Primary Stability Evaluation of a Hip-Joint Implant Systems according to Different Surgical Methods and Bone Densities under Cyclic Loading Condition

김상영,박수,박윤수,김재원,석창성 한국정밀공학회 2015 International Journal of Precision Engineering and Vol.16 No.6

Artificial joints are used when joints lose their function. The artificial joint is placed at the correct position by surgery of an expert surgeon or robot-assisted surgery. The surrounding bone grows and bonds to the surface of the artificial joint after the insertion without any adhesive. The primary stability is defined as stability before the fixation of the artificial joint, and stability after the fixation is called the long-term stability. In case of a femur-implant system, the primary stability evaluation is performed by the relative displacement measurement under a repeated load immediately after the insertion of the artificial joint. For more accurate stability evaluation, the accurate measurement of the penetration displacement of the artificial joint to the bone and the rotation angle of the artificial joint is essential. In this study, we used a relative displacement measurement method for the primary stability evaluation of the femur-implant system. By using this method, we comparatively evaluate the primary stability for different surgical methods and stiffness of the cadaver femur-implant itself.

인공뼈 및 인공관절 연구개발 동향

박기동,배진우,이승진,김상우 한국생체재료학회 2004 생체재료학회지 Vol.8 No.4

Autografting and allografting, well-known methods as a conventional bone replacement, have several disadvantages such as infections, complicating diseases and low efficacy in bone formation. Also, artificial joint replacement using polymers and ceramics have been extensively performed an operation but have some limitations in patient conditions and the abrasion degree of materials. Therefore, the clinical requirement for new bone substitutes and joint to replace and restore the function of natural bone and joint damaged by accidents or diseases has been significantly increased in orthopedic field. The annual growth rate of world market in orthopedic field runs into approximately 14% as the astronomical level and the market size in most countries has been rapidly grown. In Korea, the rate of dependence on imports of artificial bone and joint is very high. However, the localization of artificial bone and joint have great potentials in the effective development and investment through academic industrial collaboration with high level of the related-technology. This review outlines the R&D trends and the market size with the basic concepts for development of artificial bone and joint.

인공절리에 의한 암석의 파쇄도 평가

노유송,석철기,박훈 대한화약발파공학회 2018 화약발파 Vol.36 No.4

Since the rock fragmentation by blasting can affect the subsequent processes including loading, hauling and secondary crushing, its control is essential for the assessment of blasting efficiency as well as production cost. In this study, we were analyzed the rock fragmentation by the direction of artificial joint. The underground blasting experiments were performed after forming the vertical and horizontal artificial joints. The blast fragmentation was conducted by the split-desktop which is a 2D image processing program. As a result, it was found that the horizontal artificial joint was evaluated to have lower overall the size of muck pile than the vertical artificial joint and the distribution of the size of muck pile was varied. It is possible that the direction of artificial joint could suppress the occur of oversize muck pile and control to a certain size or less. 발파에 의한 암석의 파쇄도는 적재, 운반과 2차 파쇄로 이어지는 후속공정에 직접적인 영향을 미치므로파쇄도의 조절은 발파 효율성과 생산비용을 평가하는데 필수적이다. 본 연구에서는 인공절리의 방향에 따른 암석의 파쇄도에 대해 분석하였다. 갱내 암반에 수직 및 수평인공절리를 생성한 후 발파실험을 수행하였다. 생성된암석파쇄물의 입도분포는 2차원 영상해석 프로그램인 split-desktop으로 평가하였다. 평가결과 수평인공절리가 수직인공절리에 비해 전체적인 암석파쇄물의 크기가 작게 평가되었고, 다양한 크기로 암석파쇄물이 분포하였다. 인공절리의 방향에 따라 대괴발생을 억제하고 암석파쇄물을 일정한 크기 이하로 조절 할 수 있을 것으로 판단된다

고관절용 인공관절 시스템의 안정성 평가

석승휘(Sung Fie Seok),박수(Soo Park) 대한기계학회 2012 大韓機械學會論文集A Vol.36 No.9

인공관절은 관절부의 뼈가 파괴되거나 관절 손상을 입어 관절로서의 기능을 할 수 없게 된 경우에 사용된다. 고관절용 인공관절 시스템의 일차안정성을 평가하기 위해서는 인공관절이 삽입된 직후 인공관절에 반복하중을 가하여 대퇴골과 인공관절 사이의 상대변위를 측정하게 된다. 이때, 정확한 안정성을 평가하기 위해서는 인공관절이 대퇴골을 파고드는 변위와 대퇴골에서 인공관절이 회전한 각의 변화량을 정확히 측정하여야 한다. 본 연구에서는 고관절용 인공관절 시스템의 일차안정성을 평가하기위해 새로운 상대 변위측정 방식을 제안하고 이를 이용하여 수술 방법의 차이 및 대퇴골 자체 강성의 차이에 따른 일차 안정성을 사체에서 얻은 대퇴골 실험을 통해 비교 평가하였다. Artificial joints are used when joints lose their function because of either the destruction or damage of the composing bones of the joints. To evaluate the primary stability of a femur-implant system, the relative displacement caused by a repeated load is measured immediately after the insertion of the artificial joint. For more accurate stability evaluation, the accurate measurement of the penetration displacement of the artificial joint to the bone and the rotation angle of the artificial joint is essential. In this study, to evaluate the primary stability of the femur-implant system, we propose a new relative displacement measurement method. By using this new method, we comparatively evaluate the primary stability for various surgical methods and the varying stiffness of the cadaver femur-implant itself.

Failure load prediction of adhesively bonded GFRP composite joints using artificial neural networks

Bahadır Birecikli,Ömer Ali Karaman,Selahattin Bariş Çelebi,Aydın Turgut 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.11

There are different process parameters of bonding joints in the literature. The main objective of the paper was to investigate the effects of bonding angle, composite lay-up sequences and adherend thickness on failure load of adhesively bonded joints under tensile load. For this aim, the joint has four types of the bonding angles 30°, 45°, 60° and 75°. Composite materials have three different lay-up sequences and various thicknesses. The bonding angle, adherend thickness and composite lay-up sequences lead to an increase of the failure load. Moreover, artificial neural network that utilized Levenberg-Marquardt algorithm model was used to predict failure load of bonding joints. Mean square error was put into account to evaluate productivity of ANN estimation model. Experimental results have been consistent with the predicted results obtained with ANN for training, validation and testing data set at a rate of 0.998, 0.997 and 0.998 respectively.

지속적인 하중이 작용되는 인공무릎관절의 구조상의 응력분포에 관한 연구

황규완,조재웅 한국기계기술학회 2014 한국기계기술학회지 Vol.16 No.4

This study investigates area and size of stress part appeared when the continuous loads are applied at artificial joint. Upper and lower parts composed with polyethylene shock absorber and titanium alloy are applied with the loads. The configurations of stress distribution near the hole of support to fix the frame are investigated and secured as through this study. As the result of this study, the stress is concentrated from the edge end of upper artificial joint. The crack is initiated at this point. This analysis result is similar with the instance of tissue corruption due to the damage of artificial joint.

SPECT/CT에서 인공고관절에 대한 감쇠보정지도(Attenuation Map)의 매개변수 변화에 따른 금속 인공물(Metal Artifact)의 영향 평가

김상규,김정열,박민수,조승현,임한상,김재삼,Kim, Sang Gyu,Kim, Jung Yul,Park, Min Soo,Jo, Seung Hyun,Lim, Han Sang,Kim, Jae Sam 대한핵의학기술학회 2014 핵의학 기술 Vol.18 No.2

CT를 기반으로 감쇠보정이 시행되는 SPECT/CT 검사에서는 금속 삽입물에 의한 선속경화현상으로 인접한 부위의 과대평가를 유발하며, 영상의 질을 저하시킨다. 이에 대해, 본 연구에서는 인공고관절이 삽입된 팬텀을 이용하여 감쇠보정지도의 매개변수 변화에 따른 금속 인공물이 SPECT/CT 영상에 미치는 영향을 알아보고자 한다. SPECT/CT 장비는 Siemens사의 Symbia T16을 사용하였다. SPECT/PET 팬텀에 인공고관절을 삽입하고, CT영상에서 Bright Streak 영역에 직경 17 mm의 구를 배후방사능 대비 8배가 되도록 Tc-99m을 채웠다. 이후 감쇠보정지도에서 Wide Beam Coefficient[수동모드(0.1~0.9), 자동모드]변화에 따른 열소와 배후방사능의 계수를 측정하였고, 고관절의 유무에 따라 Metal과 Non-Metal의 병소 대 배후방사능 비(Region to Background Ratio, RBR)를 산출 및 비교 분석하였다. 수동모드의 값이 증가할수록 Metal과 Non-Metal의 열소 계수는 증가하는 경향을 나타냈으며, 수동모드 0.4와 0.5에서 두 군과의 열소 계수비가 가장 일치하게 나타났다(수동모드 0.4=1.001, 0.5=0.999). 또한 $RBR^{Metal}$과 $RBR^{Non-Metal}$의 비는 자동모드에서 1.135이였고, 수동모드 0.4와 0.5에서 통계적으로 유의한 차이를 보이지 않았다(0.4=0.999, 0.5=1.028, p=0.78). 감쇠보정지도에서 Wide Beam Coefficient의 자동모드는 13.52% 과 보정 되는 것을 알 수 있었으며, 수동모드 중 0.4와 0.5에서 인공물에 의한 과 보정을 최소화 할 수 있었다. 이를 활용하여 환자에게 적용하기 위해서는 추가적인 연구가 이루어져야 할 것이며, 고관절전치환술 환자의 인공고관절 주변에서 금속 인공물에 의한 과 보정을 감소시켜 진단능을 향상시킬 수 있을 것으로 사료된다. Purpose SPECT/CT scan to be performed attenuation correction on the basis of CT induce an overestimation of the site due to the beam hardening artifact by metal cover and reduce the images quality. Therefore, this study using a phantom that has been inserted artificial hip joint investigated that effect on the SPECT/CT image causing by metal artifact for varying the parameters of the Attenuation Map. Materials and Methods Siemens Symbia T16 SPECT/CT equipment was used. Artificial hip joint was inserted to SPECT/PET phantom, 17 mm sphere of Bright Streak area in CT image was filled with Tc-99m so that the radiation activity was 8 times compared to background. And then Hot and Background was measured in varying Wide Beam Coefficient on Attenuation Map and RBR (Region to Background Ratio) of Metal and Non-Metal was calculated and analyzed depending on the presence or absence of the hip joint. Results It tended to hot count of Non-Metal and Metal to increase as the value of the manual mode is increased, hot count ratio with the group of both manual mode 0.5 and 0.4 is the best match. Also, in automatic mode, the ratio of RBRNon-Metal and RBRMetal was 1.135, statistically significant difference was not observed in the manual mode 0.5 and 0.4. Conclusion In the automatic mode of Wide Beam Coefficient in attenuation correction map, it was found that it is over-correction by 13.52%, it was possible to minimize the over-correction by the artifact in 0.5 and 0.4 of manual mode. Further studies should be performed in order to apply to a patient with the help of this and it is considered possible to reduce the over-correction by the metal artifact of an artificial hip joint for Hip-Resurfacing Arthroplasty patients, and to improve the diagnostic performance.

관성센서 기반 상대위치 추정 시 연조직 변형 보상을 위한 인공신경망 적용

최지석,이정근 한국정밀공학회 2022 한국정밀공학회지 Vol.39 No.3

Relative position estimation between body segments is one essential process for inertial sensor-based human motion analysis. Conventionally, the relative position was calculated through a constant segment to joint (S2J) vector and the orientation of the segment, assuming that the segment was rigid. However, the S2J vector is deformed by soft tissue artifact (STA) of the segment. In a previous study, in order to handle the above problem, Lee and Lee proposed the relative position estimation method using time-varying S2J vectors based on inertial sensor signals. Here, time-varying S2J vectors were determined through the joint flexion angle using regression. However, it was not appropriate to consider only the flexion angle as a deformation-related variable. In addition, regression has limitations in considering complex joint motion. This paper proposed artificial neural network models to compensate for the STA by considering all three-axis motion of the joint. A verification test was conducted for lower body segments. Experimental results showed that the proposed method was superior to the previous method. For pelvis-to-foot relative position estimation, averaged root mean squared error of the previous method was 17.38 mm, while that of the proposed method was 12.71 mm.

Application of Artificial Neural Network for Compensation of Soft Tissue Artifacts in Inertial Sensor-Based Relative Position Estimation

최지석(Ji Seok Choi),이정근(Jung Keun Lee) Korean Society for Precision Engineering 2022 한국정밀공학회지 Vol.39 No.2

Relative position estimation between body segments is one essential process for inertial sensor-based human motion analysis. Conventionally, the relative position was calculated through a constant segment to joint (S2J) vector and the orientation of the segment, assuming that the segment was rigid. However, the S2J vector is deformed by soft tissue artifact (STA) of the segment. In a previous study, in order to handle the above problem, Lee and Lee proposed the relative position estimation method using time-varying S2J vectors based on inertial sensor signals. Here, time-varying S2J vectors were determined through the joint flexion angle using regression. However, it was not appropriate to consider only the flexion angle as a deformation-related variable. In addition, regression has limitations in considering complex joint motion. This paper proposed artificial neural network models to compensate for the STA by considering all three-axis motion of the joint. A verification test was conducted for lower body segments. Experimental results showed that the proposed method was superior to the previous method. For pelvis-to-foot relative position estimation, averaged root mean squared error of the previous method was 17.38 mm, while that of the proposed method was 12.71 mm.

An Advanced ANN Model for Predicting the Rotational Behaviour of Semi-rigid Composite Joints in Fire Using the Back-Propagation Paradigm

Khalifa S. Al-Jabri,M. Al-Alawi2 한국강구조학회 2010 International Journal of Steel Structures Vol.10 No.4

This paper describes an artificial neural networking (ANN) model developed to predict the behaviour of semi-rigid composite joints at elevated temperature. Three different semi-rigid composite joints were selected, two flexible end-plates and one flush end-plate. Seventeen different parameters were selected as input parameters representing the geometrical and mechanical properties of the joints as well as the joint’s temperature and the applied loading, and used to model the rotational capacity of the joints with increasing temperatures. Data from experimental fire tests were used for training and testing the ANN model. Results from nine experimental fire tests were evaluated with a total of 280 experimental cases. The results showed that the R2 value for the training and testing sets were 0.998 and 0.97, respectively. This indicates that results from the ANN model compared well with the experimental results demonstrating the capability of the ANN simulation techniques in predicting the behaviour of semi-rigid composite joints in fire. The described model can be modified to study other important parameters that can have considerable effect on the behaviour of joints at elevated temperatures such as temperature gradient, axial restraints,etc.