• Clinics in Shoulder and Elbow
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• v.11 no.2
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• pp.112-117
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• 2008

Purpose: This study prospectively evaluated the outcome of arthroscopic transtendinous repair as a treatment for partial articular side tears of the rotator cuff. Materials and Methods: Fifteen patients with symptomatic, partial articular side tears of the rotator cuff underwent modified transtendinous repair. The patient's mean age was 52.5 years and the mean duration of symptoms was 33.7 weeks. The visual analogue scale (VAS), the ASES score, the active ROM of the shoulder and the patient's satisfaction were evaluated both preoperatively and postoperatively. The clinical results were analyzed using the Wilcoxon's signed rank test. Results: The mean VAS was $6.6\pm1.1$ before treatment and $0.4\pm0.6$ at 6 month, and the ASES scores for all the patients were significantly better over the six-month period of follow-up (p<0.05). The mean active ROM in abduction was $94.3\pm22.3$ before treatment, $108.7\pm16.3$ at 1 month (p=0.0041) and $164.3\pm5.3$ at six months (p=0.0006). In flexion, it was $105.0\pm23.8$ before treatment, $119.0\pm17.4$ at 1 month(p=0.0075) and $174.3\pm5.3$ at six months (p=0.0006). At the final follow-up, 94% of patients were satisfied or very satisfied after operation. Conclusion: We experienced satisfactory clinical results after a short-term follow-up of arthroscopic transtendinous repair, and we believed this to be an effective procedure for patients with partial articular side tears of the rotator cuff.

• Journal of the Korean Arthroscopy Society
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• v.17 no.1
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• pp.1-5
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• 2013

Purpose: To evaluate the clinical results of arthroscopic repair with Ulsan University - Mason Allen - Suture Bridge (UU MA SB) stitch for the full thickness rotator cuff tear. Materials and Methods: Fifteen patients with full thickness rotator cuff tear underwent arthroscopic repair with UU MA SB stitch between September 2010 and December 2010. Clinical and functional evaluations were made according to Korean shoulder score (KSS), American shoulder and elbow surgeon (ASES), University of California, Los Angeles (UCLA), visual anabgue scale (VAS) and the range of motion. Results: The mean KSS improved from 51.4 preoperatively to 92.0 at final follow-up (p<0.05). The mean UCLA score improved from 15.07 preoperatively to 31.93 postoperatively, the mean VAS of pain during the motion was 7.2 before treatment and 0.93 at final follow-up (p<0.001). At last follow-up, the mean range of motion was improved but they had not shown statistical significance (p>0.05). Conclusion: The arthroscopic repair with UU MA SB stitch may be an effective procedure in the full thickness rotator cuff tear for pain relief and improvement of the range of motion.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.2
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• pp.117-122
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• 2006

Purpose: The purpose of this study is to investigate the relationship between rotator cuff tear and nerve injury, and prevalence of nerve injury using electromyographic study. Materials and Methods: From May 2004 to Feb. 2005, 19 cases, who underwent surgery for full-thickness rotator cuff tear, were evaluated for nerve injury using electomyogram instruments preoperatively. Rotator cuff tears caused by acute high energy trauma were excluded in this study. Mean age was 59 (range, 45-87) years and mean duration of symptoms was 45 (range, 1-360) month. Results: There were six nerve injuries (31.6%). All of them were incomplete brachial plexus injuries, and mainly postganglionic lesions. Four cases among them had minor trauma history. There were no significant differences in terms of cuff tear size, range of motion, pain score and functional score between groups with and without nerve injury. Conclusion: This study showed high prevalence (31.6%) of nerve injury in full-thickness rotator cuff tear. So careful physical examination and evaluation for nerve injury are needed in rotator cuff tear.

• Clinics in Shoulder and Elbow
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• v.12 no.1
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• pp.7-13
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• 2009

Purpose: To evaluate the clinical and radiological results of arthroscopic tuberoplasty for irreparable massive rotator cuff tears. Materials and Methods: Eleven patients underwent arthroscopic tuberoplasty for irreparable massive rotator cuff tears between December 2004 and April 2007. The mean follow-up period was 17.3 months, and the average age at the time of surgery was 61.7-year-old. Five cases underwent arthroscopic tuberoplasty and 6 cases had arthroscopic subacromial decompression and tuberoplasty, simultaneously. Results: The average Constant score improved from 61.8 to 86.9 and the average UCLA score changed from 14.8 to 31.8 with 6 excellent, 3 good and 2 poor results (p=0.003). The active forward flexion improved from $111.8^{\circ}$ to $154.1^{\circ}$(p=0.011). The acromiohumeral interval increased from 3.94 mm preoperatively to 4.22 mm postoperatively (p=0.12). In the poor UCLA score group, the acromiohumeral interval changed from 1.67 mm preoperatively to 0.94 mm postoperatively. Conclusion: Arthroscopic tuberoplasty may be a second option to relieve the pain of irreparable massive rotator cuff tears and improve the range of motion. However, good results could not be expected if the acromiohumeral interval is < 2 mm preoperatively and decreased postoperatively.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.125-139
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• 2008

The purpose of this study is to compare and analyze a kinematic characteristics of throwing performance among born visually impaired, postnatal visually impaired and visually correct people through their kinematic characteristics. Another purpose of this study is to prevent injury and improve blind's exercise leadership and physical abilities. Three video cameras were used and each camera's shooting velocity was 60field/sec. Then the longest thrown pose was collected and analyzed by using Kwon 3D ver. 3.1 program. The results obtained from this study were followings; 1. During release, the fastest speed of ball was visually corrected followed by postnatal visually impaired and then born visually impaired. 2. Visually corrected used wrist joint well and had wide body round range with similar motion patterns, however born visually impaired couldn't do this at all. 3. Visually corrected used waist to lead shoulder at Phase 2 while throwing ball, but some of born visually impaired and postnatal visually impaired couldn't use waist to lead shoulder. 4. Visually corrected looked at the way where ball would go, but blinds couldn't look where ball would go. 5. Not like visually corrected who show similar patterns, born visually impaired showed each different patterns and some postnatal visually impaired showed similar patterns with visually corrected. 6. While throwing ball, visually corrected showed flexible weight-movement, postnatal visually impaired were not good as visually corrected, and born visually impaired couldn't do weight-movement at all. Synthetically, this result showed that throwing motions are affected a lot by the time when people became blind.

• Clinics in Shoulder and Elbow
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• v.1 no.2
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• pp.205-211
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• 1998

The comminuted fracture and dislocation of the proximal humerus occur more frequently in older patient group and operative treatment is difficult due to poor bone quality. Based on Neer's work, hemiarthroplasty has now become widly accepted for the management of the three-part fracture and four-part fracture-dislocation of the proximal humerus in old age group. The purpose of this study is to evaluate function, pain relief, and patient satisfaction after hemiarthroplasty for proximal humerus fractures and dislocations. Authors reviewed and analyzed 14 prosthetic replacement in comminuted proximal humeral fracture and dislocation at the Department of Orthopaedic Surgery, Yonsei University Wonju College of Medicine from March, 1988 to May, 1997. The results were as follows the average age was 58.9years and the ratio of males and females was 5:9. The most common cause of injury was traffic accident(43%). According to the classification of Neer, three part fracture were three(21%), four-part fracture and four-part fracture-dislocation were eleven(79%). The prosthetic replacement was performed within two weeks in eight patient and six were performed after two weeks. The results were analysed according to Neer's criteria and five cases showed satisfactory results. We concluded that hemiarthroplasty for fracture and dislocation of the proximal humerus facilitated the restoration of humerus length and pain relief, thereby allowing earlier motion to prevent the development of painful shoulder: stiffness.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.5
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• pp.359-367
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• 2018

The vortex ring state that occurs during the descending flight of a rotorcraft generates a circulating flow like a donut near the rotating surface, and it often causes a rotorcraft fall due to loss of thrust. In this paper, we have physically identified the flow field in the vortex ring state of the quadcopter, one of the types of unmanned aerial vehicles. The descending flight of the quadcopter was simulated in a 1m subsonic wind tunnel of the Korea Aerospace Research Institute(KARI) and the Particle Image Velocimetry(PIV) was used for the flow field measurement. The induced velocity in the hovering state is estimated by using the momentum theory and the test was carried out in the range of descent rate at which the vortex ring condition could be caused. The development and the direction of the vortex ring were confirmed by the measurement of the flow field according to not only the descent rate but also propeller separation distance. In addition, the results of the study show the vortex ring state can be predicted sufficiently by measuring the flow velocity around the quadcopter.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.591-596
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• 2022

Since 4-bar linkage widely used in various industrial fields has a fixed link length, it is inconvenient to add an independent link structure or control device to change the movement of output link. Therefore, this paper proposes a new concept of variable 4-bar linkage mechanism to selectively adjust the movement of the output link to fit desired situations, and applied to the commercial table fans, which is a representative product using a 4-bar linkage system. The optimal rotation angle steps for efficiency are determined experimentally and the appropriate lengths of linkage to fit each step are calculated analytically. Changes in the linkage length are implemented by the rotational motion using a grooved cylindrical cam and the feasibility of the proposed variable linkage mechanism is verified through fabrication and measurement. The presented variable link mechanism is expected to improve the efficiency of industrial robots and fuel valve systems.

• Journal of the Korean Orthopaedic Association
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• v.55 no.1
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• pp.46-53
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• 2020

Purpose: Scapular body fractures have generally been treated with non-surgical methods. This study reports the clinical and radiological outcomes after lateral-posterior internal fixation for treating displaced scapular body fractures. Materials and Methods: From March 2007 to May 2017, out of 40 patients who underwent internal fixation for scapular fractures, 13 cases of lateral plate fixation of a scapular body fracture were reviewed retrospectively. Preoperative and postoperative displacement, angulation and glenopolar angle (GPA) were measured. The range of shoulder motion, visual analogue scale (VAS), and disabilities of the arm, shoulder, and hand (DASH), and Constant score were assessed at the last follow-up. Results: The mean follow-up period was 17.7 months (range, 6-45 months). The mean preoperative GPA was 23.3°±3.96° (range, 17.8°-28.1°) and the postoperative GPA was 31.1°±4.75° (range, 22.5°-40.1°). Injury to the suprascapular nerve, nonunion, fracture redisplacement, metallic failure, or infection did not occur. At the last follow-up, the mean range of motion was 150.5°±19.3° in forward flexion, 146.6°±2.34° in lateral abduction, 66.6°±19.1° in external rotation, and 61.6°±18.9° in internal rotation. The VAS, DASH, and Constant scores were 1.7±1.3, 6.2±2.4, and 86±7.9 points, respectively. Conclusion: A scapular body fracture with severe displacement, angulation and marked decreased GPA can be stabilized by lateralposterior plate fixation using the appropriate surgical technique with good functional and radiological results.

• Physical Therapy Korea
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• v.3 no.1
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• pp.32-39
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• 1996

For effective rehabilitation of the shoulder, physical therapists must have correct knowledge of shoulder movements. The purpose of this study was to determine the relationship between shoulder movements and the rotation of the humerus in the sagittal, coronal and scapular planes. Fifty normal subjects(25 male, 25 female) were tested using a Dualar-plus digital goniometer and an air-splint. The subjects performed active shoulder elevation in each plane with the humerus rotated in both medial and lateral directions. The range of motion(ROM) of the glenohumeral joint was measured three times. The paired t-test was used to determine the difference in ROM between medial and lateral rotation of the humerus. Results showed that, in the sagittal and the coronal planes, there was a significant difference(p < 0.01) in ROM of the shoulder between medial rotation and lateral rotation which was greater. But in the scapular plane, there was no difference between medial and lateral rotation. Physical therapists should consider these results when the goal of treatment is to increase ROM of the shoulder.