• Journal of the Korean Orthopaedic Association
• /
• v.56 no.3
• /
• pp.200-207
• /
• 2021

Periprosthetic femoral fractures remain as one of the most challenging complications following total hip arthroplasty. A thorough clinical and radiographic evaluation, precise classification, and understanding of modern management principles are essential to obtain optimal results for these fractures. The Vancouver classification system is a simple, effective, and reproducible method for the planning treatments of these injuries. The fractures associated with a stable femoral stem can be treated effectively with osteosynthesis, but periprosthetic femoral fractures associated with a loose stem require revision arthroplasty. This paper describes the principle of the treatment of patients with periprosthetic femoral fractures and how to assess the stability of the femoral stem.

• The Academic Congress of Korean Shoulder and Elbow Society
• /
• 2008.03a
• /
• pp.51-51
• /
• 2008

• The Journal of Korean Orthopaedic Ultrasound Society
• /
• v.7 no.1
• /
• pp.39-44
• /
• 2014

The patellar clunk syndrome is one of the patellofemoral complication, caused by formation of the fibrous nodule at the suprapatellar region after total knee arthroplasty. The symptom involves painful catching, crepitus and clunk during knee extension. It has been mainly but not exclusively associated with the posterior stabilized total knee system. The fibrous nodule is entrapped in the femoral intercondylar notch of the femoral component during flexion and as the knee is extended, it displaces back to the trochlear groove abruptly and the typical symptoms occur. The risk of developing this complication is primarily related to the design of the femoral component and higher incidence was noted with earlier designs of posterior stabilized knee prosthesis. Modifications have been made to the femoral component to optimize the kinematics of the patellofemoral joint and thereby reduced the incidence of patellar clunk syndrome but did not eliminate the problem completely. Clinical examination is the gold standard of diagnosis and imaging study has been used as a possible adjunct to diagnosis. Especially ultrasonography is an imaging modality, which can be easily performed to detect the fibrous nodule on the quadriceps tendon. We report a case of patellar clunk syndrome which was diagnosed with ultrasonography.

• Journal of the Korean Society of Radiology
• /
• v.14 no.1
• /
• pp.7-14
• /
• 2020

The purpose of this study is to assess the usefulness of IR to compensate for uncertainties in inserting high density artificial objects in radiation treatment planning in the 3D-CRT treatment technique. CT images of the subjects with phantom and titanium inserted were obtained from images without IR and images with IR, and the dose evaluation factors HI, MU and volume evaluation factors Volume and PCI were compared. The results of the stainless steel and titanium phantom experiments showed that the volume of high density artificial material was reduced by 4.850% and 11.456% respectively when applying IR. MU decreased 0.924% and 1.181%. HI was down 0.106% and 0.272%. PCI decreased 0.358% and 0.867%. When IR was applied to CT images of subjects with vertebroplasty, Femur alignment pin and wrist alignment pin, the volume of artifacts decreased by 47.76%, 23.841%, and 49.339%. MU also decreased 0.924%, 0.294% and 1.675%, while HI decreased 1.232%, 0.412% and 1.695%. PCI decreases 4.022%, 0.512%, and 13.472%. In conclusion, When IR was applied to 3D-CRT treatment plan, both dose and volume in phantom and subject case with high density artificial insert were reduced.

• 한국HCI학회:학술대회논문집
• /
• 2006.02a
• /
• pp.75-81
• /
• 2006

슬관절 전치환술은 관절염이나 사고로 인해 일상적인 활동의 제약을 받는 환자의 슬관절을 인공 관절로 대체함으로써 본래의 기능을 복원하고자 하는 수술이다. 이 수술은 인공 관절의 위치 및 정렬에 매우 민감하게 영향을 받기 때문에 수술이 잘못되는 경우 정렬 이상으로 인한 해리, 삽입물의 파손, 인공 슬관절 주위 골절, 슬개골 탈구, 굴곡 각도의 제한 등의 증상이 발생할 수 있다. 현재의 인공 관절은 임상에 적용되는 다양한 인공 관절 중에서 적당한 형상의 관절을 선택하여 시술되고 있지만 환자의 골 형상에 정확히 일치하는 인공 관절 선택의 어려움 때문에 종종 시술 후 부작용이 발생한다든지 심지어는 재수술을 해야 될 경우도 발생하게 된다. 본 논문은 Mechanical CAD 소프트웨어인 CATIA에서 제공하는 절단, Assembly, Analysis, Kinematic Simulation 기능 등을 이용하여 가상 수술을 수행하는 과정을 보여준다. 슬관절 전치환술 과정을 그대로 재현하여 절단량과 절단각을 결정하고 환자의 골격 형상에 적합한 최적의 인공 관절을 실제 수술 전에 미리 선정할 수 있다. CAD 시스템을 이용함으로써 외과의들이 실제 수술 시에 시행착오법을 통해 인공 관절을 선택하는 과정을 줄이고 수술의 정확도를 높일 수 있다. 향후 ADAMS나 ANSYS와 연계하여 수술 후 동작이나 하중을 분석할 수 있으며, 수술 과정에 대한 교육용으로 활용될 수 있다.

• Journal of the Korean Society of Radiology
• /
• v.8 no.6
• /
• pp.317-323
• /
• 2014

This study aims to suggest and test methods using an orally inserted guiding device in order to improve a motion artifact by involuntary oral motor such as removing one's dentures and swallowing saliva clinically structured cervical spine scan and to make the optimal image by minimizing motion artifact. A cervical spine test was conducted with 30 patients who wore dentures among those who had a cervical spinal disease from January 1, 2014 through June 30, 2014. As for testing methods, after removing denture, T1-TSE-Sagittal, T2-TSE-Sagittal, T1-TSE-Axial and T2-TSE-Axial were obtained in a normal position and a supine position; the orally inserted guiding device was inserted in patients' mouth; and then T1-TSE-Axial and T2-TSE-Axial were retested. As a result, in SNR, T1-TSE-Axial before inserting an orally inserted guiding device was $22.33{\pm}8.59$; T1-TSE-Axial after inserting the orally inserted guiding device was $25.21{\pm}7.93$; T2-TSE-Axial before inserting the orally inserted guiding device was $14.49{\pm}5.74$; and T2-TSE-Axial after inserting the orally inserted guiding device was $16.61{\pm}6.72$. In CNR, T1-TSE-Axial was measured at $0.23{\pm}0.01$ while T2-TSE-Axial at $0.21{\pm}0.01$. As a result of the qualitative analysis, T1-TSE-Axial before inserting the orally inserted guiding device was $3.49{\pm}0.11$; T1-TSE-Axial after inserting the orally inserted guiding device was $3.95{\pm}0.14$; T2-TSE-Axial before inserting the orally inserted guiding device was $3.25{\pm}0.18$; and T2-TSE-Axial after inserting the orally inserted guiding device was $3.68{\pm}0.09$. As a result of using an orally inserted guiding device, the resolution and contrast of the images improved as the patients' involuntary artifact decreased because of removing dentures and swallowing saliva, and it was found that the interpretation of the images and identification of the diseases improved.

• Journal of Biomedical Engineering Research
• /
• v.20 no.1
• /
• pp.37-44
• /
• 1999

Because of bone resorption, wear of ultra-high molecular weight polyethylene(UHMWPE) in total knee arthroplasty has been recognized as a major factor in long-term failure of knee implant. The surface damage and the following harmful wear debris of UHMWPE is largely related to contact stress. Most of the previous studies focused on the contact condition only at the articulating surface of UHMWPE. Recently, contact stress at the metal-backing interface has been implicated as one of major factors in UHMWPE wear. Therefore, the purpose of the is study is to investigate the effect of the contact stress for different thickness, conformity friction coefficient, and flexion degree of the UHMWPE component in total knee system, considering the contact conditions at both interfaces. In this study, a two-dimensional non-linear plane strain finite element model was developed. The results showed that the maximum value of von-Mises stress occurred below the articulating surface and the contact stress was lower for the more conforming models. All-polyethylene component showed lower stress distribution than the metal-backed component. With increased friction coefficient on the tibiofemoral contact surface, the maximum shear stress increased about twofold.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.17 no.1
• /
• pp.67-70
• /
• 2013

Purpose: Surge in patients with hepatocellular carcinoma, hepatic artery chemical embolization is one of the effective interventional procedures. The PET/CT examination plays an important role in determining the presence of residual cancer cells and metastasis, and prognosis after embolization. The other hand, the hepatic artery chemical embolization of embolic material used lipiodol produced artifacts in the PET/CT examination, and these artifacts results in quantitative evaluation influence. This study, the radioactivity density and the percentage error was evaluated by the extent of the impact of lipiodol in the image of PET/CT. Materials and Methods: 1994 NEMA Phantom was acquired for 2 minutes and 30 seconds per bed after the Teflon, water and lipiodol filled, and these three inserts into the enough to mix the rest behind radioactive injection with $20{\pm}10MBq$. Phantom reconfigure with the iterative reconstruction method the number of iterations for two times by law, a subset of 20 errors. We set up region of interest at each area of the Teflon, water, lipiodol, insert artifact occurs between regions, and background and it was calculated and compared by the radioactivity density(kBq/ml) and the% Difference. Results: Radioactivity density of the each region of interest area with the teflon, water, lipiodol, insert artifact occurs between regions, background activity was $0.09{\pm}0.04$, $0.40{\pm}0.17$, $1.55{\pm}0.75$, $2.5{\pm}1.09$, $2.65{\pm}1.16 kBq/ml$ (P <0.05) and it was statistically significant results. Percentage error of lipiodol in each area was 118%, compared to the water compared with the background activity 52%, compared with a teflon was 180% of the difference. Conclusion: We found that the error due to under the influence of the attenuation correction when PET/CT scans after lipiodol injection performed, and the radioactivity density is higher than compared to other implants, lower than background. Applying the nonattenuation correction images, and after hepatic artery chemical embolization who underwent PET/CT imaging so that the test should be take the consideration to the extent of the impact of lipiodol be.

• Journal of Biomedical Engineering Research
• /
• v.24 no.5
• /
• pp.401-410
• /
• 2003

This study investigates the biomechanical efficacies of various cement augmentation techniques with or without pressurization for varying degrees of osteoporotic femur. For this study, a biomechanical analysis using a finite element method (FEM) was undertaken to evaluate surgical procedures, Simulated models include the non-cemented(i.e., hip screw only, Type I), the cement-augmented(Type II), and the cemented augmented with pressurization(Type III) models. To simulate the fracture plane and other interfacial regions, 3-D contact elements were used with appropriate friction coefficients. Material properties of the cancellous bone were varied to accommodate varying degrees of osteoporosis(Singh indices, II∼V). For each model. the following items were analyzed to investigate the effect surgical procedures in relation to osteoporosis of varying degrees : (a) von Mises stress distribution within the femoral head in terms of volumetric percentages. (b) Peak von Mises stress(PVMS) within the femoral head and the surgical constructs. (c) Maximum von Mises strain(MVMS) within the femoral head, (d) micromotions at the fracture plane and at the interfacial region between surgical construct and surrounding bone. Type III showed the lowest PVMS and MVMS at the cancellous bone near the bone-construct interface regardless of bone densities. an indication of its least likelihood of construct loosening due to failure of the host bone. Particularly, its efficacy was more prominent when the bone density level was low. Micromotions at the interfacial surgical construct was lowest in Type III. followed by Type I and Type II. They were about 15-20% of other types. which suggested that pressurization was most effective in limiting the interfacial motion. Our results demonstrated the cement augmentation with hip screw could be more effective when used with pressurization technique for the treatment of intertrochanteric fractures. For patients with low bone density. its effectiveness can be more pronounced in limiting construct loosening and promoting bone union.

• The Korean Journal of Nuclear Medicine Technology
• /
• v.18 no.2
• /
• pp.3-7
• /
• 2014

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.