• Journal of the Korean Arthroscopy Society
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• v.12 no.1
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• pp.32-39
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• 2008

Purpose: To evaluate the effectiveness of MRI after ACL reconstruction with femoral tunnel at 10 o'clock position. Materials and Methods: MRI findings of 29 patients after ACL reconstruction using hamstring tendon autograft were evaluated. The mean period from operation to MRI was 18.9 months($7{\sim}40$ months). Signal intensity, morphology and continuity of graft, femoral insertion, graft angle, roof impingement, cross pin breakage and position were evaluated. Those findings were compared with KT-2000, Lysholm knee score and pivot shift test. Results: There was no significant correlation between signal intensity of graft and the duration to MRI. Most common pattern of the morphology was straight, and the continuity was well-preserved. 13 cases of femoral tunnel insertion were zone 4 and 16 were zone 3. There were no roof impingement. 10 cases showed cross pin breakages, of which 5 were found at the outside of distal femoral posterior cortex. 9 showed cross pin directed posteriorly in axial view. There was no significant correlation between clinical results and cross pin breakage. Conclusion: MRI examinations after ACL reconstructions are useful to evaluate the graft status, position of the graft and cross pins. Since the direction of the cross pin is important especially in 10 o'clock femoral position, care should be taken to avoid cross pin breakage.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.4
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• pp.624-631
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• 2017

This study aimed to identify the effect of the push-up plus exercise with sling on the muscle activity and lung function in adults with forward head posture over a period of 8 weeks. A total of 16 adults with forward head posture were recruited. The participants were divided into two groups : control (n-=8) and experimental (n=8). From July 6 until Aug 28, 2015, the participants were instructed to perform the knee push-up plus exercise and knee push-up plus using sling exercise three times a week to begin with and progressing to three sets of push-ups on each occasion after 8 weeks. The participants in both groups showed an increase in their craniovertebral angle (both groups p<0.001) and a decrease in their crania rotation angle (control p<0.05, experimental p<0.001). The participants in both groups showed a decrease in their trapezius activity (both groups p<0.001), an increase in their serratus anterior and lower trapezius muscle activity (both groups p<0.001), (and an increase in their) lung function (control group p<0.01, experimental group p<0.001). These findings show that push-up plus exercise improves posture and increases activation of lung function, while the push-up plus exercise in the sling is more effective in improving the forward head posture. The push-up plus exercise in the sling was more effective in improving the forward head posture, but there was no significant difference in the lung function between the two groups. Therefore, the push-up plus exercise in the sling is recommended as an exercise that is effective for the improvement of the posture and lung function of persons with forward head posture.

• Journal of the Korean Arthroscopy Society
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• v.13 no.2
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• pp.143-148
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• 2009

Purpose: To investigate the causes of failure on ACL reconstructions and evaluate the effectiveness of one stage revision ACL reconstructions. Materials and Methods: From November 2004 to July 2008, thirty three patients who had got revision ACL recontstructions after reruptures of ACL were evaluated. The causes of failure of ACL reruptures were 22 vertical femoral tunnels, 7 neglected PLRI, 3 severe traumas and 1 deep infection after ACL reconstruction. The femoral tunnels were aimed at the 10 or 2 o'clock position and the tibial tunnels were used with previous tunnels. Previous femoral screws from the improper femoral tunnels were removed and filled with the new allograft bones. Results: The average periods of follow up were 22.2 months (12~52 months). There was improvement on an average Lysholm knee score from $61.5{\pm}16.8$ to $86.3{\pm}11.5$, IKDC score from $63.9{\pm}15.1$ to $81.3{\pm}14.3$. Mean side to side difference was decreased from $6.0{\pm}2.2\;mm$ to $1.6{\pm}1.4\;mm$ using KT-2000 arthrometer. Conclusion: One stage revision ACL reconstruction can be a useful method with good clinical results.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.3
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• pp.235-245
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• 2002

The purpose of this study is to figure out the tendency of tunnel convergence during excavation and to present a methodology for the prediction of a fault zone ahead of a tunnel face by analyzing three dimensional displacements in various ways. 3-D numerical analysis was performed to investigate changes of tunnel convergence vectors near a fault zone and to propose a flow chart for predicting fault zones. Results of the site investigation and results of trend line analysis of in-situ data were compared to verify the usefulness of a trend line analysis. It is concluded that the orientation of faults can be predicted by using stereonets and the direction of initial stresses can be predicted from the arm length of a displacement vector as a tunnel approaches fault zones. The results of the trend line analysis coincided with those of the site investigation, and a methodology for the prediction of a fault zone was proposed.

• Journal of the Korean Arthroscopy Society
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• v.16 no.2
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• pp.160-166
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• 2012

Purpose: The aim of this study was to determine the patterns of the stress distribution within the reconstructed anterior cruciate ligament (ACL) double bundles in response to an anterior tibial load and rotatory load at $45^{\circ}$ flexed knee model by use of a 3-dimensional finite element analysis (FEM). Materials and Methods: The $0^{\circ}$ and $45^{\circ}$ flexed 3-D knee model were reconstructed based on the high resolution computed tomography (CT) images from the right knee of a healthy male subject. To simulate double bundle ACL reconstruction, in $0^{\circ}$ analytic model, four 7 mm diameter tunnels were created at the center of each anteromedial (AM) and posterolateral (PL) footprints on the femur and tibia. The grafts were inserted into the corresponding bone tunnels and then reconstructed knee model was flexed to $45^{\circ}$. As a next step, the 5 mm anterior tibial load and internal rotational load of $10^{\circ}$ were applied on the final Computer aided design (CAD) model. And then stress patterns of each bundle were assessed using a finite element analysis. Results: In response to the 5 mm of anterior tibial load, the AM bundle showed increased stresses around the tibial and femoral attachment sites; especially in the anterior aspect of the bundle. In the PL bundle, the highest stress concentration was also noticed on the anterior aspect of the bundle. Under $10^{\circ}$ internal rotational load, the stress concentration was predominant around the anterior aspect of the tibial attachment site within the AM bundle. The PL bundle also showed highest stress concentration on the anterior aspect of the bundle. Conclusion: Although the stress patterns were not identical among the AM and PL bundle, there were common trends in the stress distribution. The stress concentration was predominant on the anterior aspect of both bundles in response to the anterior tibial load and rotatory load.

• 대한관절경학회:학술대회논문집
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• 2008.04a
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• pp.34-34
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• 2008

• 대한치과보철학회:학술대회논문집
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• 1999.04a
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• pp.59-59
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• 1999

• The Journal of Korean Academy of Prosthodontics
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• v.51 no.3
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• pp.199-207
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• 2013

Purpose: The importance of occlusal contacts of the natural dentition for durability of teeth, mandibular stabilization, and restorative dentistry is well known. The purpose of this study is to analyze the occlusal contact and guidance pattern of Koreans by evaluating the static occlusion on maximal intercuspal position and measuring dynamic occlusion during straight protrusion. Materials and methods: The occlusal contacts at maximal interincisal position and the occlusal guidance pattern during straight protrusion of 29 subjects were recorded with shimstock foil (Whaledent, Langenau, Germany), T-Scan III (Tekscan Inc., Boston, MA, USA), polyvinylsiloxane registration material (Genie Bite, Sultan Healthcare, Hackensack, NJ, USA) and compared. Occlusal registration procedures were repeated 3 times. The position was fixed to an upright position and the head position was fixed with the Frankfurt horizontal plane paralleling the horizontal plane. Fisher's Exact Test (R-General Public License, ver. 2.14.1) and Pearson's Test were used to assess the significance level of the differences between the experimental groups (${\alpha}=.05$). Results: When using shimstock foil, T-Scan III system, and polyvinylsiloxane registration material, most of the patients showed contact on anterior, premolar, and molar teeth during maximal intercuspal position. Approximately 51% of maximal intercuspal position showed anterior contact using shimstock foil. When examining the protrusive movement using shimstock foil and T-Scan III system, guidance pattern with the central incisor was the most common. Conclusion: During maximal intercuspal position, there were cases in which not all of the teeth showed occlusal contact. During mandibular protrusive movements, one or more maxillary central incisors frequently joined in straight protrusion and the posterior teeth were disoccluded. Therefore, the anterior teeth protect the posterior teeth, and vice versa. Thus, mutually protected occlusion should be applied when reconstructing occlusion.

• The korean journal of orthodontics
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• v.32 no.6 s.95
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• pp.413-424
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• 2002

Preadolescent children with deficient maxillae are suitable candidates for the maxillary protraction appliance(MPA). The theoretical effect of the MPA is protraction or anterior displacement of the maxilla. However, it is known that complex effects such as anterior displacement of the maxillary teeth, downward and backward rotation of the mandible, linguoversion of the mandibular anterior incisors, are known to play a role in improving the Cl III malocclusion. There have been much studies with regard to maxillary protraction, but the different effects of MPAs depending on the vertical facial pattern are not known precisely. This study was based on 67 patients (31 males, 36 females) aged from 6 years 6 months to 13 years 3months, who visited the Dept. of Orthodontics at Yonsei Univ., Dental Hospital and diagnosed as skeletal Class III with maxillary deficiency. They were divided into 3 groups (low, average, high angle groups) depending on genial angle and the SNMP (Go-Gn) angle, respectively. Pretreatment and post-treatment lateral cephalograms were used to compare the effects of MPA and the following conclusions were obtained: 1) A significantly large amount of backward movement of the B point was observed in patients with a low SNMP angle. Those with a high SNMP angle had significant forward movement at A point. 2) The patients with low genial angle had the least forward movement at the A point, and those with a high angle had more forward movement. 3) In comparing the arcTan of the A point, the high angle group showed more horizontal movement while the low angle group showed more vertical movement. 4) There was no significance between the treatment duration of the SNMP and the Genial angle groups.

• Journal of the Korean Arthroscopy Society
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• v.8 no.2
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• pp.82-88
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• 2004

Purpose: In this study, we intended to ascertain the benefit of KT-2000 Knee arthrometer(KT-2000) in the diagnosis of ACL(Anterior cruciate ligament) injury by comparing the anterior displacement of normal knee with that of ACL deficient knee. Materials and Methods: We designated two examiners to measure the anterior displacement of the knee joint of 30 healthy individuals, using KT-2000, at 30$^{\circ}$ flexion setting of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation and analyzed these results according to the variables and measured the preoperative anterior displacement of the ACL injured knee in the 30 patients who have gone through an arthroscopic ACL reconstruction later. Results: The results of examiner 1 are 6.5${\pm}$1.5 mm, 2.5${\pm}$0.9 mm, 4.8${\pm}$1.2 mm, 6.4${\pm}$1.3 mm in right knee and 5.6${\pm}$1.3 mm, 2.1${\pm}$0.8 mm, 4.5${\pm}$1.2 mm, 5.2${\pm}$1.3 mm in left knee, in order of muscle full relaxation, contraction, 25$^{\circ}$ internal rotation and 25$^{\circ}$ external rotation. The results of examiner 2 are 6.9${\pm}$1.2mm, 2.9${\pm}$1.1mm, 5.6${\pm}$1.6mm, 6.9${\pm}$1.5mm in right, 5.5${\pm}$1.7 mm,1.9${\pm}$0.9 mm, 5.1${\pm}$1.9 mm, 5.7${\pm}$1.6 mm in left knee, The side to side difference of examiner 1 in the setting of muscle relaxation is 0.9${\pm}$1.0 mm. The anterior displaement of ACL injured knee is average 11${\pm}$2.93 mm and difference of average 6.5${\pm}$2.31 mm form that of normal. In comparison between the right and left knees of healthy individuals, the both results of two examiners showed the statistical difference in the setting of muscle full relaxation but, the results showed the side to side difference below 2 mm in 25case(83%), 21case(70%) respectively and above 3 mm in just 1 case. In the comparison between the normal and ACL injured knees, the results show the statistical difference of the side to side difference in the setting of muscle relaxation(p<0.05). Conclusion: The KT-2000 result is affected by relaxation of muscles around knee, flexion angle of knee joint, rotation of tibia, the strength of displacing force, time of the test and physical factors as height and weight. However, the Accuracy of diagnosis of ACL injury by KT-2000 will increase if the examiner is skillful and the tests are made on the exact position of knee joint.