelvis
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• v.34 no.2
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• pp.79-86
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• 2022

Purpose: The purpose of this study was to determine whether the direct anterior approach (DAA) can be applied to hemiarthroplasty for treatment of unstable femoral intertrochanteric fractures in elderly patients. Materials and Methods: We conducted a retrospective review of 34 cases (34 patients) who underwent bipolar hemiarthroplasty using a DAA from February 2019 to April 2020. The mean age of the patients was 82.68 years (range, 67-95 years). A cementless distal fixation hip system was used in all cases. Operation time, total amount of blood loss, intraoperative and postoperative fractures, infections, and reoperations were measured. The patients performed weight-bearing walking as tolerated immediately after surgery. Measurement of migration of the greater trochanter (GT) and progressive subsidence of the femoral stem was performed using follow-up radiographs. Results: The mean operative time was 83.50 minutes (range, 60-120 minutes). The mean amount of bleeding was 263.53 mL (range, 112-464 mL). Walking started a mean of 3.03 days (range, 3-4 days) after surgery. There was no case of progressive migration of the GT more than 5 mm even though it was not fixed. There were no cases of infection, dislocation, or reoperation. Conclusion: Bipolar hemiarthroplasty using the DAA for treatment of unstable femoral intertrochanteric fractures could be considered a useful option that provides many advantages in elderly patients.

• Hip & pelvis
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• v.34 no.4
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• pp.211-218
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• 2022

Purpose: We report on the 10-year clinical hip function and radiologic outcomes of patients who underwent hip arthroplasty using a COREN stem. Materials and Methods: A consecutive series of 224 primary cementless hip arthroplasty implantations were performed using a COREN stem between 2009 and 2011; among these, evaluation of 128 hips was performed during a minimum follow-up period of 10 years. The mean age of patients was 65.4 years (range, 40-82 years) and the mean duration of follow-up was 10.8 years (range, 10-12 years). Evaluation of clinical hip function and radiologic implant outcomes was performed according to clinical score, thigh pain, and radiologic analysis. Results: Dramatic improvement of the mean Harris hip score (HHS) from 59.4 preoperatively to 93.5 was observed at the final follow-up (P≤0.01). Stable fixation was demonstrated for all implants with no change in position except for one case of Vancouver type B2 periprosthetic femur fracture. A radiolucent line (RLL) was observed in 16 hips (12.5%). Thigh pain was observed in only two hips (1.6%) at the final follow-up. There were no cases of osteolysis around the stem. The survival rate for the COREN stem was 97.7%. Conclusion: Good long-term survival with excellent clinical and radiological outcomes can be achieved using the COREN femoral stem regardless of Dorr type.

• Journal of the Korea Institute of Building Construction
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• v.8 no.1
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• pp.57-62
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• 2008

Twelve mortars were mixed and tested to explore the effect of gypsum on the compressive strength development and shrinkage strain of alkali-activated mortars. Powder typed sodium silicate and ground granulated blast-furnace slag were employed as alkaline activator and source material, respectively, to produce cementless mortar. The main variables investigated were alkali quality coefficient combining the concentration of activator and main compositions in source material, and the adding amount of gypsum ranged between 1 and 5% with respect to the weight of binder. Initial flow, compressive strength development, modulus of rupture, and shrinkage strain behavior of mortar specimens were measured. In addition, the hydration production of alkali-activated pastes with gypsum was traced using X-ray diffraction and energy-dispersive X-ray analysis combined with scanning electron microscope image. Test results showed that the initial flow of slag-based alkali-activated mortar was little influenced by the adding amount of gypsum. On the other hand, the effect of gypsum on the compressive strength of mortar specimens was dependent on the alkali quality coefficient, indicating that the compressive strength increased with the increase of the adding amount of gypsum until a certain limit, beyond which the strength decreased slowly. Shrinkage strain of mortar tested was little influenced by the adding amount of gypsum because no ettringite as hydration product was generated. However, the adding of gypsum had a beneficial effect on reducing the microcrack in the alkali-activated mortar.

• Journal of Veterinary Clinics
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• v.31 no.2
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• pp.125-128
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• 2014

A 7-year-old, intact female Golden Retriever weighing 38 kg was referred for left coxofemoral joint luxation. On physical examination, pain and crepitus were noted atthe left hip joint during joint extension. Radiological examination revealed coxofemoral joint luxation and mild degenerative bone changes in the left hip joint. We performed minimally invasive arthroscopy-assisted reduction with TightRope$^{(R)}$ as a treatment option; however, the left coxofemoral joint was reluxated after one month postoperatively. We performed cementless total hip replacement (THR) of the luxated left coxofemoral joint. At tenmonths after surgery, the dog could sit, stand, walk normally and jump comfortably without lameness. The thigh girth measurement of the operated limb was 108.6% of the contralateral limb. Based on the present case, THR can be a successful treatment for coxofemoral joint luxation in dogs with failed coxofemoral joint reduction.