• 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.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.6
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• pp.680-685
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• 2012

Ceramic femoral heads are now widely used in Total Hip Replacement (THR). Due to their high biocompatibility and low ductility, ceramic femoral heads are considered to be suitable for young and active patients. However, as in testing the mechanical stability of the femoral head, the conventional proof test (standard ISO 7206-10) has its limit of showing axisymmetric stress distribution on the contact surface, while non-uniformed stress distribution is expected after THR. Since non-uniformed stress distribution can result in the increased probability of ceramic femoral head fracture, it is considerable to evaluate the stress distribution in vivo-like conditions. Therefore, this study simulated the ceramic femoral heads under in vivo-like conditions using finite element method. The maximum stress decreased when increasing the size of the femoral head and stress distribution was concentrated on superior contact surface of the taper region.

• Journal of Biomedical Engineering Research
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• v.29 no.3
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• pp.212-221
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• 2008

The total hip replacement (THR) has been used as the most effective way to restore the function of damaged hip joint. However, various factors have caused some side effects after the THR. Unfortunately, the success of the THR have been decided only by the proficiency of surgeons so far. Hence, It is necessary to find the way to minimize the side effect caused by those factors. The purpose of this study was to suggest the definite data, which can be used to design and choose the optimal hip implant. Using finite element analysis (FEA), the biomechanical condition of bone cement was evaluated. Stress patterns were analyzed in three conditions: cement mantle, procimal femur and stem-cement contact surface. Additionally, micro-motion was analyzed in the stem-cement contact surface. The 3-D femur model was reconstructed from 2-D computerized tomography (CT) images. Raw CT images were preprocessed by image processing technique (i.e. edge detection). In this study, automated edge detection system was created by MATLAB coding for effective and rapid image processing. The 3-D femur model was reconstructed based on anatomical parameters. The stem shape was designed using that parameters. The analysis of the finite element models was performed with the variation of parameters. The biomechanical influence of each parameter was analyzed and derived optimal parameters. Moreover, the results of FE A using commercial stem model (Zimmer's V erSys) were similar to the results of stem model that was used in this study. Through the study, the improved designs and optimal factors for clinical application were suggested. We expect that the results can suggest solutions to minimize various side effects.

• Journal of Biomedical Engineering Research
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• v.31 no.6
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• pp.449-455
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• 2010

A ceramic articulating system in total hip replacement thought to be superior to metal-on-polyethylene due to its extremely low coefficient of friction and potential for high resistance to wear. But ceramic is brittle, which makes it mechanically and theoretically susceptible to fracture under certain mechanical conditions. In the current study, nine different models of ceramic ball heads were mechanically evaluated using 3D finite element(FE) analyses. It was found that the maximum stress in all ceramic models was lower than ceramic flexural strength, and it satisfied the requirements of the FDA Gaudience for artificial hip implant. Thus, ceramic ball head models introduced in the current study could be mechanically safe for clinical applications.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.11
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• pp.2777-2785
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• 2000

In cementless total hip replacement(THR), an initial stability of the femoral component is important to long term fixation of femoral stem. The intial stability has close relationship with the relative displacement of prosthessis and sponge bone at the proximal of femur. After implantation of the proshesis, the surrounding bone is partially shielded from load carrying and starts to resorb. Stress shielding is the cause of the loss of proximal bone. Assessing stress distribution of femur is important to predict stress shielding. The initial stability and the stress shielding were investigated for two loading conditions approximating a single leg stance and a stair climbing. Three types of stems were studied by the finite element method to analyze the biomechanical effects of distal filling of cementless femoral stems. Three types of stems empolyed are a distal filling stem, a distal flexible stem, and a distal tapered stem.

• Journal of Veterinary Clinics
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• v.34 no.6
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• pp.463-466
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• 2017

A 3-year-old, 26 kg, castrated male Chow Chow was presented for assessment of weight-bearing lameness of the left hind limb. The patient had a history of triple pelvic osteotomy on the left side to correct hip dysplasia 2 years prior to his presentation of clinical signs and underwent total hip replacement on the right coxofemoral joint 1 year later. Upon physical examination, pain and crepitus were noted on the left hip joint during extension. Radiological examination revealed coxofemoral joint subluxation and moderate degenerative bone changes on the left hip joint and pelvic axis, which relates to acetabular angles that were changed after triple pelvic osteotomy (TPO). Preoperative computed tomography was used for 3-dimensional printing to establish an accurate surgical plan. The changed angles of the acetabulum after TPO were evaluated, and rehearsal surgery was performed using a 3-demensional printing bone model. Three months after the THR surgery, the function of the affected limb had improved, with no lameness. Complications, such as luxation and implant failure, were not observed until 6 months after the operation. Accurate evaluation of acetabulum angles and rehearsal surgery using a 3D-printed bone model is effective for total hip replacement after unsuccessful TPO.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1419-1420
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• 2011

• Journal of Veterinary Clinics
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• v.34 no.6
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• pp.454-458
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• 2017

A Maltese (case 1) and a Pomeranian (case 2) presented with acute right and left hind limb weight-bearing lameness. On physical examination, they exhibited severe pain and crepitus on the coxofemoral joint of affected hind limb. In addition, decreased thigh girth measurements were noted compared with the opposite leg. Radiological exam revealed necrotic areas in the femoral head of affected hind limb. These dogs were diagnosed with Legg-$Calv{\acute{e}}$-Perthes disease (LCPD). The dogs underwent micro total hip replacement (THR). After surgery, at 3 years (case 1) and 7 months (case 2), both dogs recovered normal activity. The thigh girth and lameness scores were apparently improved in the affected limbs of both dogs. No complications of prosthesis implants, such as loosening, were noted. The clinical outcomes of these cases indicate that dogs with LCPD can be successfully treated with micro THR and have a good prognosis immediately after surgery.

• Structural Engineering and Mechanics
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• v.87 no.6
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• pp.575-583
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• 2023

The postoperative period for a carrier of total hip prosthesis (THP), especially in the first months, remains the most difficult period for a patient after each operation, even if traumatologist surgeons want the relief and success of their operations. In this investigation, selected three of the daily activities for a wearer of total hip replacement (THR), such as sitting in a chair, lifting a chair, and going downstairs, and was performed a numerical simulation by finite elements based on experimental data by Bergmann (Bergmann 2001) in terms of effort for each activity. Different stresses have been extracted, and a detailed comparison between two activities with different induced stresses such as normal, tensile, and compressive shear stresses.

• Journal of Biomedical Engineering Research
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• v.22 no.6
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• pp.519-526
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• 2001

At present. about 0.3 million and more THRs (Total Hip Replacement) in a rear are being done worldwide. The increase in mechanical failure with the increase in THR, required more revisions. Revisions compensate mainly the wear of the artificial joint frictional surface and the loosening of the cup and stem. According to recent researches, loosening is mainly due to wear debris UHMWPE (Ultra High Molecular Weight Polyethylene) from frictional surfaces . To overcome the wear problems associated with artificial joint materials , new surface structures with regular Patterns were designed and fabricated The lubrication Properties were examined to evaluate the wear of the frictional surfaces. The surface structure manifested a Pattern of "dents" with a 0.2-1.0 mm of diameter and 0.6-2.0 mm of Pitch. From the friction test of the SUS316L vs UHMWPE using the frictional tester, we found that the lubrication Performance was improved due to of drastically reduced amount of abrasion. There were optimum sizes for the diameter and the pitch of the Pattern. The results demonstrated that the lubrication properties could be improved by Patterning of the frictional surfaces. The surface Patterning was effective in preventing wear of the frictional surfaces, and the life of an artificial joint could be extended with such Patterning.