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eccentric rotation

Anton Khlopas, Morad Chughtai, Randa K Elmallah, David Hip-Flores, Arthur L Malkani, Steven F Harwin, Michael A Mont, Michael D Ries
BACKGROUND: Bone loss in patients undergoing revision THA poses a considerable challenge for orthopaedic surgeons. Often, to achieve better fixation in remaining bone, larger diameter acetabular components and reaming superiorly may be necessary. However, this is likely to raise the hip center of rotation, which may lead to altered biomechanics, specifically, insufficiency of the abductor muscles, altered gait, and increased risk of dislocation from impingement. More recently, a newer acetabular shell has been designed to more closely replicate the native hip center of rotation in these circumstances while maintaining adequate fixation...
February 2018: Clinical Orthopaedics and related Research
T Patzer
BACKGROUND: In a progredient rotator cuff tear with tendon retraction, fatty infiltration and atrophy of rotator cuff muscles the humerus cannot be centered and stabilized sufficiently in the glenohumeral joint. This leads to rotator cuff defect arthropathy as an eccentric osteoarthritis with acetabularization and wear of the acromion, as well as of the glenoid. INDICATION: A painful pseudoparalysis of the shoulder indicates the implantation of a reversed total shoulder arthroplasty (rTSA) to reduce pain and restore active motion...
March 7, 2018: Der Orthopäde
Hiroki Shimodaira, Keiji Tensho, Yusuke Akaoka, Suguru Koyama, Masaaki Maruyama, Hiroyuki Kato, Naoto Saito
BACKGROUND: The acetabular fossa is thought to be located in the center of the acetabulum, and acetabular reaming in total hip arthroplasty is conventionally performed in the center of the fossa. However, the actual location of the fossa and the influence that hypoplasia or deformity may have on the position of the fossa are unknown. We hypothesized that the fossa is located in the center of the acetabulum, regardless of hypoplasia or deformity. METHODS: Fifty patients with normal hips (normal hip group), 50 patients with dysplasia who underwent rotational acetabular osteotomy (dysplastic hip group), and 46 patients with osteoarthritis who underwent total hip arthroplasty (osteoarthritic hip group) were evaluated by computed tomography (CT) imaging...
March 7, 2018: Journal of Bone and Joint Surgery. American Volume
Alexandre Lädermann, Patrick J Denard, Pascal Boileau, Alain Farron, Pierric Deransart, Gilles Walch
PURPOSE: The purpose of this study was to analyze the effect of different glenoid configurations on arm position and range of motion (ROM) following reverse shoulder arthroplasty (RSA). The hypothesis was that different glenoid configurations would lead to changes in humeral offset, acromio-humeral distance (AHD), ROM, and rotator cuff muscle length. METHODS: Using a three-dimensional (3D) computer model, implantation of an RSA was simulated with a 145° onlay humeral stem combined with five different glenoid configurations which varied in diameter and centre of rotation...
February 28, 2018: International Orthopaedics
Millard F Reschke, Scott J Wood, Gilles Clément
BACKGROUND: Ground-based studies have reported shifts of the vestibulo-ocular reflex (VOR) slow phase velocity (SPV) axis toward the resultant gravito-inertial force vector. The VOR was examined during eccentric roll rotation before, during and after an 8-day orbital mission. On orbit this vector is aligned with the head z-axis. Our hypothesis was that eccentric roll rotation on orbit would generate horizontal eye movements. METHODS: Two subjects were rotated in a semi-supine position with the head nasal-occipital axis parallel to the axis of rotation and 0...
2018: Journal of Vestibular Research: Equilibrium & Orientation
Eva Vallés-Carrascosa, Tomás Gallego-Izquierdo, José Jesús Jiménez-Rejano, Gustavo Plaza-Manzano, Daniel Pecos-Martín, Fidel Hita-Contreras, Alexander Achalandabaso Ochoa
STUDY DESIGN: Randomized clinical trial. INTRODUCTION: Eccentric exercise (EE) was shown to be an effective treatment in tendinopathies. However, the evidence of its effectiveness in subacromial syndrome (SS) is scarce. Moreover, consensus has not been reached on whether best results for SS are obtained by means of EE with or without pain. PURPOSE OF THE STUDY: The purpose of this is to compare the effect on pain, active range of motion (AROM), and shoulder function of an exercise protocol performed with pain <40 mm Visual Analog Scale (VAS) and without pain, in patients with SS...
January 9, 2018: Journal of Hand Therapy: Official Journal of the American Society of Hand Therapists
Thierry Weissland, Maryne Cozette, Clare Doyle, Antoine Gabrion
BACKGROUND: The internal (IR) and external (ER) rotator shoulder strength are often assess in the upper limb sports to prevent a risk of injuries. The purpose of this comparative study was to measure the agonist/antagonist balance of shoulder strength and to determine whether significant differences exist between the dominant and nondominant sides in basketball players compared to a control groups. METHODS: During the championship, 23 elite male-basketball players (BB) and 23 healthy males (CG) were tested bilaterally on a Cybex Norm isokinetic dynamometer in a seated position with 45° shoulder abduction in the scapular plane at 60°...
January 10, 2018: Journal of Sports Medicine and Physical Fitness
Bas Habets, J Bart Staal, Marsha Tijssen, Robert van Cingel
OBJECTIVE: To determine the intrarater reliability of the Humac NORM isokinetic dynamometer for concentric and eccentric strength tests of knee and shoulder muscles. RESULTS: 54 participants (50% female, average age 20.9 ± 3.1 years) performed concentric and eccentric strength measures of the knee extensors and flexors, and the shoulder internal and external rotators on two different Humac NORM isokinetic dynamometers, which were situated at two different centers...
January 10, 2018: BMC Research Notes
Myriam Cassagne, Vincent Soler, François Malecaze, Pierre Fournié
PURPOSE: To describe the surgical technique and report the outcomes of 2 patients treated with femtosecond laser-assisted ipsilateral rotational lamellar autokeratoplasty in central corneal scars. METHODS: The corneal scar depth was mapped using preoperative optical coherence tomography. An eccentric lamellar lenticule was cut with a femtosecond laser and rotated to decenter corneal opacity and free the pupil area in 2 patients with nonprogressive central corneal scars...
January 3, 2018: Cornea
Joseph L Demer
INTRODUCTION: A spherical globe is traditionally assumed, but this study employed magnetic resonance imaging (MRI) to demonstrate frequent occurrence of non-spherical staphylomata in strabismic patients. METHODS: High-resolution, surface coil MRI was obtained in multiple image planes in 21 highly myopic subjects (36 eyes) and compared with 17 normal controls (33 eyes). Images were analyzed for axial length, aspect ratio of eye shape, and deflection of muscle paths...
December 26, 2017: Strabismus
Vincent Bourrier, Christophe Lovis, Hervé Beust, David Ehrenreich, Gregory W Henry, Nicola Astudillo-Defru, Romain Allart, Xavier Bonfils, Damien Ségransan, Xavier Delfosse, Heather M Cegla, Aurélien Wyttenbach, Kevin Heng, Baptiste Lavie, Francesco Pepe
The angle between the spin of a star and the orbital planes of its planets traces the history of the planetary system. Exoplanets orbiting close to cool stars are expected to be on circular, aligned orbits because of strong tidal interactions with the stellar convective envelope. Spin-orbit alignment can be measured when the planet transits its star, but such ground-based spectroscopic measurements are challenging for cool, slowly rotating stars. Here we report the three-dimensional characterization of the trajectory of an exoplanet around an M dwarf star, derived by mapping the spectrum of the stellar photosphere along the chord transited by the planet...
December 18, 2017: Nature
Eric J Chaconas, Morey J Kolber, William J Hanney, Matthew L Daugherty, Stanley H Wilson, Charles Sheets
Background: Shoulder pain affects up to 67% of the population at some point in their lifetime with subacromial pain syndrome (SAPS) representing a common etiology. Despite a plethora of studies there remains conflicting evidence for appropriate management of SAPS. Purpose: To compare outcomes, for individuals diagnosed with SAPS, performing a 6-week protocol of eccentric training of the shoulder external rotators (ETER) compared to a general exercise (GE) protocol...
December 2017: International Journal of Sports Physical Therapy
Marcelo Peduzzi de Castro, Pedro Fonseca, Sara Tribuzi Morais, Márcio Borgonovo-Santos, Eduardo Filipe Cruz Coelho, Daniel Cury Ribeiro, João Paulo Vilas-Boas
The aim of the present study was to determine which approach to calculating shoulder ratios is the most sensitive for determining shoulder torque imbalance in handball players. Twenty-six participants (handball athletes, n = 13; healthy controls, n = 13) performed isokinetic concentric and eccentric shoulder internal rotation (IR) and external rotation (ER) assessment at 60, 180 and 300°/s. We used eight approaches to calculating shoulder ratios: four concentric (i.e. concentric ER torque divided by concentric IR torque), and four functional (i...
December 4, 2017: Sports Biomechanics
Yanquan Geng, Yuzhang Wang, Yongda Yan, Xuesen Zhao
This paper presents a novel atomic force microscopy (AFM)-based 5-axis nanoscale machine tool developed to fabricate nanostructures on different annuli of the micro ball. Different nanostructures can be obtained by combining the scratching trajectory of the AFM tip with the movement of the high precision air-bearing spindle. The center of the micro ball is aligned to be coincided with the gyration center of the high precision to guarantee the machining process during the rotating of the air-bearing spindle...
November 2017: Review of Scientific Instruments
Rita Kinsella, Sallie M Cowan, Lyn Watson, Tania Pizzari
Background: Subacromial pain syndrome (SPS) involving rotator cuff tendinopathy is a common cause of shoulder pain and disability. Evidence suggests that structured physiotherapy may be as effective as surgery in this condition with significant improvements demonstrated in trials involving scapular retraining, rotator cuff strengthening and flexibility exercises. Most published programs typically utilise isotonic concentric and/or eccentric strengthening modes. Recently, immediate analgesic effects and muscle strength gains following heavy-load isometric exercises in lower limb tendinopathy conditions have been observed...
2017: Pilot and Feasibility Studies
Zhihua Cui, Chi Ai, Lei Lv, Fangxian Yin
The shear swirling flow vibration cementing (SSFVC) technique rotates the downhole eccentric cascade by circulating cementing fluid. It makes the casing eccentrically revolve at high speed around the borehole axis. It produces strong agitation action to the annulus fluid, makes it in the state of shear turbulent flow, and results in the formation of pulse pressure which affects the surrounding rock stress. This study was focused on 1) the calculation of the pulse pressure in an annular turbulent flow field based on the finite volume method, and 2) the analysis of the effect of pulse pressure on borehole stability...
2017: PloS One
Brett S Pexa, Eric D Ryan, Elizabeth E Hibberd, Elizabeth Teel, Terri Jo Rucinski, Joseph B Myers
CONTEXT: Following a baseball pitching bout, changes can occur to glenohumeral range of motion that could be linked to injury. These effects are in part due to the posterior shoulder's eccentric muscle activity, which can disrupt muscle contractile elements and lead to changes in muscle cross sectional area (CSA), as measured by ultrasound. OBJECTIVE: To assess changes in muscle CSA, and range of motion immediately before and after pitching, and days 1-5 following pitching...
November 15, 2017: Journal of Sport Rehabilitation
Bryan R Picco, Meghan E Vidt, Clark R Dickerson
Scapular kinematics are important indicators of dyskinesis, often suggesting underlying shoulder pathology, but the influence of sex is unknown. This study's objective was to examine scapular kinematics in healthy males and females. Positions of surface-mounted reflective markers were tracked during arm elevation movements in 0°/30°/40°/60°/90°/120° planes. Scapulothoracic rotations (protraction/retraction, medial/lateral rotation, posterior/anterior tilt) were calculated. ANOVA analysis evaluated main and interaction effects of sex, plane, phase, elevation angle...
November 1, 2017: Journal of Applied Biomechanics
Wiebke Neumann, Lothar R Schad, Frank G Zollner
Magnetic resonance elastography (MRE) is a technique for the quantification of tissue stiffness during MR examinations. It requires consistent methods for mechanical shear wave induction to the region of interest in the human body to reliably quantify elastic properties of soft tissues. This work proposes a novel 3D-printed mechanical actuator using the principle of centrifugal force for wave induction. The driver consists of a 3D-printed turbine vibrator powered by compressed air (located inside the scanner room) and an active driver controlling the pressure of inflowing air (placed outside the scanner room)...
July 2017: Conference Proceedings: Annual International Conference of the IEEE Engineering in Medicine and Biology Society
Jun Shiraishi, Keisuke Shoji, Takashi Yanagiuchi, Masaki Yashige, Akira Shikuma, Daisuke Ito, Masayoshi Kimura, Eigo Kishita, Yusuke Nakagawa, Masayuki Hyogo, Takahisa Sawada
An 83-year-old man presented with recurrent acute coronary syndrome (ACS) at the left main coronary artery (LMCA) complicated with ostial chronic total occlusion (CTO) in the right coronary artery (RCA) (RCA-CTO). At the first LMCA-ACS approximately 1 year earlier, he had undergone LMCA-crossover stenting with a biolimus-eluting stent in the presence of RCA-CTO. At the second LMCA-ACS, we angiographically confirmed severe in-stent restenosis in the distal LMCA, in addition to angled severe stenosis in the just proximal LCx, and performed primary PCI for the LMCA bifurcation lesion under intra-aortic balloon pumping support...
October 21, 2017: International Heart Journal
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