• 대한관절경학회:학술대회논문집
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• 2009.10a
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• pp.117-118
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• 2009

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.161-164
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• 2009

Irreducible knee dislocation is a rare injury and often need an open procedure with ligaments reconstruction. This report describes a case of arthroscopic treatment of a patient with traumatic knee dislocation unable to reduce in a closed method. MRI revealed incarceration of the medial collateral ligament and capsule in the medial compartment. And arthroscopic examination confirmed incarcerated medial capsuloligamentous structures which prevented the knee from reduction. Arthroscopic procedure without ligaments reconstruction was complete when the medial condyle was well visualized and the knee reduced. After 4 weeks of immobilization in extension, range of motion exercise and gradual increases in weight bearing was allowed. At the 3- year follow-up, mild laxity was remained but the patient did not have any discomfort of doing ADL activity and showed full range of motion of the knee.

• Journal of Korean Orthopaedic Sports Medicine
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• v.8 no.1
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• pp.60-63
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• 2009

Trevor's disease, also known as dysplasia epiphysealis hemimelica, is rare abnormality characterized by aberrant cartilaginous overgrowth forming one half of epiphysis. Typically the patient is 2 to 14 years of age. Until now only six cases, including a case recurred after surgery, have been reported in Korea. A seven year-old boy complained pain of the left knee. However, any deformity of the knee was not seen. The plain radiographic findings showed multiple ossifications asymmetrically on the medial epiphysis of distal femur. The magnetic resonance imaging (MRI) clearly demonstrated the epiphyseal mass which contained low signal spots corresponding to calcified foci and abnormal cartilaginous overgrowth. We report one additional case with a brief review of literature with the MRI findings.

• Proceedings of the KSMRM Conference
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• 2001.11a
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• pp.177-177
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• 2001

목적： Head coil이나 Knee coil로 촬영하기에 부피가 작은 신체의 부위나 동물을 촬영하기 위하여 3T small birdcage coil을 개발하고 실험을 통해 코일의 효율성을 조사하였다. 대상 및 방법： 원통형 아크릴과 구리테이프를 사용하여 원통의 내경이 Knee coil보다 작은 8개의 elements를 가진 birdcage coil을 설계 제작하였고 팬톰, 지원자, 동물에 대한 MR 영상으로 그 가치를 평가하였다.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.6-10
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• 2013

Purpose: This study intends to verify the usefulness of magnetic resonance imaging (MRI) for estimate recovery after arthroscopic pull-out repair at root tears of medial meniscus. Materials and Methods: We performed 17 patients who examined MRI and arthroscopy among patients who had received repair of medial meniscus from November, 2007 to June, 2011. To determine restoration meniscus, we performed arthroscopy and MRI. Results: Lysholm knee scores before and after operation were average 56.4 and 79.0 and visual analogue scale (VAS) score was improved from 8 points to 3 points. From secondary look arthroscopy performed after operation, 17 cases showed stabilization after regeneration. However, In MRI, cleft sign implying root tears of medial meniscus was observed in all cases before and after operation, ghost sign was observed in 10 cases and 9 cases respectively, radial linear defect was showed 17 cases and 15 cases respectively. Conclusion: It was not useful that MRI after medial meniscus repair in non-anatomical site, to consider restoration of medial meniscus. To evaluate for recovery medial meniscus after repair more exactly, secondary arthroscopy would be required.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.76-78
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• 2013

The meniscus is considered "extruded" when it extends beyond the tibial margins more than 3 mm in a coronal view of magnetic resonance imaging (MRI). However, identifying the meniscal extrusion intraoperatively may be difficult because of the simple fact that most of the arthroscopic procedures are done in knee flexion position while follow up MRI studies area taken at knee extension position. Here, we demonstrate the arthroscopic technique for evaluating the meniscal extrusion.

• Investigative Magnetic Resonance Imaging
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• v.20 no.2
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• pp.95-104
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• 2016

Purpose: To evaluate the knee joint after double-bundle anterior cruciate ligament (ACL) reconstruction with three-dimensional (3D) isotropic magnetic resonance (MR) image, and to directly compare the ACL graft findings on 3D MR with the clinical results. Materials and Methods: From January 2009 to December 2014, we retrospectively reviewed MRIs of 39 patients who had reconstructed ACL with double bundle technique. The subjects were examined using 3D isotropic proton-density sequence and routine two-dimensional (2D) sequence on 3.0T scanner. The MR images were qualitatively evaluated for the intraarticular curvature, graft tear, bony impingement, intraosseous tunnel cyst, and synovitis of anteromedial and posterolateral bundles (AMB, PLB). In addition anterior tibial translation, PCL angle, PCL ratio were quantitatively measured. KT arthrometric values were reviewed for anterior tibial translation as positive or negative. The second look arthroscopy results including tear and laxity were reviewed. Results: Significant correlations were found between an AMB tear on 3D-isotropic proton density MR images and arthroscopic proven AMB tear or laxity (P < 0.05). Also, a significant correlation was observed between increased PCL ratio on 3D isotropic MRI and the arthroscopic findings such as tear, laxities of grafts (P < 0.05). KT arthrometric results were found to be significantly correlated with AMB tears (P < 0.05) and tibial tunnel cysts (P < 0.05). Conclusion: An AMB tear on 3D-isotropic MRI was correlated with arthroscopic results qualitatively and quantitatively. 3D isotropic MRI findings can aid the evaluation of ACL grafts after double bundle reconstruction.

• Journal of the Korean Arthroscopy Society
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• v.13 no.3
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• pp.272-275
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• 2009

Extraarticular synovial chondromatosis is a very rare disease which affects the hands, feet, and wrists most commonly. In cases of involvement around large joints, the tissues around knee are usually involved. It arises from tendon sheath, capsular tissue and bursae. It is an idiopathic process in which the synovial cells undergo the metaplasia into cartilage cells. Chondroid matrix of the cartilaginous nodules calcify and ossify to be the osteochondroma. On simple radiograms before calcification and/or ossification of the chondroid tissues the cartilaginous nodules look normal on radiograms. Therefore MRI is needed to establish the diagnosis. We report a case of extraarticular pan-peri-meniscal synovial chondroma around right knee, initially suspected as a ganglion cyst which clinically mimicked a large rounded lesion or a cystic lesion on MRI.

• Progress in Medical Physics
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• v.19 no.4
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• pp.269-275
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• 2008

Although MR imaging is generally applicable to depict knee joint deterioration it, is sometimes occurred to mis-read and mis-diagnose the common knee joint diseases. In this study, we employed magnetization transfer ratio (MTR) method to improve the diagnosis of the various knee joint diseases. Spin-echo (SE) T2-weighted images (TR/TE 3,400-3,500/90-100 ms) were obtained in seven cases of knee joint deterioration, FSE T2-weighted images (TR/TE 4,500-5,000/100-108 ms) were obtained in seven cases of knee joint deterioration, gradient-echo (GRE) T2-weighted images (TR/TE 9/4.56/$50^{\circ}$ flip angle, NEX 1) were obtained in 3 cases of knee joint deterioration, In six cases of knee joint deterioration, fat suppression was performed using a T2-weighted short T1/tau inverse recovery (STIR) sequence (TR/TE =2,894-3,215 ms/70 ms, NEX 3, ETL 9). Calculation of MTR for individual pixels was performed on registration of unsaturated and saturated images. After processing to make MTR images, the images were displayed in gray color. For improving diagnosis, three-dimensional isotropic volume images, the MR tristimulus color mapping and the MTR map was employed. MTR images showed diagnostic images quality to assess the patients' pathologies. The intensity difference between MTR images and conventional MRI was seen on the color bar. The profile graph on MTR imaging effect showed a quantitative measure of the relative decrease in signal intensity due to the MT pulse. To diagnose the pathologies of the knee joint, the profile graph data was shown on the image as a small cross. The present study indicated that MTR images in the knee joint were feasible. Investigation of physical change on MTR imaging enables to provide us more insight in the physical and technical basis of MTR imaging. MTR images could be useful for rapid assessment of diseases that we examine unambiguous contrast in MT images of knee disorder patients.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.896-902
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• 2005

An orthopedic surgeon normally gets the operational parameters of total knee arthroplasty from medical images(CT, MRI). Anatomical axis, mechanical axis, the width and height of femur, or tibia are the most important parameters related with accomplishment of TKA. This paper presents a methodology of simulation that virtually operates TKA according to 2D medical images. Using this simulator, some important parameters for operation can be achieved before hand. The simulator provides the 3D computational model of a knee joint and then derives the proper size of implant corresponding to the joint. The whole process of TKA can be simulated such as clipping a knee joint, assembling the joint and its implants, visualizing all the operation steps, deriving some crucial parameters such as anatomical axis and cutting thickness, and predicting the result of TKA. Some examples are given and discussed to validate the methodology.