• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.651-652
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• 2006

The choice of suitable hip implant is one of important factors in total hip replacement (THR). In clinical view points, improper adaptation of hip implant might cause abnormal stress distribution to the bone, which can shorten the lifespan of replaced hip implant. Currently, interest in custom-designed hip implants has increased as studies reveals the importance of geometric shape of patient's femur in modeling and designing custom hip implants. In this study, we have developed the custom-designed hip implant models with various sizes in hip implant, and the stress distribution in the bone was analyzed using Finite Elements methods. It was found that minimizing the gap between implant stem and femoral cavity is crucial to minimize stress concentration in the bone.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.12
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• pp.6054-6068
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• 2017

In this paper, we defined the relative cross-sectional area of forearm cortical bone and investigated its correlation with hip bone mineral density values of total femur, femoral neck, femoral trochanter, femoral inter-trochanter and femoral ward's triangle, respectively. Based on the correlations, we established a linear transformation between the relative cross-sectional area of forearm cortical bone and each hip bone BMD. We obtained forearm images using CBCT and hip bone BMDs using dual-energy X-ray absorptiometry (DXA) for 28 subjects. We also investigated the optimal forearm region to provide the strongest correlation coefficient. We used the optimized forearm region to establish each linear transformation to estimate BMD values for total femur, femoral neck, femoral trochanter, femoral inter-trochanter and femoral ward's triangle from the relative cross-sectional area of forearm cortical bone, respectively. We observed the strong correlations with total femur (r=0.889), femoral neck (r=0.924), femoral trochanter (r=0.821), femoral inter-trochanter (r=0.867) and femoral ward's triangle (r=0.895), respectively. The strongest correlation was observed in the forearm mid-shaft regions. Our results suggest that the hip bone BMD values can be simply estimated from forearm CBCT images in a convenient sitting position without X-ray exposure on a hip including genital organs, and may be useful for screening osteoporosis.

• Journal of Biomedical Engineering Research
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• v.27 no.6
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• pp.402-408
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• 2006

The choice of suitable hip implant is one of important factors in the total hip arthroplasty (THA). In clinical view point, an improper adaptation of hip implant might induce abnormal stress distribution to the bone, which can shorten the lifespan of replaced hip implant. Currently, interest in the custom-designed hip implants has increased as studies reveal the significance of geometric shape of patient's femur in modeling and designing the implants. In this study, we have developed custom-designed hip implant models with various sizes, and analyzed the stress distribution in the bone and bone cement using the Finite Element Method. It was found that minimizing the gap between implant stem and femoral cavity is crucial to minimize the stress concentration in the bone.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.2 s.173
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• pp.329-337
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• 2000

An investigation has been performed to develop an analysis tool based on a nonlinear beam theory, which can be used to predict the long-term behavior of an artificial hip joint. The nonlinear behav ior of the femur arise from the coupled dependence of the bone density and the mechanical properties on each other. The beam theory together with its numerical algorithm is developed to take into account the nonlinear bone remodeling process of the femur that is long enough to be assumed as a beam. A piecewise linear curve for the bone remodeling rate is used in the bone remodeling theory and the surface area density of bone is modeled as the third order polynomial function of bone density. At each section of the beam, a constant curvature is assumed and the longitudinal strains are also assumed to vary linearly across the section. The Newton-Rhapson iteration method is used to solve the nonlinear equations for each cross section of the bone and a backward method is used to march along the time. The density and the remodeling signal ar, calculated along with time for the various time steps, and the developed beam theory has been verified by comparing with the results of finite element analysis of a remodeling bone with an artificial hip joint of titanium prosthesis subjected to uni-axial loads and pure bending moment. It is concluded that the developed beam theory can be used to predict the long-term behavior of the femur and thus to design the artificial hip prosthesis.

• 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.

• 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 For Composite Materials Conference
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• 1999.11a
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• pp.234-238
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• 1999

This study suggests the design of the functionally gradient composite, [0/90/0/core]$_s$ cross-ply laminate, to prevent stress concentration induced from the difference of rigidity between the bone and the artificial hip joint and to reinforce the wear property of the surface and the expectation of their mechanical properties. First, the four-point bending test is done about wet bones and dry bones to know the mechanical properties of the cortical bones. In result, the wet bone shows the viscoelastic behavior and the dry bone shows the elastic behavior. Moreover, we expect the properties of the proposed gradient composites as a function of carbon fiber volume fraction in each layer to apply Halpin-Tsai equation, CLPT(classical laminate plate theory), and Bernoulli beam theory etc. and decide the thickness ratio of each lamina in order to match Young's modulus of the anisotropic cortical bone with the proposed gradient composites.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.2
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• pp.203-207
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• 2008

Rapid destructive hip osteoarthritis is a rare subset of osteoarthritis with rapid destruction of the hip joint within months of the onset of symptoms. The entity simulates rheumatoid arthritis, septic arthritis, neuropathy or malignant bone tumor. We report a case of rapidly destructive coxarthrosis of the right hip joint initially misdiagnosed as a malignant bone tumor at outside hospital in a 80-year-old woman.

• Journal of radiological science and technology
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• v.25 no.1
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• pp.49-53
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• 2002

The femoral fracture is the most serious problem of old ages haying osteoporotic fractures. First of all, prevention to reduce the incidence of hip fracture and to identify the risk factor is essential subject. The purpose of this study is to investigate which geometric parameters of proximal femur are related to the hip fracture risk in old ages. Author analyzed the bone density and bone content of over 60 years old women who had suffered hip fracture (n=60) and non fracture groups (n=60). Author concluded that geometric measurements of proximal femoral part made on dual energy x-ray absorptiometry can predict hip fracture independently of bone mineral density.

• Proceedings of the KSME Conference
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• 2001.06c
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• pp.482-484
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• 2001

In orthopedics, hip arthroplasty is the operation that replaces damaged hip joint to artificial joint. In hip arthroplasty, quite better result can be achieved if robot is applied to machine cavity in bone, especially when cementless stem is used. So several kinds of robots were introduced for hip arthroplasty, but they used MRI, CT Scan, vision analysis and real time tracking of bone position for registration of robot. To overcome shortage of conventional robot surgery, gauge based registration method was proposed and small robot was designed. In this method, small robot is mounted on femur, and its position is determined by gauge registration method. Operation procedure was performed on model femur and result was analyzed. This robotic hip surgery system is expected to more adaptable in operation room.