• Journal of the Korea Safety Management & Science
• /
• v.25 no.2
• /
• pp.107-111
• /
• 2023

This study aims to empirically investigate effects of motion repetition and external load according to joint motion on discomfort through an experiment. Eighteen college students (female: 9; male: 9) participated in an experiment measuring perceived discomfort using the Borg CR10. Joint(wrist, elbow, shoulder and trunk) motion, its repetition and external load were adopted as independent variables. The results showed that all three independent variables were statistically significant on discomfort. Participants' sex also significantly affected discomfort obtained in the experiment. While the interactions of joint motion and repetition, and joint motion and external load were not significant at α = 0.05, that of motion repetition and external load was significant. Based on the experimental results, four regression equations by the joints involved were presented, which could be used as a tool for evaluating postural loads by the joints. It may be postulated that based on the results of this study, scoring systems of RULA and REBA, and those of OWAS and REBA underestimates effects of motion repetition and external load, respectively. It is expected that the results of this study will be used as a basic data for developing an observational method properly reflecting the effects of motion repetition and external load.

• Structural Monitoring and Maintenance
• /
• v.10 no.3
• /
• pp.221-242
• /
• 2023

Internal and external corrosion are common in pressure pipes used in a variety of industries, often resulting in defects that compromise their integrity. This economically and industrially significant problem calls for both preventive and curative technical solutions to guarantee the reliability of these structures. With this in mind, our study focuses on the influence of composite and metallic patch repairs on the limit loads of pipes, particularly elbows, the critical component of piping systems. To this end, we used the nonlinear extended finite element method (X-FEM) to study elbows, a priori corroded on the internal surface of the extrados section, then repaired with composite and metallic patches. In addition, the effect of the geometry of composite materials and metal patches was examined, in particular the effect of their thickness and material on the increase in limit loads of repaired structures. The results obtained provide information on the effectiveness and optimization of patch repair of corroded elbows, with the aim of increasing their service life.

• Clinics in Shoulder and Elbow
• /
• v.5 no.2
• /
• pp.88-97
• /
• 2002

The purpose of this study was to compare the outcomes between arthroscopir repair and mini-open repair of medium and large rotator cuff tears in which arthroscopic repair was technically unsuccessful. We evaluated 76 patients of full-thickness rotator cuff tears, among them 42 patients had all-arthroscopic and 34 patients had mini-open salvage repairs. Patients who had acromioclavicular arthritis, subscapularis tear, or instability were excluded. There were 39 males and 37 females with mean age of 56 years (range,42 to 75 years). At a mean follow-up of 39 months (range, 24 to 64 months), the results of both groups were compared with regard to the UCLA and ASES shoulder rating scale s. Shoulder scores improved in all ratings in both groups (p > 0.05). Overall, sixty-six patients showed excellent or gr)of and ten patients showed fair or poor scores by the UCLA scale. Seventy-two patients satisfactorily returned to prior activity. Four showed unsatisfactory return. The range of motion, strength, and patient's satisfaction were improved postoperatively. There were no difference in shoulder scores, pain, and activity return between the arthroscopic and mini-open salvage groups (p > 0.05). However, Patients with larger size tear showed lower shoulder scores and less predictive recovery of the strength and function (p < 0.05). Postoperative pain was not different with respect to the size of the tear (p : 0.251). Arthroscopic repair of medium and large full-thickness rotator cuff tears had iln equal outcome to technically unsuccessful arthroscopic repairs, which were salvaged by conversion to a mini- open repair technique. Surgical outcome depended on the size of the tear, rather than the method of repair.

• Clinics in Shoulder and Elbow
• /
• v.3 no.2
• /
• pp.61-67
• /
• 2000

Purpose: Most proximal humeral fractures are minimally displaced and can be treated satisfactorily with a conservative method. But in many comminuted fractures, hemiarthroplasty is usually done as a primary treatment. The authors evaluated how much functional improvement was achieved after hemiarthroplasty and which factors influence on the final functional results. Materials and Methods: Eleven hemiarthroplasties were performed for three- and four-part fractures(including fracture-dislocation) between April 1992 and June 1999. There were eight women and three men, and the mean age was 65 years. According to Neer classification, six was three-part fracture and five was four-part fracture. Six patients were injured on their right shoulder and five on the left shoulder. Among the five four-part fractures, three had axillary nerve injury and among the six three-part fractures, only one patient had axillary nerve injury. The average follow-up period was 2.4 years(1 year-7 years) after operation. The functional results were evaluated with the UCLA scoring system(Modification for hemiarthroplasty). In addition to the overall results, we compared the results according to the classification of the fracture, the cause of injury, and whether the axillary nerve was injured. Results: At the last follow-up, average total UCLA score was 18.2. The mean score for pain was 7.0, mean muscle power and motion score was 5.5 and 5.7 respectively. The pain relief was more satisfactory than any other functional results. The average score for three-part fractures was 22, and the average for four-part fractures was 13.6. The average score for the patients fractured by vehicle accidents was 15.3, and 19.3 for the patients fractured by slip-down injury. In patients without axillary nerve injury, the average score was 20, and with axillary nerve injury, the score was 15. Conclusion: Shoulder hemiarthroplasty, for the treatment of proximal humeral fractures, cannot restore the shoulder function to normal, but can achieve the functional result to some degree, especially for the activity of daily living. And as for pain, we think that it is relatively effective measure. And we think that the severer the comminution, the more the chance of axillary nerve injury, and the poorer the functional results. In conclusion, the severity of initial injury seems to be the major prognostic factor.

• Clinics in Shoulder and Elbow
• /
• v.15 no.2
• /
• pp.117-122
• /
• 2012

Purpose: To assess the effectiveness of internal fixation using a precontoured locking compression plate for the treatment of the displaced clavicle fracture by analyzing both radiological and clinical outcomes. Materials and Methods: We reviewed 34 cases of displaced clavicle shaft fracture treated by internal fixation using precontoured locking compression plates between May 2009 and February 2010. Radiological outcomes were analized on the basis of bone union and the differences between the time for bone union depending on sex and age. Clinical outcomes were analyzed on the basis of quick DASH Scores and the differences in the range of motion of the affected shoulder compared to the contralateral shoulder. Results: In the radiological evaluation, all fractures showed bone union, and the average time for bone union was 12.3 weeks, without delayed unions. Time for bone union did not differ significantly with respect to sex and age (p=0.87). In the clinical evaluation, the average final quick DASH Score was 23.5 (range, 12~42). At final follow up, the range of motion after bone union in the affected shoulder was not significantly different from that of the contralateral shoulder (p=0.69). Conclusion: The internal fixation achieved using precontoured locking compression plate in displaced clavicle shaft fracture showed effective bone union and can be considered as a reliable method with fine clinical results showing early range of motion at the shoulder joint.

• Clinics in Shoulder and Elbow
• /
• v.14 no.2
• /
• pp.236-241
• /
• 2011

Purpose: To report the usefulness of dynamic ultrasonography in subluxation of the long head of the biceps tendon, which is difficult to detect with static imaging such as plain radiography, static sonography, MRI and in a subtle physical examination. Materials and Methods: Two male patients suffered from subluxation of the long head of the biceps. This difficult diagnosis? was managed by surgery (biceps soft tissue tenodesis) with the aid of dynamic ultrasonography. At final follow up, we evaluated patients' symptoms and functional outcomes using KSS, UCLA and ASES scores. Results: We diagnosed and treated subluxation of the long head of the biceps easily using dynamic ultrasonography. At the final follow up, both patients' symptoms and functional outcomes were improved. There were no significant complications. Conclusion: Dynamic ultrasonography is a useful method in the difficult and subtle diagnosis of subluxation of the long head of the biceps.

• Clinics in Shoulder and Elbow
• /
• v.13 no.1
• /
• pp.79-85
• /
• 2010

Purpose: To evaluate the results from arthroscopic repair versus debridement for full-thickness tears of the upper subscapularis tendon. Materials and Methods: Ninety-nine patient outcomes were evaluated and compared prospectively. Sixty-nine patients with full-thickness tears of the upper subscapularis tendon underwent arthroscopic repair (group I) and thirty patients underwent simple debridement (group II) between May 2003 and October 2007. In all patients, the tear was localized to the superior one third of the upper subscapularis tendon. The results of the treatment were assessed by evaluating the UCLA, ASES, and VAS for pain and internal rotation strength scores before and after the operation. Results: In groups I and II, UCLA, ASES, VAS, and internal rotation muscle power (perfect score = 5) scores were improved after surgery. In comparing group I and group II, the UCLA and VAS scores were not significantly different (p>0.05), while the ASES and internal rotation strength scores were significantly different (p<0.05). Conclusion: The arthroscopic repair of full-thickness tears of the upper subscapularis tendon was a better surgical method than simple debridement.

• Clinics in Shoulder and Elbow
• /
• v.10 no.1
• /
• pp.106-111
• /
• 2007

Purpose: The purpose of this paper is to clinically evaluate the usefulness of all arthroscopic repair with biceps incorporation in massive sized full thickness rotator cuff tears. Materials and Methods: This is a prospective comparative outcome study evaluating a series of all arthroscopic rotator cuff repairs with biceps incorporation on massive(range: $5{\sim}\;cm6$ sized) from March 2003 to May 2006. Group I was twenty two cases of arthroscopically repaired with biceps incorporation, twenty cases of group II without biceps incorporation were analyzed. The average age of the patients was 58 years(range, $41{\sim}74$ years), and mean follow-up was 24 months(range, $12{\sim}36$ months). Results were statistically compared by Mann-Whitney test. Results: Average VAS for pain, ADL, UCLA score were not significantly different between group I and group II (P>0.05 for each). Forward elevation strength was 4.3 in group I, 3.5 in group II(P<0.05). On postoperative follow up ultrasound, retear was 10 cases in the middle of 19 cases at group I, 15 cases in the middle of 17 cases at group II (P<0.05). Conclusion: This study reveals that all arthroscopic repairs with biceps incorporation in massive sized full thickness rotator cuff tears is an effective surgical method and reduced retear and enhanced strength.

• Clinics in Shoulder and Elbow
• /
• v.23 no.1
• /
• pp.11-19
• /
• 2020

Background: The purpose of this study was to evaluate and compare deltoid origin status following large rotator cuff repair carried out using either an open or an arthroscopic method with a propensity score matching technique. Methods: A retrospective review of 112 patients treated for full-thickness, large rotator cuff tear via either a classic open repair (open group) or an arthroscopic repair (arthroscopic group) was conducted. All patients included in the study had undergone postoperative magnetic resonance imaging (MRI) and clinical follow-up for at least 12 and 18 months after surgery, respectively. Propensity score matching was used to select controls matched for age, sex, body mass index, and affected site. There were 56 patients in each group, with a mean age of 63.3 years (range, 50-77 years). The postoperative functional and radiologic outcomes for both groups were compared. Radiologic evaluation for postoperative rotator cuff integrity and deltoid origin status was performed with 3-Tesla MRI. Results: The deltoid origin thickness was significantly greater in the arthroscopic group when measured at the anterior acromion (P=0.006), anterior third (P=0.005), and middle third of the lateral border of the acromion level (P=0.005). The deltoid origin thickness at the posterior third of the lateral acromion was not significantly different between the arthroscopic and open groups. The arthroscopic group had significantly higher intact deltoid integrity with less scarring (P=0.04). There were no full-thickness deltoid tears in either the open or arthroscopic group. Conclusions: Open rotator cuff repair resulted in a thinner deltoid origin, especially from the anterior acromion to the middle third of the lateral border of the acromion, at the 1-year postoperative MRI evaluation. Meticulous reattachment of the deltoid origin is as essential as rotator cuff repair when an open approach is selected.

• Korean Journal of Applied Biomechanics
• /
• v.27 no.4
• /
• pp.247-255
• /
• 2017

Objective: The purpose of this study was to investigate the maximum core muscle activation angle according to core-strengthening exercises. Method: Twenty-six young female football players (age: $17.84{\pm}0.80years$, height: $163.08{\pm}5.25cm$, weight: $54.96{\pm}7.41kg$) registered in the Korea Football Association from D High School located in Seoul were the subjects of this research. An electromyogram (Noraxon, USA) was used for monitoring the maximum core muscle contraction activity. Results: The angle for the maximum core muscle strength per core exercise and muscle was the smallest for the upper rectus abdominis in the windshield wiper exercise. The angle of the vastus medialis was significantly the largest. The range of angles at which the maximum strength was observed for each core exercise were as follows: 1) abdominal flutter kicks ($11{\sim}40^{\circ}$), 2) leg raises ($21{\sim}34^{\circ}$), 3) scissors ($45{\sim}66^{\circ}$), 4) knee to elbow sit-ups ($42{\sim}64^{\circ}$), 5) reverse crunches ($9{\sim}40^{\circ}$), 6) butt-ups ($24{\sim}32^{\circ}$), 7) V sit-ups ($5{\sim}24^{\circ}$), 8) windshield wipers ($11{\sim}20^{\circ}$), 9) bird dog ($11{\sim}18^{\circ}$), and 10) raised leg plank ($38{\sim}50^{\circ}$). Conclusion: Four kinds of motion could be classified according to the range of angles at which the core muscles were maximally activated. The first group involves the range of motion that gives the maximum muscle strength when the lower extremity and ground angle was between $5^{\circ}$ and $24^{\circ}$, such as the V sit-ups, windshield wipers, and bird dog. The second group comprised the flutter kicks and reverse crunches at an angle between $9^{\circ}$ and $40^{\circ}$. The third group comprised the leg raise and butt-up exercises at an angle between $21^{\circ}$ and $34^{\circ}$. The fourth group included the scissors, knee to elbow sit-ups, and raised leg plank at an angle between $38^{\circ}$ and $66^{\circ}$. These results may be useful as basic data for core movement and core muscle training according to the purpose of exercise.