• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.4A
• /
• pp.316-323
• /
• 2002

In this paper, we propose a counter-countermeasure (CCM) in a crossed array tracker for efficient target tracking under countermeasures (CM) operated by a target. The proposed CCM adepts two detection bands and uses the signal distribution characteristics to discriminate between the target and the CMs. To avoid wrong detection of a target position due to missing signal pulses, it predicts current target position based on previous target position. To evaluate the performance of the proposed CCM in a crossed array tracker, we perform numerical simulations for target signal extraction and target tracking under various conditions. The simulation results show that the proposed CCM removes the CM effect well and tracks the target efficiently.

• Investigative Magnetic Resonance Imaging
• /
• v.17 no.3
• /
• pp.239-242
• /
• 2013

Anomalies of the medial meniscus are rare and difficult to diagnose clinically. Among these anomalies, anomalous insertion of the medial meniscus into the anterior cruciate ligament is rare. Most of the reported cases had no relation to clinical symptoms and were found incidentally during arthroscopy. We report a rare case of anomalous insertion of the medial meniscus into the anterior cruciate ligament with a brief review of the literature.

• Journal of the Korean Arthroscopy Society
• /
• v.5 no.1
• /
• pp.13-16
• /
• 2001

Purpose : To evaluate the types of the fibrous scar formation around graft after ACL reconstruction. Materials and Methods : Between Nov 1997 and Jun. 1999, the second look arthroscopy was performed on 15 knees of 14 patients. We evaluated the changes around graft and measured the tunnel position that the tibial tunnel position as a percentage along the length of the tibial plateau from the anterior-to-posterior as seen on a lateral radiograph and the femoral tunnel position as a percentage along Blumensaat's line from anterior-to-posterior as seen on a lateral radiograph. Results : The tibial tunnel position was from $27\%\;to\;58\%(mean\;41\%)$ and the femoral tunnel position was from $58\%\;to\;83\%(mean\;76\%)$, so the tunnel position was ideal in almost cases. By arthroscopic findings, the grafts were not impinged in all cases and tile fibrous scar was formed between intercondylar notch and graft in almost cases except 3 cases. The types of fibrous scar formation were 6 cases of fibrillated fiber and 5 cases of fibrous nodule and 1 case of fibrous band. Conclusion : There was no impingement on graft in all cases and various types of fibrous scars were formed around grafts.

• Journal of the Korean Arthroscopy Society
• /
• v.6 no.2
• /
• pp.115-120
• /
• 2002

Purpose : To compare the functional evaluation with the posterior translation after arthroscopic PCL reconstruction in isolated and combined PCL-deficient knees. Materials and Methods : We retrospectively evaluated 45 patients with PCL-deficient knees who were treated by arthroscopic PCL reconstruction using Achilles tendon allograft from June 1994 to June 2000. The differences of posterior translation were measured with posterior stress lateral radiographs and KT-2000 arthrometer. The functional results were evaluated using the Lysholm knee score and IKDC evaluation form. Results : Preoperative mean side to side differences of the posterior translation were 11.83 mm in isolated PCL-deficient knees and 12.7 mm in combined PCL-deficient knees respectively. At the last follow-up in isolated and combined PCL-deficient knees, the mean radiographic side to side differences of the posterior translation were 6.38 mm and 6.7 mm, the average corrected 20 Ib posterior displacements using KT-2000 arthrometer were 3.5 mm and 4.1 mm, the mean Lysholm score were 87.4 and 81.2, the grade A and B of IKDC evaluation form were 16 cases $(88.9\%)$ and 23 cases $(85.2\%)$, respectively. Conclusion : The functional results had no relationship with the degree of posterior translation after arthroscopic PCL reconstruction. Tendency of posterior translation may be influenced by associated injury of the knee.

• Journal of the Korean Arthroscopy Society
• /
• v.3 no.2
• /
• pp.102-108
• /
• 1999

Purpose : The purpose of this study was to evaluate the clinical results of bone-patellar tendon-bone(B-PTB) allograft for ACL reconstruction without mechanical tensioning device. Material and Method : Forty-six knees in 43 patients were reviewed and evaluated with subjective evaluation, objective evaluation, Telos stress arthrometer and modified Feagin Scoring System. The average age at the time of operation was 27 years(range, 18-42) and the average follow up period was 41 months(range, 22-79). Authors reconstructed ACL using B-PTB allograft which was prepared by rehydration preoperatively without tensioning by mechanical tensioning device. The tension for allograft was obtained by full flexion and extension intraoperatively. All operation were performed arthroscopically by two-tunnel method to avoid the mismatching of allograft tendon length. Result : The modified Feagin Scoring System revealed 39 cases(84.7%) with excellent or good results and 7 cases(15.3%) with fair or poor results. The mean follow-up Lysholm Knee Score was 84. Telos arthrometer revealed 41 cases had an injured-to-uninjured difference of 5 mm or less(mean 2.3mm). The range of motion of knee was nearly normal and there was no extension lag in any cases at last follow up. Conclusion : Clinical results using B-PTB allograft showed less morbidity than B-PTB autograft. The intraoperative tensioning method by full flexion and extension without mechanical tensioning device was not bad. Therefore, B-PTB allograft is a good substitute material in reconstruction of the ACL.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.10 no.2
• /
• pp.54-60
• /
• 2011

Puropse: To evaluate the outcome of arthroscopic posterior cruciate ligament (PCL) reconstruction using fresh-frozen achilles allograft tendon with preservation of ligament remnant or elongated ligament. Materials and Methods: From October 2004 to March 2010, we performed PCL reconstruction with Achilles tendon allografts in 22 complete rupture patients. Mean age was 31.5 years. 14 cases were male and 8 cases were female. Average follow-up period was 3 years and 7 months, range from 1 year to 6 years and 4 months. Subjective and objective parameters were utilized in analyses, such as the mean range of motion, post. drawer test, Lysholm knee score, Tegner activity score, IKDC score, and second look arthroscopic examination. Results: Postoperative Lysholm knee score, IKDC scores, Tegner activity scale, and posterior displacement by the Telos stress test demonstrated statistically significant improvement compared to the preoperative state. Conclusion: Arthroscopic PCL reconstruction using fresh-frozen achilles allograft tendon with preservation of ligament remnant showed good clinical results and posterior stability.

• Journal of Korean Orthopaedic Sports Medicine
• /
• v.7 no.2
• /
• pp.95-121
• /
• 2008

Purpose: The goal is to identify the effectiveness of the IKDC subjective score in the clinical outcome study after reconstruction of the anterior cruciate ligament. Materials and Methods: Twenty-four patients after ACL reconstructions using twelve hamstring autografts and twelve Achilles allografts were evaluated. Lysholm knee score, IKDC subjective score, Knee Outcome Survey score and Tegner activity score were evaluated for the subjective outcome value. Static instability tests, Biodex dynamometer and one-legged hop for distance tests were done for the objective outcome value. Three functional performance tests (FPTs) including Carioca test, Shuttle run test and Co-contraction test were performed for deciding the final results. Each scale was compared with FPTs results and Pearson's correlation test was used to test the correlation between the parameters. Results: IKDC subjective score, single hop test, and quadriceps power in low velocity of Biodex dynamometer tests had a positive correlation with the total FPTs results. Conclusion: IKDC subjective score can be an effective test to evaluate the functional status as well as the subjective outcome after ACL reconstruction.

• Journal of the Korean Arthroscopy Society
• /
• v.12 no.1
• /
• pp.45-52
• /
• 2008

Purpose: The purpose of the study is to provide the clinical results of arthroscopic posterior cruciate ligament(PCL) reconstruction with preservation of the original PCL using transtibial tunnel and posterior transseptal portal. Materials and Methods: 36 patients underwent PCL reconstruction with achilles tendon allografts. We tried to preserve of the original PCL.At the final follow-up, patients were evaluated retrospectively by four measurements: Lysholm knee scores, IKDC grades, Telos stress radiography, and second look arthroscopy.Follow-up periods were from 12 months to 30 months. Results: The average Lysholm knee score improved from $66.0{\pm}8.67$ to $87.9{\pm}5.04$. Preoperative IKDC grades were abnormal in 15(41.7%) and severely abnormal in 21(58.3%), postoperative IKDC grades were normal in 6(16%),nearly normal in 24(66%), abnormal in 5(16%) and severely abnormal in 1(2%).The average side to side difference in Telos stress test decreased from $12.5{\pm}2.61(7{\sim}20)$ mm to $3.9{\pm}1.34(7{\sim}1)$ mm (paired sample T test, p=0.001) Conclusion: Arthroscopic posterior cruciate ligament(PCL) reconstruction with preservation of the original PCL using transtibial tunnel and posterior transseptal portal is useful surgical method.

• Journal of the Korean Arthroscopy Society
• /
• v.14 no.2
• /
• pp.107-113
• /
• 2010

Purpose: To evaluate the outcome of the two-bundle anterior cruciate ligament reconstruction with single femoral tunnel and tibialis anterior tendon allograft and to determine any functional advantages. Materials and Methods: From June 2006 to March 2008, we performed single femoral tunnel and two-bundle ACL reconstruction with tibialis anterior tendon allograft in 26 cases. Mean age was 35.5 years. 20 cases were male and 6 cases were female. Average follow-up period was 2 years and 5 months, range from 1 year to 3 years and 5 months. Subjective and objective parameters were utilized in analyses, such as the mean range of motion, Lysholm knee score, Tegner activity score, Lachman test and IKDC score. Results: Postoperative mean Lysholm knee score, IKDC Evaluation Form, Tegner activity scale, Pivot shift test, and anterior displacement by the Telos stress test demonstrated statistically significant differences compared to the preoperative. Conclusion: Two-bundle anterior cruciate ligament reconstruction with single femoral tunnel showed good clinical results and was good operative technique.

• Journal of the Korean Arthroscopy Society
• /
• v.11 no.2
• /
• pp.85-91
• /
• 2007

Purpose: To analyze the clinical results and second look arthroscopic findings of anterior cruciate ligament(ACL) reconstruction with a tibialis anterior tendon allograft and a hamstring tendon autograft. Materials and Methods: We reviewed the cases of athroscopic ACL reconstructions using allogenous tibialis anterior(TA) tendon and autogenous hamstring tendon done from March, 2002 to August, 2005 and followed-up more than 1 year. The 250 cases were included in this study and allogenous TA tendon was used in 150 cases and autogenous hamstring tendon in 100 cases. The mean follow-up period was 15 months and 14 months, respectively. The clinical evaluation was done by Lachman test, Pivot shift test, KT-1000 arthrometer and International Knee Documentation Committee(IKDC) knee score. Graft tension, synovial coverage were observed in cases of second look arthroscopy. Results: At final follow-up, there was no significance between the two groups in clinical examination. On second look arthroscopy, synovial coverage was better in autogenous hamstring tendon group than allogenous TA tendon group(p=0.005). But no difference was found in graft tension(p>0.05). Conclusion: There were no significant differences between the two groups in the clinical results. But autogenous hamstring tendon group had better synovial coverage than allogenous TA tendon group in second look arthroscopy.