• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1994년도 추계학술대회
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• pp.71-74
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• 1994

In cementless total hip arthroplasty(THA), an initial stability of the femoral component is mandatory to achieve bony ingrowth and secondary long term fixation. Bone ingrowth depends strongly on relative micromotion and stress distributions at the interface. Primary stability of the femoral component can be obtained by minimizing the magnitude of relative micromotions at bone-prosthesis interface, Hence an accurate evaluation of interface behavior and stress/strain fields in the bone implant system may be relevant for better understanding of clinical situations and improving THA design. However, complete evaluation of load transfer in the bone remains difficult to assess experimentally, Hence, recently finite element method (FEM) was introduced in orthopaedic research field to fill the gap due to its unique capacity to evaluate stress in structure of complex shape, loading and material behavior. The authors developed the 3-dimensional numerical finite element model which is composed of totally 1179 elements off and 8 node blick. We also analyzed the micromotions at the bone-stem interface and mechanical behavior of existing bone prosthesis for a loading condition simulating the single leg stance. The result indicates that the values of relative motion for this well fit Multilock stem were $150{\mu}m$ in maximum, $82{\mu}m$ in minimum, and the largest relative motion developed in medial region of proximal femur with anterior-posterior direction. The proximal region of the bone was much larger in motion than the distal region and the stress pattern shows high stress concentration on the cortex near the tip of the stem. These findings indicates that the loading in the proximal femoral bone in the early postoperative situation can produce micromotions on the interface and clinically cementless TEA patient should not be allowed weight bearing strictly early in the postoperative period.

• 한국임상수의학회지
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• 제31권2호
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• pp.121-124
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• 2014

7년령의 암컷 진도견이 뒷다리 파행을 주증으로 내원하였다. 신체검사상에서 대퇴관절의 신전시 염발음과 통증을 보였고 방사선 검사상에서 양측 대퇴 관절 이형성증에 의한 퇴행성 관절염과 오른쪽 부위의 전측 대퇴 탈구를 보여 주었다. 오른쪽 관절의 탈구의 치료를 위해 인공 대퇴 관절 전치환 술을 실시하였다. 수술 중 오른쪽 등쪽 관절절구의 결손으로 인한 인공 관절절구 컵의 탈구의 위험성을 확인하고 등쪽 관절절구의 결손을 잠김 금속판과 골시멘트를 이용하여 보강하였다. 수술 후 환자는 성공적인 결과를 보여주었다. 또한 오른쪽 대퇴관절의 관절 운동 범위과 근육량이 개선 되었다. 등쪽 관골절구 결손을 가진 대퇴 관절 탈구에서 잠김 금속판과 골시멘트 이용하여 인공 대퇴관절 전치환술을 성공적으로 실시하였다. 본 증례와 같은 수술 기법이 등쪽 관골절구 결손이 있을 시 사용될 수 있다고 생각된다.

• Advances in Computational Design
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• 제4권3호
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• pp.295-305
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• 2019

The sealing cement of total hip arthroplasty is the most widely used binder in orthopedic surgery for anchoring implants to their recipient bones. Nevertheless, this latter remains a fragile material with weak mechanical properties. Inside this material cracks initiate from cavities. These cracks propagate under the effect of fatigue and lead to the failure of this binder and consequently the loosening of the prosthesis. In this context, this work consists to predict the position of cracks initiation and their propagations path using the Extended Finite Element Method (XFEM). The results show that cracks can only be initiated from a sharp edges of an ellipsoidal cavity which the ratio of the minor axis over the major axis is equal to 0.1. A maximum crack length of 19 ?m found for a cavity situated in the proximal zone position under a static loading. All cracks propagate in same(almost) way regardless of the cavity(site of initiation) position and its inclination in the proximal zone.

• Advances in biomechanics and applications
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• 제1권3호
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• pp.187-210
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• 2014

With the goal of increasing the survivorship of the prosthesis and anticipating primary stability problems of new prosthetic implants, finite element evaluation of the micromotion, at an early stage of the development, is mandatory. This allows assessing and optimizing different designs without manufacturing prostheses. This study aimed at investigating, using finite element analysis (FEA), the difference in the prediction of the primary stability of cementless hip prostheses implanted into a $Sawbones^{(R)}$ 4th generation, using the manufacturer's mechanical properties and using mechanical properties close to that of human bone provided by the literature (39 papers). FEA was carried out on the composite $Sawbones^{(R)}$ implanted with a straight taper femoral stem subjected to a loading condition simulating normal walking. Our results show that micromotion increases with a reduction of the bone material properties and decreases with the augmentation of the bone material properties at the stem-bone interface. Indeed, a decrease of the cancellous Young modulus from 155MPa to 50MPa increased the average micromotion from $29{\mu}m$ up to $41{\mu}m$ (+42%), whereas an increase of the cancellous Young modulus from 155MPa to 1000MPa decreased the average micromotion from $29{\mu}m$ to $5{\mu}m$ (-83%). A decrease of cortical Young modulus from 16.7GPa to 9GPa increase the average global micromotion from $29{\mu}m$ to $35{\mu}m$ (+33%), whereas an increase of the cortical Young modulus from 16.7GPa to 21GPa decreased the average global micromotion from $29{\mu}m$ to $27{\mu}m$ (-7%). It can also be seen that the material properties of the cancellous structure had a greater influence on the micromotion than the material properties of the cortical structure. The present study shows that micromotion predicted at the stem-bone interface with material properties of the $Sawbones^{(R)}$ 4th generation is close to that predicted with mechanical properties of human femur.

• 한국임상수의학회지
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• 제34권6호
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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.

• Journal of Veterinary Science
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• 제22권4호
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• pp.58.1-58.13
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• 2021

Background: The morphometry of the acetabulum is one source of information that assists in the clinical diagnosis of the hip and influences the proper selection of a prosthesis, reducing post-operative complications such as those seen in total hip replacement (THR). However, acetabular parameters in small-breed dogs are rarely reported. Objectives: To investigate acetabular parameters using radiography and computed tomography (CT) in small-breed dogs with Maltese and Shih Tzu dogs used as model breeds. Methods: Standard calibrated, extended hip radiographs and CT images were obtained. Subsequently, acetabular width (AW) in various directions was measured using radiography and CT, whereas acetabular depth (AD) was obtained by CT. Acetabular index (AI) is a ratio calculated from AD and AW. Results: The values of AW and AD were much higher in Shih Tzu than in Maltese dogs. Male Shih Tzus showed higher values of these parameters than females, while sex-based differences in most of the parameters could not be detected in Maltese. Body weight, but not age, influenced AWs and ADs. While AWs and ADs were influenced by several factors, AI was comparable among the assessed factors and between Maltese and Shih Tzu dogs (p = 0.172; 31.42 ± 1.35 and 32.60 ± 1.80, respectively). Also, AI did not vary with breed, sex, or body size. Conclusions: The obtained radiographic and CT acetabular parameters could be useful as guidelines for evaluating the acetabulum of small-breed dogs in clinical practice.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 2000년도 Proceedings of 2000 International Nano Crystals/Ceramics Forum and International Symposium on Intermaterials
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• pp.165-177
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• 2000

Ceramic on ceramic total hip prostheses are developed to apply to young patients because lifetime of polyethylene joint prostheses is limited by loosening due to biological response. As mating faces of all-ceramic joint must be highly conformed to reduce stress concentration, wear properties of flat surfaces are investigated in this study. Through wear tests at 2 MPa of contact pressure and 36 mm/s of sliding velocity, alumina and silicon carbide keep low wear rate, high hardness and smooth surface. Soft surface film was detected after the test in bovine serum. This suggests that boundary lubrication is effective to reduce wear in all-ceramic joint.

• 대한정형외과학회지
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• 제56권1호
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• pp.42-50
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• 2021

목적: 종양인공관절 주위 골절은 안정된 고정의 어려움과 골유합 후에도 골질 약화로 해리 및 재골절 위험이 많다. 피질골 지주 중첩 동종골 이식술을 종양인공관절 주위 골절에 적용하면 내고정도 쉽고, 골유합 기간도 단축되며, 합병증도 줄일 수 있을 것이라고 생각하였다. 본 연구는 종양인공관절 주위 골절 27예(30 골절)의 골절의 양상과 치료 후 재건 술식에 따른 생존율 및 합병증, 중첩 동종골 이식술 추가 여부에 따라 골유합 기간 및 기능적 결과가 차이가 있는지 분석하였다. 대상 및 방법: 골절 치료 시 판형 동종골 이식을 한 군 16예와 시행하지 않은 군 14예를 비교하였다. 분석항목은 종양인공관절 치환술부터 골절까지 기간, 골절의 양상, 골유합 기간 차이, 합병증, 및 기능적 결과를 기술하였다. 결과: 골절 양상은 unified classification system (UCS) B형이 21예(70.0%, 21/30)로 가장 많았으며 그 중 B1이 14예(46.7%, 14/30), B2가 1예(3.4%, 1/30), B3가 6예(20.0%, 6/30)였고 C형이 9예(30.0%, 9/30)였다. Kaplan-Meier 법에 의한 30 재건 부위의 5년, 10년 생존율은 각각 84.5%±4.18%, 42.2%±7.83%였다. 전체 30예의 골유합 기간은 평균 5.1개월(범위, 2.0-11.2개월)이었다. 동종골 이식군은 평균 3.5개월(범위, 2.0-6.26개월)로 고식적 고정군의 평균 7.2개월(범위, 4.0-11.2개월)보다 짧았다(p<0.0001). 최종 기능평가상 동종골 이식군은 평균 26.1점으로 고식적 고정군의 평균 20.9점보다 높았다(p<0.0001). 합병증은 4예로 모두 동종골을 사용하지 않은 군에서 있었다. 결론: 종양인공관절 주위 골절은 드물고 골유합도 비교적 잘 이루어지나 유합 후 합병증 최소화가 중요하다. 판형 중첩 동종골 이식술은 골유합 기간을 단축, 골질 증가, 해리위험성 감소 효과가 있으며 종양인공관절 주위 골절에 유용한 방법이다.

• 한국전문물리치료학회지
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• 제3권1호
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• pp.65-72
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• 1996

The purpose of this study was to introduce rotation-plasty procedure and prosthetic ambulation training. The recent development of chemotherapy and diagnostic facility have permitted the orthopaedic surgeons to try limb saving procedures rather than amputations for the treatment of the malignant bone tumors. If the tumors around the knee joint were treated by mid-thigh amputation or hip disarticulation, it would impose the client with a great handicap for rehabilitation. Rotation-plasty procedure was first done by Borggreve, in 1930 for the congenital short femur. Recently this procedure was used a malignant bone tumor at the distal femur by Kotz and Salzer in 1982. In spite of its cosmetic problem of the distal stump, this procedure has the great functional advantage of converting the above-knee amputation to the below-knee amputation. The inverted foot was also good to control the prosthesis as a below-knee stump and heel functioned as a patella to support the body weight. This 15 years old girl case was had rotation-plasty due to osteosarcoma of the distal femur with 3rd postoperative chemotherapy, and admitted to Yonsei rehabilitation hospital for prosthetic ambulation training. Then, the case had excellent functional results of prosthetic ambulation training with rotaion-plasty after 3 months.

• 한국방사선학회논문지
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• 제16권3호
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• pp.281-288
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• 2022

본 연구에서는 고관절에 금속삽입물(Metal implant)이 삽입되어 있는 환자를 대상으로 일반적인 CT검사(Before MAR) 영상과 MAR을 사용하여 얻어진(After MAR) 영상을 4개의 알고리즘(Soft, Standard, Detail, Bone)에 적용하여 Noise, SNR, CNR을 비교 분석하여 정량적 평가로 최적의 알고리즘을 알아보고자 하였다. 분석방법으로는 4개의 알고리즘으로 재구성한 영상에 이미지 분석과 영역 및 픽셀값을 계산할 수 있는 Image J 프로그램을 사용하였다. Noise, SNR, CNR을 구하기 위해 측정부위를 영상에서 금속삽입물이 가장 인접해 있는 Bone(궁둥뼈, ischium)을 지정하여 HU mean값과 HU SD값을 구하고 배경잡음(Background)은 주위 근육으로 하였다. 관심영역(region of interest, ROI)은 뼈의 크기를 감안하여 동일하게 15×15 mm로 지정하였으며 SNR과 CNR의 값은 주어진 식에 의거하여 산출하였다. 결과적으로 노이즈는 After MAR, Soft 알고리즘에서 노이즈가 가장 낮게 나타났으며, SNR, CNR은 Before MAR, Soft 알고리즘이 가장 높게 나타났다. 따라서 Soft 알고리즘이 고관절 금속삽입술 CT에 가장 적절한 알고리즘으로 판단된다.