• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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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.

• 대한의용생체공학회:의공학회지
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• 제27권6호
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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.

• 한국CDE학회논문집
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• 제13권3호
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• pp.200-208
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• 2008

Total Hip Replacement(THR) is a surgical procedure that replaces a diseased hip joint with a prosthesis. A plastic or metal cup forms the socket, and the head of the femur is replaced by a metal ball on a stem placed inside the femur. Due to the various types and shapes of human hip joint of every individual, a selected commercial implant sometimes may not be the best-fit to a patient, or it cannot be applied because of its discrepancy. Hence extracting geometry parameters of hip joint is one of the most crucial processes in designing custom-made implants. This paper describes the framework of a methodology to extract the geometric parameters of the hip joint. The parameters include anatomical axis, femoral head, head offset length, femoral neck, neck shaft angle, anteversion, acetabulum, and canal flare index. The proposed system automatically recommends the size and shape of a custom-made hip implant with respect to the patient's individual anatomy from 3D models of hip structures. The proposed procedure creating these custom-made implants with some typical examples is precisely presented and discussed in this paper.

• Hip & pelvis
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• 제30권4호
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• pp.276-281
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• 2018

Pseudotumors are not uncommon complications after total hip arthroplasty (THA) and may occur due to differences in bearing surfaces of the head and the liner ranging from soft to hard articulation. The most common causes of pseudotumors are foreign-body reaction, hypersensitivity and wear debris. The spectrum of pseudotumor presentation following THA varies greatly-from completely asymptomatic to clear implant failure. We report a case of pseudo-tumor formation with acetabular cup aseptic loosening after revision ceramic-on-metal hip arthroplasty. The patient described herein underwent pseudotumor excision and re-revision complex arthroplasty using a trabecular metal shell and buttress with ceramic-on-polyethylene THA. Surgeons should be aware of the possibility of a pseudotumor when dealing with revisions to help prevent rapid progression of cup loosening and implant failure, and should intervene early to avoid complex arthroplasty procedures.

• 한국CDE학회논문집
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• 제21권4호
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• pp.426-432
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• 2016

Designing a morphologically well-fitted hip implant to a patient anatomy is desirable to improve surgical outcomes since a commercial ready-made hip implant may not well conform to the patient joint. In this study, biomechanical stability of patient-specific hip implants with two different stem lengths was compared and discussed using a 3D finite element analysis (FEA). The FEA results in this study showed that an increase in stem length brings about more the peaked von-Mises stress (PVMS) in the prosthesis and less in the femur. However the decrease in von-Mises stress in the femur causes stress shielding phenomenon that usually leads to considerable bone resorption. Although, in biomechanical stability point of view, this work recommends the use of smaller stems, the length of stem must be determined by considering both the von-Mises stress and the stress-shielding phenomenon.

• 열처리공학회지
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• 제36권4호
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• pp.215-222
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• 2023

3Y-TZP (3 mol% yttria-stabilized tetragonal zirconia polycrystals, 3Y-TZP) ceramics are emerging as dental implant materials due to their superior optical and mechanical properties as well as excellent biophysical properties, in spite of low bioactivity. In this study, we investigated to sintered properties and microstructural defects of dental zirconia implants fabricated by ceramic injection molding and post-HIP (Hot isostatic pressing) processing and analyzed the processing parameters related with the obtainment of its high sinterd density. Sintered and microstructural parameters, i.e, apparent density, grain size and phase composition of zirconia implants fabricated by injection molding were dependent on the fixtute size and implant type. Maximum sintered density of 99.2% and minimum grain size of 0.3-0.4 ㎛ were obtained from large-scaled 2-body sample. In 1-body ceramic implant, high sintered density of 99.5% was obtained, but it had a little monoclinic phase and wide grain size distribution.

• Journal of Trauma and Injury
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• 제37권1호
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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.

• 한국정밀공학회지
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• 제26권7호
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• pp.31-37
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• 2009

• Biomaterials and Biomechanics in Bioengineering
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• 제5권1호
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• pp.11-23
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• 2020

Total hip prosthesis is used for the patients who have hip fracture and are unable to recover naturally. To de-sign highly durable prostheses one has to take into account the natural processes occurring in the bone. Finite element analysis is a computer based numerical analysis method which can be used to calculate the response of a model to a set of well-defined boundary conditions. In this paper, the static load analysis is based, by se-lecting the peak load during the stumbling activity. Two different implant materials have been selected to study appropriate material. The results showed the difference of maximum von Misses stress and detected the frac-ture of the femur shaft for different model (Charnley and Osteal) implant with the extended finite element method (XFEM), and after the results of the numerical simulation of XFEM for different was used in deter-mining the stress intensity factors (SIF) to identify the crack behavior implant materials for different crack length. It has been shown that the maximum stress intensity factors were observed in the model of Charnley.

• 대한의용생체공학회:의공학회지
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• 제25권6호
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• pp.455-464
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• 2004

현재 인공고관절 전치환 수술 과정의 높은 난이도 때문에 숙련된 의사의 경험에 상당히 의존하고 있는 실정이다. 비구컵과 대퇴 임플란트의 위치 선정은 수술의 성공 여부와 밀접한 관계가 있지만 아직까지는 의사의 눈대중에 의해 이루어지는 경우가 많다. 이러한 이유로 인하여 인공삽입물(비구컵, 대퇴시스템) 삽입의 정확성이 낮아서 재치환술을 해야 하는 경우가 자주 발생한다. 본 연구에서는 환자 골반골(pelvis)과 대퇴골(femur)의 3차원적인 고유 기하학적 정보를 이용하는 모사 시술을 통하여 비구컵과 대퇴 임플란트의 정확한 위치를 선정하는 방법을 결정하였다. 이를 위하여 우선 비구컵의 위치 변화에 따른 대퇴 전염각 및 대퇴 경간각의 변화 양상을 살펴보았고 또한 대퇴 임플란트의 삽입 위치에 따른 대퇴스템 경부 길이 및 대퇴스템각의 변화 양상을 조사하였다. 본 연구에서 다양한 모사 시술을 통한 기하학적 정보의 분석 결과 비구컵과 대퇴 임플란트의 정확한 위치 선정이 가능함을 확인하였다. 본 연구의 모사 시술 방법을 이용하여 의사가 인공고관절 수술을 선행한다면 수술의 정확도와 숙련도를 향상시킬 수 있을 것으로 기대된다.