• Clinics in Shoulder and Elbow
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• v.19 no.1
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• pp.51-58
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• 2016

The arthroscopic rotator cuff repair is now considered a mainstream technique with highly satisfactory clinical results. However, concerns remain regarding healing failures for large and massive tears and high revision rate. In recent decades, various repair strategies and construct configurations have been developed for rotator cuff repair with the understanding that many factors contribute to the structural integrity of the repaired construct. The focus of biomechanical test in arthroscopic repair has been on increasing fixation strength and restoration of the footprint contact characteristics to provide early rehabilitation and improve healing. These include repaired rotator cuff tendon-footprint motion, increased tendon-footprint contact area and pressure, and tissue quality of tendon and bone. Recent studies have shown that a transosseous tunnel technique provides improved contact area and pressure between rotator cuff tendon and insertion footprint, and the technique of using double rows of suture anchors to recreate the native footprint attachment has been recently described. The transosseous equivalent suture bridge technique has the highest contact pressure and fixation force. In this review, the biomechanical tests about repair techniques of rotator cuff tear will be reviewed and discussed.

• Clinics in Shoulder and Elbow
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• v.22 no.3
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• pp.121-127
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• 2019

Background: Posterior decentering is not an uncommon finding on rotator cuff tear patients' shoulder magnetic resonance imaging. No previous study has reported on the relationship between posterior decentering and rotator cuff tear. Methods: We assessed patients' rotator cuff tear humeral head positions based on humeral-scapular alignment (HSA). Subjects were classified into centering and decentering groups based on a <2 mm or >2 mm HSA value, respectively. Differences in rotator cuff tear size, degree of tear, and fatty degeneration between the two groups were evaluated. Results: One hundred seventy-five patients (80 males, 95 females; mean age: $59.7{\pm}6.5$ years old) were selected as subjects (casecontrol study; level of evidence: 3). Tear size, degree of subscapularis tendon tear, and fatty degeneration of the supraspinatus, infraspinatus, and subscapularis muscles were significantly different between the two groups (p<0.001, p<0.001, p<0.001). Conclusions: The occurrence of decentering was related to rotator cuff tear size, degree of subscapularis tendon tear, and fatty degeneration of the rotator cuff muscles.

• Clinics in Shoulder and Elbow
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• v.9 no.2
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• pp.181-188
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• 2006

Purpose: To evaluate the integrity of repair & technical tip in use of Massive Cuff Stitch at arthroscopic repair of rotator cuff tear. Materials and Methods: Twenthy-nine cases of arthroscopically repaired full thickness tear of rotator cuffs which are medium sized were evaluated. Between December 2004 to September 2005 we have studied, the average age 53($42{\sim}69$) years old, mean follow-up was 15($12{\sim}21$) months. We analyzed the results statistically by paired t-test. The integrity of repair were verified by follow up MRI which were checked 11 cases and ultrasound which were checked 10 cases. Results: VAS of pain improved preoperative average 7.1 to postoperative 0.9, ADL improved 11.2 to 25.6 respectively, UCLA improved 13.7 to 32.9(all, P<0.05). 89.7% showed excellent & good results at the final follow-up. The satisfied rate was 93.1%(27 cases). There was re-rupture of the repaired rotator cuff in one case out of 11 cases which were checked by MRI, and in one case out of 10 cases which were checked by ultrasound, and there was one case of thinning of cuff which were checked by ultrasound. Conclusion: The use of Massive Cuff Stitch in arthroscopic repair of rotator cuff tear have been reduced technical failure. It will be good surgical technique which maintain the integrity of repairs.

• Journal of Biomedical Engineering Research
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• v.32 no.1
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• pp.45-54
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• 2011

Cuff electrodes have a benefit for chronic electroneurogram(ENG) recording while minimizing nerve damage. However, the ENG signals are usually contaminated by electromyogram(EMG) activity from the surrounding muscle, the thermal noise generated within the source resistance, and the electric noise generated primarily at the first stage of the amplifier. This paper proposes a new cuff electrode to reduce the interference of EMG signals. An additional middle electrode was placed at the center of cuff electrode. As a result, the proposed cuff electrode achieved a higher signal-to-interference ratio compared to the conventional tripolar cuff. The cuff electrode was then assembled together with closure, headstage, and hermetic case including electronic circuits. This paper also presents a lownoise amplifier system to improve signal-to-noise ratio. The circuit was designed based on the noise analysis to minimize the electronic noise. The result shows that the total noise of the amplifier was below $1{\mu}V_{rms}$ for a cuff impedance of $1\;k{\Omega}$ and the common-mode rejection ratio was 115 dB at 1 kHz. In the current study, the performance of nerve cuff electrode system was evaluated by monitoring afferent nerve signals under mechanical stimuli in a rat animal model.

• Clinics in Shoulder and Elbow
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• v.21 no.2
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• pp.101-104
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• 2018

Since shoulder have a higher proportion of muscle which would have low electrical resistance, there could be more electrical damage to the rotator cuff muscles. We present a patient with acute rotator cuff tear by sudden uncontrolled jerking contractions caused by an electrical shock. A case of 42-year-old man with acute rotator cuff tear due to electrical injury to the shoulder was presented. Magnetic resonance imaging showed a full thickness tear and an undulating appearance of the peripheral end of the torn supraspinatus and infraspinatus muscle, suggesting an acute complete rupture. By arthroscopic surgery, the torn rotator cuff tendons were repaired with a suture bridge technique. At the final follow-up, the patient had a full, pain-free range of motion and had fully recovered shoulder muscle power.

• Clinics in Shoulder and Elbow
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• v.9 no.2
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• pp.222-226
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• 2006

Full-thickness rotator cuff tears are relatively uncommon in the young adults. One of the pathogenesis of such tear is thought to be closely related to the specific trauma event. Favorable outcome is expected in young patient rotator cuff tears when it is diagnosed early following prompt surgical repair. However, early detection is sometimes difficult when the acute rotator cuff tear is combined with other injuries especially around the shoulder joints such as ipsilateral humerus fractures. Authors report an uncommon case of acute traumatic rotator cuff tear accompanied by the midhumerus shaft fracture in young adult.

• Clinics in Shoulder and Elbow
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• v.23 no.1
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• pp.48-58
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• 2020

Although the prevalence of rotator cuff tears is dependent on the size, 11% to 94% of patients experience retear or healing failure after rotator cuff repair. Treatment of patients with failed rotator cuff repair ranges widely, from conservative treatment to arthroplasty. This review article attempts to summarize the most recent and relevant surgical options for failed rotator cuff repair patients, and the outcomes of each treatment, except arthroplasty.

• Clinics in Shoulder and Elbow
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• v.20 no.2
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• pp.105-112
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• 2017

Rotator cuff tears commonly affect the shoulder joints. Despite developments in surgical techniques and instrumentation, the treatment of massive rotator cuff tears remains challenging. The problems associated with rotator cuff repairs, such as inferior mechanical properties and high retear rates are yet to be solved. Recently, patch augmentation has been suggested as an alternative treatment because it can reinforce mechanical properties at the initial stage of healing and reduce gap formation. The purpose of this article was to comprehensively summarize the concepts and the consensus surrounding patch augmentation and evaluate the clinical and anatomical outcomes after patch augmentation for massive rotator cuff tears.

• Clinics in Shoulder and Elbow
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• v.18 no.1
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• pp.52-58
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• 2015

Animal shoulder models are important in the investigation of the natural history of various pathologic conditions and for evaluation of the effectiveness of different treatments and biomaterials. The characteristics of animal shoulder models that may be used for rotator cuff related experiments are different with regard to the anatomy, behavioral pattern, advantages and disadvantages in application to each other. The lower primates and all the non-primate species, except the tree kangaroo, were neither functional overhead nor had a true rotator cuff. Utilizing more advanced primates, or perhaps even the tree kangaroo would be ideal and the most relevant to man as they possess a true rotator cuff. However, ethical concerns, costs, and many limitations in obtaining primates generally preclude the use of these animals for such research. Finally we should consider the differences in comparative anatomy and behavioral pattern of each animal model during performance or interpretation of rotator cuff experiments.

• The Korean Journal of Pain
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• v.24 no.2
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• pp.69-73
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• 2011

Although the incidence of partial-thickness rotator cuff tears (PTRCTs) was reported to be from 13% to 32% in cadaveric studies, the actual incidence is not yet known. The causes of PTRCTs can be explained by either extrinsic or intrinsic theories. Studies suggest that intrinsic degeneration within the rotator cuff is the principal factor in the pathogenesis of rotator cuff tears. Extrinsic causes include subacromial impingement, acute traumatic events, and repetitive microtrauma. However, acromially initiated rotator cuff pathology does not occur and extrinsic impingement does not cause pathology on the articular side of the tendon. An arthroscopic classification system has been developed based on the location and depth of the tear. These include the articular, bursal, and intratendinous areas. Both ultrasound and magnetic resonance image are reported with a high accuracy of 87%. Conservative treatment, such as subacromial or intra-articular injections and suprascapular nerve block with or without block of the articular branches of the circumflex nerve, should be considered prior to operative treatment for PTRCTs.