• 대한인간공학회지
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• 제34권1호
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• pp.11-18
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• 2015

Objective: The aim of this study was to understand the effects of phone weight on the typing performance and muscle recruitment in the neck and upper extremity while typing a text message with dominant hand. The iPhone4 and iPhone5 were compared due to their 28-gram differences in weight. Background: Too much use of a cellular phone can lead the musculoskeletal disorders in the upper extremity. Phone makers tend to make their new models bigger, lighter, faster and smarter. Method: Fourteen healthy volunteers without any history of neuromuscular disorders or ongoing pain who used their smartphone more than one year were recruited. A 112g phone (iPhone5) and a 142g phone (iPhone4) were used for typing the lyric of the Korean national anthem with their dominant hand. Typing duration, the typing error, the perceived fatigue, and preference was investigated. Muscle recruitment and the resting gap of neck (middle trapezius and levator scapula), shoulder (infraspinatus and mid deltoid), elbow (biceps brachii and brachioradialis), thumb (extensor and abductor policis brevis) were collected using surface electromyography. Typing error was counted and typing speed was calculated in characters per min. The data were analyzed using a paired t-test and chi-square (${\chi}^2$) analysis for the effects of phone weight on the typing performance parameters and muscle recruitment. Results: Typing text message with iPhone5 took longer but had less muscle recruitment in brachioradialis, and extensor policis brevis muscles. Lighter weight of iPhone5 made biceps brachii to rest less without increasing the mean %EMG. Conclusion/Application: Findings of this study can be valuable information for phone designers to develop more productive device and for smartphone users to prevent the musculoskeletal disorders in the upper extremities.

• Physical Therapy Rehabilitation Science
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• 제9권2호
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• pp.98-104
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• 2020

Objective: The shoulders are a particularly an important body part for elite boxers. The purpose of this study was to investigate the characteristics of the upper trapezius (UT), infraspinatus (IS) muscle tone, pain, and isokinetic muscle function of shoulder movements such as external rotation, internal rotation, protraction, and retraction according to the scapular position of elite boxers of the Korean national team. Design: Cross-sectional study. Methods: Using the double square method, the scapular position was measured and divided into the forward scapular position group (n=8) with a measurement distance of 135 mm or more, and the normal scapular position group (n=10) with a measurement distance of less than 135 mm. Through the numeric rating scale of the subject, the pain value displayed during movement was measured. The muscle tone of the subjects' UT and IS were measured. The isokinetic muscle function of ER, IR, protraction, and retraction were measured using isokinetic exercise equipment. Results: The results of this study showed statistically significant differences when comparing muscle tone of the UT and IS, shoulder pain, isokinetic function of ER and IR, protraction, and retraction according to scapular position (p<0.05). Conclusions: The findings of this study were that shoulder muscle tone, pain, and isokinetic muscle function were affected according to the scapular position of elite boxers. In the future, this information may be a useful indicator when studying the effects of medium and long-term intervention in elite boxers who possess these characteristics.

• Biomaterials and Biomechanics in Bioengineering
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• 제3권2호
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• pp.115-127
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• 2016

Shoulder pain, injury and discomfort are public health and economic issues world-wide. The function of these joints and the stresses developed during their movement is a major concern to the orthopedic surgeon to study precisely the injury mechanisms and thereby analyze the post-operative progress of the injury. Shoulder is one of the most critical joints in the human anatomy with maximum degrees of freedom. It mainly consists of the clavicle, scapula and humerus; the articulations linking them; and the muscles that move them. In order to understand the behavior of individual muscle during abduction arm movement, an attempt has been made to analyze the stresses developed in the shoulder muscles during abduction arm movement during the full range of motion by using the 3D FEM model. 3D scanning (ATOS III scanner) is used for the 3D shoulder joint cad model generation in CATIA V5. Muscles are added and then exported to the ANSYS APDL solver for stress analysis. Sensitivity Analysis is done for stress and strain behavior amongst different shoulder muscles; deltoid, supraspinatus, teres minor, infraspinatus, and subscapularies during adduction arm movement. During the individual deltoid muscle analysis, the von Mises stresses induced in deltoid muscle was maximum (4.2175 MPa) and in group muscle analysis it was (2.4127MPa) compared to other individual four rotor cuff muscles. The study confirmed that deltoid muscle is more sensitive muscle for the abduction arm movement during individual and group muscle analysis. The present work provides in depth information to the researchers and orthopedicians for the better understanding about the shoulder mechanism and the most stressed muscle during the abduction arm movement at different ROM. So during rehabilitation, the orthopedicians should focus on strengthening the deltoid muscles at earliest.

• Clinics in Shoulder and Elbow
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• 제10권2호
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• pp.227-231
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• 2007

골절이 동반된 견관절 후방 탈구는 견관절 탈구의 1% 미만을 차지하며 동반되는 골절은 상완골 두 감입 골절이나 소결절 골절이 대부분이다. 그러나 회전근 개 전 파열이 동반된 후방 탈구는 아직까지 보고된 적이 없다. 저자들은 견관절 후방 탈구와 함께 극상근건이 부착된 대결절 견열 골절, 극하근건, 소원형근건 및 견갑하근건의 완전 파열이 동반되어 수술 치료한 1예를 경험하였기에 문헌 고찰과 함께 보고하고자 한다.

• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.207-212
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• 2018

Background: Delaminated rotator cuff tear is known to be a degenerative tear having a negative prognostic effect. This study undertook to compare the anatomical and clinical outcomes of delaminated tears and single layer tears. Methods: Totally, 175 patients with medium to large rotator cuff tears enrolled for the study were divided into 2 groups, based on the tear pathology: single layer tear (group 1) and delaminated tear (group 2). Preoperatively, length of the remnant tendon, muscle atrophy of supraspinatus (SS), and fatty degeneration of SS and infraspinatus (IS) muscles were assessed on magnetic resonance imaging (MRI). For follow-up, the repair integrity of the rotator cuff was evaluated by ultrasonography. Clinical outcomes were assessed by evaluating the Constant score (CS) and Korean Shoulder Score (KSS). Results: Retears were detected in 6 cases of group 1 (6.5%) and 11 cases of group 2 (13.3%). Although higher in group 2, the retear rate was significantly not different (p=0.133). Preoperative MRI revealed length of remnant tendon to be $15.46{\pm}3.60mm$ and $14.17{\pm}3.16mm$ (p=0.013), and muscle atrophy of SS (occupation ratio) was $60.54{\pm}13.15$ and $56.55{\pm}12.88$ (p=0.045), in group 1 and group 2, respectively. Fatty degeneration of SS and IS in both groups had no significant differences. Postoperatively, no significant differences were observed for CS and KSS values between the groups. Conclusions: Delaminated rotator cuff tears showed shorter remnant tendon length and higher muscle atrophy that correlate to a negative prognosis. These prognostic effects should be considered during delaminated rotator cuff tear treatment.

• Clinics in Shoulder and Elbow
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• 제22권1호
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• pp.9-15
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• 2019

Background: Latissimus dorsi (LD) tendon transfer is used as a treatment option for massive irreparable posterosuperior rotator cuff tears, and recently, an arthroscopic-assisted technique was introduced. This study was undertaken to evaluate the clinical and radiological outcomes of arthroscopic-assisted LD tendon transfer for the management of irreparable rotator cuff tears in active middle-aged patients. Methods: The records of five patients (two males) with irreparable tears involving the supraspinatus and infraspinatus tendons managed by arthroscopic-assisted LD tendon transfer were retrospectively reviewed. Clinical outcomes were assessed using the visual analogue scale (VAS) pain scale, American Shoulder and Elbow Surgeon's (ASES) scores, the University of California Los Angeles (UCLA) scale, and ranges of motion. Postoperative integrities of transferred tendon were evaluated by magnetic resonance imaging in 4 patients and by ultrasound in one. Results: Mean patient age was 55 years (range, 48-61 years), and mean follow-up period was 20 months (range, 12.0-27.2 months). Mean VAS score significantly improved from $6.6{\pm}2.6$ preoperatively to $1.8{\pm}2.5$ postoperatively (p=0.009), mean ASES score increased from $67.6{\pm}9.2$ to $84.6{\pm}15.1$, and mean UCLA score from $18.0{\pm}1.4$ to $28.8{\pm}8.5$ (all p<0.001). Postoperative imaging of the transferred LD tendon showed intact repair in 4 patients. The remaining patient experienced LD transfer rupture and a poor outcome. Conclusions: Arthroscopic-assisted LD tendon transfer improved shoulder pain and function in patients with massive, irreparable rotator cuff tears, and may be an option for this condition, especially in physically active patients.

• Investigative Magnetic Resonance Imaging
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• 제22권4호
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• pp.229-239
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• 2018

Purpose: To assess the diagnostic performance in detecting rotator cuff tears at 3T of non-arthrographic shoulder magnetic resonance imaging (MRI) using 3D isotropic turbo spin-echo (TSE-SPACE) sequence as compared with 2D sequences. Materials and Methods: Seventy-four patients who were arthroscopically confirmed to have underwent non-arthrographic shoulder MRI with 2D sequences and TSE-SPACE were included. Three independent readers retrospectively scored supraspinatus and infraspinatus tendon (SST-IST) and subscapularis tendon (SCT) tears on 2D sequences and TSE-SPACE. Results: The mean sensitivity, specificity, and accuracy of the three readers were 95%, 100%, and 95% on TSE-SPACE and 99%, 93%, and 98% on 2D sequences for detecting SST-IST tears, respectively, whereas those were 87%, 49%, and 68% on TSESPACE and 88%, 66%, and 77% on 2D sequences for detecting SCT tears, respectively. There was no statistical difference between the two sequences, except for in the specificity of one reader for detecting SCT tears. The mean AUCs of the three readers on TSE-SPACE and 2D sequences were 0.96 and 0.98 for detecting SST-IST tears, respectively, which were not significantly different, while those were 0.71 and 0.82 for detecting SCT tears, respectively, which were significantly different (P < 0.05). Conclusion: TSE-SPACE may have accuracy and reliability comparable to conventional 2D sequences for SST-IST tears at non-arthrographic 3T shoulder MRI, whereas TSE-SPACE was less reliable than conventional 2D sequences for detecting SCT tears.

• PNF and Movement
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• 제17권1호
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• pp.11-18
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• 2019

Purpose: This study verifies the muscle activity around the amputation site during proprioceptive neuromuscular facilitation (PNF) pattern exercise for the upper extremities on the non-amputated part in upper extremity amputees and provides basic data on effective exercise around an amputation site. Methods: Manual resistance was applied to the PNF upper extremity pattern of the non-amputated part to generate muscle activity around the amputation site. The resistance was adjusted to an intensity that could cause maximal isometric contraction. The muscle activity of the amputation site and the non-amputated part was measured using a surface electromyogram for the upper trapezius, middle trapezius, infraspinatus, serratus anterior, and pectoralis major. Results: During the scapular exercise in the painless range, the amputated side showed significantly lower muscle activity and a lower muscle contraction ratio compared with the non-amputated side. During the PNF pattern exercise in the painless range, the amputated side showed lower muscle activity and a lower muscle contraction ratio compared with the non-amputated side. When the direct scapular exercise of the amputated side was compared with the PNF pattern exercise of the non-amputated side, their muscle contraction ratios were similar. Conclusion: This study confirmed the effectiveness of the PNF pattern exercise of the non-amputated part as a way to indirectly train the injured site with no pain for rehabilitation of patients with serious body injuries, such as amputation. It is necessary to develop effective exercise programs for the rehabilitation of the amputation site based on the results of this study.

• Physical Therapy Rehabilitation Science
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• 제8권1호
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• pp.15-21
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• 2019

Objective: The purpose of this study was to identify whether cutaneous sensory (CS) changes induced by mechanical intervention (MI) increases the trigger point threshold of the same spinal segment as well as to investigate the relationship between the amounts of change in CS pressure pain thresholds (PPT). Design: Randomized controlled trial. Methods: Thirty-nine persons with myofacial pain (MFP) were recruited in this experiment. The subjects consisted of 20 men and 19 women (age 20-39). MI was applied on the subjects using the Graston technique for 5 minutes to induce CS changes. The CS changes were measured with sensory tests by using the Von Frey Filament, and PPT changes were estimated by using the pressure threshold meter. For the observation of sensory and PPT changes with time, the test was conducted for 15 minutes including a pre, post, and after intervention session. Results: CS threshold increased significantly when MI was applied (p<0.001). On the same spinal segment, changes in the right infraspinatus PPT was observed (p<0.001) but the PPT changes in other muscles were not significantly different. Furthermore, the control group CS and PPT were not significantly different. In addition, regression analysis showed that the CS changes have a larger impact on PPT in the same spinal segment (p<0.001). Conclusions: CS changes induced by MI make to change PPT on the same spinal segment. In other words, it is possible to identify PPT changes following CS changes except for the muscle which belongs to a different spinal segment. Therefore, application of MI is necessary for the CS changes in the same spinal segment. Furthermore, it can be useful in the clinical fields as a method of providing pain control and increasing the PPT.

• Clinics in Shoulder and Elbow
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• 제24권2호
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• pp.55-65
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• 2021

Background: Although ultrasound-guided needle decompression (US-GND) can treat calcific tendinitis of the shoulder effectively, repeat procedures might be required for unresolved symptoms. We evaluated the overall clinical outcomes of US-GND with subacromial steroid injection and the final results and factors predisposing toward repeat procedures. Methods: Ninety-eight patients who underwent US-GND for calcific tendinitis of the supraspinatus/infraspinatus were analyzed between March 2017 and December 2018. The clinical outcomes (pain visual analog scale, functional visual analog scale [FVAS], and American Shoulder and Elbow Surgeons [ASES] score) and final subjective satisfaction were compared between groups A (single US-GND) and B (repeat US-GND). The factors predisposing toward repeated US-GNDs were analyzed. Results: We found that 59.3% (58/98) of patient ASES scores were ≥80, and 73.5% of patients (72/98) were satisfied with the outcome. Group B (n=14) demonstrated a significantly higher rate of dominant-arm involvement compared to group A (78.6% vs. 48.8%, p=0.046). However, initial calcification size, shape, number, density, subscapularis involvement, lavage, and procedure time did not differ significantly between the groups. Group B showed poorer final FVAS (7 [interquartile range, 6-8] vs. 8 [interquartile range, 7-9], p=0.036) and subjective satisfaction compared to group A (satisfied: 5 [35.7%] vs. 67 [79.8%], p<0.001]. Conclusions: US-GND with subacromial steroid injection is a viable treatment option for calcific tendinitis of the shoulder. Dominant-arm involvement was the only independent factor for repeated US-GND. Final outcome of repeated US-GND for unimproved patients was promising; however, these outcomes were poor compared to those of the patients who improved after the first procedure.