• Journal of radiological science and technology
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• v.35 no.1
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• pp.1-7
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• 2012

Dual Energy X-ray Absorptiometry(DEXA) is commonly used to diagnose Osteoporosis. The errors of DEXA bone density operation are caused by operator, bone mineral density meter, blood testing, patient. We focus on operator error then study about how much influence operator's region of intest(ROI) in bone testing result. During from March to July in 2011. 50 patients ware selected respectively from 30, 40, 50, 60, and 70 age groups who came to Korea University Medical Center(KUMC) for their Osteoporosis treatment. A-test was performed with usually ROI and B-test was performed with most widely ROI. Then, We compare A-test and B-test for find maximum difference of T-score error which occurred operator ROI controlling. Standard deviation of T-score of B-test showed 0.1 higher then A-test in femur neck. Standard deviation of B-test showed 0.2 higher then A-test in Ward's area which in Greater trocanter and Inter trocanter. Standard deviation of B-test showed 0,1 lower then A-test in L-1. Bone density testing about Two hundred patients results are as follow. When operator ROI was changed wider than normal ROI, bone density of femur was measured more higher but bone density of L-spine was measured more lower then normal bone density. That means, sometime DEXA bone density testing result is dependent by operator ROI controlling. This is relevant with the patient's medicine and health insurance, thus, tester always keep the size of ROI for to prevent any problem in the patient.

• Journal of the Korean Arthroscopy Society
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• v.11 no.1
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• pp.63-68
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• 2007

Purpose: The authors introduce a new technique of arthroscopic all inside repair using anterolateral and anteromedial portals for lateral meniscus root complete radial tear in patients who underwent concurrent anterior cruciate ligament (ACL) reconstruction. Operative technique: Arthroscope is placed through anteromedial portal and suture hook ($Linvatec^{TM}$, Largo, Florida, USA) is delivered through anterolateral portal. By rotating the suture hook, it penetrates posterior horn of the torn meniscus from femoral to tibial surface for vertical orientation. PDS No. 1 ($Ethicon^{TM}$, Somerville, NJ, USA) is delivered through the suture hook, and then it is withdrawn. Both end of PDS No. 1 are taken out through the anterolateral portal. MAXON 2-0 ($Syneture^{TM}$, Norwalk, Connecticut, USA) is used to penetrates remnant of tibial attachment of the torn meniscus from tibial to femoral surface in a same manner. MAXON 2-0 is changed for PDS No. 1 from tibial to femoral surface by shuttle relay technique. PDS No. 1 is tied using SMC (Samsung Medical Center) knot. Conclusion: All inside repair is a useful technique to achieve anatomical repair and to restore the hoop tension in lateral meniscus root complete radial tear.

• The Journal of the Korean bone and joint tumor society
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• v.11 no.2
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• pp.175-182
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• 2005

Purpose: Bone tumor occurred in femur frequently involve proximal intertrochanteric region or distal metaphyseal region. Sometimes, the pathologic fracture can happen according to the size of tumor due to the substantial biomechanical stresses. Therefore, the prognosis can be improved biomechanically by the angled blade plate considering the anatomic configuration after the excision of tumor. Materials and Methods: Between October 1991 and April 2005, there were a total of 16 patients(17 cases) who were treated by the excision of tumor and internal fixation with the angled blade plate for bone tumor occurred in femur. After the excision of tumor, we filled the cavity by bone graft in 11 cases and bone cement in 6 cases. The internal fixation was used by angled blade plate in all cases. Result: The average follow-up time was 55.5 months(6-144 months) in 16 patients(17 cases). No metal failure occurred after the operation. Reoperation was performed in 4 cases due to tumor recurrence, and the internal fixation was firm until that. Conclusion: The angled blade plate can prevent the fracture until grafted bone incorporated to host bone, and protect fragile connection between cement and host bone.

• Journal of the Korean Arthroscopy Society
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• v.7 no.2
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• pp.215-219
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• 2003

Purpose : To report the 'condylar cut-off sign', a new radiographic sign in knees with discoid lateral meniscus and to report the sensitivity, specificity, positive predictive value and negative predictive value of the sign to elucidate the diagnostic significance of the sign for discoid meniscus. Materials and Methods : Fifty knees with complete discoid lateral meniscus and fifty normal knees formed the basis of this study. All of them were arthroscopically confirmed fer the discoid or normal lateral meniscus. The authors developed a method to measure the length of the medial and lateral condylar were compare and analyzed. Results : Tile average ratio was 0.716 in the discoid meniscus group, and 0.902 in the normal group. The stastistical analysis by the T-test revealed the t-value -11.13(p<0.0001). Stastistical analysis by chi-square test using cut point 0.8, also showed significant difference between the two groups, with $76\%$ sensitivity, $100\%$ specificity, $100\%$ positive predictive predictive value and $81\%$ negative predictive value. The 'condylar cut-off sign' was readily detectable in all cases of discoid lateral meniscus, suggesting that the cut off sign could serve as a simple and reliable radiographic sign fur the diagnosis of discoid meniscus. Conclusion : The condylar cut-off sign on the Tunnel view of simple radiography of the knee can serve as a good sign for the diagnosis of discoid lateral meniscus, with $100\%$ positive predictive value.

• Journal of the Korean Arthroscopy Society
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• v.9 no.1
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• pp.70-76
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• 2005

Purpose: We describe a new technique of arthroscopic repair with using autogenous hamstring tendon graft augmentation for the acute posterior cruciate ligament rupture. Operative technique: A routine arthroscopic examination of the knee joint is initially performed, then the posterior trans-septal portal is prepared with the using the posteromedial and posterolateral portals. The torn tibial stump that is retracted to the posterior compartment is repaired by a suture hook that is introduced through the anteromedial portal; visualization during this procedure is done with the arthroscope via the posteromedial portal. Using the retrieved suture, both suture ends are brought out to the anteromedial portal. The torn tibial stump is pulled to the intercondylar notch and then repaired with stitches at the anterior compartment. After the tibial and femoral tunnels are prepared without damaging the remnant PCL bundle, the combined torn PCL fibers and the autogenous single-bundle semitendinosus and gracilis tendon grafts are passed through the femoral tunnel and fixed together Conclusion: Arthroscopic repair of the torn tibial stump and autogenous hamstring tendon graft augmentation after preparing the tibial and femoral tunnels by using the trans-septal portal, without damaging the remnant PCL bundle, seems to be a very effective method for the treatment for acute PCL injuries, and especially for tears at the femoral attachment.

• Investigative Magnetic Resonance Imaging
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• v.2 no.1
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• pp.89-95
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• 1998

Purpose : To investigate the phosphorus metabolic abnormalities in skeletal muscle of patients with mitochondrial myopathy using in vivo $^{31}P$ magnetic resonance spectroscopy(MRS). Materials and Methods : Patients with mitochondrial myopathy(N=10) and normal control subjects (N=10) participated. All in vivo $^{31}P$ MRS examinations were performed on 1.5T whole-body MRI/MRS system by using an image selected in vivo spectroscopy (ISIS) pulse sequence that provided a $4{\times}4{\times}4{\;}cm^{3}$ volume of interest (VOI) in the right thigh muscle tissue. Peak areas for each phophorus methabolite were measured using a Marquart algorithm. Results : The specific features in patients with mitochondrial myopathy were a significant increase of Pi/PCr ratio (p=0.003) and a significant decrease of ATP/PCr ratio (p=0.004) as compared with normal controls. In particular, the ${\beta}-ATP/PCr$ ratio between controls and patients with mitochondrial myopathy was predominantly altered. Conclusions : In vivo $^{31}P$ MRS may be a useful modality in the clinical evaluation of patients with mitochondrial myopathy based on ATP/PCr and Pi/PCr ratios in skeletal muscle tissue and provides a valuable information in further understanding disorders of muscle metabolism.

• Journal of the Korean Arthroscopy Society
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• v.4 no.2
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• pp.138-143
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• 2000

Purpose : We analyzed clinical and radiological results of the treatment of osteochondritis dissecans in the femoral condyle under arthroscopic guidance. Materials and Methods : The study group consists 19 cases in 17 patients. Average follow up period was 34 months and average age was 16 years. The cases were classified by 4 different groups, using the fellowing system: Group 1-stable lesion and no specific treatment after arthroscopic examination; Group 2-early separation and multiple drilling; Croup 3-unstable lesion and Herbert screw fixation; Croup 4-loose body removal and/or crater curettage. The results were analyzed by the criteria of Hughston which including clinical and radiologic outcomes. Results : There were 14 cases$(74\%)$ of good and excellent results in 19 knees in which, $75\%$(3/4) in Group 1, $75\%$(3/4) in Group 2, $86\%$(7/8) in Group 3 and $33\%$(1/3) in Group 4. The result of Herbert screw fixation group was better than that of other groups with statistically significant differences. Conclusion : In the treatment of osteochondritis dissecans of skekletally immature patients, arthroscopic finding was reliable guidance in decision of treatment method and active fixation was recommended in patients with large, unstable lesion.

• Journal of the Korean Arthroscopy Society
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• v.10 no.1
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• pp.118-122
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• 2006

Purpose: We introduce a technique of all inside arthroscopic capsular imbrication and lateral release used to treat patellofemoral instability. Methods: With the arthroscope in the anteromedial portal for best viewing, the arthroscopic scissor is placed through superolateral portal for proximal to distal release. The release performed 5mm to 1cm from the edge of the patella. After completion of the procedure, with the arthroscope in anterolateral portal, we inserted 5mm cannula in superolateral portal and made working portal from superomedial portal. Medial reefing was performed with all inside technique by using curved needle of the spectrum suturing system and No. 1 monofilament PDS suture is passed through the superomedial portal percutaneously and retrieved through a superolateral portal. Conclusion: Several methods for arthroscopic patella realignment have been proposed, but they have consisted primarily of arthroscopically assisted techniques using a medial incision. We believe that our procedure is preferable to arthroscopically assisted methods commonly used, in that an incision is avoided and the vastus medialis obliqqus is not violated. Our technique is minimally invasive and is easy to control the tightness of the medial patellofemoral ligament (MPFL) under direct vision.

• The Journal of the Korean bone and joint tumor society
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• v.14 no.2
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• pp.157-162
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• 2008

Nowadays, most of the malignant bone tumor patient underwent limb salvage operation, however, reconstructive options for skeletally immature group are still controversial. There are three necessary conditions of most ideal reconstructive method in treating the skeletally immature children. As the epiphyseal plate sacrification is usually inevitable in malignant bone tumor around knee joint, ideal reconstructive technique would be as follows; 1)minimal or no damage to theadjacent epiphyseal plate, 2) maintaining mobile joint, 3) index procedure does not disturb subsequent operation such as lengthening. Segmental resection and reconstruction using autogenous pasteurized graft was done for 4 years old meta-diaphyseal osteosarcoma of femur. At 6 months from index operation, plain radiograph showed pasteurized bone resorption and loosening of fixation devise. To overcome the complication, we used allograft reconstruction by impacting the proximal host bone to the fluted portion of allobone. Three months later, proximal bone union was observed and patient showed good functional outcome.

• Journal of the Korean Society of Radiology
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• v.82 no.6
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• pp.1556-1564
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• 2021

Purpose This study aimed to apply MR elastography (MRE) to achieve in vivo evaluation of the elastic properties of thigh muscles and validate the feasibility of quantifying the elasticity of normal thigh muscles using MRE. Materials and Methods This prospective study included 10 volunteer subjects [mean age, 32.5 years, (range, 23-45 years)] who reported normal activities of daily living and underwent both T2-weighted axial images and MRE of thigh muscles on the same day. A sequence with a motion-encoding gradient was used in the MRE to map the propagating shear waves in the muscle. Elastic properties were quantified as the shear modulus of the following four thigh muscles at rest; the vastus medialis, vastus lateralis, adductor magnus, and biceps femoris. Results The mean shear modulus was 0.98 ± 0.32 kPa and 1.00 ± 0.33 kPa for the vastus medialis, 1.10 ± 0.46 kPa and 1.07 ± 0.43 kPa for the vastus lateralis, 0.91 ± 0.41 kPa and 0.93 ± 0.47 kPa for the adductor magnus, and 0.99 ± 0.37 kPa and 0.94 ± 0.32 kPa for the biceps femoris, with reader 1 and 2, respectively. No significant difference was observed in the shear modulus based on sex (p < 0.05). Aging consistently showed a statistically significant negative correlation (p < 0.05) with the shear modulus of the thigh muscles, except for the vastus medialis (p = 0.194 for reader 1 and p = 0.355 for reader 2). Conclusion MRE is a quantitative technique used to measure the elastic properties of individual muscles with excellent inter-observer agreement. Age was consistently significantly negatively correlated with the shear stiffness of muscles, except for the vastus medialis.