• Clinics in Shoulder and Elbow
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• v.27 no.2
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• pp.183-195
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• 2024

Background: Reverse total shoulder arthroplasty (rTSA) has gained popularity in recent years and is indicated for a wide variety of shoulder pathologies. However, use of rTSA in patients with "weight-bearing" shoulders that support wheelchair use or crutches has higher risk. The aim of this study was to assess the results of rTSA in such patients. Methods: Between 2005 and 2014, 24 patients (30 shoulders) with weight-bearing shoulders were treated with rTSA at our unit. Patients had cuff arthropathy (n=21), rheumatoid arthritis (n=3), osteoarthritis (n=1), acute fracture (n=3), or fracture sequela (n=2). Postoperatively, patients were advised not to push themselves up and out of their wheelchair for 6 weeks. This study was performed in 2016, and 21 patients (27 shoulders) were available for a mean follow-up of 5.6 years (range, 2-10 years). The mean age at surgery was 78 years (range, 54-90 years). Results: Constant-Murley score improved from 9.4 preoperatively to 59.8 at the final follow-up (P=0.001). Pain score improved from 2/15 to 13.8/15 (P=0.001). Patient satisfaction (Subjective Shoulder Value) improved from 0.6/10 to 8.7/10 (P=0.001). Significant improvement in mean range of motion from 46° to 130° of elevation, 14° to 35° of external rotation, and 29° to 78° internal rotation was recorded (P=0.001). Final mean Activities of Daily Living External and Internal Rotation was 32.4/36. Only three patients showed Sirveaux-Nerot grade-1 (10%) glenoid notching and three grade 2 (10%). Conclusions: rTSA can be used for treatment of patients with weight-bearing shoulders. Such patients reported pain free movement, resumed daily activities, and high satisfaction rates.

• Advances in aircraft and spacecraft science
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• v.5 no.2
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• pp.225-237
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• 2018

The difficulties of satellite vibration testing are due to the commonly expressed qualification requirements being incompatible with the limited performance of the entire controlled system (satellite + interface + shaker + controller). Two features cause the problem: firstly, the main satellite modes (i.e., the first structural mode and the high and low tank modes) are very weakly damped; secondly, the controller is just too basic to achieve the expected performance in such cases. The combination of these two issues results in oscillations around the notching levels and high amplitude beating immediately after the mode. The beating overshoots are a major risk source because they can result in the test being aborted if the qualification upper limit is exceeded. Although the abort is, in itself, a safety measure protecting the tested satellite, it increases the risk of structural fatigue, firstly because the abort threshold has been already reached, and secondly, because the test must restart at the same close-resonance frequency and remain there until the qualification level is reached and the sweep frequency can continue. The beat minimum relates only to small successive frequency ranges in which the qualification level is not reached. Although they are less problematic because they do not cause an inadvertent test shutdown, such situations inevitably result in waiver requests from the client. A controlled-system analysis indicates an operating principle that cannot provide sufficient stability: the drive calculation (which controls the process) simply multiplies the frequency reference (usually called cola) and a function of the following setpoint, the ratio between the amplitude already reached and the previous setpoint, and the compression factor. This function value changes at each cola interval, but it never takes into account the sensor signal phase. Because of these limitations, we firstly examined whether it was possible to empirically determine, using a series of tests with a very simple dummy, a controller setting process that significantly improves the results. As the attempt failed, we have performed simulations seeking an optimum adjustment by finding the Least Mean Square of the difference between the reference and response signal. The simulations showed a significant improvement during the notch beat and a small reduction in the beat amplitude. However, the small improvement in this process was not useful because it highlighted the need to change the reference at each cola interval, sometimes with instructions almost twice the qualification level. Another uncertainty regarding the consequences of such an approach involves the impact of differences between the estimated model (used in the simulation) and the actual system. As limitations in the current controller were identified in different approaches, we considered the feasibility of a new controller that takes into account an estimated single-input multi-output (SIMO) model. Its parameters were estimated from a very low-level throughput. Against this backdrop, we analyzed the feasibility of an LQG control in cancelling beating, and this article highlights the relevance of such an approach.

• Journal of Korean Foot and Ankle Society
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• v.1 no.1
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• pp.43-50
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• 1997

The tarsometatarsal joint complex is formed by articulation of the five metatarsal bases with the three cuneiform bones and the cuboid bone. Fracture-dislocation of tarsometatarsal area are difficult to recognize on standard radiographs. The exact diagnosis is occasionally delayed. As a result, improper treatment and late sequelae remains. We decided to make a study of patients with normal foot radiographs on 200 cases. Standard radiographic evaluation was used to study the normal variants of the foot and to evaluate the coincided alignment of the lisfranc joint. Accurate accessment on AP & lateral & $30^{\circ}$ oblique projection of radiographs are very adventageous & important, and next final outcome was detected. : 1. Coincided alignment below 1mm and unfolded lisfranc joint on AP projection was well visalized on 1st cuneiform-metatarsal lateral border and 2nd cuneiform-metatarsal medial border. 2. Coincided alignment below 1mm and unfolded lisfranc joint on oblique projection was well visualized on 2nd cuneiform-metatarsal lateral border and 3rd cuneiform-metatarsal medial border and 3rd cuneform-metatarsal lateral border. 3. More proximal location of 2nd lisfranc joint compared to another joint was 196 cases (98%). It is due to inceleration of 2nd metatarsal base between 3rd & 1st cuneiform. 4. 3rd lisfranc joint was volarward position compared to 2nd listranc on lateral projection at 191 cases (95.5%). It's due to anterior covexity of lisfranc joint. 5. Wide dorsal sided 2nd lisfranc is investigated at 189 cases (94.5%). Because of it. 2nd & 3rd lisfrances are mainly volar dislocated usually. 6. Notching on 5th metatarsal base is visible on 171 cases (85.5%). 7. 4th lisfranc joint had offset normally within $2\sim3mm$ at 98 cases (49%). 8. 5th Lisfranc joint had normally offset within $2\sim3mm$ at 99 cases (49.5%). 9. On lateral projection, slight dorsal location of cuneiform to metatarsal base is investigated at 82 cases (41%).

• The korean journal of orthodontics
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• v.41 no.6
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• pp.399-410
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• 2011

Objective: The purpose of this study was to evaluate the difference in frictional resistance among metal, ceramic, self-ligation brackets and coated or non-coated Ni-Ti archwires at various bracket-archwire angulations during the sliding movement of an orthodontic archwire, using an orthodontic sliding simulation device. Methods: Four types of bracket (Micro-arch Perpect Clear2 Clippy-C and Damon3 and 5 types of orthodontic archwire (0.014", 0.016", and 0.016" ${\times}$ 0.022" inch coated Ni-Ti, and 0.016" and 0.016" ${\times}$ 0.022" inch Ni-Ti) were used. Further, the bracket- archwire angles were set at 4 different angulations: $0^{\circ}$, $3^{\circ}$, $6^{\circ}$, and $9^{\circ}$. Results: The frictions from all the experimental groups were found to be significantly increased in order of self-ligation brackets, Micro-arch and Perpect Clear2 ($p$ < 0.001). The presence of a coat had no effect on the friction of the same sized archwires at $0^{\circ}$ and $3^{\circ}$ bracket-archwire angles ($p$ < 0.001). Coated archwires had significantly higher frictions than the same sized non-coated archwires at $6^{\circ}$ and $9^{\circ}$ bracket-archwire angles ($p$ < 0.001). The frictions increased significantly as the bracket-archwire angles were increased ($p$ < 0.001). Conclusions: The use of self-ligation brackets will be beneficial in clinical situations where a low frictional force is required. Further, in cases where crowding is not severe, the use of coated archwires should not cause problems. However, more additional explanation is required considering the fact that the damage of coated archwire and exposure of the metal portion in case of binding and notching and the effects of saliva were not taken into account.

• Clinics in Shoulder and Elbow
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• v.16 no.2
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• pp.73-83
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• 2013

Purpose: The goal of this study is to evaluate the minimum three-year follow-up results of reverse total shoulder arthroplasty (RTSA) for glenohumeral (GH) arthritic and pseudoparalytic patients with severe rotator cuff deficiency. Materials and Methods: We evaluated 13 patients (three males and 10 females) who underwent RTSA from July 2007 to July 2010. The average follow-up duration was 54.2 months (range, 37~74 months). Clinical results were evaluated using the Visual Analog Scale (VAS) for pain, active Range of Motion (ROM): active forward flexion (aFF); active external rotation at the side (aERs); active internal rotation to the back (aIRb), American Shoulder and Elbow Surgeons (ASES) score, Korean Shoulder Score (KSS), and intraoperative and postoperative complications. Results: VAS score improved from 7.5(6~10) points to 1.5(0~4), and ROM of active forward elevation improved from $42.7(10{\sim}100)^{\circ}$ to $129.1(110{\sim}180)^{\circ}$. In addition, ASES score improved from preoperative 32.9 (11.7~46.7) points to 80.2(58.3~95.0) postoperatively, and KSS score improved from 36.8(24~47) points to 78.4 (61~92). Twelve out of 13 cases showed various degrees of scapular notching at the last follow-up. There was one case of intraoperative anterior glenoid fracture and two cases of temporary nerve injury. Revision surgery was performed in two cases for treatment of delayed postoperative deep infection. Conclusion: According to minimum three-year follow-up results, RTSA may be an effective treatment option for glenohumeral (GH) arthritic and pseudoparalytic patients. However, considering the possibility of complications related to delayed deep infection or surgeon's technique, RTSA should be judiciously and carefully indicated by expert surgeons.