Shoulder muscle forces during driving: Sudden steering can load the rotator cuff beyond its repair limit

PubMed Central

Pandis, Petros; Prinold, Joe A.I.; Bull, Anthony M.J.

2015-01-01

Background Driving is one of the most common everyday tasks and the rotator cuff muscles are the primary shoulder stabilisers. Muscle forces during driving are not currently known, yet knowledge of these would influence important clinical advice such as return to activities after surgery. The aim of this study is to quantify shoulder and rotator cuff muscle forces during driving in different postures. Methods A musculoskeletal modelling approach is taken, using a modified driving simulator in combination with an upper limb musculoskeletal model (UK National Shoulder Model). Motion data and external force vectors were model inputs and upper limb muscle and joint forces were the outputs. Findings Comparisons of the predicted glenohumeral joint forces were compared to in vivo literature values, with good agreement demonstrated (61 SD 8% body weight mean peak compared to 60 SD 1% body weight mean peak). High muscle activation was predicted in the rotator cuff muscles; particularly supraspinatus (mean 55% of the maximum and up to 164 SD 27 N). This level of loading is up to 72% of mean failure strength for supraspinatus repairs, and could therefore be dangerous for some cases. Statistically significant and large differences are shown to exist in the joint and muscle forces for different driving positions as well as steering with one or both hands (up to 46% body weight glenohumeral joint force). Interpretation These conclusions should be a key consideration in rehabilitating the shoulder after surgery, preventing specific upper limb injuries and predicting return to driving recommendations. PMID:26139549

Formation of a physiological reverse shoulder joint.

PubMed

Lerner, Markus; Turkmen, Ismail; Bernd, Ludger

2016-01-20

Congenital shoulder deformities are rarely seen in orthopaedic practice. Proximal humeral defects and glenoid hypoplasia have been reported separately in the literature. We present a case involving a 31-year-old woman having a cosmetic problem with her upper arm who was diagnosed with reverse shoulder joint deformity. This article presents the clinical, radiological and biomechanical findings of a physiological reverse shoulder joint. This is the first such reported case. 2016 BMJ Publishing Group Ltd.

Cryotherapy does not impair shoulder joint position sense.

PubMed

Dover, Geoffrey; Powers, Michael E

2004-08-01

To determine the effects of a cryotherapy treatment on shoulder proprioception. Crossover design with repeated measures. University athletic training and sports medicine research laboratory. Thirty healthy subjects (15 women, 15 men). A 30-minute cryotherapy treatment. Joint position sense was measured in the dominant shoulder by using an inclinometer before and after receiving 30 minutes of either no ice or a 1-kg ice bag application. Skin temperature was measured below the tip of the acromion process and recorded every 5 minutes for the entire 30 minutes and immediately after testing. Three different types of error scores were calculated for data analyses and used to determine proprioception. Separate analyses of absolute, constant, and variable error failed to identify changes in shoulder joint proprioception as a function of the cryotherapy application. Application of an ice bag to the shoulder does not impair joint position sense. The control of proprioception at the shoulder may be more complex than at other joints in the body. Clinical implications may involve modifying rehabilitation considerations when managing shoulder injuries.

ULTRASOUND MEASUREMENTS AND OBJECTIVE FORCES OF GLENOHUMERAL TRANSLATIONS DURING SHOULDER ACCESSORY PASSIVE MOTION TESTING IN HEALTHY INDIVIDUALS

PubMed Central

Worst, Haley; Decarreau, Ryan; Davies, George

2016-01-01

Background Clinical examination of caspuloligamentous structures of the glenohumeral joint has historically been subjective in nature, as demonstrated by limited intra-rater and inter-rater reproducibility. Musculoskeletal diagnostic ultrasound was utilized to develop a clinically objective measurement technique for glenohumeral inferior and posterolateral translation. Purpose The purpose of this study was to measure the accessory passive force required to achieve end range glenohumeral posterolateral and inferior accessory translation, as well as, to quantify the amount of translation of the glenohumeral joint caused by the applied force. Study Design Cross-sectional descriptive correlational study Methods Twenty-five asymptomatic subjects between the ages of 18 and 30 were recruited via convenience sampling. Posterolateral and inferior shoulder accessory passive translation was assessed and measured using a GE LOGIQe ultrasound, while concurrently using a hand held dynamometer to quantify the passive force applied during assessment. Normative values for force and translation were described as means and standard deviations. Results Mean values for posterolateral translation were 6.5 +/− 4.0 mm on the right shoulder and 6.3 +/− 3.5 mm on the left with an associated mean force of 127.1 +/− 55.6 N and 114.4 +/− 50.7 N, respectively. Mean values for inferior translation were 4.8 +/− 1.7 mm on the right shoulder and 5.4 +/− 1.8 mm on the left with an associated mean force of 84.5 +/− 30.5 N and 76.1 +/− 30.1 N, respectively. There was a significant association between inferior translation and inferior force (r = .51). No significant association was found between posterolateral translation and posterolateral force. Significant differences were found between dominant and non-dominant shoulders for posterolateral translation, posterolateral force to produce translation, and inferior translation values

The effects of progressive lateralization of the joint center of rotation of reverse total shoulder implants.

PubMed

Costantini, Oren; Choi, Daniel S; Kontaxis, Andreas; Gulotta, Lawrence V

2015-07-01

There has been a renewed interest in lateralizing the center of rotation (CoR) in implants used in reverse shoulder arthroplasty. The aim of this study was to determine the sensitivity of lateralization of the CoR on the glenohumeral joint contact forces, muscle moment arms, torque across the bone-implant interface, and the stability of the implant. A 3-dimensional virtual model was used to investigate how lateralization affects deltoid muscle moment arm and glenohumeral joint contact forces. This model was virtually implanted with 5 progressively lateralized reverse shoulder prostheses. The joint contact loads and deltoid moment arms were calculated for each lateralization over the course of 3 simulated standard humerothoracic motions. Lateralization of the CoR leads to an increase in the overall joint contact forces across the glenosphere. Most of this increased loading occurred through compression, although increases in anterior/posterior and superior/inferior shear were also observed. Moment arms of the deltoid consistently decreased with lateralization. Bending moments at the implant interface increased with lateralization. Progressive lateralization resulted in improved stability ratios. Lateralization results in increased joint loading. Most of that loading occurs through compression, although there were also increases in shear forces. Anterior/posterior shear is currently not accounted for in implant fixation studies, leaving its effect on implant fixation unknown. Future studies should incorporate shear forces into their models to more accurately assess fixation methods. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits minimally (less than normal anatomic constraints) translation in one or...

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits minimally (less than normal anatomic constraints) translation in one or...

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits minimally (less than normal anatomic constraints) translation in one or...

Echographic and kinetic changes in the shoulder joint after manual wheelchair propulsion under two different workload settings.

PubMed

Gil-Agudo, Ángel; Solís-Mozos, Marta; Crespo-Ruiz, Beatriz; Del-Ama Eng, Antonio J; Pérez-Rizo, Enrique; Segura-Fragoso, Antonio; Jiménez-Díaz, Fernando

2014-01-01

Manual wheelchair users with spinal cord injury (SCI) have a high prevalence of shoulder pain due to the use of the upper extremity for independent mobility, transfers, and other activities of daily living. Indeed, shoulder pain dramatically affects quality of life of these individuals. There is limited evidence obtained through radiographic techniques of a relationship between the forces acting on the shoulder during different propulsion conditions and shoulder pathologies. Today, ultrasound is widely accepted as a precise tool in diagnosis, displaying particularly effectiveness in screening the shoulder rotator cuff. Thus, we set out to perform an ultrasound-based study of the acute changes to the shoulder soft tissues after propelling a manual wheelchair in two workload settings. Shoulder joint kinetics was recorded from 14 manual wheelchair users with SCI while they performed high- and low-intensity wheelchair propulsion tests (constant and incremental). Shoulder joint forces and moments were obtained from inverse dynamic methods, and ultrasound screening of the shoulder was performed before and immediately after the test. Kinetic changes were more relevant after the most intensive task, showing the significance of high-intensity activity, yet no differences were found in ultrasound-related parameters before and after each propulsion task. It therefore appears that further studies will be needed to collect clinical data and correlate data regarding shoulder pain with both ultrasound images and data from shoulder kinetics.

Echographic and Kinetic Changes in the Shoulder Joint after Manual Wheelchair Propulsion Under Two Different Workload Settings

PubMed Central

Gil-Agudo, Ángel; Solís-Mozos, Marta; Crespo-Ruiz, Beatriz; del-Ama Eng, Antonio J.; Pérez-Rizo, Enrique; Segura-Fragoso, Antonio; Jiménez-Díaz, Fernando

2014-01-01

Manual wheelchair users with spinal cord injury (SCI) have a high prevalence of shoulder pain due to the use of the upper extremity for independent mobility, transfers, and other activities of daily living. Indeed, shoulder pain dramatically affects quality of life of these individuals. There is limited evidence obtained through radiographic techniques of a relationship between the forces acting on the shoulder during different propulsion conditions and shoulder pathologies. Today, ultrasound is widely accepted as a precise tool in diagnosis, displaying particularly effectiveness in screening the shoulder rotator cuff. Thus, we set out to perform an ultrasound-based study of the acute changes to the shoulder soft tissues after propelling a manual wheelchair in two workload settings. Shoulder joint kinetics was recorded from 14 manual wheelchair users with SCI while they performed high- and low-intensity wheelchair propulsion tests (constant and incremental). Shoulder joint forces and moments were obtained from inverse dynamic methods, and ultrasound screening of the shoulder was performed before and immediately after the test. Kinetic changes were more relevant after the most intensive task, showing the significance of high-intensity activity, yet no differences were found in ultrasound-related parameters before and after each propulsion task. It therefore appears that further studies will be needed to collect clinical data and correlate data regarding shoulder pain with both ultrasound images and data from shoulder kinetics. PMID:25566539

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits translation and rotation in one or more planes via the geometry of its...

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits translation and rotation in one or more planes via the geometry of its...

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint... shoulder joint. The device limits translation and rotation in one or more planes via the geometry of its...

Shoulder joint loading and posture during medicine cart pushing task.

PubMed

Xu, Xu; Lin, Jia-Hua; Boyer, Jon

2013-01-01

Excessive physical loads and awkward shoulder postures during pushing and pulling are risk factors for shoulder pain. Pushing a medicine cart is a major component of a work shift for nurses and medical assistants in hospitals and other health care facilities. A laboratory experiment was conducted to examine the effects of common factors (e.g., lane congestion, cart load stability, floor surface friction) on shoulder joint moment and shoulder elevation angle of participants during cart pushing. Participants pushed a medicine cart on straight tracks and turning around right-angle corners. Peak shoulder joint moments reached 25.1 Nm, 20.3 Nm, and 26.8 Nm for initial, transition, and turning phases of the pushing tasks, indicating that shoulder joint loading while pushing a medical cart is comparable to levels previously reported from heavy manual activities encountered in industry (e.g., garbage collection). Also, except for user experience, all other main study factors, including congestion level, cart load stability, location of transition strip, shoulder tendency, surface friction, and handedness, significantly influenced shoulder joint moment and shoulder elevation angle. The findings provide a better understanding of shoulder exposures associated with medicine cart operations and may be helpful in designing and optimizing the physical environment where medicine carts are used.

Cadaveric Study of the Articular Branches of the Shoulder Joint.

PubMed

Eckmann, Maxim S; Bickelhaupt, Brittany; Fehl, Jacob; Benfield, Jonathan A; Curley, Jonathan; Rahimi, Ohmid; Nagpal, Ameet S

This cadaveric study investigated the anatomic relationships of the articular branches of the suprascapular (SN), axillary (AN), and lateral pectoral nerves (LPN), which are potential targets for shoulder analgesia. Sixteen embalmed cadavers and 1 unembalmed cadaver, including 33 shoulders total, were dissected. Following dissections, fluoroscopic images were taken to propose an anatomical landmark to be used in shoulder articular branch blockade. Thirty-three shoulders from 17 total cadavers were studied. In a series of 16 shoulders, 16 (100%) of 16 had an intact SN branch innervating the posterior head of the humerus and shoulder capsule. Suprascapular sensory branches coursed laterally from the spinoglenoid notch then toward the glenohumeral joint capsule posteriorly. Axillary nerve articular branches innervated the posterolateral head of the humerus and shoulder capsule in the same 16 (100%) of 16 shoulders. The AN gave branches ascending circumferentially from the quadrangular space to the posterolateral humerus, deep to the deltoid, and inserting at the inferior portion of the posterior joint capsule. In 4 previously dissected and 17 distinct shoulders, intact LPNs could be identified in 14 (67%) of 21 specimens. Of these, 12 (86%) of 14 had articular branches innervating the anterior shoulder joint, and 14 (100%) of 14 LPN articular branches were adjacent to acromial branches of the thoracoacromial blood vessels over the superior aspect of the coracoid process. Articular branches from the SN, AN, and LPN were identified. Articular branches of the SN and AN insert into the capsule overlying the glenohumeral joint posteriorly. Articular branches of the LPN exist and innervate a portion of the anterior shoulder joint.

Primary and Secondary Consequences of Rotator Cuff Injury on Joint Stabilizing Tissues in the Shoulder.

PubMed

Rahman, Hafizur; Currier, Eric; Johnson, Marshall; Goding, Rick; Johnson, Amy Wagoner; Kersh, Mariana E

2017-11-01

Rotator cuff tears (RCTs) are one of the primary causes of shoulder pain and dysfunction in the upper extremity accounting over 4.5 million physician visits per year with 250,000 rotator cuff repairs being performed annually in the U.S. While the tear is often considered an injury to a specific tendon/tendons and consequently treated as such, there are secondary effects of RCTs that may have significant consequences for shoulder function. Specifically, RCTs have been shown to affect the joint cartilage, bone, the ligaments, as well as the remaining intact tendons of the shoulder joint. Injuries associated with the upper extremities account for the largest percent of workplace injuries. Unfortunately, the variable success rate related to RCTs motivates the need for a better understanding of the biomechanical consequences associated with the shoulder injuries. Understanding the timing of the injury and the secondary anatomic consequences that are likely to have occurred are also of great importance in treatment planning because the approach to the treatment algorithm is influenced by the functional and anatomic state of the rotator cuff and the shoulder complex in general. In this review, we summarized the contribution of RCTs to joint stability in terms of both primary (injured tendon) and secondary (remaining tissues) consequences including anatomic changes in the tissues surrounding the affected tendon/tendons. The mechanical basis of normal shoulder joint function depends on the balance between active muscle forces and passive stabilization from the joint surfaces, capsular ligaments, and labrum. Evaluating the role of all tissues working together as a system for maintaining joint stability during function is important to understand the effects of RCT, specifically in the working population, and may provide insight into root causes of shoulder injury.

Putting the shoulder to the wheel: a new biomechanical model for the shoulder girdle.

PubMed

Levin, S M

1997-01-01

The least successfully modeled joint complex has been the shoulder. In multi-segmented mathematical shoulder models rigid beams (the bones) act as a series of columns or levers to transmit forces or loads to the axial skeleton. Forces passing through the almost frictionless joints must, somehow, always be directed perfectly perpendicular to the joints as only loads directed at right angles to the surfaces could transfer across frictionless joints. Loads transmitted to the axial skeleton would have to pass through the moving ribs or the weak jointed clavicle and then through the ribs. A new model of the shoulder girdle, based on the tension icosahedron described by Buckminster Fuller, is proposed that permits the compression loads passing through the arm and shoulder to be transferred to the axial skeleton through its soft tissues. In this model the scapula 'floats' in the tension network of shoulder girdle muscles just as the hub of the wire wheel is suspended in its tension network of spokes. With this construct inefficient beams and levers are eliminated. A more energy efficient, load distributing, integrated, hierarchical system is created.

21 CFR 888.3660 - Shoulder joint metal/polymer semi-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer semi-constrained... Shoulder joint metal/polymer semi-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer semi-constrained cemented prosthesis is a device intended to be implanted to replace a...

21 CFR 888.3650 - Shoulder joint metal/polymer non-constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer non-constrained... Shoulder joint metal/polymer non-constrained cemented prosthesis. (a) Identification. A shoulder joint metal/polymer non-constrained cemented prosthesis is a device intended to be implanted to replace a...

Microstructure and mechanical properties of friction stir lap welded Mg/Al joint assisted by stationary shoulder

NASA Astrophysics Data System (ADS)

Ji, Shude; Li, Zhengwei

2017-11-01

Using magnesium alloy as upper sheet, 3 mm-thick AZ31 magnesium alloy and 6061 aluminum alloy were joined using friction stir lap welding assisted by stationary shoulder. The effects of tool rotating speed on cross-sections, microstructure and mechanical properties of Mg/Al lap joints were mainly discussed. Results showed that stationary shoulder contributed to joint formation, by which stir zones (SZ) were characterized by big onion rings after welding. Because of the big forging force exerted by stationary shoulder, the upper region of hook was well bonded. SZ showed much higher hardness because of intermetallic compounds (IMCs). The bonding conditions at the base material (BM)/SZ interface at advancing side and the hook region played important roles on joint lap shear properties. The X-ray diffraction pattern analysis revealed that the main IMCs were Al3Mg2 and Al12Mg17.

[The Throwing Shoulder].

PubMed

Wieser, Karl; Gerber, Christian; Meyer, Dominik C

2016-02-03

Repetitive top-performance of overhead athletes induces a tremendous stress for the throwing shoulder. Throwers reach rotational speed of their arm of more than 7000°/s with joint compression and distraction forces of more than 1000 N. This performance is tributary to adaption of the shoulder muscles and the joint itself. These adaptions may, however lead to two specific problems of the throwing shoulder: 1. The posterosuperior internal impingement of the rotator cuff and labrum between glenoid and humeral head during late cooking phase; 2. A decreased internal rotation of the glenohumeral joint (GIRD) with compensatory problems of the scapula-stabilizing muscles. Precise analysis of kinematics and pathomechanics aims to improve understanding and treatment of those specific problems of the throwing shoulder.

Mathematical modelling as a tool to assessment of loads in volleyball player's shoulder joint during spike.

PubMed

Jurkojć, Jacek; Michnik, Robert; Czapla, Krzysztof

2017-06-01

This article deals with kinematic and kinetic conditions in volleyball attack and identifies loads in the shoulder joint. Joint angles and velocities of individual segments of upper limb were measured with the use of the motion capture system XSENS. Muscle forces and loads in skeletal system were calculated by means of mathematical model elaborated in AnyBody system. Spikes performed by players in the best and worst way were compared with each other. The relationships were found between reactions in shoulder joint and flexion/extension, abduction/adduction and rotation angles in the same joint and flexion/extension in the elbow joint. Reactions in shoulder joint varied from 591 N to 2001 N (in relation to body weight [BW] 83-328%). The analysis proved that hand velocity at the moment of the ball hit (which varied between 6.8 and 13.3 m s -1 ) influences on the value of reaction in joints, but positions of individual segments relative to each other are also crucial. It was also proved in objective way, that position of the upper limb during spike can be more or less harmful assuming that bigger reaction increases possibility of injury, what can be an indication for trainers and physiotherapists how to improve injury prevention.

Computational reverse shoulder prosthesis model: Experimental data and verification.

PubMed

Martins, A; Quental, C; Folgado, J; Ambrósio, J; Monteiro, J; Sarmento, M

2015-09-18

The reverse shoulder prosthesis aims to restore the stability and function of pathological shoulders, but the biomechanical aspects of the geometrical changes induced by the implant are yet to be fully understood. Considering a large-scale musculoskeletal model of the upper limb, the aim of this study is to evaluate how the Delta reverse shoulder prosthesis influences the biomechanical behavior of the shoulder joint. In this study, the kinematic data of an unloaded abduction in the frontal plane and an unloaded forward flexion in the sagittal plane were experimentally acquired through video-imaging for a control group, composed of 10 healthy shoulders, and a reverse shoulder group, composed of 3 reverse shoulders. Synchronously, the EMG data of 7 superficial muscles were also collected. The muscle force sharing problem was solved through the minimization of the metabolic energy consumption. The evaluation of the shoulder kinematics shows an increase in the lateral rotation of the scapula in the reverse shoulder group, and an increase in the contribution of the scapulothoracic joint to the shoulder joint. Regarding the muscle force sharing problem, the musculoskeletal model estimates an increased activity of the deltoid, teres minor, clavicular fibers of the pectoralis major, and coracobrachialis muscles in the reverse shoulder group. The comparison between the muscle forces predicted and the EMG data acquired revealed a good correlation, which provides further confidence in the model. Overall, the shoulder joint reaction force was lower in the reverse shoulder group than in the control group. Copyright © 2015 Elsevier Ltd. All rights reserved.

Problems With Large Joints: Shoulder Conditions.

PubMed

Campbell, Michael

2016-07-01

The shoulder is the most mobile joint in the body. It requires an extensive support system to create mobility while providing stability. Although there are many etiologies of shoulder pain, weakness, and instability, most injuries in the shoulder are due to overuse. Rotator cuff tears, labral tears, calcific tendinopathy, and impingement often result from chronic overuse injuries. Acute injuries include dislocations that can cause labral tears or other complications. Frozen shoulder refers to a typically benign condition of restricted range of motion that may spontaneously resolve but can cause prolonged pain and discomfort. The history combined with specific shoulder examination techniques can help family physicians successfully diagnose shoulder conditions. X-ray imaging typically is sufficient to rule out more serious etiologies when evaluating patients with shoulder conditions. However, imaging with magnetic resonance imaging (MRI) study or ultrasonography for rotator cuff tears, and MRI study with intra-articular contrast for labral tears, is needed to confirm these diagnoses. Corticosteroid injections and physical therapy are first-line treatments for most shoulder conditions. Surgical options typically are reserved for patients for whom conservative treatments are ineffective, and typically are performed arthroscopically. Written permission from the American Academy of Family Physicians is required for reproduction of this material in whole or in part in any form or medium.

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

21 CFR 888.3640 - Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Shoulder joint metal/metal or metal/polymer... § 888.3640 Shoulder joint metal/metal or metal/polymer constrained cemented prosthesis. (a) Identification. A shoulder joint metal/metal or metal/polymer constrained cemented prosthesis is a device...

The effect of glenosphere diameter and eccentricity on deltoid power in reverse shoulder arthroplasty.

PubMed

Scalise, J; Jaczynski, A; Jacofsky, M

2016-02-01

The eccentric glenosphere was principally introduced into reverse shoulder arthroplasty to reduce the incidence of scapular notching. There is only limited information about the influence of its design on deltoid power and joint reaction forces. The aim of our study was to investigate how the diameter and eccentricity of the glenosphere affect the biomechanics of the deltoid and the resultant joint reaction forces. Different sizes of glenosphere and eccentricity were serially tested in ten cadaveric shoulders using a custom shoulder movement simulator. Increasing the diameter of the glenosphere alone did not alter the deltoid moment arm. However, using an eccentric glenosphere increased the moment arm of the deltoid, lowered the joint reaction force and required less deltoid force to generate movement. Eccentricity is an independent variable which increases deltoid efficiency and lowers joint reaction forces in a reverse shoulder arthroplasty. Cite this article: Bone Joint J 2016;98-B:218-23. ©2016 The British Editorial Society of Bone & Joint Surgery.

Septic shoulder presenting as a shoulder dislocation in the pediatric patient: a case report.

PubMed

Maguire, Kathleen J; Otsuka, Norman Y

2017-05-01

Shoulder dislocation is relatively uncommon in the younger pediatric population. Because of the relative strength of the surrounding soft tissue structures of the shoulder compared with the proximal humeral physis, subluxation or dislocation resulting from a traumatic event or application of force is rare and instead a proximal humeral physeal injury occurs. Case presentation - We present a 5-year-old male who presented to the office with post-traumatic left shoulder pain for about 1 week. Radiographs of the left shoulder indicated inferior subluxation of the humeral head. He was ultimately diagnosed and treated for a septic shoulder. Septic arthritis of the glenohumeral joint accounts for about 3% of all septic arthritis cases. About half of the pediatric patients with a septic arthritis will present with a concomitant osteomyelitis about the joint involved. Widening of the glenohumeral joint and subluxation clinically as well as radiographically have been described in cases of large joint effusions because of an increase in intra-articular fluid in adults. This inferior subluxation is often noted without a frank dislocation. The case described in this report is unique in that this is the first to describe a pediatric septic shoulder presenting as a shoulder subluxation. Given the rarity of pediatric shoulder dislocations and subluxations, the pediatric orthopaedist and pediatrician should maintain a suspicion for a septic joint. Level V.

Comparison of 3-Dimensional Shoulder Complex Kinematics in Individuals With and Without Shoulder Pain, Part 2: Glenohumeral Joint

PubMed Central

LAWRENCE, REBEKAH L.; BRAMAN, JONATHAN P.; STAKER, JUSTIN L.; LAPRADE, ROBERT F.; LUDEWIG, PAULA M.

2015-01-01

STUDY DESIGN Cross-sectional. OBJECTIVES To compare differences in glenohumeral joint angular motion and linear translations between symptomatic and asymptomatic individuals during shoulder motion performed in 3 planes of humerothoracic elevation. BACKGROUND Numerous clinical theories have linked abnormal glenohumeral kinematics, including decreased glenohumeral external rotation and increased superior translation, to individuals with shoulder pain and impingement diagnoses. However, relatively few studies have investigated glenohumeral joint angular motion and linear translations in this population. METHODS Transcortical bone pins were inserted into the scapula and humerus of 12 a symptomatic and 10 symptomatic participants for direct bone-fixed tracking using electromagnetic sensors. Glenohumeral joint angular positions and linear translations were calculated during active shoulder flexion, abduction, and scapular plane abduction. RESULTS Differences between groups in angular positions were limited to glenohumeral elevation, coinciding with a reduction in scapulothoracic upward rotation. Symptomatic participants demonstrated 1.4 mm more anterior glenohumeral translation between 90° and 120° of shoulder flexion and an average of 1 mm more inferior glenohumeral translation throughout shoulder abduction. CONCLUSION Differences in glenohumeral kinematics exist between symptomatic and a symptomatic individuals. The clinical implications of these differences are not yet understood, and more research is needed to understand the relationship between abnormal kinematics, shoulder pain, and pathoanatomy. PMID:25103132

Multibody system of the upper limb including a reverse shoulder prosthesis.

PubMed

Quental, C; Folgado, J; Ambrósio, J; Monteiro, J

2013-11-01

The reverse shoulder replacement, recommended for the treatment of several shoulder pathologies such as cuff tear arthropathy and fractures in elderly people, changes the biomechanics of the shoulder when compared to the normal anatomy. Although several musculoskeletal models of the upper limb have been presented to study the shoulder joint, only a few of them focus on the biomechanics of the reverse shoulder. This work presents a biomechanical model of the upper limb, including a reverse shoulder prosthesis, to evaluate the impact of the variation of the joint geometry and position on the biomechanical function of the shoulder. The biomechanical model of the reverse shoulder is based on a musculoskeletal model of the upper limb, which is modified to account for the properties of the DELTA® reverse prosthesis. Considering two biomechanical models, which simulate the anatomical and reverse shoulder joints, the changes in muscle lengths, muscle moment arms, and muscle and joint reaction forces are evaluated. The muscle force sharing problem is solved for motions of unloaded abduction in the coronal plane and unloaded anterior flexion in the sagittal plane, acquired using video-imaging, through the minimization of an objective function related to muscle metabolic energy consumption. After the replacement of the shoulder joint, significant changes in the length of the pectoralis major, latissimus dorsi, deltoid, teres major, teres minor, coracobrachialis, and biceps brachii muscles are observed for a reference position considered for the upper limb. The shortening of the teres major and teres minor is the most critical since they become unable to produce active force in this position. Substantial changes of muscle moment arms are also observed, which are consistent with the literature. As expected, there is a significant increase of the deltoid moment arms and more fibers are able to elevate the arm. The solutions to the muscle force sharing problem support the

Effects of hook plate on shoulder function after treatment of acromioclavicular joint dislocation.

PubMed

Chen, Chang-Hong; Dong, Qi-Rong; Zhou, Rong-Kui; Zhen, Hua-Qing; Jiao, Ya-Jun

2014-01-01

Internal fixation with hook plate has been used to treat acromioclavicular joint dislocation. This study aims to evaluate the effect of its use on shoulder function, to further analyze the contributing factors, and provide a basis for selection and design of improved internal fixation treatment of the acromioclavicular joint dislocation in the future. A retrospective analysis was performed on patients treated with a hook plate for acromioclavicular joint dislocation in our hospital from January 2010 to February 2013. There were 33 cases in total, including 25 males and 8 females, with mean age of 48.27 ± 8.7 years. There were 29 cases of Rockwood type III acromioclavicular dislocation, 4 cases of type V. The Constant-Murley shoulder function scoring system was used to evaluate the shoulder function recovery status after surgery. Anteroposterior shoulder X-ray was used to assess the position of the hook plate, status of acromioclavicular joint reduction and the occurrence of postoperative complications. According to the Constant-Murley shoulder function scoring system, the average scores were 78 ± 6 points 8 to 12 months after the surgery and before the removal of the hook plate, the average scores were 89 ± 5 minutes two months after the removal of hook plate. Postoperative X-ray imaging showed osteolysis in 10 cases (30.3%), osteoarthritis in six cases (18.1%), osteolysis associated with osteoarthritis in four cases(12.1%), and steel hook broken in one case (3%). The use of hook plate on open reduction and internal fixation of the acromioclavicular joint dislocation had little adverse effect on shoulder function and is an effective method for the treatment of acromioclavicular joint dislocation. Osteoarthritis and osteolysis are the two common complications after hook plate use, which are associated with the impairment of shoulder function. Shoulder function will be improved after removal of the hook plate.

Shoulder joint luxation in large animals: 14 cases (1976-1997).

PubMed

Semevolos, S A; Nixon, A J; Goodrich, L R; Ducharme, N G

1998-12-01

To determine clinical and radiographic findings in and treatment and outcome of large animals with shoulder joint luxations. Retrospective study. 5 horses, 3 goats, 1 calf, 1 sheep, 1 Himalayan tahr, 1 pot-bellied pig, 1 reindeer, and 1 white-tailed deer. Medical records and radiographs were reviewed to determine signalment, history, physical examination findings, type of luxation, treatment, and outcome. Owners and referring veterinarians were contracted for follow-up information. Goats, sexually intact males, and animals < 1 year old were overrepresented, compared with the general hospital population during the study period. Closed reduction was attempted in 3 animals and was successful in 1. Open reduction and internal stabilization was attempted in 4 animals, including 1 in which closed reduction was unsuccessful. Long-term stabilization of the joint was achieved in 3 animals, but overall results were poor because of osteoarthritis and chronic lameness. Three animals were not treated, and 5 were euthanatized because of a poor prognosis. Large animals with shoulder joint luxation and concurrent fractures had a poorer prognosis than did those with shoulder joint luxation alone.

21 CFR 888.3670 - Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Shoulder joint metal/polymer/metal nonconstrained... ORTHOPEDIC DEVICES Prosthetic Devices § 888.3670 Shoulder joint metal/polymer/metal nonconstrained or semi-constrained porous-coated uncemented prosthesis. (a) Identification. A shoulder joint metal/polymer/metal...

VARIABILITY OF PEAK SHOULDER FORCE DURING WHEELCHAIR PROPULSION IN MANUAL WHEELCHAIR USERS WITH AND WITHOUT SHOULDER PAIN

PubMed Central

Moon, Y.; Chandrasekaran, J.; Hsu, I.M.K.; Rice, I.M.; Hsiao-Wecksler, E.T.; Sosnoff, J.J.

2013-01-01

Background Manual wheelchair users report a high prevalence of shoulder pain. Growing evidence shows that variability in forces applied to biological tissue is related to musculoskeletal pain. The purpose of this study was to examine the variability of forces acting on the shoulder during wheelchair propulsion as a function of shoulder pain. Methods Twenty-four manual wheelchair users (13 with pain, 11 without pain) participated in the investigation. Kinetic and kinematic data of wheelchair propulsion were recorded for three minutes maintaining a constant speed at three distinct propulsion speeds (fast speed of 1.1 m/s, a self-selected speed, and a slow speed of 0.7 m/s). Peak resultant shoulder forces in the push phase were calculated using inverse dynamics. Within individual variability was quantified as the coefficient of variation of cycle to cycle peak resultant forces. Findings There was no difference in mean peak shoulder resultant force between groups. The pain group had significantly smaller variability of peak resultant force than the no pain group (p < 0.01, η2 = 0.18). Interpretation The observations raise the possibility that propulsion variability could be a novel marker of upper limb pain in manual wheelchair users. PMID:24210512

Comparison of 3-Dimensional Shoulder Complex Kinematics in Individuals With and Without Shoulder Pain, Part 1: Sternoclavicular, Acromioclavicular, and Scapulothoracic Joints

PubMed Central

LAWRENCE, REBEKAH L.; BRAMAN, JONATHAN P.; LAPRADE, ROBERT F.; LUDEWIG, PAULA M.

2015-01-01

STUDY DESIGN Cross-sectional. OBJECTIVES To compare sternoclavicular, acromioclavicular, and scapulothoracic joint motion between symptomatic and asymptomatic individuals during shoulder motion performed in 3 planes of humerothoracic elevation. BACKGROUND Differences in scapulothoracic kinematics are associated with shoulder pain. Several studies have measured these differences using surface sensors, but the results of this technique may be affected by skin-motion artifact. Furthermore, previous studies have not included the simultaneous measurement of sternoclavicular and acromioclavicular joint motion. METHODS Transcortical bone pins were inserted into the clavicle, scapula, and humerus of 12 asymptomatic and 10 symptomatic individuals for direct, bone-fixed tracking using electromagnetic sensors. Angular positions for the sternoclavicular, acromioclavicular, and scapulothoracic joints were measured during shoulder flexion, abduction, and scapular plane abduction. RESULTS Differences between groups were found for sternoclavicular and scapulothoracic joint positions. Symptomatic individuals consistently demonstrated less sternoclavicular posterior rotation, regardless of angle, phase, or plane of shoulder motion. Symptomatic individuals also demonstrated less scapulothoracic upward rotation at 30° and 60° of humerothoracic elevation during shoulder abduction and scapular plane abduction. CONCLUSION The results of this study show that differences in shoulder complex kinematics exist between symptomatic and asymptomatic individuals. However, the magnitude of these differences was small, and the resulting clinical implications are not yet fully understood. The biomechanical coupling of the sternoclavicular and acromioclavicular joints requires further research to better understand scapulothoracic movement deviations and to improve manual therapy and exercise-based physical therapy interventions. PMID:25103135

Hierarchy of stability factors in reverse shoulder arthroplasty.

PubMed

Gutiérrez, Sergio; Keller, Tony S; Levy, Jonathan C; Lee, William E; Luo, Zong-Ping

2008-03-01

Reverse shoulder arthroplasty is being used more frequently to treat irreparable rotator cuff tears in the presence of glenohumeral arthritis and instability. To date, however, design features and functions of reverse shoulder arthroplasty, which may be associated with subluxation and dislocation of these implants, have been poorly understood. We asked: (1) what is the hierarchy of importance of joint compressive force, prosthetic socket depth, and glenosphere size in relation to stability, and (2) is this hierarchy defined by underlying and theoretically predictable joint contact characteristics? We examined the intrinsic stability in terms of the force required to dislocate the humerosocket from the glenosphere of eight commercially available reverse shoulder arthroplasty devices. The hierarchy of factors was led by compressive force followed by socket depth; glenosphere size played a much lesser role in stability of the reverse shoulder arthroplasty device. Similar results were predicted by a mathematical model, suggesting the stability was determined primarily by compressive forces generated by muscles.

Effects of hook plate on shoulder function after treatment of acromioclavicular joint dislocation

PubMed Central

Chen, Chang-Hong; Dong, Qi-Rong; Zhou, Rong-Kui; Zhen, Hua-Qing; Jiao, Ya-Jun

2014-01-01

Introduction: Internal fixation with hook plate has been used to treat acromioclavicular joint dislocation. This study aims to evaluate the effect of its use on shoulder function, to further analyze the contributing factors, and provide a basis for selection and design of improved internal fixation treatment of the acromioclavicular joint dislocation in the future. Methods: A retrospective analysis was performed on patients treated with a hook plate for acromioclavicular joint dislocation in our hospital from January 2010 to February 2013. There were 33 cases in total, including 25 males and 8 females, with mean age of 48.27 ± 8.7 years. There were 29 cases of Rockwood type III acromioclavicular dislocation, 4 cases of type V. The Constant-Murley shoulder function scoring system was used to evaluate the shoulder function recovery status after surgery. Anteroposterior shoulder X-ray was used to assess the position of the hook plate, status of acromioclavicular joint reduction and the occurrence of postoperative complications. Results: According to the Constant-Murley shoulder function scoring system, the average scores were 78 ± 6 points 8 to 12 months after the surgery and before the removal of the hook plate, the average scores were 89 ± 5 minutes two months after the removal of hook plate. Postoperative X-ray imaging showed osteolysis in 10 cases (30.3%), osteoarthritis in six cases (18.1%), osteolysis associated with osteoarthritis in four cases(12.1%), and steel hook broken in one case (3%). Conclusion: The use of hook plate on open reduction and internal fixation of the acromioclavicular joint dislocation had little adverse effect on shoulder function and is an effective method for the treatment of acromioclavicular joint dislocation. Osteoarthritis and osteolysis are the two common complications after hook plate use, which are associated with the impairment of shoulder function. Shoulder function will be improved after removal of the hook plate. PMID

Shoulder joint impairment among Finns aged 30 years or over: prevalence, risk factors and co-morbidity.

PubMed

Mäkelä, M; Heliövaara, M; Sainio, P; Knekt, P; Impivaara, O; Aromaa, A

1999-07-01

To describe the prevalence, risk factors and consequences of shoulder joint impairment in the population. A representative sample (n = 7217) of the Finnish population aged > or = 30 yr participated in a health examination survey (the Mini-Finland Health Survey). The design of the survey allowed an independent assessment of disability, reported shoulder pain, shoulder joint impairment and major chronic co-morbidity. Shoulder impairment was observed in 8.8%, while pain was reported by 30%. The prevalence of shoulder pain decreased among the elderly, whereas impairments increased up to 20% of those aged 75-80 yr. In addition to age, sex, previous injury to the shoulder joint and a history of physically heavy work, diabetes was associated with shoulder impairment (OR 1.6, 95% CI 1.2-2.1). Shoulder impairment was associated with disability (adjusted OR 2.0, CI 1.6-2.5). Shoulder impairment is an important component of ill health among the elderly, and cannot be reduced to reported pain alone.

Cytokine mRNA expression in synovial fluid of affected and contralateral stifle joints and the left shoulder joint in dogs with unilateral disease of the stifle joint.

PubMed

de Bruin, Tanya; de Rooster, Hilde; van Bree, Henri; Duchateau, Luc; Cox, Eric

2007-09-01

To examine mRNA expression of cytokines in synovial fluid (SF) cells from dogs with cranial cruciate ligament (CrCL) rupture and medial patellar luxation (MPL) and determine mRNA expression for 3 joints (affected stifle, unaffected contralateral stifle, and left shoulder joints) in dogs with unilateral CrCL rupture. 29 stifle joints with CrCL rupture (29 dogs), 8 stifle joints with MPL (7 dogs), and 24 normal stifle joints (16 clinically normal dogs). Immediately before reconstructive surgery, SF was aspirated from the cruciate-deficient stifle joint or stifle joint with MPL. Fourteen of 29 dogs had unilateral CrCL rupture; SF was also aspirated from the unaffected contralateral stifle joint and left shoulder joint. Those 14 dogs were examined 6 and 12 months after reconstructive surgery. Total RNA was extracted from SF cells and reverse transcription-PCR assay was performed to obtain cDNA. Canine-specific cytokine mRNA expression was determined by use of a real-time PCR assay. Interleukin (IL)-8 and -10 and interferon-gamma expression differed significantly between dogs with arthropathies and dogs with normal stifle joints. For the 14 dogs with unilateral CrCL rupture, a significant difference was found for IL-8 expression. Before reconstructive surgery, IL-8 expression differed significantly between the affected stifle joint and left shoulder joint or contralateral stifle joint. Six months after surgery, IL-8 expression was significantly increased in the unaffected contralateral stifle joint, compared with the shoulder joint. No conclusions can be made regarding the role of the examined cytokines in initiation of CrCL disease.

Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects.

PubMed

Lin, Yin-Liang; Karduna, Andrew

2016-10-01

Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. Copyright © 2016 Elsevier B.V. All rights reserved.

Exercises focusing on rotator cuff and scapular muscles do not improve shoulder joint position sense in healthy subjects

PubMed Central

Lin, Yin-Liang; Karduna, Andrew

2016-01-01

Proprioception is essential for shoulder neuromuscular control and shoulder stability. Exercise of the rotator cuff and scapulothoracic muscles is an important part of shoulder rehabilitation. The purpose of this study was to investigate the effect of rotator cuff and scapulothoracic muscle exercises on shoulder joint position sense. Thirty-six healthy subjects were recruited and randomly assigned into either a control or training group. The subjects in the training group received closed-chain and open-chain exercises focusing on rotator cuff and scapulothoracic muscles for four weeks. Shoulder joint position sense errors in elevation, including the humerothoracic, glenohumeral and scapulothoracic joints, was measured. After four weeks of exercise training, strength increased overall in the training group, which demonstrated the effect of exercise on the muscular system. However, the changes in shoulder joint position sense errors in any individual joint of the subjects in the training group were not different from those of the control subjects. Therefore, exercises specifically targeting individual muscles with low intensity may not be sufficient to improve shoulder joint position sense in healthy subjects. Future work is needed to further investigate which types of exercise are more effective in improving joint position sense, and the mechanisms associated with those changes. PMID:27475714

Risk of subacromial shoulder disorder in airport baggage handlers: combining duration and intensity of musculoskeletal shoulder loads.

PubMed

Møller, Sanne Pagh; Brauer, Charlotte; Mikkelsen, Sigurd; Alkjær, Tine; Koblauch, Henrik; Pedersen, Ellen Bøtker; Simonsen, Erik B; Thygesen, Lau Caspar

2018-04-01

Musculoskeletal shoulder load among baggage handlers measured by combining duration and intensity based on biomechanical and epidemiological information may be a stronger predictor of subacromial shoulder disorders than baggage handler seniority. In 2012, a cohort of baggage handlers employed at Copenhagen Airport in 1990-2012, and a cohort of unskilled otherwise employed men answered a survey. Self-reported information on work tasks during employment in the airport in combination with work task specific biomechanically modelled forces in the shoulder joint was used to estimate shoulder load. Exposure measures were accumulated shoulder abduction moment, accumulated shoulder compression force, accumulated supraspinatus force and baggage handler seniority. The outcome was subacromial shoulder disorder registered in the Danish National Patient Register. When analyses were adjusted by all confounders except age, exposure variables showed close to significant associations with subacromial shoulder disorder. Results could not confirm our hypothesis that combined information on work task duration and shoulder load intensity was stronger associated with subacromial shoulder disorder than seniority. Practitioner Summary: In this study we sought to identify if the exposure to work-related musculoskeletal shoulder loading including duration and intensity among baggage handlers was associated with subacromial shoulder disorder. We found that there was an association but this was not stronger than that between baggage handler seniority and subacromial shoulder disorder.

Muscle forces analysis in the shoulder mechanism during wheelchair propulsion.

PubMed

Lin, Hwai-Ting; Su, Fong-Chin; Wu, Hong-Wen; An, Kai-Nan

2004-01-01

This study combines an ergometric wheelchair, a six-camera video motion capture system and a prototype computer graphics based musculoskeletal model (CGMM) to predict shoulder joint loading, muscle contraction force per muscle and the sequence of muscular actions during wheelchair propulsion, and also to provide an animated computer graphics model of the relative interactions. Five healthy male subjects with no history of upper extremity injury participated. A conventional manual wheelchair was equipped with a six-component load cell to collect three-dimensional forces and moments experienced by the wheel, allowing real-time measurement of hand/rim force applied by subjects during normal wheelchair operation. An ExpertVision six-camera video motion capture system collected trajectory data of markers attached on anatomical positions. The CGMM was used to simulate and animate muscle action by using an optimization technique combining observed muscular motions with physiological constraints to estimate muscle contraction forces during wheelchair propulsion. The CGMM provides results that satisfactorily match the predictions of previous work, disregarding minor differences which presumably result from differing experimental conditions, measurement technologies and subjects. Specifically, the CGMM shows that the supraspinatus, infraspinatus, anterior deltoid, pectoralis major and biceps long head are the prime movers during the propulsion phase. The middle and posterior deltoid and supraspinatus muscles are responsible for arm return during the recovery phase. CGMM modelling shows that the rotator cuff and pectoralis major play an important role during wheelchair propulsion, confirming the known risk of injury for these muscles during wheelchair propulsion. The CGMM successfully transforms six-camera video motion capture data into a technically useful and visually interesting animated video model of the shoulder musculoskeletal system. The CGMM further yields accurate

The validation of a human force model to predict dynamic forces resulting from multi-joint motions

NASA Technical Reports Server (NTRS)

Pandya, Abhilash K.; Maida, James C.; Aldridge, Ann M.; Hasson, Scott M.; Woolford, Barbara J.

1992-01-01

The development and validation is examined of a dynamic strength model for humans. This model is based on empirical data. The shoulder, elbow, and wrist joints were characterized in terms of maximum isolated torque, or position and velocity, in all rotational planes. This data was reduced by a least squares regression technique into a table of single variable second degree polynomial equations determining torque as a function of position and velocity. The isolated joint torque equations were then used to compute forces resulting from a composite motion, in this case, a ratchet wrench push and pull operation. A comparison of the predicted results of the model with the actual measured values for the composite motion indicates that forces derived from a composite motion of joints (ratcheting) can be predicted from isolated joint measures. Calculated T values comparing model versus measured values for 14 subjects were well within the statistically acceptable limits and regression analysis revealed coefficient of variation between actual and measured to be within 0.72 and 0.80.

Compensating for intersegmental dynamics across the shoulder, elbow, and wrist joints during feedforward and feedback control.

PubMed

Maeda, Rodrigo S; Cluff, Tyler; Gribble, Paul L; Pruszynski, J Andrew

2017-10-01

Moving the arm is complicated by mechanical interactions that arise between limb segments. Such intersegmental dynamics cause torques applied at one joint to produce movement at multiple joints, and in turn, the only way to create single joint movement is by applying torques at multiple joints. We investigated whether the nervous system accounts for intersegmental limb dynamics across the shoulder, elbow, and wrist joints during self-initiated planar reaching and when countering external mechanical perturbations. Our first experiment tested whether the timing and amplitude of shoulder muscle activity account for interaction torques produced during single-joint elbow movements from different elbow initial orientations and over a range of movement speeds. We found that shoulder muscle activity reliably preceded movement onset and elbow agonist activity, and was scaled to compensate for the magnitude of interaction torques arising because of forearm rotation. Our second experiment tested whether elbow muscles compensate for interaction torques introduced by single-joint wrist movements. We found that elbow muscle activity preceded movement onset and wrist agonist muscle activity, and thus the nervous system predicted interaction torques arising because of hand rotation. Our third and fourth experiments tested whether shoulder muscles compensate for interaction torques introduced by different hand orientations during self-initiated elbow movements and to counter mechanical perturbations that caused pure elbow motion. We found that the nervous system predicted the amplitude and direction of interaction torques, appropriately scaling the amplitude of shoulder muscle activity during self-initiated elbow movements and rapid feedback control. Taken together, our results demonstrate that the nervous system robustly accounts for intersegmental dynamics and that the process is similar across the proximal to distal musculature of the arm as well as between feedforward (i

Effect of forearm axially rotated posture on shoulder load and shoulder abduction / flexion angles in one-armed arrest of forward falls.

PubMed

Hsu, Hsiu-Hao; Chou, You-Li; Lou, Shu-Zon; Huang, Ming-Jer; Chou, Paul Pei-Hsi

2011-03-01

Falling onto the outstretched hand is the most common cause of upper extremity injury. This study develops an experimental model for evaluating the shoulder load during a simulated forward fall onto one hand with three different forearm axially rotated postures, and examines the shoulder abduction angle and shoulder flexion angle in each case. Fifteen healthy young male subjects with an average age of 23.7 years performed a series of one-armed arrests from a height of 5 cm onto a force plate. The kinematics and kinetics of the upper extremity were analyzed for three different forearm postures, namely 45° externally rotated, non-rotated, and 45° internally rotated. The shoulder joint load and shoulder abduction/flexion angles were significantly dependent on the rotational posture of the forearm. The shoulder medio-lateral shear forces in the externally rotated group were found to be 1.61 and 2.94 times higher than those in the non-rotated and internally rotated groups, respectively. The shoulder flexion angles in the externally rotated, non-rotated and internally rotated groups were 0.6°, 8.0° and 19.2°, respectively, while the corresponding shoulder abduction angles were 6.1°, 34.1° and 46.3°, respectively. In falls onto the outstretched hand, an externally rotated forearm posture should be avoided in order to reduce the medio-lateral shear force acting on the shoulder joint. In falls of this type, a 45° internally rotated forearm posture represents the most effective fall strategy in terms of minimizing the risk of upper extremity injuries. Copyright © 2010 Elsevier Ltd. All rights reserved.

Effects of hand grip exercise on shoulder joint internal rotation and external rotation peak torque.

PubMed

Lee, Dong-Rour; Jong-Soon Kim, Laurentius

2016-08-10

The goal of this study is to analyze the effects of hand grip training on shoulder joint internal rotation (IR)/external rotation (ER) peak torque for healthy people. The research was conducted on 23 healthy adults in their 20 s-30 s who volunteered to participate in the experiment. Hand grip power test was performed on both hands of the research subjects before/after the test to study changes in hand grip power. Isokinetic machine was used to measure the concentric IRPT (internal rotation peak torque) and concentric ERPT (external rotation peak torque) at the velocity of 60°/sec, 90°/sec, and 180°/sec before/after the test. Hand grip training was performed daily on the subject's right hand only for four weeks according to exercise program. Finally, hand grip power of both hands and the maximum torque values of shoulder joint IR/ER were measured before/after the test and analyzed. There was a statistically significant difference in the hand grip power of the right hand, which was subject to hand grip training, after the experiment. Also, statistically significant difference for shoulder ERPT was found at 60°/sec. Hand grip training has a positive effect on shoulder joint IRPT/ERPT and therefore can help strengthen muscles around the shoulder without using weight on the shoulder. Consequently, hand grip training would help maintain strengthen the muscles around the shoulder in the early phase of rehabilitation process after shoulder surgery.

Periprosthetic Joint Infection of Shoulder Arthroplasties: Diagnostic and Treatment Options

PubMed Central

Sevelda, Florian

2017-01-01

Periprosthetic joint infection (PJI) is one of the most frequent reasons for painful shoulder arthroplasties and revision surgery of shoulder arthroplasties. Cutibacterium acnes (Propionibacterium acnes) is one of the microorganisms that most often causes the infection. However, this slow growing microorganism is difficult to detect. This paper presents an overview of different diagnostic test to detect a periprosthetic shoulder infection. This includes nonspecific diagnostic tests and specific tests (with identifying the responsible microorganism). The aspiration can combine different specific and nonspecific tests. In dry aspiration and suspected joint infection, we recommend a biopsy. Several therapeutic options exist for the treatment of PJI of shoulder arthroplasties. In acute infections, the options include leaving the implant in place with open debridement, septic irrigation with antibacterial fluids like octenidine or polyhexanide solution, and exchange of all removable components. In late infections (more than four weeks after implantation) the therapeutic options are a permanent spacer, single-stage revision, and two-stage revision with a temporary spacer. The functional results are best after single-stage revisions with a success rate similar to two-stage revisions. For single-stage revisions, the microorganism should be known preoperatively so that specific antibiotics can be mixed into the cement for implantation of the new prosthesis and specific systemic antibiotic therapy can be applied to support the surgery. PMID:29423407

Shoulder injuries from attacking motion

NASA Astrophysics Data System (ADS)

Yanagi, Shigeru; Nishimura, Tetsu; Itoh, Masaru; Wada, Yuhei; Watanabe, Naoki

1997-03-01

Sports injuries have bothered professional players. Although many medical doctors try to treat injured players, to prevent sports injuries is more important. Hence, it is required to clear a kinematic mechanism of the sport injuries. A shoulder of volleyball attacker or baseball pitcher is often inured by playing motion. The injuries are mainly caused at the end of long head tendon, which is located in the upper side of scapula. Generally, a muscle and tendon have enough strength against tensile force, however, it seems that they are sometimes defeated by the lateral force. It is imagined that the effect of the lateral force has a possibility of injuring the tendon. If we find the influence of the lateral force on the injured portion, the mechanism of injuries must be cleared. In our research, volleyball attacking motion is taken by high speed video cameras. We analyze the motion as links system and obtain an acceleration of an arm and a shoulder from video image data. The generated force at a shoulder joint is calculated and resolved into the lateral and longitudinal forces. Our final goal is to discuss a possibility that the lateral force causes the injuries.

Maternal Endogenous Forces and Shoulder Dystocia.

PubMed

Grimm, Michele J

2016-12-01

Childbirth is a complicated biomechanical process that many take for granted. However, the delivery forces generated by a mother (uterine contractions and maternal pushing) are strong and have a significant effect on the body and tissues of the fetus, especially during the second stage of labor. Although most infants are born without negative, force-related outcomes, in some infants the normal forces of labor cause an injury that can have either temporary or permanent sequelae. The biomechanical situation is further complicated when an infant's shoulder impacts the maternal pelvis, which provides increased resistance and creates added stresses within the neonatal body and tissues.

The Acute Effect of Cryotherapy on Muscle Strength and Shoulder Proprioception.

PubMed

Torres, Rui; Silva, Filipa; Pedrosa, Vera; Ferreira, João; Lopes, Alexandre

2017-11-01

Cryotherapy, a common intervention used by clinicians, poses several benefits in managing acute injuries. However, cooling muscle tissue can interfere with muscular properties and the sensory-motor system. The aim of this study was to analyze the influence of cryotherapy with a crushed-ice pack on shoulder proprioception concerning joint position sense, force sense, the threshold for detecting passive movement, and maximal force production. A randomized, double-blind controlled trial. 48 healthy women aged 22.6 ± 0.4 y with a mean body mass index of 22.8 ±0.37 kg/m2 and a percentage of body fat of 15.4 ± 1.5%. In the experimental group, a crushed-ice pack was applied to the shoulder for 15 min, whereas participants in the control group applied a sandbag at skin temperature, also for 15 min. An isokinetic dynamometer was used to assess maximal voluntary contraction, force sense, joint position sense, and the threshold for detecting passive movement. Paired sample t tests revealed that maximal voluntary isometric contraction decreased significantly after cryotherapy (P ≤ .001), or approximately 10% of the reduction found in both muscular groups assessed. Shoulder position sense (P < .001) and the threshold for detecting passive movement (P = .01 and P = .01 for lateral and medial shoulder rotator muscles, respectively) also suffered significant impairment. Nevertheless, no significant differences emerged in force sense at 20% and 50% of maximal force reproduction (P = .41 and P = .10 for lateral rotator muscles at 20% and 50%, respectively; and P = .20 and P = .09 for medial rotator muscles at 20% and 50%, respectively). Applying a crushed-ice pack to the shoulder for 15 min negatively affected muscle strength and impaired shoulder proprioception by decreasing joint position sense and the threshold for detecting passive movement.

Joint Kinetics to Assess the Influence of the Racket on a Tennis Player’s Shoulder

PubMed Central

Creveaux, Thomas; Dumas, Raphaël; Hautier, Christophe; Macé, Pierre; Chèze, Laurence; Rogowski, Isabelle

2013-01-01

This study aimed at investigating the influence of three rackets on shoulder net joint moments, power and muscle activity during the flat tennis serve under field- conditions. A 6-camera Eagle® motion analysis system, operating at 256 Hz, captured racket and dominant upper limb kinematics of the serve in five tennis players under three racket conditions (A: low mass, high balance and polar moment, B: low three moments of inertia, and C: high mass, swingweight and twistweight). The electromyographic activity of six trunk and arm muscles was simultaneously recorded. Shoulder net joint moments and power were computed by 3D inverse dynamics. The results showed that greater shoulder joint power and internal/external rotation peak moments were found to accelerate and decelerate racket A in comparison with the racket C. Moreover, serving with the racket A resulted in less activity in latissimus dorsi muscle during the acceleration phase, and biceps brachii muscle during the follow-through phase when compared with racket C. These initial findings encourage studying the biomechanical measurements to quantify the loads on the body during play in order to reduce them, and then prevent shoulder injuries. Racket specifications may be a critical point for coaches who train players suffering from shoulder pain and chronic upper limb injuries should be considered in relation to the racket specifications of the players. Key Points Light racket required more joint power than heavy one to achieve similar post impact ball velocity. Serving with a light racket resulted in higher shoulder internal and external rotation moments than using a heavy one for similar performance. Chronic shoulder pain should encourage coaches to check for potentially inappropriate racket specifications of their players. PMID:24149804

Evaluation of traction stirrup distraction technique to increase the joint space of the shoulder joint in the dog: A cadaveric study.

PubMed

Devesa, V; Rovesti, G L; Urrutia, P G; Sanroman, F; Rodriguez-Quiros, J

2015-06-01

The objective of this study was to evaluate technical feasibility and efficacy of a joint distraction technique by traction stirrup to facilitate shoulder arthroscopy and assess potential soft tissue damage. Twenty shoulders were evaluated radiographically before distraction. Distraction was applied with loads from 40 N up to 200 N, in 40 N increments, and the joint space was recorded at each step by radiographic images. The effects of joint flexion and intra-articular air injection at maximum load were evaluated. Radiographic evaluation was performed after distraction to evaluate ensuing joint laxity. Joint distraction by traction stirrup technique produces a significant increase in the joint space; an increase in joint laxity could not be inferred by standard and stress radiographs. However, further clinical studies are required to evaluate potential neurovascular complications. A wider joint space may be useful to facilitate arthroscopy, reducing the likelihood for iatrogenic damage to intra-articular structures. Copyright © 2015 Elsevier Ltd. All rights reserved.

Evaluation of clinical, radiographical and cytological findings compared to arthroscopic findings in shoulder joint lameness in the dog.

PubMed

Akerblom, S; Sjöström, L

2007-01-01

Forty-two dogs with lameness emanating from the shoulder joint were studied by clinical examination, radiographic examination, joint fluid analysis, and arthroscopic examination, following a set protocol. Dogs with mild clinical signs, absent or mild radiographic signs of osteoarthrosis, and without or with very mild changes in the synovial fluid, may still have moderate to severe degenerative pathological changes in the shoulder joint.

Biomechanical benefits of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: A cadaveric study.

PubMed

Kim, Hyun-Min Mike; Chacon, Alexander C; Andrews, Seth H; Roush, Evan P; Cho, Edward; Conaway, William K; Kunselman, Allen R; Lewis, Gregory S

2016-04-01

Restoration of joint stability during total shoulder arthroplasty can be challenging in the face of severe glenoid retroversion. A novel technique of humeral head component anterior-offsetting has been proposed to address posterior instability. We evaluated the biomechanical benefits of this technique in cadaveric specimens. Total shoulder arthroplasty was performed in 14 cadaveric shoulders from 7 donors. Complementary shoulders were assigned to either 10° or 20° glenoid retroversion, with retroversion created by eccentric reaming. Two humeral head component offset positions were tested in each specimen: The anatomic (posterior) and anterior (reverse). With loads applied to the rotator cuff and deltoid, joint contact pressures and the force and energy required for posterior humeral head translation were measured. The force and energy required to displace the humeral head posteriorly increased significantly with the anterior offset position compared to the anatomic offset position. The joint contact pressures were significantly shifted anteriorly, and the joint contact area significantly increased with the anterior offset position. Anterior offsetting of the humeral head component increased the resistance to posterior humeral head translation, shifted joint contact pressures anteriorly, and increased joint contact area, thus, potentially increasing the joint stability in total shoulder arthroplasty with simulated glenoid retroversion. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Characteristics of clinical shoulder research over the last decade: a review of shoulder articles in The Journal of Bone & Joint Surgery from 2004 to 2014.

PubMed

Gartsman, Gary M; Morris, Brent J; Unger, R Zackary; Laughlin, Mitzi S; Elkousy, Hussein A; Edwards, T Bradley

2015-03-04

The purpose of this study was to determine characteristics and trends in published shoulder research over the last decade in a leading orthopaedic journal. We examined all clinical shoulder articles published in The Journal of Bone & Joint Surgery from 2004 to 2014. The number of citations, authorship, academic degrees of the authors, country and institution of origin, topic, level of evidence, positive or nonpositive outcome, and inclusion of validated patient-reported outcome measures were assessed for each article. Shoulder articles that included an author with an advanced research degree (MD [Doctor of Medicine] with a PhD [Doctor of Philosophy] or other advanced degree) increased during the study period (p = 0.047). Level-I, II, and III studies were more likely to have an author with an advanced research degree, and Level-IV studies were more likely to have MDs only (p = 0.03). Overall, there was great variability of outcome measures, with at least thirty-nine different validated or nonvalidated outcome measures reported. Over the last decade, there was an improvement in the level of evidence of shoulder articles published in The Journal of Bone & Joint Surgery that corresponds with recent emphasis on evidence-based medicine. A consensus is needed in shoulder research for more consistent application of validated patient-reported outcome measurement tools. Copyright © 2015 by The Journal of Bone and Joint Surgery, Incorporated.

Effect of lateral offset center of rotation in reverse total shoulder arthroplasty: a biomechanical study.

PubMed

Henninger, Heath B; Barg, Alexej; Anderson, Andrew E; Bachus, Kent N; Burks, Robert T; Tashjian, Robert Z

2012-09-01

Lateral offset center of rotation (COR) reduces the incidence of scapular notching and potentially increases external rotation range of motion (ROM) after reverse total shoulder arthroplasty (rTSA). The purpose of this study was to determine the biomechanical effects of changing COR on abduction and external rotation ROM, deltoid abduction force, and joint stability. A biomechanical shoulder simulator tested cadaveric shoulders before and after rTSA. Spacers shifted the COR laterally from baseline rTSA by 5, 10, and 15 mm. Outcome measures of resting abduction and external rotation ROM, and abduction and dislocation (lateral and anterior) forces were recorded. Resting abduction increased 20° vs native shoulders and was unaffected by COR lateralization. External rotation decreased after rTSA and was unaffected by COR lateralization. The deltoid force required for abduction significantly decreased 25% from native to baseline rTSA. COR lateralization progressively eliminated this mechanical advantage. Lateral dislocation required significantly less force than anterior dislocation after rTSA, and both dislocation forces increased with lateralization of the COR. COR lateralization had no influence on ROM (adduction or external rotation) but significantly increased abduction and dislocation forces. This suggests the lower incidence of scapular notching may not be related to the amount of adduction deficit after lateral offset rTSA but may arise from limited impingement of the humeral component on the lateral scapula due to a change in joint geometry. Lateralization provides the benefit of increased joint stability, but at the cost of increasing deltoid abduction forces. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

A musculoskeletal shoulder model based on pseudo-inverse and null-space optimization.

PubMed

Terrier, Alexandre; Aeberhard, Martin; Michellod, Yvan; Mullhaupt, Philippe; Gillet, Denis; Farron, Alain; Pioletti, Dominique P

2010-11-01

The goal of the present work was assess the feasibility of using a pseudo-inverse and null-space optimization approach in the modeling of the shoulder biomechanics. The method was applied to a simplified musculoskeletal shoulder model. The mechanical system consisted in the arm, and the external forces were the arm weight, 6 scapulo-humeral muscles and the reaction at the glenohumeral joint, which was considered as a spherical joint. The muscle wrapping was considered around the humeral head assumed spherical. The dynamical equations were solved in a Lagrangian approach. The mathematical redundancy of the mechanical system was solved in two steps: a pseudo-inverse optimization to minimize the square of the muscle stress and a null-space optimization to restrict the muscle force to physiological limits. Several movements were simulated. The mathematical and numerical aspects of the constrained redundancy problem were efficiently solved by the proposed method. The prediction of muscle moment arms was consistent with cadaveric measurements and the joint reaction force was consistent with in vivo measurements. This preliminary work demonstrated that the developed algorithm has a great potential for more complex musculoskeletal modeling of the shoulder joint. In particular it could be further applied to a non-spherical joint model, allowing for the natural translation of the humeral head in the glenoid fossa. Copyright © 2010 IPEM. Published by Elsevier Ltd. All rights reserved.

Effect of linear polarized near-infrared light irradiation on flexibility of shoulder and ankle joints.

PubMed

Demura, S; Yamaji, S; Ikemoto, Y

2002-12-01

There is a possibility that heat stimulus by linear polarized near-infrared light irradiation (PL: Super Lizer HA-30, Tokyo Medical Laboratory) improves the range of joint motion, because the flexibility of soft-part tissues, such as a muscle or a tendon, is improved by increasing the muscle temperature. The purpose of this study was to examine the influence of PL-irradiation on the ranges of shoulder and ankle motions. 30 healthy young adults (15 males: mean+/-SD, age 19.1+/-0.8 yrs, height 173.3+/-4.6 cm, body mass 68.5+/-8.0 kg and 15 females: mean+/-SD, age 19.2+/-0.7 yrs, height 162.3+/-4.5 cm, body mass 58.1+/-6.6 kg) participated in the experiment under PL-irradiation and no-irradiation (placebo) conditions. the angles of shoulder and ankle joint motions were measured twice, before and after the PL- and placebo-irradiations. The angle of a motion was defined as the angle connecting 3 points at linearity as follows: for the shoulder, the greater trochanter, acromion, and caput ulnare, and for the ankle, the knee joint, fassa of lateral malleolus and metacarpal bone. Each angle was measured when a subject extended or flexed maximally without support. The trial-to-trial reliability of each range of joint motion was very high. All parameters in PL-irradiation were significantly larger in postirradiation than pre-irradiation, and the value of postirradiation in PL-irradiation was significantly greater than that for placebo. The ranges of shoulder and ankle motions in placebo-irradiation were also significantly greater in postirradiation than pre-irradiation. Moreover, the change rate for each range of joint motion between pre- and postirradiations was significantly greater in PL-irradiation in both joints. In PL-irradiation, most subject's motions were greater in postirradiation than pre-irradiation, but not in the placebo-irradiation. The effect of PL-irradiation tended to be greater on subjects with a small range of a joint motion. It is considered from the

A prospective cohort study investigating the effect of generalized joint hypermobility on outcomes after arthroscopic anterior shoulder stabilization.

PubMed

Koyonos, Loukas; Kraeutler, Matthew J; O'Brien, Daniel F; Ciccotti, Michael G; Dodson, Christopher C

2016-11-01

Generalized joint laxity has been proposed as a significant risk factor for failure after arthroscopic anterior shoulder stabilization. The purpose of this study was to prospectively measure joint mobility in patients undergoing arthroscopic anterior shoulder stabilization and to determine whether hypermobility is a risk factor for worse outcomes compared with patients having normal joint mobility. Patients with anterior shoulder instability were prospectively enrolled. Generalized joint hypermobility was measured using the Beighton Hypermobility Score and the Rowe, UCLA, SANE, SST, and WOSI scores were administered and reported as patient outcomes preoperatively and following arthroscopic anterior shoulder stabilization at 6 weeks, 6 months, 12 months, and 24 months postoperatively. Patients were stratified into two groups based on their Beighton Hypermobility Score, with scores ≥ 4/9 indicative of joint hypermobility. Sixteen patients with joint hypermobility (JH) and 18 non-hypermobile patients (NJH) were enrolled. At baseline, there were no significant differences in demographic characteristics or baseline patient-reported outcomes. Significantly more patients in the NJH group had SLAP tears (n = 10) compared to the JH group (n = 2) (p = .013). At all follow-up times, there were no significant differences between the NJH and JH groups with regard to patient-reported outcome scores (p > .05). In the JH group, 17% of patients reported recurrent instability at two years postoperatively compared to 25% of patients in the NJH group. There was no significant difference in failure rate (p = .67). There was no significant difference in patient-reported outcomes or recurrent instability in patients with versus without joint hypermobility undergoing arthroscopic anterior shoulder stabilization.

A novel cadaveric model for anterior-inferior shoulder dislocation using forcible apprehension positioning.

PubMed

McMahon, Patrick J; Chow, Stephen; Sciaroni, Laura; Yang, Bruce Y; Lee, Thay Q

2003-01-01

A novel cadaveric model for anterior-inferior shoulder dislocation using forcible apprehension positioning is presented. This model simulates an in vivo mechanism and yields capsulolabral lesions. The scapulae of 14 cadaveric entire upper limbs (82 +/- 9 years, mean +/- standard deviation) were each rigidly fixed to a custom shoulder-testing device. A pneumatic system was used with pulleys and cables to simulate the rotator cuff and the deltoid muscles (anterior and middle portions). The glenohumeral joint was then positioned in the apprehension position of abduction, external rotation, and horizontal abduction. A 6-degree-of-freedom load cell (Assurance Technologies, Garner, North Carolina) measured the joint reaction force that was then resolved into three orthogonal components of compression force, anteriorly directed force, and superiorly directed force. With the use of a thrust bearing, the humerus was moved along a rail with a servomotor-controlled system at 50 mm/s that resulted in horizontal abduction. Force that developed passively in the pectoralis major muscle was recorded with an independent uniaxial load cell. Each of the glenohumeral joints dislocated anterior-inferior, six with avulsion of the capsulolabrum from the anterior-inferior glenoid bone and eight with capsulolabral stretching. Pectoralis major muscle force as well as the joint reaction force increased with horizontal abduction until dislocation. At dislocation, the magnitude of the pectoralis major muscle force, 609.6 N +/- 65.2 N was similar to the compression force, 569.6 N +/- 37.8 N. A cadaveric model yielded an anterior dislocation with a mechanism of forcible apprehension positioning when the appropriate shoulder muscles were simulated and a passive pectoralis major muscle was included. Capsulolabral lesions resulted, similar to those observed in vivo.

Sensorimotor control and neuromuscular activity of the shoulder in adolescent competitive swimmers with generalized joint hypermobility.

PubMed

Frydendal, Thomas; Eshøj, Henrik; Liaghat, Behnam; Edouard, Pascal; Søgaard, Karen; Juul-Kristensen, Birgit

2018-05-05

Shoulder pain is highly prevalent in competitive swimmers, and generalized joint hypermobility (GJH) is considered a risk factor. Sensorimotor control deficiencies and altered neuromuscular activation of the shoulder may represent underlying factors. To investigate whether competitive swimmers with GJH including shoulder hypermobility (GJHS) differ in shoulder sensorimotor control and muscle activity from those without GJH and no shoulder hypermobility (NGJH). Competitive swimmers (aged 13-17) were recruited. GJHS or NGJH status was determined using the Beighton score (0-9) and Rotès-Quérol test (positive/negative). Inclusion criteria for GJHS were a Beighton score ≥5 and minimum one hypermobile shoulder, while NGJH was defined as a Beighton score ≤3 and no shoulder hypermobility. Three prone lying, upper-extremity weight-bearing shoulder stabilometric tests were performed on a force platform: Bilateral upper-extremity support eyes open (BL-EO) and eyes closed (BL-EC) and unilateral upper-extremity support eyes open (UL-EO). Surface electromyography (SEMG) was measured from the upper trapezius, lower trapezius, serratus anterior, infraspinatus and pectoralis major muscles. SEMG was normalized using maximal voluntary isometric contractions and presented relative to maximal voluntary SEMG (%MVE). Co-contraction index (CCI) was calculated for the following muscle pairs: upper trapezius-lower trapezius, upper trapezius-serratus anterior, and infraspinatus-pectoralis major. Between-group differences in stabilometric parameters, %MVE, and CCI were analyzed with a mixed effects model. Thirty-eight swimmers were enrolled as GJHS (n = 19) or NGJH (n = 19). There were no group differences in stabilometric parameters or CCI. GJHS displayed significantly decreased (29%) pectoralis major activity during BL-EO compared to NGJH (5.35 ± 1.77%MVE vs. 7.51 ± 1.96%MVE; p = 0.043). Adolescent competitive swimmers with GJHS displayed no shoulder sensorimotor

[Shoulder joint pain of rotator cuff injury treated with electroacupuncture and Mulligan's mobilization: a randomized controlled trial].

PubMed

Wang, Yanwu; Wang, Chongmin; Chen, Huade; Ye, Xinmiao

2018-01-12

To verify the clinical therapeutic effects on shoulder joint pain of rotator cuff injury treated with electroacupuncture (EA) and Mulligan's mobilization. A total of 120 patients of shoulder joint pain of rotator cuff injury were randomized into an EA group, a rehabilitation group and a combined therapy group, 40 cases in each one. In the EA group, EA was applied to Jianzhen (SI 9), Jianliao (TE 14), Jianyu (LI 15), Tianzong (SI 11), Jianqian (extra) and Binao (LI 14) in the affected side. Of these acupoints, Jianliao (TE 14) and Jianyu (LI 15), Jianzhen (SI 9) and Tianzong (SI 11) were stimulated with Han 's electric apparatus. In the rehabilitation group, Mulligan's mobilization was used, including scapular mobilization, static joint mobilization and dynamic joint mobilization. In the combined therapy group, EA was used in combination with Mulligan mobilization. The treatment was given once a day in each group, 5 sessions a week, totally for 6 weeks. The pain intensity of shoulder joint (VAS), the University of California at Los Angeles shoulder rating scale (UCLA) and the range of motion (ROM) of shoulder joint were evaluated before and 6 weeks after treatment separately. The adverse reactions were recorded in each group. VAS scores were all reduced, UCLA scores increased and ROM improved after treatment as compared with those before treatment in the patients of the three groups (all P <0.05). After treatment, VAS score, UCLA score and ROM in the combined therapy group were remarkably improved as compared with those in the EA group and the rehabilitation group (all P <0.05). Regarding the improvements of VAS and UCLA scores, the results in the EA group were better than those in the rehabilitation group (both P <0.05). Regarding ROM improvement, the results in the rehabilitation group were superior to those in the EA group (all P <0.05). There was no adverse reaction in the two groups. The combined therapy of EA and Mulligan's mobilization relieves shoulder joint

Shoulder and hip joint for hard space suits

NASA Technical Reports Server (NTRS)

Vykukal, H. C.

1986-01-01

Shoulder and hip joints for hard space suits are disclosed which are comprised of three serially connected truncated spherical sections, the ends of which converge. Ball bearings between the sections permit relative rotation. The proximal end of the first section is connected to the torso covering by a ball bearing and the distal end of the outermost section is connected to the elbow or thigh covering by a ball bearing. The sections are equi-angular and this alleviates lockup, the condition where the distal end of the joint leaves the plane in which the user is attempting to flex. The axes of rotation of the bearings and the bearing mid planes are arranged to intersect in a particular manner that provides the joint with a minimum envelope. In one embodiment, the races of the bearing between the innermost section and the second section is partially within the inner race of the bearing between the torso and the innermost spherical section further to reduce bulk.

Determinants and magnitudes of manual force strengths and joint moments during two-handed standing maximal horizontal pushing and pulling.

PubMed

Chow, Amy Y; Dickerson, Clark R

2016-04-01

Pushing and pulling are common occupational exertions that are increasingly associated with musculoskeletal complaints. This study focuses on the sensitivity of shoulder capacity to gender, handle height, exertion type (push or pull) and handle orientation for these tasks. All factors except for handle orientation influenced unilateral and total manual force strength (p < 0.01), with exertion type being the most influential. Interaction effects also existed between handle height and exertion type. Additionally, joint moments at the shoulders and low back were influenced by all factors studied (p < 0.01), with exertion type again being most influential. Knowledge of the relative influence of multiple factors on shoulder capacity can provide guidance regarding these factors when designing or evaluating occupational pushing and pulling tasks for a diverse population. Practitioner Summary: pushing and pulling comprise nearly half of all manual materials handling tasks. Practitioners often assess, design or modify these tasks while incorporating constraints, including manual force direction and handle interface. This study provides guidance to aid design of pushing and pulling tasks in the context of shoulder physical capacity.

Upper limb joint kinetic analysis during tennis serve: Assessment of competitive level on efficiency and injury risks.

PubMed

Martin, C; Bideau, B; Ropars, M; Delamarche, P; Kulpa, R

2014-08-01

The aim of this work was to compare the joint kinetics and stroke production efficiency for the shoulder, elbow, and wrist during the serve between professionals and advanced tennis players and to discuss their potential relationship with given overuse injuries. Eleven professional and seven advanced tennis players were studied with an optoelectronic motion analysis system while performing serves. Normalized peak kinetic values of the shoulder, elbow, and wrist joints were calculated using inverse dynamics. To measure serve efficiency, all normalized peak kinetic values were divided by ball velocity. t-tests were used to determine significant differences between the resultant joint kinetics and efficiency values in both groups (advanced vs professional). Shoulder inferior force, shoulder anterior force, shoulder horizontal abduction torque, and elbow medial force were significantly higher in advanced players. Professional players were more efficient than advanced players, as they maximize ball velocity with lower joint kinetics. Since advanced players are subjected to higher joint kinetics, the results suggest that they appeared more susceptible to high risk of shoulder and elbow injuries than professionals, especially during the cocking and deceleration phases of the serve. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

[Case-control study on shoulder pain caused by hook palte for the treatment of acromioclavicular joint dislocation].

PubMed

Yang, Ying-guo; Cai, Xiao-bing; Wang, Xiao-min; Zhu, Yong-gan; Pan, He-yong

2015-06-01

To explore causes of shoulder pain and propose prevention measures in treating acromioclavicular joint dislocation. From January 2005 to January 2013, 86 patients with acromioclavicular joint dislocation (Tossy III) were treated with hook plate fixation, and were divided into two groups. Bsaed on recovery of shoulder function mostly, the patients who suffered from rest pain, motion pain were named as shoulder pain group, while the patients without pain were named as painless group. In shoulder pain group, there were 21 cases including 15 males and and 6 females ranging the age from 22 to 62 years old with an average of (40.6±11.2) years old. There were 8 cases were on the left side and 13 cases were on the right side. In painless group, there were 65 cases including 36 males and and 29 females ranging the age from 19 to 65 years old with an average of (40.0±11.3) years old. There were 33 cases were on the left side and 32 cases were on the right side. The time from injury to operation ranged from 3 h to 8 d with an average of 34.6 h. Shoulder function of all patients were normal before injuried. Postoperative pain, activity of daily living (ADL), range of motion, deltoid muscle strength were compared. Anteflexion,rear protraction, abduction and upthrow of shoulder joint were also compared. Postoperative complications between two groups were observed and compared. All patients were followed up from 12 to 48 months with an average of 18.5 months. Constant-Murley score were used to evaluate clinical efficacy at the least following up, and 13 cases got an excellent results, 5 moderate, 2 good and 1 poor in shoulder pain group ; while 61 cases were obtained excellent results, 3 moderate and 1 good in painless group. There were significantly differences between two groups in Constant-Murley score and activity of shoulder joint (P<0.05). In shoulder pain group, 3 cases were disconnected, 1 case occurred stress fracture, 9 cases were subacromial impingement syndrome, 5

Clinical Evaluation of the TITAN™ Total Shoulder System

ClinicalTrials.gov

2018-02-14

Arthritis; Arthritis, Degenerative; Rheumatoid Arthritis; Post-traumatic Arthrosis of Other Joints, Shoulder Region; Rotator Cuff Syndrome of Shoulder and Allied Disorders; Fracture; Avascular Necrosis; Joint Instability; Joint Trauma; Dislocation, Shoulder; Pain, Shoulder

Effect of brief daily resistance training on rapid force development in painful neck and shoulder muscles: randomized controlled trial

PubMed Central

Jay, Kenneth; schraefel, mc; Andersen, Christoffer H; Ebbesen, Frederik S; Christiansen, David H; Skotte, Jørgen; Zebis, Mette K; Andersen, Lars L

2013-01-01

Objective: To determine the effect of small daily amounts of progressive resistance training on rapid force development of painful neck/shoulder muscles. Methods: 198 generally healthy adults with frequent neck/shoulder muscle pain (mean: age 43·1 years, computer use 93% of work time, 88% women, duration of pain 186 day during the previous year) were randomly allocated to 2- or 12 min of daily progressive resistance training with elastic tubing or to a control group receiving weekly information on general health. A blinded assessor took measures at baseline and at 10-week follow-up; participants performed maximal voluntary contractions at a static 90-degree shoulder joint angle. Rapid force development was determined as the rate of torque development and maximal muscle strength was determined as the peak torque. Results: Compared with the control group, rate of torque development increased 31·0 Nm s−1 [95% confidence interval: (1·33–11·80)] in the 2-min group and 33·2 Nm s−1 (1·66–12·33) in the 12-min group from baseline to 10-week follow-up, corresponding to an increase of 16·0% and 18·2% for the two groups, respectively. The increase was significantly different compared to controls (P<0·05) for both training groups. Maximal muscle strength increased only ∼5–6% [mean and 95% confidence interval for 2- and 12-min groups to control, respectively: 2·5 Nm (0·05–0·73) and 2·2 Nm (0·01–0·70)]. No significant differences between the 2- and 12-min groups were evident. A weak but significant relationship existed between changes in rapid force development and pain (r = 0·27, P<0·01), but not between changes in maximal muscle strength and pain. Conclusion: Small daily amounts of progressive resistance training in adults with frequent neck/shoulder pain increases rapid force development and, to a less extent, maximal force capacity. PMID:23758661

Sternoclavicular joint palpation pain: the shoulder's Waddell sign?

PubMed

Ponce, Brent A; Archie, Adam T; Watson, Shawna L; Hudson, Parke W; Menendez, Mariano E; McGwin, Gerald; Brabston, Eugene W

2018-07-01

Pain is a complex and subjective reality and can be magnified by nonorganic or nonanatomic sources. Multiple studies have demonstrated a correlation between psychological factors and patients' perceptions of musculoskeletal pain and disability. In addition, nonorganic findings as part of the physical examination are well and long recognized. The purpose of this study was to analyze the relationship between a shoulder examination test, palpation of the sternoclavicular joint (SCJ), and psychosocial conditions including chronic pain, depression, and anxiety. From June until October 2016, all new patients of 2 sports/shoulder fellowship-trained surgeons at an academic practice were screened for study enrollment. After their consent was obtained, patients were given a set of 5 surveys (Pain Catastrophizing Scale; Patient-Health Questionnaire 2; Pain Self-Efficacy Questionnaire; shortened Disabilities of the Arm, Shoulder and Hand questionnaire; and Shoulder Pain and Disability Index) to complete. The physician then completed a comprehensive standardized physical examination, with the examining physician being blinded to the patient's survey responses. Palpation of the SCJ was done with the examiner's thumbs and was accompanied by the question "Does this hurt?" If a positive pain response was given, clarification as to the correct side of the pain was made. A total of 132 patients were enrolled and completed the surveys and physical examination. Of the patients, 26 (19.7%) reported SCJ pain with SCJ palpation. Patients with and without confirmed pain on SCJ palpation had significantly different (P < .001) mean scores for all 5 surveys. A review of the medical histories between the 2 groups identified a significantly increased prevalence of chronic pain and mental health disorders, such as anxiety and depression, in SCJ palpation-positive patients. Patients who confirmed pain on SCJ palpation had significantly higher scores on various psychological surveys than those

Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers.

PubMed

Post, Eric G; Laudner, Kevin G; McLoda, Todd A; Wong, Regan; Meister, Keith

2015-06-01

Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. Cross-sectional study. Motion-analysis laboratory. Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r(2) = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = -0.043, 0.419; r(2) = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = -0.147, 0.329; r(2) = 0.009; P = .217). Although a weak positive correlation was present between ball velocity and shoulder-distraction force, no significant association was seen between ball velocity and elbow

Defining forces that are associated with shoulder dystocia: the use of a mathematic dynamic computer model.

PubMed

Gonik, Bernard; Zhang, Ning; Grimm, Michele J

2003-04-01

A computer model was modified to study the impact of maternal endogenous and clinician-applied exogenous delivery loads on the contact force between the anterior fetal shoulder and the maternal symphysis pubis. Varying endogenous and exogenous loads were applied, and the contact force was determined. Experiments also examined the effect of pelvic orientation and the direction of load application on contact force behind the symphysis pubis. Exogenous loading forces (50-100 N) resulted in anterior shoulder contact forces of 107 to 127 N, with delivery accomplished at 100 N of applied load. Higher contact forces (147-272 N) were noted for endogenously applied loads (100-400 N), with delivery occurring at 400 N of maternal force. Pelvic rotation from lithotomy to McRoberts' positioning resulted in reduced contact forces. Downward lateral flexion of the fetal head led to little difference in contact force but required 30% more exogenous load to achieve delivery. Compared with clinician-applied exogenous force, larger maternally derived endogenous forces are needed to clear the impacted anterior fetal shoulder. This is associated with >2 times more contact force by the obstructing symphysis pubis. McRoberts' positioning reduces shoulder-symphysis pubis contact force. Lateral flexion of the fetal head results in the larger forces that are needed for delivery but has little effect on contact force. Model refinements are needed to examine delivery forces and brachial plexus stretching more specifically.

Correlations among visual analogue scale, neck disability index, shoulder joint range of motion, and muscle strength in young women with forward head posture.

PubMed

Shin, Young Jun; Kim, Won Hyo; Kim, Seong Gil

2017-08-01

This study investigated the correlation between the neck disability index (NDI) and visual analogue scale (VAS), which are indicators of neck pain, shoulder joint range of motion (ROM), and muscle strength in women with a slight forward head posture. This study was carried out on 42 female college students attending Uiduk University in Gyeongju, Korea. The neck pain and disability index for each subject was measured using VAS and NDI, respectively. Two physiotherapists measured the shoulder joint ROM and muscle strengths of the subjects using a goniometer and a dynamometer, respectively. External rotation, internal rotation, and abduction of the shoulder joint were measured for each subject. A significant negative correlation between neck pain and shoulder joint ROM in external rotation and the muscle strength of the shoulder joint in abduction was found in the subjects. In addition, a significant positive correlation was observed between ROM in external rotation and muscle strength in abduction. This study showed a significant negative correlation between neck pain and ROM in external rotation as well as between neck pain and the muscle strength in abduction.

Dynamic Analysis of the Abnormal Isometric Strength Movement Pattern between Shoulder and Elbow Joint in Patients with Hemiplegia.

PubMed

Liu, Yali; Hong, Yuezhen; Ji, Linhong

2018-01-01

Patients with hemiplegia usually have weak muscle selectivity and usually perform strength at a secondary joint (secondary strength) during performing a strength at one joint (primary strength). The abnormal strength pattern between shoulder and elbow joint has been analyzed by the maximum value while the performing process with strength changing from 0 to maximum then to 0 was a dynamic process. The objective of this study was to develop a method to dynamically analyze the strength changing process. Ten patients were asked to perform four group asks (maximum and 50% maximum voluntary strength in shoulder abduction, shoulder adduction, elbow flexion, and elbow extension). Strength and activities from seven muscles were measured. The changes of secondary strength had significant correlation with those of primary strength in all tasks ( R > 0.76, p < 0.01). The antagonistic muscles were moderately influenced by the primary strength ( R > 0.4, p < 0.01). Deltoid muscles, biceps brachii, triceps brachii, and brachioradialis had significant influences on the abnormal strength pattern (all p < 0.01). The dynamic method was proved to be efficient to analyze the different influences of muscles on the abnormal strength pattern. The muscles, deltoid muscles, biceps brachii, triceps brachii, and brachioradialis, much influenced the stereotyped movement pattern between shoulder and elbow joint.

Dynamic Analysis of the Abnormal Isometric Strength Movement Pattern between Shoulder and Elbow Joint in Patients with Hemiplegia

PubMed Central

2018-01-01

Patients with hemiplegia usually have weak muscle selectivity and usually perform strength at a secondary joint (secondary strength) during performing a strength at one joint (primary strength). The abnormal strength pattern between shoulder and elbow joint has been analyzed by the maximum value while the performing process with strength changing from 0 to maximum then to 0 was a dynamic process. The objective of this study was to develop a method to dynamically analyze the strength changing process. Ten patients were asked to perform four group asks (maximum and 50% maximum voluntary strength in shoulder abduction, shoulder adduction, elbow flexion, and elbow extension). Strength and activities from seven muscles were measured. The changes of secondary strength had significant correlation with those of primary strength in all tasks (R > 0.76, p < 0.01). The antagonistic muscles were moderately influenced by the primary strength (R > 0.4, p < 0.01). Deltoid muscles, biceps brachii, triceps brachii, and brachioradialis had significant influences on the abnormal strength pattern (all p < 0.01). The dynamic method was proved to be efficient to analyze the different influences of muscles on the abnormal strength pattern. The muscles, deltoid muscles, biceps brachii, triceps brachii, and brachioradialis, much influenced the stereotyped movement pattern between shoulder and elbow joint. PMID:29610654

Influence of anthropometry on meat-packing plant workers: an approach to the shoulder joint.

PubMed

Reis, Pedro Ferreira; Peres, Luis Sérgio; Tirloni, Adriana Seára; dos Reis, Diogo Cunha; Estrázulas, Jansen Atier; Rossato, Mateus; Moro, Antônio Renato Pereira

2012-01-01

This study was conducted with 90 poultry slaughterhouse workers, which perform the function of removing chicken parts from the conveyor belt, and sample was composed of 66 women (33.5 ± 6.5 years) and 24 men (35.7 ± 7.2 years), aiming to analyze the influence of anthropometry in the shoulder joint of these workers. Body discomfort was evaluated by a human body diagram, being applied at the end of the work shift. The anthropometric measurement of shoulder was performed by measuring the height of the acromion process, being compared with the height of the conveyor belt. Analysis of the results was performed by descriptive statistics, mean, standard deviation, percentage and percentiles 5%, 50% and 95%. It was found that the height of the conveyor belt was 1.74 meters, while the average shoulder height of workers was 1.38 meters for percentile 5%, 1.41 meters for percentile 50% and 1.65 meters for percentile 95%. The discomfort regions were shoulder 45%, neck 29%, column 26%, arms 23%, and wrists and hand 20%. The upper limb assessment was performed with percentile 5% through the Rapid Upper Limb Assessment method, resulting in a final score > 7, indicating the need for adjustments of the work organization. It was concluded that the workplace does not meet the workers' anthropometric characteristics, mainly affecting the shoulder joint, and correction ergonomics becomes necessary so that the workers involved in this study can perform their functions with health, comfort and safety.

Evaluation and management of adult shoulder pain: a focus on rotator cuff disorders, acromioclavicular joint arthritis, and glenohumeral arthritis.

PubMed

Armstrong, April

2014-07-01

Shoulder pain is a common reason for a patient to see their primary care physician. This article focuses on the evaluation and management of 3 common shoulder disorders; rotator cuff disorders, acromioclavicular joint arthritis, and glenohumeral joint arthritis. The typical history and physical examination findings for each of these entities are highlighted, in addition to treatment options. Copyright © 2014 Elsevier Inc. All rights reserved.

Comfort and convenience specifications for safety belts : shoulder belt fit, pressure and pullout forces

DOT National Transportation Integrated Search

1980-04-30

A three-part study was conducted to further define comfort requirements for seat belt systems with respect to shoulder belt fit, shoulder belt contact pressure, and 3-point restraint system pullout forces. Objective of the belt-fit portion of the stu...

Shoulder replacement

MedlinePlus

... the opening at the end of the shoulder blade, called the socket. This type of joint allows ... head. The socket part (glenoid) of your shoulder blade will be replaced with a smooth plastic shell ( ...

A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements

PubMed Central

Seth, Ajay; Matias, Ricardo; Veloso, António P.; Delp, Scott L.

2016-01-01

The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual’s anthropometry. We compared the model to “gold standard” bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models. PMID:26734761

A Biomechanical Model of the Scapulothoracic Joint to Accurately Capture Scapular Kinematics during Shoulder Movements.

PubMed

Seth, Ajay; Matias, Ricardo; Veloso, António P; Delp, Scott L

2016-01-01

The complexity of shoulder mechanics combined with the movement of skin relative to the scapula makes it difficult to measure shoulder kinematics with sufficient accuracy to distinguish between symptomatic and asymptomatic individuals. Multibody skeletal models can improve motion capture accuracy by reducing the space of possible joint movements, and models are used widely to improve measurement of lower limb kinematics. In this study, we developed a rigid-body model of a scapulothoracic joint to describe the kinematics of the scapula relative to the thorax. This model describes scapular kinematics with four degrees of freedom: 1) elevation and 2) abduction of the scapula on an ellipsoidal thoracic surface, 3) upward rotation of the scapula normal to the thoracic surface, and 4) internal rotation of the scapula to lift the medial border of the scapula off the surface of the thorax. The surface dimensions and joint axes can be customized to match an individual's anthropometry. We compared the model to "gold standard" bone-pin kinematics collected during three shoulder tasks and found modeled scapular kinematics to be accurate to within 2 mm root-mean-squared error for individual bone-pin markers across all markers and movement tasks. As an additional test, we added random and systematic noise to the bone-pin marker data and found that the model reduced kinematic variability due to noise by 65% compared to Euler angles computed without the model. Our scapulothoracic joint model can be used for inverse and forward dynamics analyses and to compute joint reaction loads. The computational performance of the scapulothoracic joint model is well suited for real-time applications; it is freely available for use with OpenSim 3.2, and is customizable and usable with other OpenSim models.

Shoulder torques resulting from luggage handling tasks in non-inertial frames.

PubMed

Shippen, James; May, Barbara

2018-05-18

This paper reports on the torques developed in the shoulder joint experienced by occupants of moving vehicles during manual handling tasks. Handling heavy weights can cause musculoskeletal injuries, especially if handling is done with arms extended or at high levels. The aim of the study was to measure the longitudinal and lateral accelerations in a variety of passenger vehicles together with the postures of subjects lifting luggage onto storage shelves. This data enabled the application of inverse dynamics methods in a non-inertial reference frame to calculate the shoulder joint torques. The subjects lifted 3 pieces of luggage of masses of 5 kg, 10 kg and 14 kg onto shelving which were at heights of 1.2 m, 1.6 m and 1.8 m. The movement of subjects was measured using a 12 camera, 3-dimensional optical tracking system. The subjects stood on force plates to measure the ground reaction forces. Sixty-three trials were completed, although 9 trials were aborted because subjects felt unable to complete the task. It was found that the shoulder torques exceeded the levels recommend by the UK Health and Safety Executive for manual handling. A lift assistance device is suggested to reduce the shoulder torques required for luggage handling.

Correlation of Shoulder and Elbow Kinetics With Ball Velocity in Collegiate Baseball Pitchers

PubMed Central

Post, Eric G.; Laudner, Kevin G.; McLoda, Todd A.; Wong, Regan; Meister, Keith

2015-01-01

Context Throwing a baseball is a dynamic and violent act that places large magnitudes of stress on the shoulder and elbow. Specific injuries at the elbow and glenohumeral joints have been linked to several kinetic variables throughout the throwing motion. However, very little research has directly examined the relationship between these kinetic variables and ball velocity. Objective To examine the correlation of peak ball velocity with elbow-valgus torque, shoulder external-rotation torque, and shoulder-distraction force in a group of collegiate baseball pitchers. Design Cross-sectional study. Setting Motion-analysis laboratory. Patients or Other Participants Sixty-seven asymptomatic National Collegiate Athletic Association Division I baseball pitchers (age = 19.5 ± 1.2 years, height = 186.2 ± 5.7 cm, mass = 86.7 ± 7.0 kg; 48 right handed, 19 left handed). Main Outcome Measure(s) We measured peak ball velocity using a radar gun and shoulder and elbow kinetics of the throwing arm using 8 electronically synchronized, high-speed digital cameras. We placed 26 reflective markers on anatomical landmarks of each participant to track 3-dimensional coordinate data. The average data from the 3 highest-velocity fastballs thrown for strikes were used for data analysis. We calculated a Pearson correlation coefficient to determine the associations between ball velocity and peak elbow-valgus torque, shoulder-distraction force, and shoulder external-rotation torque (P < .05). Results A weak positive correlation was found between ball velocity and shoulder-distraction force (r = 0.257; 95% confidence interval [CI] = 0.02, 0.47; r2 = 0.066; P = .018). However, no significant correlations were noted between ball velocity and elbow-valgus torque (r = 0.199; 95% CI = −0.043, 0.419; r2 = 0.040; P = .053) or shoulder external-rotation torque (r = 0.097; 95% CI = −0.147, 0.329; r2 = 0.009; P = .217). Conclusions Although a weak positive correlation was present between ball velocity

Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia

PubMed Central

Mulroy, Sara J.; Ruparel, Puja; Hatchett, Patricia E.; Haubert, Lisa Lighthall; Eberly, Valerie J.; Gronley, JoAnne K.

2015-01-01

Background: Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). Objective: To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Methods: Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Results: Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P < .001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes — posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Conclusions: Current

Relationship Between Hand Contact Angle and Shoulder Loading During Manual Wheelchair Propulsion by Individuals with Paraplegia.

PubMed

Requejo, Philip Santos; Mulroy, Sara J; Ruparel, Puja; Hatchett, Patricia E; Haubert, Lisa Lighthall; Eberly, Valerie J; Gronley, JoAnne K

2015-01-01

Shoulder loading during manual wheelchair propulsion (WCP) contributes to the development of shoulder pain in individuals with spinal cord injury (SCI). To use regression analysis to investigate the relationships between the hand contact angle (location of the hand on the pushrim at initial contact and release during the push phase of the WCP cycle) with propulsion characteristics, pushrim forces, and shoulder kinetics during WCP in individuals with paraplegia. Biomechanical data were collected from 222 individuals (198 men and 24 women) with paraplegia from SCI during WCP on a stationary ergometer at a self-selected speed. The average age of participants was 34.7 years (±9.3), mean time since SCI was 9.3 years (±6.1), and average body weight was 74.4 kg (±15.9). The majority (n = 127; 56%) of participants had lower level paraplegia (T8 to L5) and 95 (42%) had high paraplegia (T2 to T7). Increased push arc (mean = 75.3°) was associated with greater velocity (R = 0.384, P < .001) and cycle distance (R = 0.658, P < .001) and reduced cadence (R = -0.419, P <.001). Initial contact angle and hand release angles were equally associated with cycle distance and cadence, whereas a more anterior release angle was associated with greater velocity (R = 0.372, P < .001). When controlling for body weight, a more posterior initial contact angle was associated with greater posterior shoulder net joint force (R = 0.229, P = .001) and greater flexor net joint moment (R = 0.204, P = .002), whereas a more anterior hand release angle was significantly associated with increased vertical (R = 0.270, P < .001) and greater lateral (R = .293, P < .001) pushrim forces; greater shoulder net joint forces in all 3 planes - posterior (R = 0.164, P = .015), superior (R = 0.176, P = .009), and medial (R = 0.284, P < .001); and greater external rotator (R = 0.176, P = .009) and adductor (R = 0.259, P = .001) net joint moments. Current clinical practice guidelines recommend using long, smooth

[Shoulder injuries in golf].

PubMed

Liem, D; Gosheger, G; Schmidt, C

2014-03-01

Due to its growing popularity golf has now come into the focus of orthopedic sports medicine. With a wide range of age groups and playing levels, orthopedic surgeons will encounter a wide range of musculoskeletal problems which are usually the result of overuse rather than trauma. The shoulder joint plays an important role in the golf swing whereby not only the muscles around the glenohumeral joint but also the scapula stabilizing muscles are extremely important for an effective golf swing. Golf is strictly not considered to be an overhead sport; however, the extreme peak positions of the golf swing involve placing the shoulder joint in maximum abduction and adduction positions which can provoke impingement, lesions of the pulley system or even a special form of posterior shoulder instability. Even after complex shoulder operations, such as rotator cuff repair or shoulder arthroplasty, a return to the golf course at nearly the same level of play can be expected.

[Arthroscopic therapy of the unstable shoulder joint--acceptance and critical considerations].

PubMed

Jerosch, J

1997-01-01

The purpose of this study was to document and to present the acceptance of arthroscopically performed stabilising procedures of the glenohumeral joint. In a nationwide survey of instructors of the association of arthroscopy, members of the arthroscopy group of the german orthopedic society, and orthopedic and trauma surgeons with special interest in joint surgery we evaluated the current treatment modalities for patients with unstable shoulder joints. After an average of 2.09 +/- 1.0 shoulder redislocations surgery is recommended. The Bankart-operation (63.4%) is the favourite procedure for open surgery. In a descended order the Weber rotation-osteotomie, the Putti-Platt operation, the Max-Lange procedure, and in a minimal amount of the cases the Bristow-procedure are performed. Looking at the arthroscopic procedures, the distribution is much more equal. The Caspari technique is used by 27.6% and the Morgan technique by 25.1%. Bone anchors are used by 20.4% and the Suretac is used by 18.9% of the surgeons. The anchor knot technique (8%) is only rarely performed. In case of an elongated capsule the majority of the surgeons would not perform arthroscopic surgery. 42.4% of the surgeons judge the arthroscopic technique less secure. However, 38.9% do not see any difference to open procedures. Taking the available information, arthroscopic stabilising procedures seems to have slightly inferior results compared to standard open surgery. The Bankart procedure with or without a capsular shift is still the golden standard.

A proposal for a new definition of the axial rotation angle of the shoulder joint.

PubMed

Masuda, Tadashi; Ishida, Akimasa; Cao, Lili; Morita, Sadao

2008-02-01

The Euler/Cardan angles are commonly used to define the motions of the upper arm with respect to the trunk. This definition, however, has a problem in that the angles of both the horizontal flexion/extension and the axial rotation of the shoulder joint become unstable at the gimbal-lock positions. In this paper, a new definition of the axial rotation angle was proposed. The proposed angle was stable over the entire range of the shoulder motion. With the new definition, the neutral position of the axial rotation agreed with that in the conventional anatomy. The advantage of the new definition was demonstrated by measuring actual complex motions of the shoulder with a three-dimensional motion capture system.

Investigation of a relationship between external force to shoulder and chest injury of WorldSID and THUMS in 32 km/h oblique pole side impact.

PubMed

Tanaka, Shinobu; Hayashi, Shigeki; Fukushima, Satoshi; Yasuki, Tsuyoshi

2013-01-01

This article describes the chest injury risk reduction effect of shoulder restraints using finite element (FE) models of the worldwide harmonized side impact dummy (WorldSID) and Total Human Model for Safety (THUMS) in an FE model 32 km/h oblique pole side impact. This research used an FE model of a mid-sized vehicle equipped with various combinations of curtain shield air bags, torso air bags, and shoulder restraint air bags. As occupant models, AM50 WorldSID and THUMS AM50 Version 4 were used for comparison. The research investigated the effect of shoulder restraint air bag on chest injury by comparing cases with and without a shoulder side air bag. The maximum external force to the chest was reduced by shoulder restraint air bag in both WorldSID and THUMS, reducing chest injury risk as measured by the amount of rib deflection, number of the rib fractures, and rib deflection ratio. However, it was also determined that the external force to shoulder should be limited to the chest injury threshold because the external shoulder force transmits to the chest via the arm in the case of WorldSID and via the scapula in the case of THUMS. Because these results show the shoulder restraint air bag effect on chest injury risk, the vent hole size of the shoulder restraint air bag was changed for varying reaction forces to investigate the relationship between the external force to the shoulder and the risk of chest injury. In the case of THUMS, an external shoulder force of 1.8 kN and more force from the shoulder restraint air bag was necessary to help prevent rib fracture. Increasing external force applied to shoulder up to 6.2 kN (the maximum force used in this study) did not induce any rib or clavicle fractures in the THUMS. When the shoulder restraint air bag generated external force to the shoulder from 1.8 to 6.2 kN in THUMS, which were applied to the WorldSID, the shoulder deflection ranged from 35 to 68 mm, and the shoulder force ranged from 1.8 to 2.3 kN. In the test

Shoulder pain in hemiplegia.

PubMed

Andersen, L T

1985-01-01

Development of a painful shoulder in the hemiplegic patient is a significant and serious problem, because it can limit the patient's ability to reach his or her maximum functional potential. Several etiologies of shoulder pain have been identified, such as immobilization of the upper extremity, trauma to the joint structures, including brachial plexus injuries, and subluxation of the gleno-humeral joint. A review of the literature explains the basic anatomy and kinesiology of the shoulder complex, the various etiologies of hemiplegic shoulder pain, and the pros and cons of specific treatment techniques. This knowledge is essential for the occupational therapist to evaluate effectively techniques used to treat the patient with hemiplegic shoulder pain. More effective management of this problem will facilitate the patient's ability to reach his or her maximum functional potential.

Management of acromioclavicular joint injuries.

PubMed

Li, Xinning; Ma, Richard; Bedi, Asheesh; Dines, David M; Altchek, David W; Dines, Joshua S

2014-01-01

Acromioclavicular joint injuries are among the most common shoulder girdle injuries in athletes and most commonly result from a direct force to the acromion with the arm in an adducted position. Acromioclavicular joint injuries often present with associated injuries to the glenohumeral joint, including an increased incidence of superior labrum anterior posterior (SLAP) tears that may warrant further evaluation and treatment. Anteroposterior stability of the acromioclavicular joint is conferred by the capsule and acromioclavicular ligaments, of which the posterior and superior ligaments are the strongest. Superior-inferior stability is maintained by the coracoclavicular (conoid and trapezoid) ligaments. Type-I or type-II acromioclavicular joint injuries have been treated with sling immobilization, early shoulder motion, and physical therapy, with favorable outcomes. Return to activity can occur when normal shoulder motion and strength are obtained and the shoulder is asymptomatic as compared with the contralateral normal extremity. The management of type-III injuries remains controversial and is individualized. While a return to the previous level of functional activity with nonsurgical treatment has been documented in a number of case series, surgical reduction and coracoclavicular ligament reconstruction has been associated with a favorable outcome and can be considered in patients who place high functional demands on their shoulders or in athletes who participate in overhead sports. Surgical management is indicated for high-grade (≥type IV) acromioclavicular joint injuries to achieve anatomic reduction of the acromioclavicular joint, reconstruction of the coracoclavicular ligaments, and repair of the deltotrapezial fascia. Outcomes after surgical reconstruction of the coracoclavicular ligaments have been satisfactory with regard to achieving pain relief and return to functional activities, but further improvements in the biomechanical strength of these

On the organizing role of nonmuscular forces during performance of a giant circle in gymnastics.

PubMed

Sevrez, Violaine; Rao, Guillaume; Berton, Eric; Bootsma, Reinoud J

2012-02-01

Five elite gymnasts performed giant circles on the high bar under different conditions of loading (without and with 6-kg loads attached to the shoulders, waist or ankles). Comparing the gymnasts' kinematic pattern of movement with that of a triple-pendulum moving under the sole influence of nonmuscular forces revealed qualitative similarities, including the adoption of an arched position during the downswing and a piked position during the upswing. The structuring role of nonmuscular forces in the organization of movement was further reinforced by the results of an inverse dynamics analysis, assessing the contributions of gravitational, inertial and muscular components to the net joint torques. Adding loads at the level of the shoulders, waist or ankles systematically influenced movement kinematics and net joint torques. However, with the loads attached at the level of the shoulders or waist, the load-induced changes in gravitational and inertial torques provided the required increase in net joint torque, thereby allowing the muscular torques to remain unchanged. With the loads attached at the level of the ankles, this was no longer the case and the gymnasts increased the muscular torques at the shoulder and hip joints. Together, these results demonstrate that expert gymnasts skillfully exploit the operative nonmuscular forces, employing muscle force only in the capacity of complementary forces needed to perform the task.

Wheelchair pushing and turning: lumbar spine and shoulder loads and recommended limits.

PubMed

Weston, Eric B; Khan, Safdar N; Marras, William S

2017-12-01

The objective of this study was to determine how simulated manual wheelchair pushing influences biomechanical loading to the lumbar spine and shoulders. Sixty-two subjects performed simulated wheelchair pushing and turning in a laboratory. An electromyography-assisted biomechanical model was used to estimate spinal loads. Moments at the shoulder joint, external hand forces and net turning torque were also assessed. Multiple linear regression techniques were employed to develop biomechanically based wheelchair pushing guidelines relating resultant hand force or net torque to spinal load. Male subjects experienced significantly greater spinal loading (p < 0.01), and spine loads were also increased for wheelchair turning compared to straight wheelchair pushing (p < 0.001). Biomechanically determined maximum acceptable resultant hand forces were 17-18% lower than psychophysically determined limits. We conclude that manual wheelchair pushing and turning can pose biomechanical risk to the lumbar spine and shoulders. Psychophysically determined maximum acceptable push forces do not appear to be protective enough of this biomechanical risk. Practitioner Summary: This laboratory study investigated biomechanical risk to the low back and shoulders during simulated wheelchair pushing. Manual wheelchair pushing posed biomechanical risk to the lumbar spine (in compression and A/P shear) and to the shoulders. Biomechanically determined wheelchair pushing thresholds are presented and are more protective than the closest psychophysically determined equivalents.

Arthrographic and clinical findings in patients with hemiplegic shoulder pain.

PubMed

Lo, Sui-Foon; Chen, Shu-Ya; Lin, Hsiu-Chen; Jim, Yick-Fung; Meng, Nai-Hsin; Kao, Mu-Jung

2003-12-01

To identify the etiology of hemiplegic shoulder pain by arthrographic and clinical examinations and to determine the correlation between arthrographic measurements and clinical findings in patients with hemiplegic shoulder pain. Case series. Medical center of a 1582-bed teaching institution in Taiwan. Thirty-two consecutive patients with hemiplegic shoulder pain within a 1-year period after first stroke were recruited. Not applicable. Clinical examinations included Brunnstrom stage, muscle spasticity distribution, presence or absence of subluxation and shoulder-hand syndrome, and passive range of motion (PROM) of the shoulder joint. Arthrographic measurements included shoulder joint volume and capsular morphology. Most patients had onset of hemiplegic shoulder pain less than 2 months after stroke. Adhesive capsulitis was the main cause of shoulder pain, with 50% of patients having adhesive capsulitis, 44% having shoulder subluxation, 22% having rotator cuff tears, and 16% having shoulder-hand syndrome. Patients with adhesive capsulitis showed significant restriction of passive shoulder external rotation and abduction and a higher incidence of shoulder-hand syndrome (P=.017). Those with irregular capsular margins had significantly longer shoulder pain duration and more restricted passive shoulder flexion (P=.017) and abduction (P=.020). Patients with shoulder subluxation had significantly larger PROM (flexion, P=.007; external rotation, P<.001; abduction, P=.001; internal rotation, P=.027), lower muscle tone (P=.001), and lower Brunnstrom stages of the proximal upper extremity (P=.025) and of the distal upper extremity (P=.001). Muscle spasticity of the upper extremity was slightly negatively correlated with shoulder PROM. Shoulder joint volume was moderately positively correlated with shoulder PROM. After investigating the hemiplegic shoulder joint through clinical and arthrographic examinations, we found that the causes of hemiplegic shoulder pain are complicated

[Possibilities of magnetic resonance tomography in diagnostic imaging of the shoulder joint].

PubMed

Reiser, M; Erlemann, R; Bongartz, G; Pauly, T; Kunze, V; Mathiass, H H; Peters, P E

1988-02-01

By virtue of its multiplanar representation, magnetic resonance imaging (MRI) allows clear visualization of the complex anatomical relationships of the shoulder joint. In addition to axial planes, slices perpendicular and parallel to the glenoid cavity are used to good advantage. In tears of the rotator cuff an increase in signal intensity within the cuff is recognized in T2- and proton-density-weighted images. Lesions of the glenoid labrum following luxations of the glenohumeral joint can be detected and classified using MRI. The diagnostic value of MRI as compared with other imaging modalities will have to be evaluated in larger series with operative verification.

Towards computer-assisted surgery in shoulder joint replacement

NASA Astrophysics Data System (ADS)

Valstar, Edward R.; Botha, Charl P.; van der Glas, Marjolein; Rozing, Piet M.; van der Helm, Frans C. T.; Post, Frits H.; Vossepoel, Albert M.

A research programme that aims to improve the state of the art in shoulder joint replacement surgery has been initiated at the Delft University of Technology. Development of improved endoprostheses for the upper extremities (DIPEX), as this effort is called, is a clinically driven multidisciplinary programme consisting of many contributory aspects. A part of this research programme focuses on the pre-operative planning and per-operative guidance issues. The ultimate goal of this part of the DIPEX project is to create a surgical support infrastructure that can be used to predict the optimal surgical protocol and can assist with the selection of the most suitable endoprosthesis for a particular patient. In the pre-operative planning phase, advanced biomechanical models of the endoprosthesis fixation and the musculo-skeletal system of the shoulder will be incorporated, which are adjusted to the individual's morphology. Subsequently, the support infrastructure must assist the surgeon during the operation in executing his surgical plan. In the per-operative phase, the chosen optimal position of the endoprosthesis can be realised using camera-assisted tools or mechanical guidance tools. In this article, the pathway towards the desired surgical support infrastructure is described. Furthermore, we discuss the pre-operative planning phase and the per-operative guidance phase, the initial work performed, and finally, possible approaches for improving prosthesis placement.

[Shoulder instability].

PubMed

Sailer, J; Imhof, H

2004-06-01

Shoulder instability is a common clinical feature leading to recurrent pain and limited range of motion within the glenohumeral joint. Instability can be due a single traumatic event, general joint laxity or repeated episodes of microtrauma. Differentiation between traumatic and atraumatic forms of shoulder instability requires careful history and a systemic clinical examination. Shoulder laxity has to be differentiated from true instability followed by the clinical assessment of direction and degree of glenohumeral translation. Conventional radiography and CT are used for the diagnosis of bony lesions. MR imaging and MR arthrography help in the detection of soft tissue affection, especially of the glenoid labrum and the capsuloligamentous complex. The most common lesion involving the labrum is the anterior labral tear, associated with capsuloperiostal stripping (Bankart lesion). A number of variants of the Bankart lesion have been described, such as ALPSA, SLAP or HAGL lesions. The purpose of this review is to highlight different forms of shoulder instability and its associated radiological findings with a focus on MR imaging.

Management of Shoulder Problems Following Obstetric Brachial Plexus Injury

PubMed Central

Nixon, Matthew; Trail, Ian

2013-01-01

Obstetric brachial plexus injuries are common, with an incidence of 0.42 per 1000 live births in the UK, and with 25% of patients being left with permanent disability without intervention. The shoulder is the most commonly affected joint and, as a result of the subsequent imbalance of musculature, the abnormal deforming forces cause dysplasia of the glenohumeral joint. In the growing child, this presents with changing pattern of pathology, which requires a multidisciplinary approach and a broad range of treatment modalities to optimize function. PMID:27582903

Program Calculates Forces in Bolted Structural Joints

NASA Technical Reports Server (NTRS)

Buder, Daniel A.

2005-01-01

FORTRAN 77 computer program calculates forces in bolts in the joints of structures. This program is used in conjunction with the NASTRAN finite-element structural-analysis program. A mathematical model of a structure is first created by approximating its load-bearing members with representative finite elements, then NASTRAN calculates the forces and moments that each finite element contributes to grid points located throughout the structure. The user selects the finite elements that correspond to structural members that contribute loads to the joints of interest, and identifies the grid point nearest to each such joint. This program reads the pertinent NASTRAN output, combines the forces and moments from the contributing elements to determine the resultant force and moment acting at each proximate grid point, then transforms the forces and moments from these grid points to the centroids of the affected joints. Then the program uses these joint loads to obtain the axial and shear forces in the individual bolts. The program identifies which bolts bear the greatest axial and/or shear loads. The program also performs a fail-safe analysis in which the foregoing calculations are repeated for a sequence of cases in which each fastener, in turn, is assumed not to transmit an axial force.

Evaluation of anticollagen type I antibody titers in synovial fluid of both stifle joints and the left shoulder joint of dogs with unilateral cranial cruciate disease.

PubMed

de Bruin, Tanya; de Rooster, Hilde; van Bree, Henri; Cox, Eric

2007-03-01

To evaluate anticollagen type I antibodies in synovial fluid of the affected stifle joint, the contralateral stifle joint, and the left shoulder joint of dogs with unilateral cranial cruciate ligament (CrCL) rupture during an extended period of 12 to 18 months. 13 client-owned dogs with CrCL rupture and 2 sham-operated dogs. All dogs were examined and arthrocentesis of all 3 joints was performed every 6 months after surgery. Synovial fluid samples were tested for anticollagen type I antibodies by use of an ELISA. Dogs with partial CrCL rupture had higher antibody titers than dogs with complete rupture. Six of 13 dogs ruptured the contralateral CrCL during the study, whereby higher antibody titers were found for the stifle joints than for the shoulder joint. Seronegative dogs or dogs with extremely low antibody titers and 2 dogs with high antibody titers did not sustain a CrCL rupture in the contralateral stifle joint. In most dogs that had a CrCL rupture of the contralateral stifle joint, a distinct antibody titer gradient toward the stifle joints was detected, suggesting that there was a local inflammatory process in these joints. However, only a small number of sham-operated dogs were used to calculate the cutoff values used to determine the anticollagen type I antibody titers in these patients. Synovial fluid antibodies against collagen type I alone do not initiate CrCL rupture because not all dogs with high antibody titers sustained a CrCL rupture in the contralateral stifle joint.

Outpatient Shoulder Arthroplasty.

PubMed

Brolin, Tyler J; Throckmorton, Thomas W

2018-01-01

Health care policy makers have placed increased attention on the cost of health care making outpatient joint arthroplasty an attractive alternative to routine hospital admission. Recent studies have shown outpatient shoulder arthroplasty is a safe and cost-effective alternative to inpatient shoulder arthroplasty. Proper patient selection, patient education, effective pain management strategies, and attention to intraoperative blood loss are keys in the success of outpatient shoulder arthroplasty. Copyright © 2017 Elsevier Inc. All rights reserved.

Glenohumeral contact force during flat and topspin tennis forehand drives.

PubMed

Blache, Yoann; Creveaux, Thomas; Dumas, Raphaël; Chèze, Laurence; Rogowski, Isabelle

2017-03-01

The primary role of the shoulder joint in tennis forehand drive is at the expense of the loadings undergone by this joint. Nevertheless, few studies investigated glenohumeral (GH) contact forces during forehand drives. The aim of this study was to investigate GH compressive and shearing forces during the flat and topspin forehand drives in advanced tennis players. 3D kinematics of flat and topspin forehand drives of 11 advanced tennis players were recorded. The Delft Shoulder and Elbow musculoskeletal model was implemented to assess the magnitude and orientation of GH contact forces during the forehand drives. The results showed no differences in magnitude and orientation of GH contact forces between the flat and topspin forehand drives. The estimated maximal GH contact force during the forward swing phase was 3573 ± 1383 N, which was on average 1.25 times greater than during the follow-through phase, and 5.8 times greater than during the backswing phase. Regardless the phase of the forehand drive, GH contact forces pointed towards the anterior-superior part of the glenoid therefore standing for shearing forces. Knowledge of GH contact forces during real sport tasks performed at high velocity may improve the understanding of various sport-specific adaptations and causative factors for shoulder problems.

Maintaining Shoulder Health After Spinal Cord Injury: A Guide to Understanding Treatments for Shoulder Pain

PubMed Central

Van Straaten, Meegan G.; Cloud, Beth A.; Zhao, Kristin D.; Fortune, Emma; Morrow, Melissa M. B.

2017-01-01

Shoulder pain from overuse of the arm is common after spinal cord injury (SCI). This pain can be difficult to eliminate. There are many other complications after SCI; therefore, shoulder pain is sometimes not the first priority. However, if neglected for too long, shoulder pain could mean that more serious problems are happening inside the shoulder joint. Here we present the options available when treatment for shoulder pain is needed. PMID:28185640

Measurement of strain and tensile force of the supraspinatus tendon under conditions that simulates low angle isometric elevation of the gleno-humeral joint: Influence of adduction torque and joint positioning.

PubMed

Miyamoto, Hiroki; Aoki, Mitsuhiro; Hidaka, Egi; Fujimiya, Mineko; Uchiyama, Eiichi

2017-12-01

Recently, supraspinatus muscle exercise has been reported to treat rotator cuff disease and to recover shoulder function. However, there have been no report on the direct measurement of strain on the supraspinatus tendon during simulated isometric gleno-humeral joint elevation. Ten fresh-frozen shoulder specimens with the rotator cuff complex left intact were used as experimental models. Isometric gleno-humeral joint elevation in a sitting position was reproduced with low angle of step-by-step elevation in the scapular plane and strain was measured on the surface layer of the supraspinatus tendon. In isometric conditions, applied tensile force of the supraspinatus tendon increased significantly with increases in adduction torque on the gleno-humeral joint. Significant increases in the strain on the layer were observed by increase in adduction torque, which were recorded in isometric elevation at -10° and 0°, but little increase in the strain was observed at 10° or greater gleno-humeral elevation. Increased strain on the surface layer of the supraspinatus tendon was observed during isometric gleno-humeral elevation from -10 to 0°. These findings demonstrate a potential risk of inducing overstretching of the supraspinatus tendon during supraspinatus muscle exercise. Copyright © 2017 Elsevier Ltd. All rights reserved.

Shoulder Kinematics and Spatial Pattern of Trapezius Electromyographic Activity in Real and Virtual Environments

PubMed Central

Samani, Afshin; Pontonnier, Charles; Dumont, Georges; Madeleine, Pascal

2015-01-01

The design of an industrial workstation tends to include ergonomic assessment steps based on a digital mock-up and a virtual reality setup. Lack of interaction and system fidelity is often reported as a main issue in such virtual reality applications. This limitation is a crucial issue as thorough ergonomic analysis is required for an investigation of the biomechanics. In the current study, we investigated the biomechanical responses of the shoulder joint in a simulated assembly task for comparison with the biomechanical responses in virtual environments. Sixteen male healthy novice subjects performed the task on three different platforms: real (RE), virtual (VE), and virtual environment with force feedback (VEF) with low and high precision demands. The subjects repeated the task 12 times (i.e., 12 cycles). High density electromyography from the upper trapezius and rotation angles of the shoulder joint were recorded and split into the cycles. The angular trajectories and velocity profiles of the shoulder joint angles over a cycle were computed in 3D. The inter-subject similarity in terms of normalized mutual information on kinematics and electromyography was investigated. Compared with RE the task in VE and VEF was characterized by lower kinematic maxima. The inter-subject similarity in RE compared with intra-subject similarity across the platforms was lower in terms of movement trajectories and greater in terms of trapezius muscle activation. The precision demand resulted in lower inter- and intra-subject similarity across platforms. The proposed approach identifies biomechanical differences in the shoulder joint in both VE and VEF compared with the RE platform, but these differences are less marked in VE mostly due to technical limitations of co-localizing the force feedback system in the VEF platform. PMID:25768123

Proximal arm kinematics affect grip force-load force coordination

PubMed Central

Vermillion, Billy C.; Lum, Peter S.

2015-01-01

During object manipulation, grip force is coordinated with load force, which is primarily determined by object kinematics. Proximal arm kinematics may affect grip force control, as proximal segment motion could affect control of distal hand muscles via biomechanical and/or neural pathways. The aim of this study was to investigate the impact of proximal kinematics on grip force modulation during object manipulation. Fifteen subjects performed three vertical lifting tasks that involved distinct proximal kinematics (elbow/shoulder), but resulted in similar end-point (hand) trajectories. While temporal coordination of grip and load forces remained similar across the tasks, proximal kinematics significantly affected the grip force-to-load force ratio (P = 0.042), intrinsic finger muscle activation (P = 0.045), and flexor-extensor ratio (P < 0.001). Biomechanical coupling between extrinsic hand muscles and the elbow joint cannot fully explain the observed changes, as task-related changes in intrinsic hand muscle activation were greater than in extrinsic hand muscles. Rather, between-task variation in grip force (highest during task 3) appears to contrast to that in shoulder joint velocity/acceleration (lowest during task 3). These results suggest that complex neural coupling between the distal and proximal upper extremity musculature may affect grip force control during movements, also indicated by task-related changes in intermuscular coherence of muscle pairs, including intrinsic finger muscles. Furthermore, examination of the fingertip force showed that the human motor system may attempt to reduce variability in task-relevant motor output (grip force-to-load force ratio), while allowing larger fluctuations in output less relevant to task goal (shear force-to-grip force ratio). PMID:26289460

Effect of power-assisted hand-rim wheelchair propulsion on shoulder load in experienced wheelchair users: A pilot study with an instrumented wheelchair.

PubMed

Kloosterman, Marieke G M; Buurke, Jaap H; de Vries, Wiebe; Van der Woude, Lucas H V; Rietman, Johan S

2015-10-01

This study aims to compare hand-rim and power-assisted hand-rim propulsion on potential risk factors for shoulder overuse injuries: intensity and repetition of shoulder loading and force generation in the extremes of shoulder motion. Eleven experienced hand-rim wheelchair users propelled an instrumented wheelchair on a treadmill while upper-extremity kinematic, kinetic and surface electromyographical data was collected during propulsion with and without power-assist. As a result during power-assisted propulsion the peak resultant force exerted at the hand-rim decreased and was performed with significantly less abduction and internal rotation at the shoulder. At shoulder level the anterior directed force and internal rotation and flexion moments decreased significantly. In addition, posterior and the minimal inferior directed forces and the external rotation moment significantly increased. The stroke angle decreased significantly, as did maximum shoulder flexion, extension, abduction and internal rotation. Stroke-frequency significantly increased. Muscle activation in the anterior deltoid and pectoralis major also decreased significantly. In conclusion, compared to hand-rim propulsion power-assisted propulsion seems effective in reducing potential risk factors of overuse injuries with the highest gain on decreased range of motion of the shoulder joint, lower peak propulsion force on the rim and reduced muscle activity. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

Increasing Running Step Rate Reduces Patellofemoral Joint Forces

PubMed Central

Lenhart, Rachel L.; Thelen, Darryl G.; Wille, Christa M.; Chumanov, Elizabeth S.; Heiderscheit, Bryan C.

2013-01-01

Purpose Increasing step rate has been shown to elicit changes in joint kinematics and kinetics during running, and has been suggested as a possible rehabilitation strategy for runners with patellofemoral pain. The purpose of this study was to determine how altering step rate affects internal muscle forces and patellofemoral joint loads, and then to determine what kinematic and kinetic factors best predict changes in joint loading. Methods We recorded whole body kinematics of 30 healthy adults running on an instrumented treadmill at three step rate conditions (90%, 100%, and 110% of preferred step rate). We then used a 3D lower extremity musculoskeletal model to estimate muscle, patellar tendon, and patellofemoral joint forces throughout the running gait cycles. Additionally, linear regression analysis allowed us to ascertain the relative influence of limb posture and external loads on patellofemoral joint force. Results Increasing step rate to 110% of preferred reduced peak patellofemoral joint force by 14%. Peak muscle forces were also altered as a result of the increased step rate with hip, knee and ankle extensor forces, and hip abductor forces all reduced in mid-stance. Compared to the 90% step rate condition, there was a concomitant increase in peak rectus femoris and hamstring loads during early and late swing, respectively, at higher step rates. Peak stance phase knee flexion decreased with increasing step rate, and was found to be the most important predictor of the reduction in patellofemoral joint loading. Conclusion Increasing step rate is an effective strategy to reduce patellofemoral joint forces and could be effective in modulating biomechanical factors that can contribute to patellofemoral pain. PMID:23917470

Sex differences in the shoulder joint position sense acuity: a cross-sectional study.

PubMed

Vafadar, Amir K; Côté, Julie N; Archambault, Philippe S

2015-09-30

Work-related musculoskeletal disorders (WMSD) is the most expensive form of work disability. Female sex has been considered as an individual risk factor for the development of WMSD, specifically in the neck and shoulder region. One of the factors that might contribute to the higher injury rate in women is possible differences in neuromuscular control. Accordingly the purpose of this study was to estimate the effect of sex on shoulder joint position sense acuity (as a part of shoulder neuromuscular control) in healthy individuals. Twenty-eight healthy participants, 14 females and 14 males were recruited for this study. To test position sense acuity, subjects were asked to flex their dominant shoulder to one of the three pre-defined angle ranges (low, mid and high-ranges) with eyes closed, hold their arm in that position for three seconds, go back to the starting position and then immediately replicate the same joint flexion angle, while the difference between the reproduced and original angle was taken as the measure of position sense error. The errors were measured using Vicon motion capture system. Subjects reproduced nine positions in total (3 ranges × 3 trials each). Calculation of absolute repositioning error (magnitude of error) showed no significant difference between men and women (p-value ≥ 0.05). However, the analysis of the direction of error (constant error) showed a significant difference between the sexes, as women tended to mostly overestimate the target, whereas men tended to both overestimate and underestimate the target (p-value ≤ 0.01, observed power = 0.79). The results also showed that men had a significantly more variable error, indicating more variability in their position sense, compared to women (p-value ≤ 0.05, observed power = 0.78). Differences observed in the constant JPS error suggest that men and women might use different neuromuscular control strategies in the upper limb. In addition, higher JPS

Joint moments and contact forces in the foot during walking.

PubMed

Kim, Yongcheol; Lee, Kyoung Min; Koo, Seungbum

2018-06-06

The net force and moment of a joint have been widely used to understand joint disease in the foot. Meanwhile, it does not reflect the physiological forces on muscles and contact surfaces. The objective of the study is to estimate active moments by muscles, passive moments by connective tissues and joint contact forces in the foot joints during walking. Joint kinematics and external forces of ten healthy subjects (all males, 24.7 ± 1.2 years) were acquired during walking. The data were entered into the five-segment musculoskeletal foot model to calculate muscle forces and joint contact forces of the foot joints using an inverse dynamics-based optimization. Joint reaction forces and active, passive and net moments of each joint were calculated from muscle and ligament forces. The maximum joint reaction forces were 8.72, 4.31, 2.65, and 3.41 body weight (BW) for the ankle, Chopart's, Lisfranc and metatarsophalangeal joints, respectively. Active and passive moments along with net moments were also obtained. The maximum net moments were 8.6, 8.4, 5.4 and 0.8%BW∙HT, respectively. While the trend of net moment was very similar between the four joints, the magnitudes and directions of the active and passive moments varied between joints. The active and passive moments during walking could reveal the roles of muscles and ligaments in each of the foot joints, which was not obvious in the net moment. This method may help narrow down the source of joint problems if applied to clinical studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Contributions of muscle imbalance and impaired growth to postural and osseous shoulder deformity following brachial plexus birth palsy: a computational simulation analysis.

PubMed

Cheng, Wei; Cornwall, Roger; Crouch, Dustin L; Li, Zhongyu; Saul, Katherine R

2015-06-01

Two potential mechanisms leading to postural and osseous shoulder deformity after brachial plexus birth palsy are muscle imbalance between functioning internal rotators and paralyzed external rotators and impaired longitudinal growth of paralyzed muscles. Our goal was to evaluate the combined and isolated effects of these 2 mechanisms on transverse plane shoulder forces using a computational model of C5-6 brachial plexus injury. We modeled a C5-6 injury using a computational musculoskeletal upper limb model. Muscles expected to be denervated by C5-6 injury were classified as affected, with the remaining shoulder muscles classified as unaffected. To model muscle imbalance, affected muscles were given no resting tone whereas unaffected muscles were given resting tone at 30% of maximal activation. To model impaired growth, affected muscles were reduced in length by 30% compared with normal whereas unaffected muscles remained normal in length. Four scenarios were simulated: normal, muscle imbalance only, impaired growth only, and both muscle imbalance and impaired growth. Passive shoulder rotation range of motion and glenohumeral joint reaction forces were evaluated to assess postural and osseous deformity. All impaired scenarios exhibited restricted range of motion and increased and posteriorly directed compressive glenohumeral joint forces. Individually, impaired muscle growth caused worse restriction in range of motion and higher and more posteriorly directed glenohumeral forces than did muscle imbalance. Combined muscle imbalance and impaired growth caused the most restricted joint range of motion and the highest joint reaction force of all scenarios. Both muscle imbalance and impaired longitudinal growth contributed to range of motion and force changes consistent with clinically observed deformity, although the most substantial effects resulted from impaired muscle growth. Simulations suggest that treatment strategies emphasizing treatment of impaired longitudinal

Scapulohumeral rhythm in shoulders with reverse shoulder arthroplasty.

PubMed

Walker, David; Matsuki, Keisuke; Struk, Aimee M; Wright, Thomas W; Banks, Scott A

2015-07-01

Little is known about kinematic function of reverse total shoulder arthroplasty (RTSA). Scapulohumeral rhythm (SHR) is a common metric for assessing muscle function and shoulder joint motion. The purpose of this study was to compare SHR in shoulders with RTSA to normal shoulders. Twenty-eight subjects, more than 12 months after unilateral RTSA, were recruited for an Institutional Review Board-approved study. Subjects performed arm abduction in the coronal plane with and without a 1.4-kg hand-held weight. Three-dimensional model-image registration techniques were used to measure orientation and position for the humerus and scapula from fluoroscopic images. Analysis of variance and Tukey tests were used to assess groupwise and pairwise differences. SHR in RTSA shoulders (1.3:1) was significantly lower than in normal shoulders (3:1). Below 30° abduction, RTSA and normal shoulders show a wide range of SHR (1.3:1 to 17:1). Above 30° abduction, SHR in RTSA shoulders was 1.3:1 for unweighted abduction and 1.3:1 for weighted abduction. Maximum RTSA shoulder abduction in weighted trials was lower than in unweighted trials. SHR variability in RTSA shoulders decreased with increasing arm elevation. RTSA shoulders show kinematics that are significantly different from normal shoulders. SHR in RTSA shoulders was significantly lower than in normal shoulders, indicating that RTSA shoulders use more scapulothoracic motion and less glenohumeral motion to elevate the arm. With these observations, it may be possible to improve rehabilitation protocols, with particular attention to the periscapular muscles, and implant design or placement to optimize functional outcomes in shoulders with RTSA. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Tightening force and torque of nonlocking screws in a reverse shoulder prosthesis.

PubMed

Terrier, A; Kochbeck, S H; Merlini, F; Gortchacow, M; Pioletti, D P; Farron, A

2010-07-01

Reversed shoulder arthroplasty is an accepted treatment for glenohumeral arthritis associated to rotator cuff deficiency. For most reversed shoulder prostheses, the baseplate of the glenoid component is uncemented and its primary stability is provided by a central peg and peripheral screws. Because of the importance of the primary stability for a good osteo-integration of the baseplate, the optimal fixation of the screws is crucial. In particular, the amplitude of the tightening force of the nonlocking screws is clearly associated to this stability. Since this force is unknown, it is currently not accounted for in experimental or numerical analyses. Thus, the primary goal of this work is to measure this tightening force experimentally. In addition, the tightening torque was also measured, to estimate an optimal surgical value. An experimental setup with an instrumented baseplate was developed to measure simultaneously the tightening force, tightening torque and screwing angle, of the nonlocking screws of the Aquealis reversed prosthesis. In addition, the amount of bone volume around each screw was measured with a micro-CT. Measurements were performed on 6 human cadaveric scapulae. A statistically correlated relationship (p<0.05, R=0.83) was obtained between the maximal tightening force and the bone volume. The relationship between the tightening torque and the bone volume was not statistically significant. The experimental relationship presented in this paper can be used in numerical analyses to improve the baseplate fixation in the glenoid bone. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Structural Analysis and Design of PCC Shoulders

DOT National Transportation Integrated Search

1982-04-01

A structural evaluation of PCC highway shoulders has been conducted and a comprehensive design procedure for plain jointed concrete shoulders developed. The procedure can be used to provide PCC shoulders either for rehabilitation of existing pavement...

Shoulder arthroscopy (image)

MedlinePlus

... is a type of surgery to examine or repair the tissues inside or around your shoulder joint. The procedure ... small incision. If the surgeon is going to repair the joint, small surgical instruments are also used, such as a shaver to remove unwanted tissue.

Quantification of shoulder and elbow passive moments in the sagittal plane as a function of adjacent angle fixations.

PubMed

Kodek, Timotej; Munih, Marko

2003-01-01

The goal of this study was an assessment of the shoulder and elbow joint passive moments in the sagittal plane for six healthy individuals. Either the shoulder or elbow joints were moved at a constant speed, very slowly throughout a large portion of their range by means of an industrial robot. During the whole process the arm was held fully passively, while the end point force data and the shoulder, elbow and wrist angle data were collected. The presented method unequivocally reveals a large passive moment adjacent angle dependency in the central angular range, where most everyday actions are performed. It is expected to prove useful in the future work when examining subjects with neuromuscular disorders. Their passive moments may show a fully different pattern than the ones obtained in this study.

The Effect of Shoulder Muscle Fatigue on Acromiohumeral Distance and Scapular Dyskinesis in Women With Generalized Joint Hypermobility.

PubMed

Alibazi, Razie J; Moghadam, Afsun Nodehi; Cools, Ann M; Bakhshi, Enayatollah; Ahari, Alireza Aziz

2017-12-01

Muscle fatigue is considered to be one cause of shoulder pain, and subjects with generalized joint hypermobility (GJH) are affected more by shoulder pain. The purpose of this study was to examine the effects of muscle fatigue on acromiohumeral distance (AHD) and scapular dyskinesis in women with GJH. Thirty-six asymptomatic participants were assigned to either a GJH (n = 20) or control group (n = 16) using the Beighton scale. Before and after elevation fatigue trials, AHD was measured with ultrasonography at rest and when the arm was in 90° active elevation. A scapular dyskinesis test was used to visually observe alterations in scapular movement. Our results showed that in both groups, the fatigue reduced AHD in the 90° elevation position and increased the presence of scapular dyskinesis; however, no differences were found between the two groups. Although GJH has been identified as a factor for developing musculoskeletal disorders, generalized joint hypermobility did not result in changes to scapular dyskinesis or AHD, even after an elevation fatigue task. More studies are needed to evaluate the effects of muscle fatigue in subjects with GJH and a history of shoulder instability.

Estimation of distal arm joint angles from EMG and shoulder orientation for transhumeral prostheses.

PubMed

Akhtar, Aadeel; Aghasadeghi, Navid; Hargrove, Levi; Bretl, Timothy

2017-08-01

In this paper, we quantify the extent to which shoulder orientation, upper-arm electromyography (EMG), and forearm EMG are predictors of distal arm joint angles during reaching in eight subjects without disability as well as three subjects with a unilateral transhumeral amputation and targeted reinnervation. Prior studies have shown that shoulder orientation and upper-arm EMG, taken separately, are predictors of both elbow flexion/extension and forearm pronation/supination. We show that, for eight subjects without disability, shoulder orientation and upper-arm EMG together are a significantly better predictor of both elbow flexion/extension during unilateral (R 2 =0.72) and mirrored bilateral (R 2 =0.72) reaches and of forearm pronation/supination during unilateral (R 2 =0.77) and mirrored bilateral (R 2 =0.70) reaches. We also show that adding forearm EMG further improves the prediction of forearm pronation/supination during unilateral (R 2 =0.82) and mirrored bilateral (R 2 =0.75) reaches. In principle, these results provide the basis for choosing inputs for control of transhumeral prostheses, both by subjects with targeted motor reinnervation (when forearm EMG is available) and by subjects without target motor reinnervation (when forearm EMG is not available). In particular, we confirm that shoulder orientation and upper-arm EMG together best predict elbow flexion/extension (R 2 =0.72) for three subjects with unilateral transhumeral amputations and targeted motor reinnervation. However, shoulder orientation alone best predicts forearm pronation/supination (R 2 =0.88) for these subjects, a contradictory result that merits further study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of core muscle thickness and static or dynamic balance on prone bridge exercise with sling by shoulder joint angle in healthy adults.

PubMed

Park, Mi Hwa; Yu, Jae Ho; Hong, Ji Heon; Kim, Jin Seop; Jung, Sang Woo; Lee, Dong Yeop

2016-03-01

[Purpose] To date, core muscle activity detected using ultrasonography during prone bridge exercises has not been reported. Here we investigated the effects of core muscle thickness and balance on sling exercise efficacy by shoulder joint angle in healthy individuals. [Subjects and Methods] Forty-three healthy university students were enrolled in this study. Ultrasonography thickness of external oblique, internal oblique, and transversus abdominis during sling workouts was investigated. Muscle thickness was measured on ultrasonography imaging before and after the experiment. Dynamic balance was tested using a functional reaching test. Static balance was tested using a Tetrax Interactive Balance System. [Results] Different muscle thicknesses were observed during the prone bridge exercise with the shoulder flexed at 60°, 90° or 120°. Shoulder flexion at 60° and 90° in the prone bridge exercise with a sling generated the greatest thickness of most transversus abdominis muscles. Shoulder flexion at 120° in the prone bridge exercise with a sling generated the greatest thickness of most external oblique muscles. [Conclusion] The results suggest that the prone bridge exercise with shoulder joint angle is an effective method of increasing global and local muscle strength.

Surgical stabilization of shoulder luxation in a pot-bellied pig.

PubMed

Rubio-Martínez, Luis M; Rioja, Eva; Shakespeare, A S

2013-03-15

Case Description-A 4.6-month-old pot-bellied pig was evaluated because of non-weight-bearing lameness (grade 5/5) in the right forelimb of 4 days' duration. Clinical Findings-Clinical and radiographic examination revealed a closed, lateral luxation of the right shoulder joint. Treatment and Outcome-Initial attempts at closed reduction failed to provide adequate stability of the shoulder joint. Open reduction and internal fixation by placement of 2 lateral tension sutures with a system designed for canine cranial cruciate ligament repair provided adequate joint stability and a successful outcome. Conclusions and Clinical Relevance-Stabilization of the shoulder joint with lateral tension sutures after open reduction should be considered for management of lateral shoulder luxation in pot-bellied pigs.

A nondestructive, reproducible method of measuring joint reaction force at the distal radioulnar joint.

PubMed

Canham, Colin D; Schreck, Michael J; Maqsoodi, Noorullah; Doolittle, Madison; Olles, Mark; Elfar, John C

2015-06-01

To develop a nondestructive method of measuring distal radioulnar joint (DRUJ) joint reaction force (JRF) that preserves all periarticular soft tissues and more accurately reflects in vivo conditions. Eight fresh-frozen human cadaveric limbs were obtained. A threaded Steinmann pin was placed in the middle of the lateral side of the distal radius transverse to the DRUJ. A second pin was placed into the middle of the medial side of the distal ulna colinear to the distal radial pin. Specimens were mounted onto a tensile testing machine using a custom fixture. A uniaxial distracting force was applied across the DRUJ while force and displacement were simultaneously measured. Force-displacement curves were generated and a best-fit polynomial was solved to determine JRF. All force-displacement curves demonstrated an initial high slope where relatively large forces were required to distract the joint. This ended with an inflection point followed by a linear area with a low slope, where small increases in force generated larger amounts of distraction. Each sample was measured 3 times and there was high reproducibility between repeated measurements. The average baseline DRUJ JRF was 7.5 N (n = 8). This study describes a reproducible method of measuring DRUJ reaction forces that preserves all periarticular stabilizing structures. This technique of JRF measurement may also be suited for applications in the small joints of the wrist and hand. Changes in JRF can alter native joint mechanics and lead to pathology. Reliable methods of measuring these forces are important for determining how pathology and surgical interventions affect joint biomechanics. Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Multimodal assessment of sensorimotor shoulder function in patients with untreated anterior shoulder instability and asymptomatic handball players.

PubMed

Mornieux, Guillaume; Hirschmüller, Anja; Gollhofer, Albert; Südkamp, Norbert P; Maier, Dirk

2018-04-01

Functional evaluation of sensorimotor function of the shoulder joint is important for guidance of sports-specific training, prevention and rehabilitation of shoulder instability. Such assessment should be multimodal and comprise all qualities of sensorimotor shoulder function. This study evaluates feasibility of such multimodal assessment of glenohumeral sensorimotor function in patients with shoulder instability and handball players. Nine patients with untreated anterior instability of their dominant shoulder and 15 asymptomatic recreational handball players performed proprioceptive joint position sense and dynamic stabilization evaluations on an isokinetic device, as well as a functional throwing performance task. Outcome measures were analysed individually and equally weighted in a Shoulder-Specific Sensorimotor Index (S-SMI). Finally, isokinetic strength evaluations were conducted. We observed comparable sensorimotor functions of unstable dominant shoulders compared to healthy, contralateral shoulders (e.g. P=0.59 for S-SMI). Handball players demonstrated superior sensorimotor function of their dominant shoulders exhibiting a significantly higher throwing performance and S-SMI (P<0.001 and P=0.002, respectively), but comparable internal rotator peak torques for both shoulders (P>0.22). The present study proves feasibility of multimodal assessment of shoulder sensorimotor function in overhead athletes and patients with symptomatic anterior shoulder instability. Untreated shoulder instability led to a loss of dominance-related sensorimotor superiority indicating functional internal rotation deficiency. Dominant shoulders of handball players showed a superior overall sensorimotor function but weakness of dominant internal rotation constituting a risk factor for occurrence of posterior superior impingement syndrome. The S-SMI could serve as a diagnostic tool for guidance of sports-specific training, prevention and rehabilitation of shoulder instability.

Mechanisms of traumatic shoulder injury in elite rugby players.

PubMed

Crichton, James; Jones, Doug R; Funk, Lennard

2012-06-01

Shoulder injuries in rugby players are common, but the mechanisms of injury are less well understood. This study aims to elucidate common mechanisms of injury and identify the patterns of injury they produce. Twenty-four elite rugby players, referred to the senior author for diagnosis and management of shoulder injuries, were selected. Videos of the injuries were independently reviewed by rugby-medical experts to describe the mechanisms of injury. The mechanisms reported were collated and analysed to determine the level of agreement between reviewers and conclude an overall description of injury mechanisms. The authors identified three mechanisms of shoulder injury from the video analysis. These are the 'Try-Scorer', characterised by hyperflexion of the outstretched arm such as when scoring a try; the 'Tackler', extension of the abducted arm behind the player while tackling; and the 'Direct Impact', a direct blow to the arm or shoulder when held by the side in neutral or slight adduction. The Try Scorer and Tackler mechanisms both involve a levering force on the glenohumeral joint (GHJ). These mechanisms predominantly cause GHJ dislocation, with Bankart, reverse Bankart and superior labrum anterior-posterior tears. The Try-Scorer Mechanism also caused the majority (83%) of rotator cuff tears. The Direct Hit mechanism resulted in GHJ dislocation and labral injury in 37.5% of players and was most likely to cause acromioclavicular joint dislocation and scapula fractures, injuries that were not seen with the other mechanisms. Greater understanding of the mechanisms involved in rugby shoulder injury is useful in understanding the pathological injuries, guiding treatment and rehabilitation and aiding the development of injury-prevention methods.

Mechanisms of traumatic shoulder injury in elite rugby players

PubMed Central

Crichton, James; Jones, Doug R; Funk, Lennard

2012-01-01

Background Shoulder injuries in rugby players are common, but the mechanisms of injury are less well understood. This study aims to elucidate common mechanisms of injury and identify the patterns of injury they produce. Materials and methods Twenty-four elite rugby players, referred to the senior author for diagnosis and management of shoulder injuries, were selected. Videos of the injuries were independently reviewed by rugby-medical experts to describe the mechanisms of injury. The mechanisms reported were collated and analysed to determine the level of agreement between reviewers and conclude an overall description of injury mechanisms. Results The authors identified three mechanisms of shoulder injury from the video analysis. These are the ‘Try-Scorer’, characterised by hyperflexion of the outstretched arm such as when scoring a try; the ‘Tackler’, extension of the abducted arm behind the player while tackling; and the ‘Direct Impact’, a direct blow to the arm or shoulder when held by the side in neutral or slight adduction. The Try Scorer and Tackler mechanisms both involve a levering force on the glenohumeral joint (GHJ). These mechanisms predominantly cause GHJ dislocation, with Bankart, reverse Bankart and superior labrum anterior–posterior tears. The Try-Scorer Mechanism also caused the majority (83%) of rotator cuff tears. The Direct Hit mechanism resulted in GHJ dislocation and labral injury in 37.5% of players and was most likely to cause acromioclavicular joint dislocation and scapula fractures, injuries that were not seen with the other mechanisms. Conclusion Greater understanding of the mechanisms involved in rugby shoulder injury is useful in understanding the pathological injuries, guiding treatment and rehabilitation and aiding the development of injury-prevention methods. PMID:22510645

Shoulder range of motion and strength in young competitive tennis players with and without history of shoulder problems.

PubMed

Gillet, Benoît; Begon, Mickaël; Diger, Marine; Berger-Vachon, Christian; Rogowski, Isabelle

2018-05-01

To assess the effect of a history of shoulder problems on the shoulder flexibility and strength in young competitive tennis players. Cross-sectional study. Ninety-one competitive and asymptomatic tennis players aged between 8 and 15 years old were divided into two groups according to the presence or absence of a history of shoulder problems. Glenohumeral joint ranges of motion and the strength of eight shoulder muscles were bilaterally assessed. Five agonist/antagonist muscle strength ratios were also reported. Ranges of motion, strengths and strength ratios were bilaterally compared between the two groups. Players with a history of shoulder problems presented a higher total arc of rotation for both glenohumeral joints (p = 0.02) and a lower external/internal glenohumeral rotator muscle strength ratio (p = 0.02) for both sides. They also presented stronger upper trapezius (p = 0.03) and dominant serratus anterior (p = 0.008) muscles than players without a history of shoulder problems. Having a history of shoulder problems may alter the balance between mobility and stability within the shoulder complex suggesting that particular attention should be given to dominant and non-dominant shoulder functions by coaches and clinicians. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Forensic identification of floating shoulder injury].

PubMed

Li, Sheng-Ya; Huang, Si-Xing; Zhao, Xing-Bin; Zheng, Xiao-Hong; Zhu, Yi

2006-10-15

To discuss forensic identification of floating shoulder injury (FSI). To analyze fifteen cases of FSI which were accepted from Jan. 1993 to Jan. 2006, including 15 shoulder neck fracture, 13 clavide stem fracture and 2 distal end clavide fracture, the function of shoulder joint was evaluated six months after injure considering the following three aspects: result of forensic examination such as X-ray photograph, CT and MRI, the injurers' symptom, objective sign and joint function, shoulder joint territory, degree of pain and local muscle power. Basing on the curative effect standard of Herscovic, all cases were divided into good. Modest, worst, which included 2, 4, 9 cases respectively; referring the standard of GA35-92, GB18667-2002, all cases were divided into six, seven, eight, nine and ten degree, which included 2,9,2,1,1 cases respectively. As a special powerful injure, FSI always companied with concurrent and multiple injure, and characterized by missed, incorrect and delayed diagnosis and infelicitous treatment, which lead to the high frequency and degree of injure. To prevent missed and incorrect forensic identification, we should have a full realization of the particularity of FSI, and evaluate the function of shoulder all-sidely, objectively and synseticaly.

Generalised joint hypermobility and shoulder joint hypermobility, - risk of upper body musculoskeletal symptoms and reduced quality of life in the general population.

PubMed

Juul-Kristensen, Birgit; Østengaard, Lasse; Hansen, Sebrina; Boyle, Eleanor; Junge, Tina; Hestbaek, Lise

2017-05-30

Generalised Joint Hypermobility (GJH) is a hereditary condition with an ability to exceed the joints beyond the normal range. The prevalence of GJH in the adult population and its impact on upper body musculoskeletal health and quality of life has mostly been studied in selected populations. The aims of this study were therefore, firstly to study the prevalence of GJH and GJH including shoulder hypermobility (GJHS), in the general Danish adult population; secondly to test the associations between GJH or GJHS and upper body musculoskeletal symptoms and health-related quality of life (HRQoL). The study was cross-sectional where 2072 participants, aged 25-65, randomly extracted from the Danish Civil Registration System), were invited to answer a questionnaire battery (Five-Part Questionnaire for classification of GJH, Standardised Nordic Questionnaire for musculoskeletal symptoms, EuroQoL-5D for HRQoL). Totally 1006 (49%) participants responded. The prevalence of GJH and GJHS were 30% (n = 300) and 5% (n = 51), respectively. Compared with Non GJH (NGJH), participants with GJH and GJHS had Odds Ratio (OR) of 1.5-3.5 for upper body musculoskeletal symptoms within the last 12 months (mostly shoulders and hands/wrists). GJH and GJHS also had OR 1.6-4.4 for being prevented from usual activities, mostly due to shoulder and neck symptoms. Furthermore, GJH and GJHS had OR 2.2-3.1 for upper body musculoskeletal symptoms lasting for more than 90 days (neck, shoulders, hand/wrists), and 1.5-3.5 for reduced HRQoL (all dimensions, but anxiety/depression) compared with NGJH. Generally, most OR for GJHS were about twice as high as for those having GJH alone. GJH and GJHS are frequently self-reported musculoskeletal conditions in the Danish adult population. Compared with NGJH, GJH and especially GJHS, present with higher OR for upper body musculoskeletal symptoms, more severe symptoms and decreased HRQoL.

Kinematic evaluation of patients with total and reverse shoulder arthroplasty during rehabilitation exercises with different loads.

PubMed

de Toledo, Joelly Mahnic; Loss, Jefferson Fagundes; Janssen, Thomas W; van der Scheer, Jan W; Alta, Tjarco D; Willems, W Jaap; Veeger, DirkJan H E J

2012-10-01

Following shoulder arthroplasty, any well-planned rehabilitation program should include muscle strengthening. However, it is not always clear how different external loads influence shoulder kinematics in patients with shoulder prostheses. The objective of this study was to describe shoulder kinematics and determine the contribution of the scapulothoracic joint to total shoulder motion of patients with total and reverse shoulder arthroplasties and of healthy individuals during rehabilitation exercises (anteflexion and elevation in the scapular plane) using different loading conditions (without external load, 1 kg and elastic resistance). Shoulder motions were measured using an electromagnetic tracking device. A force transducer was used to record force signals during loaded conditions using elastic resistance. Statistical comparisons were made using a three-way repeated-measures analysis of variance with a Bonferroni post hoc testing. The scapula contributed more to movement of the arm in subjects with prostheses compared to healthy subjects. The same applies for loaded conditions (1 kg and elastic resistance) relative to unloaded tasks. For scapular internal rotation, upward rotation and posterior tilt no significant differences among groups were found during both exercises. Glenohumeral elevation angles during anteflexion were significantly higher in the total shoulder arthroplasty group compared to the reverse shoulder arthroplasty group. Differences in contribution of the scapula to total shoulder motion between patients with different types of arthroplasties were not significant. However, compared to healthy subjects, they were. Furthermore, scapular kinematics of patients with shoulder arthroplasty was influenced by implementation of external loads, but not by the type of load. Copyright © 2012 Elsevier Ltd. All rights reserved.

Physical examination of the shoulder.

PubMed

King, Joseph J; Wright, Thomas W

2014-10-01

This article summarizes the overall assessment of the shoulder joint and seeks to help direct clinicians to diagnose shoulder pathology using standard and specific physical examinations. The history and standard examination can prompt the examiner to focus on specific tests to further evaluate the shoulder and limit the differential diagnoses. An appropriate and directed shoulder physical examination allows the clinician to focus on further diagnostic strategies and treatment options for the patient. Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

Using the American alligator and a repeated-measures design to place constraints on in vivo shoulder joint range of motion in dinosaurs and other fossil archosaurs.

PubMed

Hutson, Joel D; Hutson, Kelda N

2013-01-15

Using the extant phylogenetic bracket of dinosaurs (crocodylians and birds), recent work has reported that elbow joint range of motion (ROM) studies of fossil dinosaur forearms may be providing conservative underestimates of fully fleshed in vivo ROM. As humeral ROM occupies a more central role in forelimb movements, the placement of quantitative constraints on shoulder joint ROM could improve fossil reconstructions. Here, we investigated whether soft tissues affect the more mobile shoulder joint in the same manner in which they affect elbow joint ROM in an extant archosaur. This test involved separately and repeatedly measuring humeral ROM in Alligator mississippiensis as soft tissues were dissected away in stages to bare bone. Our data show that the ROMs of humeral flexion and extension, as well as abduction and adduction, both show a statistically significant increase as flesh is removed, but then decrease when the bones must be physically articulated and moved until they separate from one another and/or visible joint surfaces. A similar ROM pattern is inferred for humeral pronation and supination. All final skeletonized ROMs were less than initial fully fleshed ROMs. These results are consistent with previously reported elbow joint ROM patterns from the extant phylogenetic bracket of dinosaurs. Thus, studies that avoid separation of complementary articular surfaces may be providing fossil shoulder joint ROMs that underestimate in vivo ROM in dinosaurs, as well as other fossil archosaurs.

Joint Force Quarterly. Number 1, Summer 1993

DTIC Science & Technology

1993-01-01

Contributors Joint Force Quarterly A PROFESSIONAL MILITARY JOURNAL Editor-in-Chief Alvin H. Bernstein Executive Editor Patrick M. Cronin Managing Editor Robert...understanding of the integrated employ- ment of land, sea, air, space, and special operations forces. The journal focuses on joint doctrine, coalition...other agency of the Federal Government. Por- tions of this journal are protected by copyright and may not be reproduced or extracted without the

Physical exam of the adolescent shoulder: tips for evaluating and diagnosing common shoulder disorders in the adolescent athlete.

PubMed

Lazaro, Lionel E; Cordasco, Frank A

2017-02-01

In the young athlete, the shoulder is one of the most frequently injured joints during sports activities. The injuries are either from an acute traumatic event or overuse. Shoulder examination can present some challenges; given the multiple joints involved, the difficulty palpating the underlying structures, and the potential to have both intra- and/or extra-articular problems. Many of the shoulder examination tests can be positive in multiple problems. They usually have high sensitivity but low specificity and therefore low predictive value. The medical history coupled with a detailed physical exam can usually provide the information necessary to obtain an accurate diagnosis. A proficient shoulder examination and the development of an adequate differential diagnosis are important before considering advanced imaging. The shoulder complex relies upon the integrity of multiple structures for normal function. A detailed history is of paramount importance when evaluating young athletes with shoulder problems. A systematic physical examination is extremely important to guiding an accurate diagnosis. The patient's age and activity level are very important when considering the differential diagnosis. Findings obtain through history and physical examination should dictate the decision to obtain advanced imaging of the shoulder.

Questions and Answers About Shoulder Problems

MedlinePlus

... months your shoulder is not better. Rotator Cuff Tear Treatment for a rotator cuff tear may also include: Heat or cold to the ... into your shoulder joint. Surgery to repair the tear if you don’t see improvement with other ...

Patellofemoral joint contact forces during activities with high knee flexion.

PubMed

Trepczynski, Adam; Kutzner, Ines; Kornaropoulos, Evgenios; Taylor, William R; Duda, Georg N; Bergmann, Georg; Heller, Markus O

2012-03-01

The patellofemoral (PF) joint plays an essential role in knee function, but little is known about the in vivo loading conditions at the joint. We hypothesized that the forces at the PF joint exceed the tibiofemoral (TF) forces during activities with high knee flexion. Motion analysis was performed in two patients with telemetric knee implants during walking, stair climbing, sit-to-stand, and squat. TF and PF forces were calculated using a musculoskeletal model, which was validated against the simultaneously measured in vivo TF forces, with mean errors of 10% and 21% for the two subjects. The in vivo peak TF forces of 2.9-3.4 bodyweight (BW) varied little across activities, while the peak PF forces showed significant variability, ranging from less than 1 BW during walking to more than 3 BW during high flexion activities, exceeding the TF forces. Together with previous in vivo measurements at the hip and knee, the PF forces determined here provide evidence that peak forces across these joints reach values of around 3 BW during high flexion activities, also suggesting that the in vivo loading conditions at the knee can only be fully understood if the forces at the TF and the PF joints are considered together. Copyright © 2011 Orthopaedic Research Society.

Imaging of shoulder instability

PubMed Central

Martínez Martínez, Alberto; Tomás Muñoz, Pablo; Pozo Sánchez, José; Zarza Pérez, Antonio

2017-01-01

This extended review tries to cover the imaging findings of the wide range of shoulder injuries secondary to shoulder joint instability. Usefulness of the different imaging methods is stressed, including radiography, computed tomography (CT) and magnetic resonance. The main topics to be covered include traumatic, atraumatic and minor instability syndromes. Radiography may show bone abnormalities associated to instability, including developmental and post-traumatic changes. CT is the best technique depicting and quantifying skeletal changes. MR-arthrography is the main tool in diagnosing the shoulder instability injuries. PMID:28932699

Effect of load, cadence, and fatigue on tibio-femoral joint force during a half squat.

PubMed

Hattin, H C; Pierrynowski, M R; Ball, K A

1989-10-01

Ten male university student volunteers were selected to investigate the 3D articular force at the tibio-femoral joint during a half squat exercise, as affected by cadence, different barbell loads, and fatigue. Each subject was required to perform a half squat exercise with a barbell weight centered across the shoulders at two different cadences (1 and 2 s intervals) and three different loads (15, 22 and 30% of the one repetition maximum). Fifty repetitions at each experimental condition were recorded with an active optoelectronic kinematic data capture system (WATSMART) and a force plate (Kistler). Processing the data involved a photogrammetric technique to obtain subject tailored anthropometric data. The findings of this study were: 1) the maximal antero-posterior shear and compressive force consistently occurred at the lowest position of the weight, and the forces were very symmetrically disposed on either side of this halfway point; 2) the medio-lateral shear forces were small over the squat cycle with few peaks and troughs; 3) cadence increased the antero-posterior shear (50%) and the compressive forces (28%); 4) as a subject fatigues, load had a significant effect on the antero-posterior shear force; 5) fatigue increased all articular force components but it did not manifest itself until about halfway through the 50 repetitions of the exercise; 6) the antero-posterior shear force was most affected by fatigue; 7) cadence had a significant effect on fatigue for the medio-lateral shear and compressive forces.

Stress analysis of bolted joints under centrifugal force

NASA Astrophysics Data System (ADS)

Imura, Makoto; Iizuka, Motonobu; Nakae, Shigeki; Mori, Takeshi; Koyama, Takayuki

2014-06-01

Our objective is to develop a long-life rotary machine for synchronous generators and motors. To do this, it is necessary to design a high-strength bolted joint, which is responsible for fixing a salient pole on a rotor shaft. While the rotary machine is in operation, not only centrifugal force but also moment are loaded on a bolted joint, because a point of load is eccentric to a centre of a bolt. We tried to apply the theory proposed in VDI2230-Blatt1 to evaluate the bolted joint under eccentric force, estimate limited centrifugal force, which is the cause of partial separation between the pole and the rotor shaft, and then evaluate additional tension of a bolt after the partial separation has occurred. We analyzed the bolted joint by FEM, and defined load introduction factor in that case. Additionally, we investigated the effect of the variation of bolt preload on the partial separation. We did a full scale experiment with a prototype rotor to reveal the variation of bolt preload against tightening torque. After that, we verified limited centrifugal force and the strength of the bolted joint by the VDI2230-Blatt1 theory and FEM considering the variation of bolt preload. Finally, we could design a high-strength bolted joint verified by the theoretical study and FEM analysis.

Constructing a simple parametric model of shoulder from medical images

NASA Astrophysics Data System (ADS)

Atmani, H.; Fofi, D.; Merienne, F.; Trouilloud, P.

2006-02-01

The modelling of the shoulder joint is an important step to set a Computer-Aided Surgery System for shoulder prosthesis placement. Our approach mainly concerns the bones structures of the scapulo-humeral joint. Our goal is to develop a tool that allows the surgeon to extract morphological data from medical images in order to interpret the biomechanical behaviour of a prosthesised shoulder for preoperative and peroperative virtual surgery. To provide a light and easy-handling representation of the shoulder, a geometrical model composed of quadrics, planes and other simple forms is proposed.

Shoulder Strength and Physical Activity Predictors of Shoulder Pain in People With Paraplegia From Spinal Injury: Prospective Cohort Study

PubMed Central

Hatchett, Patricia; Eberly, Valerie J.; Lighthall Haubert, Lisa; Conners, Sandy; Requejo, Philip S.

2015-01-01

Background Shoulder joint pain is a frequent secondary complaint for people following spinal cord injury (SCI). Objective The purpose of this study was to determine predictors of shoulder joint pain in people with paraplegia. Methods/Design A 3-year longitudinal study was conducted. Participants were people with paraplegia who used a manual wheelchair for at least 50% of their mobility and were asymptomatic for shoulder pain at study entry. Participants were classified as having developed shoulder pain if they experienced an increase of ≥10 points on the Wheelchair User's Shoulder Pain Index in the 3-year follow-up period. Measurements of maximal isometric shoulder torques were collected at study entry (baseline), 18 months, and 3 years. Daily activity was measured using a wheelchair odometer, and self-reported daily transfer and raise frequency data were collected by telephone every 6 weeks. Results Two hundred twenty-three participants were enrolled in the study; 39.8% developed shoulder pain over the 3-year follow-up period. Demographic variables and higher activity levels were not associated with shoulder pain onset. Baseline maximal isometric torque (normalized by body weight) in all shoulder muscle groups was 10% to 15% lower in participants who developed shoulder pain compared with those who remained pain-free. Lower shoulder adduction torque was a significant predictor of shoulder pain development (log-likelihood test=11.38), but the model explained only 7.5% of shoulder pain onset and consequently is of limited clinical utility. Limitations Time since SCI varied widely among participants, and transfer and raise activity was measured by participant recall. Conclusions Participants who developed shoulder pain had decreased muscle strength, particularly in the shoulder adductors, and lower levels of physical activity prior to the onset of shoulder pain. Neither factor was a strong predictor of shoulder pain onset. PMID:25721123

Effect of a redesigned two-wheeled container for refuse collecting on mechanical loading of low back and shoulders.

PubMed

Kuijer, P Paul F M; Hoozemans, Marco J M; Kingma, Idsart; Van Dieën, Jaap H; De Vries, Wiebe H K; Veeger, Dirk Jan; Van der Beek, Allard J; Visser, Bart; Frings-Dresen, Monique H W

2003-05-15

The objective of this study was to compare the mechanical and perceived workload when working with a redesigned two-wheeled container and working with a standard two-wheeled container for refuse collecting. The three changes in the design of the container were a displacement of the position of the centre of mass in the direction of the axis of the wheels, a slight increase in the height of the handle and a slight increase in the horizontal distance between the handle and the wheel-axis, and an increase in the diameter of the wheels. The volume of the container remained 0.240 m3. Nine refuse collectors performed some of their most frequent daily activities with both types of containers in the laboratory. Kinematics and exerted hand forces were assessed as input for detailed 3D biomechanical models of the low back and shoulder to estimate net moments at the low back and shoulders, compressive forces at the low back and contact forces at the glenohumeral joint. Also, the refuse collectors rated the ease of handling the two-wheeled containers on a five point scale. The use of the redesigned container resulted in a decrease of the exerted hand forces of 27%, decreases in the net moments at the low back and shoulders of 8% and 20%, respectively, and a decrease of 32% of the contact force at the glenohumeral joint when compared to the standard container. However, pulling an empty redesigned container on to the pavement resulted in an increase of the shoulder moment of more than 100%. No differences between container types were found for the compressive forces at the low back. Pushing and pulling with the redesigned container was rated as easier than pushing and pulling with the standard container. No differences in subjective ratings were found for the tasks of turning the container or pulling an empty container onto the pavement. It is concluded that, provided that empty containers are placed back onto the pavement as infrequently as possible, the introduction of the

Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty

PubMed Central

von Engelhardt, Lars V; Manzke, Michael; Breil-Wirth, Andreas; Filler, Timm J; Jerosch, Joerg

2017-01-01

AIM To evaluate the joint geometry and the clinical outcome of stemless, anatomical shoulder arthroplasty with the TESS system. METHODS Twenty-one shoulders with a mean follow-up 18 of months were included. On scaled digital radiographs the premorbid center of rotation (CoR) was assessed and compared to the CoR of the prosthesis by using the MediCAD® software. Additionally, the pre- and post-operative geometry of the CoR was assessed in relation to the glenoid, the acromion as well as to the proximal humerus. Radiological changes, such as radiolucencies, were also assessed. Clinical outcome was assessed with the Constant and DASH score. RESULTS Both, the Constant and DASH scores improved significantly from 11% to 75% and from 70 to 30 points, P < 0.01 respectively. There were no significant differences regarding age, etiology, cemented or metal-backed glenoids, etc. (P > 0.05). The pre- and postoperative humeral offset, the lateral glenohumeral offset, the height of the CoR, the acromiohumeral distance as well as neck-shaft angle showed no significant changes (P > 0.05). The mean deviation of the CoR of the prosthesis from the anatomic center was 1.0 ± 2.8 mm. Three cases showed a medial deviation of more than 3 mm. These deviations of 5.1, 5.7 and 7.6 mm and were caused by an inaccurate humeral neck cut. These 3 patients showed a relatively poor outcome scoring. CONCLUSION TESS arthroplasty allows an anatomical joint reconstruction with a very good outcome. Outliers described in this study sensitize the surgeon for an accurate humeral neck cut. PMID:29094010

Joint Ordnance Test Procedure (JOTP)-010 Safety and Suitability for Service Assessment Testing for Shoulder Launched Munitions

DTIC Science & Technology

2016-05-09

electromagnetic environment for which they are designed to be used. These tests are performed on a powered weapon during simulated normal operation and are...010B SAFETY AND SUITABILITY FOR SERVICE ASSESSMENT TESTING FOR SHOULDER LAUNCHED MUNITIONS Joint Services Munition Safety Test Working Group JOTP...12 6.8 Test Sample Quantities .......................................................... 13 7. PRE- AND POST - TEST INSPECTIONS

ShouldeRO, an alignment-free two-DOF rehabilitation robot for the shoulder complex.

PubMed

Dehez, Bruno; Sapin, Julien

2011-01-01

This paper presents a robot aimed to assist the shoulder movements of stroke patients during their rehabilitation process. This robot has the general form of an exoskeleton, but is characterized by an action principle on the patient no longer requiring a tedious and accurate alignment of the robot and patient's joints. It is constituted of a poly-articulated structure whose actuation is deported and transmission is ensured by Bowden cables. It manages two of the three rotational degrees of freedom (DOFs) of the shoulder. Quite light and compact, its proximal end can be rigidly fixed to the patient's back on a rucksack structure. As for its distal end, it is connected to the arm through passive joints and a splint guaranteeing the robot action principle, i.e. exert a force perpendicular to the patient's arm, whatever its configuration. This paper also presents a first prototype of this robot and some experimental results such as the arm angular excursions reached with the robot in the three joint planes. © 2011 IEEE

Avoiding Shoulder Injury from Resistance Training.

ERIC Educational Resources Information Center

Durall, Chris J.; Manske, Robert C.; Davies, George J.

2001-01-01

Identifies shoulder exercises commonly performed in fitness centers that may contribute to or exacerbate glenohumeral joint (shoulder) injury, describing alternative exercises that may be substituted and a offering rationale for the variations. The article focuses on anterior and posterior glenohumeral instability, subacromial impingement (primary…

Biomechanical comparison of reverse total shoulder arthroplasty systems in soft tissue-constrained shoulders.

PubMed

Henninger, Heath B; King, Frank K; Tashjian, Robert Z; Burks, Robert T

2014-05-01

Numerous studies have examined the biomechanics of isolated variables in reverse total shoulder arthroplasty. This study directly compared the composite performance of two reverse total shoulder arthroplasty systems; each system was designed around either a medialized or a lateralized glenohumeral center of rotation. Seven pairs of shoulders were tested on a biomechanical simulator. Center of rotation, position of the humerus, passive and active range of motion, and force to abduct the arm were quantified. Native arms were tested, implanted with a Tornier Aequalis or DJO Surgical Reverse Shoulder Prosthesis (RSP), and then retested. Differences from the native state were then documented. Both systems shifted the center of rotation medially and inferiorly relative to native. Medial shifts were greater in the Aequalis implant (P < .037). All humeri shifted inferior compared with native but moved medially with the Aequalis (P < .001). Peak passive abduction, internal rotation, and external rotation did not differ between systems (P > .05). Both reverse total shoulder arthroplasty systems exhibited adduction deficits, but the RSP implant deficit was smaller (P = .046 between implants). Both systems reduced forces to abduct the arm compared with native, although the Aequalis required more force to initiate motion from the resting position (P = .022). Given the differences in system designs and configurations, outcome variables were generally comparable. The RSP implant allowed slightly more adduction, had a more lateralized humeral position, and required less force to initiate elevation. These factors may play roles in limiting scapular notching, improving active external rotation by normalizing the residual rotator cuff length, and limiting excessive stress on the deltoid. Copyright © 2014 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Shoulder Impingement Treatment

MedlinePlus

... imbalance in the rotator cuff or scapular muscles, postural abnormalities, shoulder joint instability, or improper training or ... and corrected. Phase Goals Methods Comments I Pain control Limit overhead activity or anything that causes pain. ...

Effects of a compression garment on shoulder external rotation force outputs during isotonic contractions.

PubMed

Tsuruike, Masaaki; Ellenbecker, Todd S

2013-02-01

The use of compression garments (CGs) has been advocated for performance enhancement and recovery in athletes. The effect of a CG on humeral rotation motor control has not been previously tested. The purpose of this study was to examine the isotonic contraction of external rotation (ER) of the glenohumeral joint at different force outputs to determine the effect of wearing a long sleeve CG on muscular performance. Twelve male college tennis players and 12 male college soccer players were tested for ER of the dominant shoulder during both concentric and eccentric isotonic contractions. The subjects performed 5 consecutive repetitions of both concentric and eccentric ER at 20-30% and 40-50% of maximum voluntary isometric contraction (MVIC) intensities. All subjects were tested with and without CG as well as with and without ongoing visual feedback information (OVFI). The order of CG wearing and the presence of OVFI were randomly assigned across all subjects. The results indicated a significant 3-way interaction between CG wearing and OVFI across 2 loads. Specifically, significantly different mean value of the completion time was found between OVFI and no-OVFI without CG wearing at 40-50% of MVIC, whereas no difference in the completion time was found with and without OVFI with CG wearing. Taken together, with CG wearing, athletes may have ER at 40-50% of MVIC more readily maintained by peripheral feedback without visuomotor control imposed on force outputs as compared without CG wearing.

3 CFR - Disestablishment of United States Joint Forces Command

Code of Federal Regulations, 2012 CFR

2012-01-01

... Command Presidential Documents Other Presidential Documents Memorandum of January 6, 2011 Disestablishment of United States Joint Forces Command Memorandum for the Secretary of Defense Pursuant to my... States Joint Forces Command, effective on a date to be determined by the Secretary of Defense. I direct...

What It Takes. Air Force Command of Joint Operations

DTIC Science & Technology

2009-01-01

Iraq Assistance Group IDE intermediate developmental education IO international organization ISAF International Security and Assistance Force ISR...Operations Table A.1—Continued Joint Task Force Mission/Operation Start End Service Command Rank JTF–Joint Area Support Group (JASG) Iraqi Freedom...be of interest to a wide group of Air Force personnel involved in the development and func- tion of the service’s command organizations, including

Joint Task Force-Bravo

Science.gov Websites

Air Base Squadron Joint Security Forces Medical Element (MEDEL) JSB / ARFOR En Español Noticias Hojas to provide medical care in Waspam Call to Duty - Senior Airman Nicholas Carssow Operations Support JTF-Bravo partners with Nicaragua to provide medical care in Waspam JTF-Bravo partners with Nicaragua

Anma massage (Japanese massage) therapy for patients with Parkinson's disease in geriatric health services facilities: Effectiveness on limited range of motion of the shoulder joint.

PubMed

Suoh, Sachie; Donoyama, Nozomi; Ohkoshi, Norio

2016-04-01

To determine the efficacy of Anma massage therapy for patients with Parkinson's disease (PD) in geriatric health services facilities. (1) Immediate treatment effects: 10 PD patients, in the intervention period with Hoehn and Yahr (H&Y) scale at stage 5, received 30-40 min sessions of Anma massage therapy. In the non-intervention period, six PD patients did not undergo this therapy. The shoulder joint range of motion (ROM) was measured before and after each session. (2) Continuous treatment effects: Six PD patients in the intervention period received the same massage sessions once a week continuously for seven weeks. One week after the completion of the treatment, the ROM of the shoulder joints was measured. (1) Shoulder abduction on the more affected side showed immediate significant improvements. (2) Shoulder abduction on the more affected side and less affected side showed notable effects of continuous treatment procedure leading to significant improvement. The above results suggested the efficacy of successive Anma massage therapy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shoulder Injuries in US Astronauts Related to EVA Suit Design

NASA Technical Reports Server (NTRS)

Scheuring, R. A.; McCulloch, P.; Van Baalen, Mary; Minard, Charles; Watson, Richard; Blatt, T.

2011-01-01

Introduction: For every one hour spent performing extravehicular activity (EVA) in space, astronauts in the US space program spend approximately six to ten hours training in the EVA spacesuit at NASA-Johnson Space Center's Neutral Buoyancy Lab (NBL). In 1997, NASA introduced the planar hard upper torso (HUT) EVA spacesuit which subsequently replaced the existing pivoted HUT. An extra joint in the pivoted shoulder allows increased mobility but also increased complexity. Over the next decade a number of astronauts developed shoulder problems requiring surgical intervention, many of whom performed EVA training in the NBL. This study investigated whether changing HUT designs led to shoulder injuries requiring surgical repair. Methods: US astronaut EVA training data and spacesuit design employed were analyzed from the NBL data. Shoulder surgery data was acquired from the medical record database, and causal mechanisms were obtained from personal interviews Analysis of the individual HUT designs was performed as it related to normal shoulder biomechanics. Results: To date, 23 US astronauts have required 25 shoulder surgeries. Approximately 48% (11/23) directly attributed their injury to training in the planar HUT, whereas none attributed their injury to training in the pivoted HUT. The planar HUT design limits shoulder abduction to 90 degrees compared to approximately 120 degrees in the pivoted HUT. The planar HUT also forces the shoulder into a forward flexed position requiring active retraction and extension to increase abduction beyond 90 degrees. Discussion: Multiple factors are associated with mechanisms leading to shoulder injury requiring surgical repair. Limitations to normal shoulder mechanics, suit fit, donning/doffing, body position, pre-existing injury, tool weight and configuration, age, in-suit activity, and HUT design have all been identified as potential sources of injury. Conclusion: Crewmembers with pre-existing or current shoulder injuries or certain

[Muscle efficiency in total shoulder prosthesis implantation: dependence on position of the humeral head and rotator cuff function].

PubMed

Klages, A; Hurschler, C; Wülker, N; Windhagen, H

2001-09-01

Modern shoulder prostheses permit an anatomic reconstruction of the joint, although the biomechanical advantages are not proven. The goal of this study was to investigate the relationship between position of the humeral head and function of the shoulder prosthesis (muscle efficiency). Shoulder elevation-motion and rotator cuff defects were simulated in vitro in a robot-assisted shoulder simulator. The EPOCA Custom Offset shoulder prosthesis (Argomedical AG, Cham, CH) was implanted in seven normal shoulders (77 +/- 20 kg, 55 +/- 14 years). Active elevation was simulated by hydraulic cylinders, and scapulothoratic motion by a specially programmed industrial robot. Muscle efficiency (elevation-angle/muscle-force of the deltoid muscle) was measured in anatomic (ANA), medialised (MED) and lateralised (LAT) positions of the humeral head, with or without rotator cuff muscle deficiency. Medialisation increased efficiency by 0.03 +/- 0.04 deg/N (p = 0.022), lateralisation decreased it by 0.04 +/- 0.06 deg/N (p = 0.009). Supraspinatus muscle deficiency increased the deltoid force required to elevate the arm, and thus decreased efficiency (ANA p = 0.091, MED p = 0.018, LAT p = 0.028). The data confirm that the position of the humeral head affects the mechanics of total shoulder arthroplasty. Medialisation increases efficiency of the deltoid muscle and may prove useful in compensating isolated supraspinatus muscle deficiency. Lateralisation, in contrast, leads to an unfavorable situation.

Anatomy and Biomechanics of the Unstable Shoulder

PubMed Central

Cuéllar, Ricardo; Ruiz-Ibán, Miguel Angel; Cuéllar, Adrián

2017-01-01

Purpose: To review the anatomy of the shoulder joint and of the physiology of glenohumeral stability is essential to manage correctly shoulder instability. Methods: It was reviewed a large number of recently published research studies related to the shoulder instability that received a higher Level of Evidence grade. Results: It is reviewed the bony anatomy, the anatomy and function of the ligaments that act on this joint, the physiology and physiopathology of glenohumeral instability and the therapeutic implications of the injured structures. Conclusion: This knowledge allows the surgeon to evaluate the possible causes of instability, to assess which are the structures that must be reconstructed and to decide which surgical technique must be performed. PMID:28979600

Relationship Between the Range of Motion and Isometric Strength of Elbow and Shoulder Joints and Ball Velocity in Women Team Handball Players.

PubMed

Schwesig, René; Hermassi, Souhail; Wagner, Herbert; Fischer, David; Fieseler, Georg; Molitor, Thomas; Delank, Karl-Stefan

2016-12-01

Schwesig, R, Hermassi, S, Wagner, H, Fischer, D, Fieseler, G, Molitor, T, and Delank, K-S. Relationship between the range of motion and isometric strength of elbow and shoulder joints and ball velocity in women team handball players. J Strength Cond Res 30(12): 3428-3435, 2016-The aims of this study were to investigate relationships between isometric strength and range of motion (ROM) of shoulder and elbow joints and compare 2 different team handball throwing techniques in women team handball. Twenty highly experienced women team handball players (age: 20.7 ± 2.9 years; body mass: 68.4 ± 6.0 kg; and height: 1.74 ± 0.06 m) participated in this study. The isometric strength (hand-held dynamometer) and ROM (goniometer) of shoulder and elbow joints were measured at the beginning of the preseasonal training. After clinical examination, the subjects performed 3 standing throws with run-up (10 m) and 3 jump throws over a hurdle (0.20 m). The mean ball velocity was calculated from 3 attempts and measured using a radar gun. The results showed that the ball velocity of the standing throw with run-up (vST) was significantly higher than that of the jump throw (vJT) (25.5 ± 1.56 vs. 23.2 ± 1.31 m·s; p < 0.001). Therefore, significant playing position effects (p = 0.021) were only found for ST. Goalkeepers (n = 2) had the lowest (22.6 ± 0.04 m·s) and backcourt players (n = 9), the highest (26.1 ± 1.36 m·s) vST. The retroversion strength in the shoulder was the only parameter with relevant correlations to both throws (vST: r = 0.52, and vJT: r = 0.43). Other relevant relationships to vJT were found for adduction strength shoulder (r = 0.55) and ROM flexion elbow (r = -0.54). The vST was only correlated to the glenohumeral internal rotation deficit. As a consequence, strength is more important than the ROM, and in addition to this, the shoulder, compared with the elbow, has a greater influence on the vST in highly experienced women team handball players.

Proprioception and throwing accuracy in the dominant shoulder after cryotherapy.

PubMed

Wassinger, Craig A; Myers, Joseph B; Gatti, Joseph M; Conley, Kevin M; Lephart, Scott M

2007-01-01

Application of cryotherapy modalities is common after acute shoulder injury and as part of rehabilitation. During athletic events, athletes may return to play after this treatment. The effects of cryotherapy on dominant shoulder proprioception have been assessed, yet the effects on throwing performance are unknown. To determine the effects of a cryotherapy application on shoulder proprioception and throwing accuracy. Single-group, pretest-posttest control session design. University-based biomechanics laboratory. Healthy college-aged subjects (n = 22). Twenty-minute ice pack application to the dominant shoulder. Active joint position replication, path of joint motion replication, and the Functional Throwing Performance Index. Subjects demonstrated significant increases in deviation for path of joint motion replication when moving from 90 degrees of abduction with 90 degrees of external rotation to 20 degrees of flexion with neutral shoulder rotation after ice pack application. Also, subjects exhibited a decrease in Functional Throwing Performance Index after cryotherapy application. No differences were found in subjects for active joint position replication after cryotherapy application. Proprioception and throwing accuracy were decreased after ice pack application to the shoulder. It is important that clinicians understand the deficits that occur after cryotherapy, as this modality is commonly used following acute injury and during rehabilitation. This information should also be considered when attempting to return an athlete to play after treatment.

A COMPARISON OF STATIC AND DYNAMIC OPTIMIZATION MUSCLE FORCE PREDICTIONS DURING WHEELCHAIR PROPULSION

PubMed Central

Morrow, Melissa M.; Rankin, Jeffery W.; Neptune, Richard R.; Kaufman, Kenton R.

2014-01-01

The primary purpose of this study was to compare static and dynamic optimization muscle force and work predictions during the push phase of wheelchair propulsion. A secondary purpose was to compare the differences in predicted shoulder and elbow kinetics and kinematics and handrim forces. The forward dynamics simulation minimized differences between simulated and experimental data (obtained from 10 manual wheelchair users) and muscle co-contraction. For direct comparison between models, the shoulder and elbow muscle moment arms and net joint moments from the dynamic optimization were used as inputs into the static optimization routine. RMS errors between model predictions were calculated to quantify model agreement. There was a wide range of individual muscle force agreement that spanned from poor (26.4 % Fmax error in the middle deltoid) to good (6.4 % Fmax error in the anterior deltoid) in the prime movers of the shoulder. The predicted muscle forces from the static optimization were sufficient to create the appropriate motion and joint moments at the shoulder for the push phase of wheelchair propulsion, but showed deviations in the elbow moment, pronation-supination motion and hand rim forces. These results suggest the static approach does not produce results similar enough to be a replacement for forward dynamics simulations, and care should be taken in choosing the appropriate method for a specific task and set of constraints. Dynamic optimization modeling approaches may be required for motions that are greatly influenced by muscle activation dynamics or that require significant co-contraction. PMID:25282075

Techniques of Force and Pressure Measurement in the Small Joints of the Wrist.

PubMed

Schreck, Michael J; Kelly, Meghan; Canham, Colin D; Elfar, John C

2018-01-01

The alteration of forces across joints can result in instability and subsequent disability. Previous methods of force measurements such as pressure-sensitive films, load cells, and pressure-sensing transducers have been utilized to estimate biomechanical forces across joints and more recent studies have utilized a nondestructive method that allows for assessment of joint forces under ligamentous restraints. A comprehensive review of the literature was performed to explore the numerous biomechanical methods utilized to estimate intra-articular forces. Methods of biomechanical force measurements in joints are reviewed. Methods such as pressure-sensitive films, load cells, and pressure-sensing transducers require significant intra-articular disruption and thus may result in inaccurate measurements, especially in small joints such as those within the wrist and hand. Non-destructive methods of joint force measurements either utilizing distraction-based joint reaction force methods or finite element analysis may offer a more accurate assessment; however, given their recent inception, further studies are needed to improve and validate their use.

Shoulder and hip joints for hard space suits and the like

NASA Technical Reports Server (NTRS)

Vykukal, H. C.

1986-01-01

For use in hard space suits and the like, a joint between the torso covering and the upper arm covering (i.e., shoulder) or between the torso covering and upper leg covering (i.e., hip) is disclosed. Each joint has an outer covering and a inner covering. The outer covering has plural perferably truncated toroidal sections decreasing in size proceeding outwardly. In one embodiment at each joint there are two bearings, the first larger than the second. The outer race of the larger bearing is attached to the outer edge of the smaller end of each section and the inner race of the larger bearing is attached to the end wall. The inner race of the smaller bearing is attached to the end wall. The outer race of the smaller bearing is attached to the larger end of the next section. Each bearing hask appropriate seals. Between each section is a rubber ring for the comfort of the wearer. Such rubber rings have radial flanges attached to the inner races of two adjacent bearings. Matching semicircular grooves are formed in the abutting overlapping surfaces. Bellows-like inner walls are also provided for each section fixed at one end to an inner cylindrical flange and, at the opposite end, to an end wall. Each outer section may rotate 360 deg relative to the next outer section, whereas the bellows sections do not rotate, but rather expand or contract locally as the rigid sections rotate relative to each other.

Joint forces and torques when walking in shallow water.

PubMed

Orselli, Maria Isabel Veras; Duarte, Marcos

2011-04-07

This study reports for the first time an estimation of the internal net joint forces and torques on adults' lower limbs and pelvis when walking in shallow water, taking into account the drag forces generated by the movement of their bodies in the water and the equivalent data when they walk on land. A force plate and a video camera were used to perform a two-dimensional gait analysis at the sagittal plane of 10 healthy young adults walking at comfortable speeds on land and in water at a chest-high level. We estimated the drag force on each body segment and the joint forces and torques at the ankle, knee, and hip of the right side of their bodies using inverse dynamics. The observed subjects' apparent weight in water was about 35% of their weight on land and they were about 2.7 times slower when walking in water. When the subjects walked in water compared with walking on land, there were no differences in the angular displacements but there was a significant reduction in the joint torques which was related to the water's depth. The greatest reduction was observed for the ankle and then the knee and no reduction was observed for the hip. All joint powers were significantly reduced in water. The compressive and shear joint forces were on average about three times lower during walking in water than on land. These quantitative results substantiate the use of water as a safe environment for practicing low-impact exercises, particularly walking. Copyright © 2011 Elsevier Ltd. All rights reserved.

Point-of-care ultrasound facilitates diagnosing a posterior shoulder dislocation.

PubMed

Mackenzie, David C; Liebmann, Otto

2013-05-01

Posterior shoulder dislocation is an uncommon disruption of the glenohumeral joint. Risk factors include seizure, electric shock, and underlying instabilities of the shoulder joint. A 27-year-old man with a history of recurrent posterior shoulder dislocation presented to the Emergency Department with sudden shoulder pain and reduced range of motion about the shoulder after abducting and internally rotating his arm. Radiographs did not show fracture or dislocation. The treating physician suspected an occult posterior shoulder dislocation, but wanted to avoid performing a computed tomography scan of the shoulder, as the patient had undergone numerous scans during the evaluation of similar complaints. Instead, a point-of-care ultrasound was performed, demonstrating posterior displacement of the humeral head relative to the glenoid rim, confirming the presence of a posterior shoulder dislocation. The patient received procedural sedation, and the shoulder was reduced with real-time ultrasound visualization. The patient tolerated the procedure well, and had decreased pain and improved range of motion. He was discharged with a sling, swathe, and orthopedic follow-up. Point-of-care ultrasound of the shoulder may be used to demonstrate posterior shoulder dislocation. This may have particular utility in the setting of non-diagnostic radiographs. Copyright © 2013. Published by Elsevier Inc.

Electromyographical Comparison of Four Common Shoulder Exercises in Unstable and Stable Shoulders

PubMed Central

Sciascia, Aaron; Kuschinsky, Nina; Nitz, Arthur J.; Mair, Scott D.; Uhl, Tim L.

2012-01-01

This study examines if electromyographic (EMG) amplitude differences exist between patients with shoulder instability and healthy controls performing scaption, prone horizontal abduction, prone external rotation, and push-up plus shoulder rehabilitation exercises. Thirty nine subjects were categorized by a single orthopedic surgeon as having multidirectional instability (n = 10), anterior instability (n = 9), generalized laxity (n = 10), or a healthy shoulder (n = 10). Indwelling and surface electrodes were utilized to measure EMG activity (reported as a % of maximum voluntary isometric contraction (MVIC)) in various shoulder muscles during 4 common shoulder exercises. The exercises studied effectively activated the primary musculature targeted in each exercise equally among all groups. The serratus anterior generated high activity (50–80% MVIC) during a push-up plus, while the infraspinatus and teres major generated moderate-to-high activity (30–80% MVIC) during both the prone horizontal and prone external rotation exercises. Scaption exercise generated moderate activity (20–50% MVIC) in both rotator cuff and scapular musculature. Clinicians should feel confident in prescribing these shoulder-strengthening exercises in patients with shoulder instability as the activation levels are comparable to previous findings regarding EMG amplitudes and should improve the dynamic stabilization capability of both rotator cuff and scapular muscles using exercises designed to address glenohumeral joint instability. PMID:22919499

Proprioception and Throwing Accuracy in the Dominant Shoulder After Cryotherapy

PubMed Central

Wassinger, Craig A; Myers, Joseph B; Gatti, Joseph M; Conley, Kevin M; Lephart, Scott M

2007-01-01

Context: Application of cryotherapy modalities is common after acute shoulder injury and as part of rehabilitation. During athletic events, athletes may return to play after this treatment. The effects of cryotherapy on dominant shoulder proprioception have been assessed, yet the effects on throwing performance are unknown. Objective: To determine the effects of a cryotherapy application on shoulder proprioception and throwing accuracy. Design: Single-group, pretest-posttest control session design. Setting: University-based biomechanics laboratory. Patients or Other Participants: Healthy college-aged subjects (n = 22). Intervention(s): Twenty-minute ice pack application to the dominant shoulder. Main Outcome Measure(s): Active joint position replication, path of joint motion replication, and the Functional Throwing Performance Index. Results: Subjects demonstrated significant increases in deviation for path of joint motion replication when moving from 90° of abduction with 90° of external rotation to 20° of flexion with neutral shoulder rotation after ice pack application. Also, subjects exhibited a decrease in Functional Throwing Performance Index after cryotherapy application. No differences were found in subjects for active joint position replication after cryotherapy application. Conclusions: Proprioception and throwing accuracy were decreased after ice pack application to the shoulder. It is important that clinicians understand the deficits that occur after cryotherapy, as this modality is commonly used following acute injury and during rehabilitation. This information should also be considered when attempting to return an athlete to play after treatment. PMID:17597948

Validation of Shoulder Response of Human Body Finite-Element Model (GHBMC) Under Whole Body Lateral Impact Condition.

PubMed

Park, Gwansik; Kim, Taewung; Panzer, Matthew B; Crandall, Jeff R

2016-08-01

In previous shoulder impact studies, the 50th-percentile male GHBMC human body finite-element model was shown to have good biofidelity regarding impact force, but under-predicted shoulder deflection by 80% compared to those observed in the experiment. The goal of this study was to validate the response of the GHBMC M50 model by focusing on three-dimensional shoulder kinematics under a whole-body lateral impact condition. Five modifications, focused on material properties and modeling techniques, were introduced into the model and a supplementary sensitivity analysis was done to determine the influence of each modification to the biomechanical response of the body. The modified model predicted substantially improved shoulder response and peak shoulder deflection within 10% of the observed experimental data, and showed good correlation in the scapula kinematics on sagittal and transverse planes. The improvement in the biofidelity of the shoulder region was mainly due to the modifications of material properties of muscle, the acromioclavicular joint, and the attachment region between the pectoralis major and ribs. Predictions of rib fracture and chest deflection were also improved because of these modifications.

Consequences of impact on arm (elbow and shoulder joints) caused by ball hitting, theoretical analysis

NASA Astrophysics Data System (ADS)

Negrea, Adina; Busuioceanu, Ioana Iuliana

2018-02-01

Present paper estimates the mechanics of the impact of a ball and a hand-arm, during the sports training using a classical model for the hand-arm system, avoiding the contribution of the coefficient of restitution. The results of this investigation are focused on the equations needed to find out theimpact reactions in elbow and shoulder joints, for different anthropometric data. Also, the computing of the position of mass centers and the moments of inertia for each constitutive part of hand-arm system is made.

CT arthrography of capsular structures of the shoulder.

PubMed

Rafii, M; Firooznia, H; Golimbu, C; Minkoff, J; Bonamo, J

1986-02-01

The capsular mechanism of the shoulder joint consists of the joint capsule, which is strengthened by the glenohumeral ligaments and the rotator cuff, the glenoid labrum, and a variable number of synovial recesses. Although the fibrous capsule is a lax structure, the normal function of the capsular mechanism makes it an effective barrier against anterior dislocation, particularly in external rotation. There has been a tendency in the past to overestimate the role of the glenoid labrum in stability of the shoulder joint. In patients with instability, the significance of the capsular attachment or its anomalous insertions to the glenoid has not been adequately recognized. Labral tears may develop as secondary lesions due to repeated dislocations and subluxations rather than representing the primary lesion responsible for instability. Operative visualization of capsular defects or detachments is often difficult. Prior knowledge of these lesions can effectively help the choice of an appropriate surgical procedure and reduce operating time. The results of computed tomographic (CT) arthrography of the shoulder joint in 45 patients are reported and the normal and pathologic variations of the joint capsule and particularly the capsular insertions are described. Configuration of the joint recesses and the glenoid labrum are also evaluated. These CT findings were correlated and verified by surgery or arthroscopy in 26 cases.

Ultrasonographic Findings of the Shoulder in Patients with Rheumatoid Arthritis and Comparison with Physical Examination

PubMed Central

Kim, Su Ho; Seo, Young-Il

2007-01-01

The objectives of this study were: 1) to identify the ultrasonographic (US) abnormalities and 2) to compare the findings of physical examination with US findings in rheumatoid arthritis (RA) patients with shoulder pain. We studied 30 RA patients. Physical examination was performed systemically as follows: 1) area of tenderness; 2) range of passive and active shoulder motion; 3) impingement tests; 4) maneuvers for determining the location of the tendon lesions. US investigations included the biceps, the supraspinatus, infraspinatus, and subscapularis tendons; the subacromial-subdeltoid bursa; and the glenohumeral and acromioclavicular joints. Thirty RA patients with 35 painful and 25 non-painful shoulders were examined. The range of motion affected the most by shoulder pain was abduction. The most frequent US finding of shoulder joint was effusion in the long head of the biceps tendon. Among the rotator cuff tendons, subscapularis was the most frequently involved. Tendon tear was also common among non-painful shoulders. Physical examination used for the diagnosis of shoulder pain had low sensitivity and specificity for detecting abnormalities in the rheumatoid shoulder joint. In conclusion, US abnormalities showed frequent tendon tears in our RA patients. Physical examination had low sensitivity and specificity for detecting rotator cuff tear in the rheumatoid shoulder joint. PMID:17728506

Shoulder Arthroplasty, from Indications to Complications: What the Radiologist Needs to Know.

PubMed

Lin, Dana J; Wong, Tony T; Kazam, Jonathan K

2016-01-01

The replaced shoulder is increasingly encountered by the radiologist, both on a dedicated and incidental basis, in this era of the growing population of aging patients wishing to preserve their mobility and function. Knowledge of the normal biomechanics of the glenohumeral joint-particularly the function of the rotator cuff and the unique relationship of the humeral head to the glenoid-is essential for understanding the need for shoulder replacement and its subsequent complications, because the intent of shoulder arthroplasty is to approximate the normal joint as closely as possible. The most common indications for shoulder arthroplasty are osteoarthritis, inflammatory arthritis, proximal humerus fractures, irreparable rotator cuff tears, rotator cuff arthropathy, and avascular necrosis of the humeral head. Knowledge of the key imaging features of these indications helps facilitate a correlative understanding between the initial diagnosis and the choice of which type of arthroplasty is used-total shoulder arthroplasty, reverse total shoulder arthroplasty, or partial joint replacement (humeral head resurfacing arthroplasty or hemiarthroplasty). The preoperative requirements and usual postoperative appearance of each arthroplasty type are summarized, as well as the complications of shoulder arthroplasty, including those unique to or closely associated with each type of arthroplasty and those that can be encountered with any type of shoulder arthroplasty. ©RSNA, 2016.

Influence of clamp-up force on the strength of bolted composite joints

NASA Astrophysics Data System (ADS)

Horn, Walter J.; Schmitt, Ron R.

1994-03-01

Composite materials offer the potential for a reduction in the number of individual parts and joints in a structure because large one-piece components can replace multipart assemblies. Nevertheless, there are many situations where composite parts must be joined and often mechanical fasteners provide the only practical method of joining those parts. The long-term strength of mechanically fastened joints of composite members can be directly affected by the clamp-up force of the fastener and thus perhaps by the relaxation of this force due to the viscoelastic character of the composite materials of the joint. Methods for predicting the effect of bolt clamp-up force relaxation on the strength of mechanically fastened joints of thermoplastic composite materials were investigated during the present study. A test program, using two thermoplastic composite materials, was conducted to determine the influence of clamp-up force on joint strength, to measure the relaxation of the joint clamp-up force with time, and to measure the change of joint strength as a function of time.

The collision forces and lower-extremity inter-joint coordination during running.

PubMed

Wang, Li-I; Gu, Chin-Yi; Wang, I-Lin; Siao, Sheng-Wun; Chen, Szu-Ting

2018-06-01

The purpose of this study was to compare the lower extremity inter-joint coordination of different collision forces runners during running braking phase. A dynamical system approach was used to analyse the inter-joint coordination parameters. Data were collected with six infra-red cameras and two force plates. According to the impact peak of the vertical ground reaction force, twenty habitually rearfoot-strike runners were categorised into three groups: high collision forces runners (HF group, n = 8), medium collision forces runners (MF group, n = 5), and low collision forces runners (LF group, n = 7). There were no significant differences among the three groups in the ankle and knee joint angle upon landing and in the running velocity (p > 0.05). The HF group produced significantly smaller deviation phase (DP) of the hip flexion/extension-knee flexion/extension during the braking phase compared with the MF and LF groups (p < 0.05). The DP of the hip flexion/extension-knee flexion/extension during the braking phase correlated negatively with the collision force (p < 0.05). The disparities regarding the flexibility of lower extremity inter-joint coordination were found in high collision forces runners. The efforts of the inter-joint coordination and the risk of running injuries need to be clarified further.

Interrater reliability of the cervicothoracic and shoulder physical examination in patients with a primary complaint of shoulder pain.

PubMed

Burns, Scott A; Cleland, Joshua A; Carpenter, Kristin; Mintken, Paul E

2016-03-01

Examine the interrater reliability of cervicothoracic and shoulder physical examination in patients with a primary complaint of shoulder pain. Single-group repeated-measures design for interrater reliability. Orthopaedic physical therapy clinics. Twenty-one patients with a primary complaint of shoulder pain underwent a standardized examination by a physical therapist (PT). A PT conducted the first examination and one of two additional PTs conducted the 2nd examination. The Cohen κ and weighted κ were used to calculate the interrater reliability of ordinal level data. Intraclass correlation coefficients model 2,1 (ICC2,1) and the 95% confidence intervals were calculated to determine the interrater reliability. The kappa coefficients ranged from -.24 to .83 for the mobility assessment of the glenohumeral, acromioclavicular and sternoclavicular joints. The kappa coefficients ranged from -.20 to .58 for joint mobility assessment of the cervical and thoracic spine. The kappa coefficients ranged from .23 to 1.0 for special tests of the shoulder and cervical spine. The present study reported the reliability of a comprehensive upper quarter physical examination for a group of patients with a primary report of shoulder pain. The reliability varied considerably for the cervical and shoulder examination and was significantly higher for the examination of muscle length and cervical range of motion. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of altered gait patterns on the hip joint contact forces.

PubMed

Carriero, Alessandra; Zavatsky, Amy; Stebbins, Julie; Theologis, Tim; Lenaerts, Gerlinde; Jonkers, Ilse; Shefelbine, Sandra J

2014-01-01

Children who exhibit gait deviations often present a range of bone deformities, particularly at the proximal femur. Altered gait may affect bone growth and lead to deformities by exerting abnormal stresses on the developing bones. The objective of this study was to calculate variations in the hip joint contact forces with different gait patterns. Muscle and hip joint contact forces of four children with different walking characteristics were calculated using an inverse dynamic analysis and a static optimisation algorithm. Kinematic and kinetic analyses were based on a generic musculoskeletal model scaled down to accommodate the dimensions of each child. Results showed that for all the children with altered gaits both the orientation and magnitude of the hip joint contact force deviated from normal. The child with the most severe gait deviations had hip joint contact forces 30% greater than normal, most likely due to the increase in muscle forces required to sustain his crouched stance. Determining how altered gait affects joint loading may help in planning treatment strategies to preserve correct loading on the bone from a young age.

Isokinetic strength differences between patients with primary reverse and total shoulder prostheses: muscle strength quantified with a dynamometer.

PubMed

Alta, Tjarco D W; Veeger, DirkJan H E J; de Toledo, Joelly M; Janssen, Thomas W J; Willems, W Jaap

2014-11-01

Range of motion after total shoulder arthroplasty is better than after reverse shoulder arthroplasty, however with similar clinical outcome. It is unclear if this difference can only be found in the different range of motion or also in the force generating capacity. (1) are isokinetically produced joint torques of reverse shoulder arthroplasty comparable to those of total shoulder arthroplasty? (2) Does this force-generating capacity correlate with functional outcome? Eighteen reverse shoulder arthroplasty patients (71years (SD 9years)) (21 shoulders, follow-up of 21months (SD 10months)) were recruited, 12 total shoulder arthroplasty patients (69years (SD 9years)) (14 shoulders, follow-up of 35months (SD 11months)). Pre- and post-operative Constant-Murley scores were obtained; two isokinetic protocols (ab-/adduction and ex-/internal rotations) at 60°/s were performed. Twelve of 18 reverse shoulder arthroplasty patients generated enough speed to perform the test (13 shoulders). Mean ab-/adduction torques are 16.3Nm (SD 5.6Nm) and 20.4Nm (SD 11.8Nm). All total shoulder arthroplasty patients generated enough speed (14 shoulders). Mean ab-/adduction torques are 32.1Nm (SD 13.3Nm) and 43.1Nm (SD 21.5Nm). Only 8 reverse shoulder arthroplasty patients (9 shoulders) could perform ex-/internal rotation tasks and all total shoulder arthroplasty patients. Mean ex-/internal rotation torques are 9.3Nm (SD 4.7Nm) and 9.2Nm (SD 2.1Nm) for reverse shoulder arthroplasty, and 17.9Nm (SD 7.7Nm) and 23.5Nm (SD 10.6Nm) for total shoulder arthroplasty. Significant correlations between sub-scores: activity, mobility and strength and external rotation torques for reverse shoulder arthroplasty. Moderate to strong correlation for sub-scores: strength in relation to abduction, adduction and internal rotation torques for total shoulder arthroplasty. Shoulders with a total shoulder arthroplasty are stronger. This can be explained by the absence of rotator cuff muscles and (probably

Assessment of anterior shoulder instability by CT arthrography.

PubMed

Yang, S O; Cho, K J; Kim, M J; Ro, I W

1987-09-01

Computed tomography (CT) immediately after double-contrast shoulder arthrography was taken in twenty-two young male patients with anterior shoulder instability including recurrent dislocation and subluxation. This recently developed technique called CT arthrography can provide significant information about patients with glenohumeral instability which is difficult to obtain by conventional arthrography. Information about glenoid labrum pathology is useful for proper management of the shoulder with instability. Lesions identified in this study include anterior labral defects (attenuation, tear, displacement), anterior capsular distension and/or detachment, Hill-Sachs lesion, anterior glenoid rim compression fracture, and fracture of scapula. This article describes the method used in CT arthrography of the glenohumeral joint, reviews the normal cross-sectional anatomy, and emphasizes the importance of the application of CT arthrography in the shoulder disorder with instability. CT arthrography of the glenohumeral joint is easy to perform, is accurate, and has lower radiation dose than arthrotomography.

Effect of increased pushoff during gait on hip joint forces

PubMed Central

Lewis, Cara L.; Garibay, Erin J.

2014-01-01

Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to “push more with your foot when you walk”. We collected motion data of markers placed on the subjects’ trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual 3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to “push more with your foot when you walk” reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces was 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. PMID:25468661

Effect of increased pushoff during gait on hip joint forces.

PubMed

Lewis, Cara L; Garibay, Erin J

2015-01-02

Anterior acetabular labral tears and anterior hip pain may result from high anteriorly directed forces from the femur on the acetabulum. While providing more pushoff is known to decrease sagittal plane hip moments, it is unknown if this gait modification also decreases hip joint forces. The purpose of this study was to determine if increasing pushoff decreases hip joint forces. Nine healthy subjects walked on an instrumented force treadmill at 1.25 m/s under two walking conditions. For the natural condition, subjects were instructed to walk as they normally would. For the increased pushoff condition, subjects were instructed to "push more with your foot when you walk". We collected motion data of markers placed on the subjects' trunk and lower extremities to capture trunk and leg kinematics and ground reaction force data to determine joint moments. Data were processed in Visual3D to produce the inverse kinematics and model scaling files. In OpenSim, the generic gait model (Gait2392) was scaled to the subject, and hip joint forces were calculated for the femur on the acetabulum after computing the muscle activations necessary to reproduce the experimental data. The instruction to "push more with your foot when you walk" reduced the maximum hip flexion and extension moment compared to the natural condition. The average reduction in the hip joint forces were 12.5%, 3.2% and 9.6% in the anterior, superior and medial directions respectively and 2.3% for the net resultant force. Increasing pushoff may be an effective gait modification for people with anterior hip pain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Soft tissue balance changes depending on joint distraction force in total knee arthroplasty.

PubMed

Nagai, Kanto; Muratsu, Hirotsugu; Matsumoto, Tomoyuki; Miya, Hidetoshi; Kuroda, Ryosuke; Kurosaka, Masahiro

2014-03-01

The influence of joint distraction force on intraoperative soft tissue balance was evaluated using Offset Repo-Tensor® for 78 knees that underwent primary posterior-stabilized total knee arthroplasty. The joint center gap and varus ligament balance were measured between osteotomized surfaces using 20, 40 and 60 lbs of joint distraction force. These values were significantly increased at extension and flexion as the distraction force increased. Furthermore, lateral compartment stiffness was significantly lower than medial compartment stiffness. Thus, larger joint distraction forces led to larger varus ligament balance and joint center gap, because of the difference in soft tissue stiffness between lateral and medial compartments. These findings indicate the importance of the strength of joint distraction force in the assessment of soft tissue balance, especially when using gap-balancing technique. © 2014.

Estimation of Human Arm Joints Using Two Wireless Sensors in Robotic Rehabilitation Tasks.

PubMed

Bertomeu-Motos, Arturo; Lledó, Luis D; Díez, Jorge A; Catalan, Jose M; Ezquerro, Santiago; Badesa, Francisco J; Garcia-Aracil, Nicolas

2015-12-04

This paper presents a novel kinematic reconstruction of the human arm chain with five degrees of freedom and the estimation of the shoulder location during rehabilitation therapy assisted by end-effector robotic devices. This algorithm is based on the pseudoinverse of the Jacobian through the acceleration of the upper arm, measured using an accelerometer, and the orientation of the shoulder, estimated with a magnetic angular rate and gravity (MARG) device. The results show a high accuracy in terms of arm joints and shoulder movement with respect to the real arm measured through an optoelectronic system. Furthermore, the range of motion (ROM) of 50 healthy subjects is studied from two different trials, one trying to avoid shoulder movements and the second one forcing them. Moreover, the shoulder movement in the second trial is also estimated accurately. Besides the fact that the posture of the patient can be corrected during the exercise, the therapist could use the presented algorithm as an objective assessment tool. In conclusion, the joints' estimation enables a better adjustment of the therapy, taking into account the needs of the patient, and consequently, the arm motion improves faster.

Intra-Articular Knee Contact Force Estimation During Walking Using Force-Reaction Elements and Subject-Specific Joint Model.

PubMed

Jung, Yihwan; Phan, Cong-Bo; Koo, Seungbum

2016-02-01

Joint contact forces measured with instrumented knee implants have not only revealed general patterns of joint loading but also showed individual variations that could be due to differences in anatomy and joint kinematics. Musculoskeletal human models for dynamic simulation have been utilized to understand body kinetics including joint moments, muscle tension, and knee contact forces. The objectives of this study were to develop a knee contact model which can predict knee contact forces using an inverse dynamics-based optimization solver and to investigate the effect of joint constraints on knee contact force prediction. A knee contact model was developed to include 32 reaction force elements on the surface of a tibial insert of a total knee replacement (TKR), which was embedded in a full-body musculoskeletal model. Various external measurements including motion data and external force data during walking trials of a subject with an instrumented knee implant were provided from the Sixth Grand Challenge Competition to Predict in vivo Knee Loads. Knee contact forces in the medial and lateral portions of the instrumented knee implant were also provided for the same walking trials. A knee contact model with a hinge joint and normal alignment could predict knee contact forces with root mean square errors (RMSEs) of 165 N and 288 N for the medial and lateral portions of the knee, respectively, and coefficients of determination (R2) of 0.70 and -0.63. When the degrees-of-freedom (DOF) of the knee and locations of leg markers were adjusted to account for the valgus lower-limb alignment of the subject, RMSE values improved to 144 N and 179 N, and R2 values improved to 0.77 and 0.37, respectively. The proposed knee contact model with subject-specific joint model could predict in vivo knee contact forces with reasonable accuracy. This model may contribute to the development and improvement of knee arthroplasty.

Ultrasound-guided interventional procedures around the shoulder.

PubMed

Messina, Carmelo; Banfi, Giuseppe; Orlandi, Davide; Lacelli, Francesca; Serafini, Giovanni; Mauri, Giovanni; Secchi, Francesco; Silvestri, Enzo; Sconfienza, Luca Maria

2016-01-01

Ultrasound is an established modality for shoulder evaluation, being accurate, low cost and radiation free. Different pathological conditions can be diagnosed using ultrasound and can be treated using ultrasound guidance, such as degenerative, traumatic or inflammatory diseases. Subacromial-subdeltoid bursitis is the most common finding on ultrasound evaluation for painful shoulder. Therapeutic injections of corticosteroids are helpful to reduce inflammation and pain. Calcific tendinopathy of rotator cuff affects up to 20% of painful shoulders. Ultrasound-guided treatment may be performed with both single- and double-needle approach. Calcific enthesopathy, a peculiar form of degenerative tendinopathy, is a common and mostly asymptomatic ultrasound finding; dry needling has been proposed in symptomatic patients. An alternative is represented by autologous platelet-rich plasma injections. Intra-articular injections of the shoulder can be performed in the treatment of a variety of inflammatory and degenerative diseases with corticosteroids or hyaluronic acid respectively. Steroid injections around the long head of the biceps brachii tendon are indicated in patients with biceps tendinopathy, reducing pain and humeral tenderness. The most common indication for acromion-clavicular joint injection is degenerative osteoarthritis, with ultrasound representing a useful tool in localizing the joint space and properly injecting various types of drugs (steroids, lidocaine or hyaluronic acid). Suprascapular nerve block is an approved treatment for chronic shoulder pain non-responsive to conventional treatments as well as candidate patients for shoulder arthroscopy. This review provides an overview of these different ultrasonography-guided procedures that can be performed around the shoulder.

Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces.

PubMed

Gerus, Pauline; Sartori, Massimo; Besier, Thor F; Fregly, Benjamin J; Delp, Scott L; Banks, Scott A; Pandy, Marcus G; D'Lima, Darryl D; Lloyd, David G

2013-11-15

Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. © 2013 Published by Elsevier Ltd.

Subject-specific knee joint geometry improves predictions of medial tibiofemoral contact forces

PubMed Central

Gerus, Pauline; Sartori, Massimo; Besier, Thor F.; Fregly, Benjamin J.; Delp, Scott L.; Banks, Scott A.; Pandy, Marcus G.; D’Lima, Darryl D.; Lloyd, David G.

2013-01-01

Estimating tibiofemoral joint contact forces is important for understanding the initiation and progression of knee osteoarthritis. However, tibiofemoral contact force predictions are influenced by many factors including muscle forces and anatomical representations of the knee joint. This study aimed to investigate the influence of subject-specific geometry and knee joint kinematics on the prediction of tibiofemoral contact forces using a calibrated EMG-driven neuromusculoskeletal model of the knee. One participant fitted with an instrumented total knee replacement walked at a self-selected speed while medial and lateral tibiofemoral contact forces, ground reaction forces, whole-body kinematics, and lower-limb muscle activity were simultaneously measured. The combination of generic and subject-specific knee joint geometry and kinematics resulted in four different OpenSim models used to estimate muscle-tendon lengths and moment arms. The subject-specific geometric model was created from CT scans and the subject-specific knee joint kinematics representing the translation of the tibia relative to the femur was obtained from fluoroscopy. The EMG-driven model was calibrated using one walking trial, but with three different cost functions that tracked the knee flexion/extension moments with and without constraint over the estimated joint contact forces. The calibrated models then predicted the medial and lateral tibiofemoral contact forces for five other different walking trials. The use of subject-specific models with minimization of the peak tibiofemoral contact forces improved the accuracy of medial contact forces by 47% and lateral contact forces by 7%, respectively compared with the use of generic musculoskeletal model. PMID:24074941

Rescuing Joint Personnel Recovery: Using Air Force Capability to Address Joint Shortfalls

DTIC Science & Technology

2011-06-01

of an IP, the IP is not successfully reintegrated or the lessons learned are not incorporated into other operations. Adversaries will benefit from...Washington, D.C.: Office of Air Force History , United States Air Force, 1980, 117. 47 Durant , Michael J. In the Company of Heroes, Penguin Group... Lessons Learned, 22 September 2005, 3. 2 US Joint Task Force Katrina. The Federal Response to Hurricane Katrina Lessons Learned, February 2006, 54

Effects of whole-body cryotherapy in the management of adhesive capsulitis of the shoulder.

PubMed

Ma, Sang-Yeol; Je, Hyun Dong; Jeong, Ji Hoon; Kim, Hae-Young; Kim, Hyeong-Dong

2013-01-01

To compare 2 different treatment approaches, physical therapy modalities, and joint mobilization versus whole-body cryotherapy (WBC) combined with physical therapy modalities and joint mobilization, for symptoms of adhesive capsulitis (AC) of the shoulder. A randomized trial. Hospital. Patients with AC of the shoulder (N=30). Patients were randomly assigned to 2 groups. The WBC group received physical therapy modalities, passive joint mobilization of the shoulder, and WBC, whereas the non-WBC group received only physical therapy modalities and passive joint mobilization of the shoulder. Visual analog scale (VAS), active range of motion (ROM) of flexion, abduction, internal and external rotation of the shoulder, and the American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) were measured before and after the intervention. A statistically significant difference between groups was found for the VAS, active ROM of flexion, abduction, internal rotation, and external rotation, and the ASES with greater improvements in the WBC group (Ps<.01). Overall, both groups showed a significant improvement in all outcome measures and ROM measures from pre to post at a level of P<.01. There is significant improvement with the addition of WBC to treatment interventions in this sample of patients. Copyright © 2013 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

The influence of patellofemoral joint contact geometry on the modeling of three dimensional patellofemoral joint forces.

PubMed

Powers, Christopher M; Chen, Yu-Jen; Scher, Irving; Lee, Thay Q

2006-01-01

The purpose of this study was to determine the influence of patellofemoral joint contact geometry on the modeling of three-dimensional patellofemoral joint forces. To achieve this goal, patellofemoral joint reaction forces (PFJRFs) that were measured from an in-vitro cadaveric set-up were compared to PFJRFs estimated from a computer model that did not consider patellofemoral joint contact geometry. Ten cadaver knees were used in this study. Each was mounted on a custom jig that was fixed to an Instron frame. Quadriceps muscle loads were accomplished using a pulley system and weights. The force in the patellar ligament was obtained using a buckle transducer. To quantify the magnitude and direction of the PFJRF, a six-axis load cell was incorporated into the femoral fixation system so that a rigid body assumption could be made. PFJRF data were obtained at 0 degrees , 20 degrees , 40 degrees and 60 degrees of knee flexion. Following in vitro testing, SIMM modeling software was used to develop computational models based on the three-dimensional coordinates (Microscribe digitizer) of individual muscle and patellar ligament force vectors obtained from the cadaver knees. The overall magnitude of the PFJRF estimated from the computer generated models closely matched the direct measurements from the in vitro set-up (Pearson's correlation coefficient, R(2)=0.91, p<0.001). Although the computational model accurately estimated the posteriorly directed forces acting on the joint, some discrepancies were noted in the forces acting in the superior and lateral directions. These differences however, were relatively small when expressed as a total of the overall PFJRF magnitude.

Reflexes in the shoulder muscles elicited from the human coracoacromial ligament.

PubMed

Diederichsen, Louise Pyndt; Nørregaard, Jesper; Krogsgaard, Michael; Fischer-Rasmussen, Torsten; Dyhre-Poulsen, Poul

2004-09-01

Morphological studies have demonstrated mechanoreceptors in the capsuloligamentous structures of the shoulder joint, however knowledge of the role these joint receptors play in the control of shoulder stability is limited. We therefore investigated the effect of electrically induced afferent activity from mechanoreceptors in the coracoacromial ligament (CAL) on the activity of voluntary activated shoulder muscles in healthy humans. In study I, wire electrodes, for electrical stimulation, were inserted into the CAL in eight normal shoulders. In study II, a needle electrode was inserted into the CAL in seven normal shoulders. Electric activity was recorded from eight shoulder muscles by surface and intramuscular electrodes. During isometric contractions, electrical stimulation was applied to the CAL at two different stimulus intensities, a weak stimulus (stim-1) and a stronger stimulus (stim-2). In both experiments, electrical stimulation of the CAL elicited a general inhibition in the voluntary activated shoulder muscles. In study I the average latencies (mean+/-SE) of the muscular inhibition were 66+/-4 ms (stim-1) and 62+/-4 ms (stim-2) during isometric flexion and 73+/-3 ms (stim-1) and 73+/-5 ms (stim-2) during isometric extension. In study II the average latency (mean+/-SE) of the response was 66+/-4 ms (stim-1) during isometric flexion. Our results demonstrated a response, probably of reflex origin, from mechanoreceptors in the CAL to the shoulder muscles. The existence of this synaptic connection between mechanoreceptors in CAL and the shoulder muscles suggest a role of these receptors in muscle coordination and in the functional joint stability.

Bidirectional transfer between joint and individual actions in a task of discrete force production.

PubMed

Masumoto, Junya; Inui, Nobuyuki

2017-07-01

The present study examined bidirectional learning transfer between joint and individual actions involving discrete isometric force production with the right index finger. To examine the effects of practice of joint action on performance of the individual action, participants performed a pre-test (individual condition), practice blocks (joint condition), and a post-test (individual condition) (IJI task). To examine the effects of practice of the individual action on performance during the joint action, the participants performed a pre-test (joint condition), practice blocks (individual condition), and a post-test (joint condition) (JIJ task). Whereas one participant made pressing movements with a target peak force of 10% maximum voluntary contraction (MVC) in the individual condition, two participants produced the target force of the sum of 10% MVC produced by each of them in the joint condition. In both the IJI and JIJ tasks, absolute errors and standard deviations of peak force were smaller post-test than pre-test, indicating bidirectional transfer between individual and joint conditions for force accuracy and variability. Although the negative correlation between forces produced by two participants (complementary force production) became stronger with practice blocks in the IJI task, there was no difference between the pre- and post-tests for the negative correlation in the JIJ task. In the JIJ task, the decrease in force accuracy and variability during the individual action did not facilitate complementary force production during the joint action. This indicates that practice performed by two people is essential for complementary force production in joint action.

In Vivo Measurement of Glenohumeral Joint Contact Patterns

NASA Astrophysics Data System (ADS)

Bey, Michael J.; Kline, Stephanie K.; Zauel, Roger; Kolowich, Patricia A.; Lock, Terrence R.

2009-12-01

The objectives of this study were to describe a technique for measuring in-vivo glenohumeral joint contact patterns during dynamic activities and to demonstrate application of this technique. The experimental technique calculated joint contact patterns by combining CT-based 3D bone models with joint motion data that were accurately measured from biplane x-ray images. Joint contact patterns were calculated for the repaired and contralateral shoulders of 20 patients who had undergone rotator cuff repair. Significant differences in joint contact patterns were detected due to abduction angle and shoulder condition (i.e., repaired versus contralateral). Abduction angle had a significant effect on the superior/inferior contact center position, with the average joint contact center of the repaired shoulder 12.1% higher on the glenoid than the contralateral shoulder. This technique provides clinically relevant information by calculating in-vivo joint contact patterns during dynamic conditions and overcomes many limitations associated with conventional techniques for quantifying joint mechanics.

Stochastic estimation of human shoulder impedance with robots: an experimental design.

PubMed

Park, Kyungbin; Chang, Pyung Hun

2011-01-01

Previous studies assumed the shoulder as a hinge joint during human arm impedance measurement. This is obviously a vast simplification since the shoulder is a complex of several joints with multiple degrees of freedom. In the present work, a practical methodology for more general and realistic estimation of human shoulder impedance is proposed and validated with a spring array. It includes a gravity compensation scheme, which is developed and used for the experiments with a spatial three degrees of freedom PUMA-type robot. The experimental results were accurate and reliable, and thus it has shown a strong potential of the proposed methodology in the estimation of human shoulder impedance. © 2011 IEEE

Thrust Force Analysis of Tripod Constant Velocity Joint Using Multibody Model

NASA Astrophysics Data System (ADS)

Sugiura, Hideki; Matsunaga, Tsugiharu; Mizutani, Yoshiteru; Ando, Yosei; Kashiwagi, Isashi

A tripod constant velocity joint is used in the driveshaft of front wheel drive vehicles. Thrust force generated by this joint causes lateral vibration in these vehicles. To analyze the thrust force, a detailed model is constructed based on a multibody dynamics approach. This model includes all principal parts of the joint defined as rigid bodies and all force elements of contact and friction acting among these parts. This model utilizes a new contact modeling method of needle roller bearings for more precise and faster computation. By comparing computational and experimental results, the appropriateness of this model is verified and the principal factors inducing the second and third rotating order components of the thrust force are clarified. This paper also describes the influence of skewed needle rollers on the thrust force and evaluates the contribution of friction forces at each contact region to the thrust force.

Controversies In The Surgical Management Of Shoulder Instability: Associated Soft Tissue Procedures.

PubMed

Marco, Santos Moros; Lafuente, José Luis Ávila; Ibán, Miguel Angel Ruiz; Heredia, Jorge Diaz

2017-01-01

The glenohumeral joint is a ball-and-socket joint that is inherently unstable and thus, susceptible to dislocation. The traditional and most common anatomic finding is the Bankart lesion (anterior-inferior capsule labral complex avulsion), but there is a wide variety of anatomic alterations that can cause shoulder instability or may be present as a concomitant injury or in combination, including bone loss (glenoid or humeral head), complex capsule-labral tears, rotator cuff tears, Kim´s lesions (injuries to the posterior-inferior labrum) and rotator interval pathology. A review of articles related to shoulder anatomy and soft tissue procedures that are performed during shoulder instability arthroscopic management was conducted by querying the Pubmed database and conclusions and controversies regarding this injury were exposed. Due to the complex anatomy of the shoulder and the large range of movement of this joint, a wide variety of anatomic injuries and conditions can lead to shoulder instability, specially present in young population. Recognizing and treating all of them including Bankart repair, capsule-labral plicatures, SLAP repair, circumferential approach to pan-labral lesions, rotator interval closure, rotator cuff injuries and HAGL lesion repair is crucial to achieve the goal of a stable, full range of movement and not painful joint. Physicians must be familiarized with all the lesions involved in shoulder instability, and should be able to recognize and subsequently treat them to achieve the goal of a stable non-painful shoulder. Unrecognized or not treated lesions may result in recurrence of instability episodes and pain while overuse of some of the techniques previously described can lead to stiffness, thus the importance of an accurate diagnosis and treatment when facing a shoulder instability.

Improving anterior deltoid activity in a musculoskeletal shoulder model - an analysis of the torque-feasible space at the sternoclavicular joint.

PubMed

Ingram, David; Engelhardt, Christoph; Farron, Alain; Terrier, Alexandre; Müllhaupt, Philippe

2016-01-01

Modelling the shoulder's musculature is challenging given its mechanical and geometric complexity. The use of the ideal fibre model to represent a muscle's line of action cannot always faithfully represent the mechanical effect of each muscle, leading to considerable differences between model-estimated and in vivo measured muscle activity. While the musculo-tendon force coordination problem has been extensively analysed in terms of the cost function, only few works have investigated the existence and sensitivity of solutions to fibre topology. The goal of this paper is to present an analysis of the solution set using the concepts of torque-feasible space (TFS) and wrench-feasible space (WFS) from cable-driven robotics. A shoulder model is presented and a simple musculo-tendon force coordination problem is defined. The ideal fibre model for representing muscles is reviewed and the TFS and WFS are defined, leading to the necessary and sufficient conditions for the existence of a solution. The shoulder model's TFS is analysed to explain the lack of anterior deltoid (DLTa) activity. Based on the analysis, a modification of the model's muscle fibre geometry is proposed. The performance with and without the modification is assessed by solving the musculo-tendon force coordination problem for quasi-static abduction in the scapular plane. After the proposed modification, the DLTa reaches 20% of activation.

Three-dimensional knee joint contact forces during walking in unilateral transtibial amputees.

PubMed

Silverman, Anne K; Neptune, Richard R

2014-08-22

Individuals with unilateral transtibial amputations have greater prevalence of osteoarthritis in the intact knee joint relative to the residual leg and non-amputees, but the cause of this greater prevalence is unclear. The purpose of this study was to compare knee joint contact forces and the muscles contributing to these forces between amputees and non-amputees during walking using forward dynamics simulations. We predicted that the intact knee contact forces would be higher than those of the residual leg and non-amputees. In the axial and mediolateral directions, the intact and non-amputee legs had greater peak tibio-femoral contact forces and impulses relative to the residual leg. The peak axial contact force was greater in the intact leg relative to the non-amputee leg, but the stance phase impulse was greater in the non-amputee leg. The vasti and hamstrings muscles in early stance and gastrocnemius in late stance were the largest contributors to the joint contact forces in the non-amputee and intact legs. Through dynamic coupling, the soleus and gluteus medius also had large contributions, even though they do not span the knee joint. In the residual leg, the prosthesis had large contributions to the joint forces, similar to the soleus in the intact and non-amputee legs. These results identify the muscles that contribute to knee joint contact forces during transtibial amputee walking and suggest that the peak knee contact forces may be more important than the knee contact impulses in explaining the high prevalence of intact leg osteoarthritis. Copyright © 2014 Elsevier Ltd. All rights reserved.

Diaphragm-Sparing Nerve Blocks for Shoulder Surgery.

PubMed

Tran, De Q H; Elgueta, Maria Francisca; Aliste, Julian; Finlayson, Roderick J

Shoulder surgery can result in significant postoperative pain. Interscalene brachial plexus blocks (ISBs) constitute the current criterion standard for analgesia but may be contraindicated in patients with pulmonary pathology due to the inherent risk of phrenic nerve block and symptomatic hemidiaphragmatic paralysis. Although ultrasound-guided ISB with small volumes (5 mL), dilute local anesthetic (LA) concentrations, and LA injection 4 mm lateral to the brachial plexus have been shown to reduce the risk of phrenic nerve block, no single intervention can decrease its incidence below 20%. Ultrasound-guided supraclavicular blocks with LA injection posterolateral to the brachial plexus may anesthetize the shoulder without incidental diaphragmatic dysfunction, but further confirmatory trials are required. Ultrasound-guided C7 root blocks also seem to offer an attractive, diaphragm-sparing alternative to ISB. However, additional large-scale studies are needed to confirm their efficacy and to quantify the risk of periforaminal vascular breach. Combined axillary-suprascapular nerve blocks may provide adequate postoperative analgesia for minor shoulder surgery but do not compare favorably to ISB for major surgical procedures. One intriguing solution lies in the combined use of infraclavicular brachial plexus blocks and suprascapular nerve blocks. Theoretically, the infraclavicular approach targets the posterior and lateral cords, thus anesthetizing the axillary nerve (which supplies the anterior and posterior shoulder joint), as well as the subscapular and lateral pectoral nerves (both of which supply the anterior shoulder joint), whereas the suprascapular nerve block anesthetizes the posterior shoulder. Future randomized trials are required to validate the efficacy of combined infraclavicular-suprascapular blocks for shoulder surgery.

[Isokinetic testing of the shoulder of handball players].

PubMed

Michael, J W-P; König, D P; Bertram, C; Hessling, U; Eysel, P

2005-09-01

Aim of the study was to evaluate an isokinetic profile testing handball players to describe muscular imbalance. 30 athletes (15 male and 15 female) were measured at the Cybex 6000 test-unit for concentric internal and external rotation. Both shoulders, throwing arm (dominant shoulder) and the opposite shoulder were tested by speeds at 60 degrees/s and 180 degrees/s. There were sex specific differences which are also found in other sports. But these contrary data are not useful to define effective training concepts for handball-players with shoulder problems. From our point of view isokinetic testing of the shoulder joint in handball players can not reach any sufficient result. From our point of view there is no reason for using isokinetic testing to evaluate shoulder problems.

Shoulder instability: evaluation with MR imaging.

PubMed

Seeger, L L; Gold, R H; Bassett, L W

1988-09-01

Instability of the glenohumeral joint is a common cause of chronic shoulder pain and disability. One or more episodes of subluxation or dislocation may result in a tear, detachment, or attenuation of the glenoid labrum, stripping of the joint capsule from the scapula, or trauma to the tendons or muscles of the rotator cuff. A series of 27 shoulders examined with magnetic resonance (MR) imaging showed changes of glenohumeral instability, which were confirmed with open or arthroscopic surgery. MR imaging was capable of displaying common types of pathologic conditions resulting from instability, including labral trauma, capsular detachment, and retraction of the subscapularis muscle. MR imaging is a valuable diagnostic tool for the evaluation of glenohumeral instability.

In Vivo Shoulder Function After Surgical Repair of a Torn Rotator Cuff

PubMed Central

Bey, Michael J.; Peltz, Cathryn D.; Ciarelli, Kristin; Kline, Stephanie K.; Divine, George W.; van Holsbeeck, Marnix; Muh, Stephanie; Kolowich, Patricia A.; Lock, Terrence R.; Moutzouros, Vasilios

2015-01-01

Background Surgical repair of a torn rotator cuff is based on the belief that repairing the tear is necessary to restore normal glenohumeral joint (GHJ) mechanics and achieve a satisfactory clinical outcome. Hypothesis Dynamic joint function is not completely restored by rotator cuff repair, thus compromising shoulder function and potentially leading to long-term disability. Study Design Controlled laboratory study and Case series; Level of evidence, 4. Methods Twenty-one rotator cuff patients and 35 control participants enrolled in the study. Biplane radiographic images were acquired bilaterally from each patient during coronal-plane abduction. Rotator cuff patients were tested at 3, 12, and 24 months after repair of a supraspinatus tendon tear. Control participants were tested once. Glenohumeral joint kinematics and joint contact patterns were accurately determined from the biplane radiographic images. Isometric shoulder strength and patient-reported outcomes were measured at each time point. Ultrasound imaging assessed rotator cuff integrity at 24 months after surgery. Results Twenty of 21 rotator cuff repairs appeared intact at 24 months after surgery. The humerus of the patients’ repaired shoulder was positioned more superiorly on the glenoid than both the patients’ contralateral shoulder and the dominant shoulder of control participants. Patient-reported outcomes improved significantly over time. Shoulder strength also increased over time, although strength deficits persisted at 24 months for most patients. Changes over time in GHJ mechanics were not detected for either the rotator cuff patients’ repaired or contralateral shoulders. Clinical outcome was associated with shoulder strength but not GHJ mechanics. Conclusion Surgical repair of an isolated supraspinatus tear may be sufficient to keep the torn rotator cuff intact and achieve satisfactory patient-reported outcomes, but GHJ mechanics and shoulder strength are not fully restored with current

Effects of anterior offsetting of humeral head component in posteriorly unstable total shoulder arthroplasty: Finite element modeling of cadaver specimens.

PubMed

Lewis, Gregory S; Conaway, William K; Wee, Hwabok; Kim, H Mike

2017-02-28

A novel technique of "anterior offsetting" of the humeral head component to address posterior instability in total shoulder arthroplasty has been proposed, and its biomechanical benefits have been previously demonstrated experimentally. The present study sought to characterize the changes in joint mechanics associated with anterior offsetting with various amounts of glenoid retroversion using cadaver specimen-specific 3-dimensional finite element models. Specimen-specific computational finite element models were developed through importing digitized locations of six musculotendinous units of the rotator cuff and deltoid muscles based off three cadaveric shoulder specimens implanted with total shoulder arthroplasty in either anatomic or anterior humeral head offset. Additional glenoid retroversion angles (0°, 10°, 20°, and 30°) other than each specimen׳s actual retroversion were modeled. Contact area, contact force, peak pressure, center of pressure, and humeral head displacement were calculated at each offset and retroversion for statistical analysis. Anterior offsetting was associated with significant anterior shift of center of pressure and humeral head displacement upon muscle loading (p<0.05). Although statistically insignificant, anterior offsetting was associated with increased contact area and decreased peak pressure (p > 0.05). All study variables showed significant differences when compared between the 4 different glenoid retroversion angles (p < 0.05) except for total force (p < 0.05). The study finding suggests that the anterior offsetting technique may contribute to joint stability in posteriorly unstable shoulder arthroplasty and may reduce eccentric loading on glenoid components although the long term clinical results are yet to be investigated in future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Magnetic Resonance Imaging and Arthroscopic Correlation in Shoulder Instability.

PubMed

Knapik, Derrick M; Voos, James E

2017-12-01

The shoulder is the most inherently unstable joint in the body, prone to high rates of anterior dislocations with subsequent injuries to soft tissue and bony stabilizing structures, resulting in recurrent shoulder instability. Advanced imaging utilizing magnetic resonance (MR) imaging and MR arthrography allows for thorough evaluation of lesions present in the unstable shoulder and is critical for preoperative planning. Arthroscopic shoulder stabilization in the appropriately selected patient can help restore stability and function. This review highlights correlations between MR imaging and arthroscopy of the most commonly reported soft tissue and bony injuries present in patients with shoulder instability.

Two-stage reimplantation for treating prosthetic shoulder infections.

PubMed

Sabesan, Vani J; Ho, Jason C; Kovacevic, David; Iannotti, Joseph P

2011-09-01

Two-stage reimplantation for prosthetic joint infection reportedly has the lowest risk for recurrent infection. Most studies to date have evaluated revision surgery for infection using an anatomic prosthetic. As compared with anatomic prostheses, reverse total shoulder arthroplasty is reported to have a higher rate of infection. We determined reinfection rates, functional improvement, types and rates of complications, and influence of rotator cuff tissue on function for two-stage reimplantation for prosthetic joint infection treated with reverse shoulder arthroplasty. We retrospectively reviewed 27 patients treated with a two-stage reimplantation for prosthetic shoulder infection using a uniform protocol for management of infection; of these, 17 had reverse shoulder arthroplasty at second-stage surgery. Types of organisms cultured, recurrence rates, complications, function, and radiographic followup were reviewed for all patients. One of the 17 patients had recurrence of infection. The mean (± SD) Penn shoulder scores for patients treated with reverse shoulder arthroplasty improved from 24.9 ± 22.3 to 66.4 ± 20.8. The average motion at last followup was 123° ± 33° of forward flexion and 26° ± 8° of external rotation in patients treated with a reverse shoulder arthroplasty. The major complication rate was 35% in reverse shoulder arthroplasty, with five dislocations and one reinfection. There was no difference in final Penn score between patients with and without external rotation weakness. Shoulder function and pain improved in patients treated with a second-stage reimplantation of a reverse prosthesis and the reinfection rate was low. Level IV, case series. See Guidelines for Authors for a complete description of levels of evidence.

Shoulder arthroplasty in osteoarthritis: current concepts in biomechanics and surgical technique

PubMed Central

Merolla, G; Nastrucci, G; Porcellini, G

Shoulder arthroplasty is a technically demanding procedure to restore shoulder function in patients with severe osteoarthritis of the glenohumeral joint. The modern prosthetic system exploit the benefits of modularity and the availibility of additional sizes of the prosthetic components. In this paper we describe the biomechanics of shoulder arthroplasty and the technique for shoulder replacement including total shoulder arthroplasty (TSA) with all-polyethylene and metal-backed glenoid component, humeral head resurfacing and stemless humeral replacement. PMID:24251240

Evaluation of knee joint forces during kneeling work with different kneepads.

PubMed

Xu, Hang; Jampala, Sree; Bloswick, Donald; Zhao, Jie; Merryweather, Andrew

2017-01-01

The main purpose of this study is to determine knee joint forces resulting from kneeling work with and without kneepads to quantify how different kneepads redistribute force. Eleven healthy males simulated a tile setting task to different locations during six kneepad states (five different kneepad types and without kneepad). Peak and average forces on the anatomical landmarks of both knees were obtained by custom force sensors. The results revealed that kneepad design can significantly modify the forces on the knee joint through redistribution. The Professional Gel design was preferred among the five tested kneepads which was confirmed with both force measurements and participants' responses. The extreme reaching locations induced significantly higher joint forces on left knee or right knee depending on task. The conclusion of this study is that a properly selected kneepad for specific tasks and a more neutral working posture can modify the force distribution on the knees and likely decrease the risk of knee disorders from kneeling work. Copyright © 2016 Elsevier Ltd. All rights reserved.

Controversies In The Surgical Management Of Shoulder Instability: Associated Soft Tissue Procedures

PubMed Central

Moros Marco, Santos; Ávila Lafuente, José Luis; Ruiz Ibán, Miguel Angel; Diaz Heredia, Jorge

2017-01-01

Background: The glenohumeral joint is a ball-and-socket joint that is inherently unstable and thus, susceptible to dislocation. The traditional and most common anatomic finding is the Bankart lesion (anterior-inferior capsule labral complex avulsion), but there is a wide variety of anatomic alterations that can cause shoulder instability or may be present as a concomitant injury or in combination, including bone loss (glenoid or humeral head), complex capsule-labral tears, rotator cuff tears, Kim´s lesions (injuries to the posterior-inferior labrum) and rotator interval pathology. Methods: A review of articles related to shoulder anatomy and soft tissue procedures that are performed during shoulder instability arthroscopic management was conducted by querying the Pubmed database and conclusions and controversies regarding this injury were exposed. Results: Due to the complex anatomy of the shoulder and the large range of movement of this joint, a wide variety of anatomic injuries and conditions can lead to shoulder instability, specially present in young population. Recognizing and treating all of them including Bankart repair, capsule-labral plicatures, SLAP repair, circumferential approach to pan-labral lesions, rotator interval closure, rotator cuff injuries and HAGL lesion repair is crucial to achieve the goal of a stable, full range of movement and not painful joint. Conclusion: Physicians must be familiarized with all the lesions involved in shoulder instability, and should be able to recognize and subsequently treat them to achieve the goal of a stable non-painful shoulder. Unrecognized or not treated lesions may result in recurrence of instability episodes and pain while overuse of some of the techniques previously described can lead to stiffness, thus the importance of an accurate diagnosis and treatment when facing a shoulder instability. PMID:28979603

Anatomy and Selected Biomechanical Aspects of the Shoulder.

ERIC Educational Resources Information Center

Keene, James S.

This paper focuses on the anatomy and functions of the shoulder that are relevant to the evaluation and treatment of athletic injuries. A discussion is presented on the four basic components of the shoulder mechanism: (1) super structure--bony components; (2) moving parts--joints involved; (3) motor power--musculature; and (4) communications…

A pragmatic regional interdependence approach to primary frozen shoulder: a retrospective case series.

PubMed

Wong, Christopher Kevin; Strang, Bryanna L; Schram, Galen A; Mercer, Elizabeth A; Kesting, Rebecca S; Deo, Kabi S

2018-05-01

Although the shoulder is known to move together with the scapula and other upper quarter joints, the current frozen shoulder clinical practice guidelines describe only physical therapy study treatments directed to the shoulder. None received a strong recommendation, highlighting the need for alternate interventions. This retrospective case series describes a pragmatic regional interdependence approach to frozen shoulder with impairment and functional outcomes, noting whether final ROM approached normal. Five consecutive patients referred with frozen shoulder diagnoses attended 11-21 sessions over 5-10 weeks with one physical therapist. Treatment addressed inter-related regions (shoulder, shoulder girdle, scapulothoracic/humerothoracic, and spine) following a pragmatic approach using impairment-based interventions (joint/soft tissue mobilization, muscle stretching/strengthening) as well as patient education, modalities and warm up that addressed individual presentations. All patients improved on all outcomes. Mean shoulder ROM at discharge, the impairment outcome, demonstrated large effect size increases: flexion (117 ± 10-179 ± 12, d  = 5.9), abduction (74 ± 8-175 ± 9, d  = 9.3), external rotation (23 ± 7-89 ± 2, d  = 12.0). The Disability of Arm Shoulder Hand functional outcome score upon follow up demonstrated a large effect size improvement ( d  = 1.5) from 40.0 ± 19.4-6.2 ± 3.7. Final ROM approached normal. This case series utilized a regional interdependence approach to frozen shoulder that included manual therapy interventions directed to consistent upper quarter body segments. Shoulder ROM was returned to near normal with functional improvements evident months after discharge. A pragmatic regional interdependence approach addressing multiple joints related to shoulder function may benefit other people with frozen shoulder. 4.

Neuromuscular adaptations associated with knee joint angle-specific force change.

PubMed

Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

2014-08-01

Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

Joint contact forces can be reduced by improving joint moment symmetry in below-knee amputee gait simulations.

PubMed

Koelewijn, Anne D; van den Bogert, Antonie J

2016-09-01

Despite having a fully functional knee and hip in both legs, asymmetries in joint moments of the knee and hip are often seen in gait of persons with a unilateral transtibial amputation (TTA), possibly resulting in excessive joint loading. We hypothesize that persons with a TTA can walk with more symmetric joint moments at the cost of increased effort or abnormal kinematics. The hypothesis was tested using predictive simulations of gait. Open loop controls of one gait cycle were found by solving an optimization problem that minimizes a combination of walking effort and tracking error in joint angles, ground reaction force and gait cycle duration. A second objective was added to penalize joint moment asymmetry, creating a multi-objective optimization problem. A Pareto front was constructed by changing the weights of the objectives and three solutions were analyzed to study the effect of increasing joint moment symmetry. When the optimization placed more weight on moment symmetry, walking effort increased and kinematics became less normal, confirming the hypothesis. TTA gait improved with a moderate increase in joint moment symmetry. At a small cost of effort and abnormal kinematics, the peak hip extension moment in the intact leg was decreased significantly, and so was the joint contact force in the knee and hip. Additional symmetry required a significant increase in walking effort and the joint contact forces in both hips became significantly higher than in able-bodied gait. Copyright © 2016 Elsevier B.V. All rights reserved.

Proposal for SICSeG guidelines for rehabilitation after anatomical shoulder prosthesis in concentric shoulder osteoarthritis.

PubMed

Fusaro, I; Orsini, S; Stignani, S; Creta, D; Cava, F C; Benedetti, M G

2013-06-01

The purpose of this paper is to provide up-to-date guidelines on rehabilitation after anatomical shoulder prosthesis for concentric shoulder osteoarthritis, as previous guidelines date back to late 1970s and are no longer adequate due to the evolution of prosthesis models and surgical techniques. The physiatric committee of the Italian Society of Shoulder and Elbow Surgery (SICSeG-Società Italiana di Chirurgia della Spalla e del Gomito) performed a search for all the existing literature related to rehabilitation after shoulder replacement. A total of 29 papers concerning shoulder rehabilitation were reviewed. In addition, the main Italian orthopedic surgeons and physiatrists dealing with shoulder surgery and rehabilitation were interviewed to obtain indications when literature was not conclusive. From literature evaluation and expert consultation, we produced guidelines concerning: patient evaluation by means of adequate rating scales, preoperative treatment, early intermediate and advanced postoperative phases, rehabilitation of scapulo-thoracic joint, return to work and sports, length of rehabilitation and follow-up. This proposal for guidelines was presented during the 11th SICSeG Congress on May 2012 and to the main scientific societies concerned in shoulder surgery and rehabilitation. A consensus conference is needed in order to formalize and make them usable from all the professional figures involved in this field.

The friction coefficient of shoulder joints remains remarkably low over 24 h of loading.

PubMed

Jones, Brian K; Durney, Krista M; Hung, Clark T; Ateshian, Gerard A

2015-11-05

The frictional response of whole human joints over durations spanning activities of daily living has not been reported previously. This study measured the friction of human glenohumeral joints during 24 h of reciprocal loading in a pendulum testing device, at moderate (0.2 mm/s, 4320 cycles) and low (0.02 mm/s, 432 cycles) sliding speeds, under a 200 N load. The effect of joint congruence was also investigated by testing human humeral heads against significantly larger mature bovine glenoids. Eight human joints and six bovine joints were tested in four combinations: human joints tested at moderate (hHCMS, n=6) and low speed (hHCLS, n=3), human humeral heads tested against bovine glenoids at moderate speed (LCMS, n=3), and bovine joints tested at moderate speed (bHCMS, n=3). In the first half hour the mean±standard deviation of the friction coefficient was hHCMS: 0.0016±0.0011, hHCLS: 0.0012±0.0002, LCMS: 0.0008±0.0002 and bHCMS: 0.0024±0.0008; in the last four hours it was hHCMS: 0.0057±0.0025, hHCLS: 0.0047±0.0017, LCMS: 0.0012±0.0003 and bHCMS: 0.0056±0.0016. The initial value was lower than the final value (p<0.0001). The value in LCMS was significantly lower than in hHCMS and bHCMS (p<0.01). No visual damage was observed in any of the specimens. These are the first results to demonstrate that the friction coefficient of natural human shoulders remains remarkably low (averaging as little as 0.0015 and no greater than 0.006) for up to 24 h of continuous loading. The sustained low friction coefficients observed in incongruent joints (~0.001) likely represent rolling rather than sliding friction. Copyright © 2015. Published by Elsevier Ltd.

Effect of hammer mass on upper extremity joint moments.

PubMed

Balendra, Nilanthy; Langenderfer, Joseph E

2017-04-01

This study used an OpenSim inverse-dynamics musculoskeletal model scaled to subject-specific anthropometrics to calculate three-dimensional intersegmental moments at the shoulder, elbow and wrist while 10 subjects used 1 and 2 lb hammers to drive nails. Motion data were collected via an optoelectronic system and the interaction of the hammer with nails was recorded with a force plate. The larger hammer caused substantial increases (50-150%) in moments, although increases differed by joint, anatomical component, and significance of the effect. Moment increases were greater in cocking and strike/follow-through phases as opposed to swinging and may indicate greater potential for injury. Compared to shoulder, absolute increases in peak moments were smaller for elbow and wrist, but there was a trend toward larger relative increases for distal joints. Shoulder rotation, elbow varus-valgus and pronation-supination, and wrist radial-ulnar deviation and rotation demonstrated large relative moment increases. Trial and phase durations were greater for the larger hammer. Changes in moments and timing indicate greater loads on musculoskeletal tissues for an extended period with the larger hammer. Additionally, greater variability in timing with the larger hammer, particularly for cocking phase, suggests differences in control of the motion. Increased relative moments for distal joints may be particularly important for understanding disorders of the elbow and wrist associated with hammer use. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Management of the worker affected by shoulder pathology].

PubMed

Rotini, Roberto; Bonfiglioli, Roberta

2014-01-01

Shoulder disorders due to overexertion include joint and soft tissues chronic conditions and are an important cause of disability. Shoulder pain is one of the most common musculoskeletal disorders and has been associated to manual handling of heavy loads, high repetition jobs, exposure to hand-arm vibration and to overhead activities. Diagnosis of shoulder disorders is primarily based on clinical examination; selected cases should be referred to an orthopedic specialist and to imaging. Return to normal activities should be encouraged.

[Nuclear magnetic tomography in shoulder dislocation].

PubMed

Runkel, M; Kreitner, K F; Wenda, K; Rudig, L; Degreif, J; Grebe, P

1993-03-01

Sixty-two patients with anterior shoulder dislocations were examined by magnetic resonance imaging (MRI). After a primary dislocation, 30 patients showed 23 (77%) tears of the glenoid labrum, 13 (45%) anterior-inferior separation of the capsula, 24 (83%) Hill-Sachs lesions, 6 fractures of the greater tuberosity and 4 glenoid rim fractures. Thirty-two patients with recurrent shoulder dislocation had 14 (44%) tears and 15 (47%) defects of the glenoid labrum, 16 (50%) anterior-inferior separation of the capsula, 28 (88%) Hill-Sachs lesions and 3 glenoid rim fractures. MRI permits complete non-invasive documentation of glenohumeral instability if joint effusion is present. In the absence of joint effusion, diagnostic accuracy can be improved by application of a contrast medium.

Arthroscopic findings after shoulder dislocation.

PubMed

Hintermann, B; Gächter, A

1995-01-01

The purpose of this study was to evaluate prospectively the arthroscopic findings of the unstable shoulder, to provide insights into the causes and mechanisms of shoulder instability, and to establish a rationale for using special surgical procedures. Arthroscopic examination was performed on 212 patients who had at least 1 documented shoulder dislocation. Of these 212 patients, 184 (87%) patients had anterior glenoid labral tears, 168 (79%) patients had ventral capsule insufficiency, 144 (68%) patients had Hill-Sachs compression fractures, 116 (55%) patients had glenohumeral ligament insufficiency, 30 (14%) patients had complete rotator cuff tendon tears, 26 (12%) patients had posterior glenoid labral tears, 14 (7%) patients had superior labrum anterior and inferior lesions. As this prospective study shows, multiple morphologic changes are associated with instability of the glenohumeral joint; there is no single cause for an unstable shoulder. Arthroscopic examination of the shoulder before surgery revealed a significant amount of information that would have been undetected without the aid of expensive diagnostic tools. For instance, the labrum and rim of the anteroinferior glenoid showed typical abnormalities corresponding to different entities of anterior instability.

Arthroscopic Management of Anterior, Posterior, and Multidirectional Shoulder Instabilities.

PubMed

Field, Larry D; Ryu, Richard K N; Abrams, Jeffrey S; Provencher, Matthew

2016-01-01

Arthroscopic shoulder stabilization offers several potential advantages compared with open surgery, including the opportunity to more accurately evaluate the glenohumeral joint at the time of diagnostic assessment; comprehensively address multiple pathologic lesions that may be identified; and avoid potential complications unique to open stabilization, such as postoperative subscapularis failure. A thorough understanding of normal shoulder anatomy and biomechanics, along with the pathoanatomy responsible for anterior, posterior, and multidirectional shoulder instability patterns, is very important in the management of patients who have shoulder instability. The treating physician also must be familiar with diagnostic imaging and physical examination maneuvers that are required to accurately diagnose shoulder instability.

Long-latency reflexes of elbow and shoulder muscles suggest reciprocal excitation of flexors, reciprocal excitation of extensors, and reciprocal inhibition between flexors and extensors

PubMed Central

Meriggi, Jenna; Parikh, Nidhi; Saad, Kenneth

2016-01-01

Postural corrections of the upper limb are required in tasks ranging from handling an umbrella in the changing wind to securing a wriggling baby. One complication in this process is the mechanical interaction between the different segments of the arm where torque applied at one joint induces motion at multiple joints. Previous studies have shown the long-latency reflexes of shoulder muscles (50–100 ms after a limb perturbation) account for these mechanical interactions by integrating information about motion of both the shoulder and elbow. It is less clear whether long-latency reflexes of elbow muscles exhibit a similar capability and what is the relation between the responses of shoulder and elbow muscles. The present study utilized joint-based loads tailored to the subjects' arm dynamics to induce well-controlled displacements of their shoulder and elbow. Our results demonstrate that the long-latency reflexes of shoulder and elbow muscles integrate motion from both joints: the shoulder and elbow flexors respond to extension at both joints, whereas the shoulder and elbow extensors respond to flexion at both joints. This general pattern accounts for the inherent flexion-extension coupling of the two joints arising from the arm's intersegmental dynamics and is consistent with spindle-based reciprocal excitation of shoulder and elbow flexors, reciprocal excitation of shoulder and elbow extensors, and across-joint inhibition between the flexors and extensors. PMID:26864766

From Conception to Birth: The Forces Responsible for AFCyber’s Evolution

DTIC Science & Technology

2014-06-01

matter how good or bad my days were – and I experienced a fair number of both during the 11-month course – she provided a shoulder to cry on, a...Robert J.  Lamb , “Joint Task Force for Computer Network Defense,” IA Newsletter, Winter 98/99,  Vol 2, No. 3, http://www.iwar.org.uk/infocon/dtic‐ia...Future of Warfare.” Real Clear Defense, 24 February 2014. Lamb , Robert J. “Joint Task Force for Computer Network Defense.” IA Newsletter, Winter 98

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

PubMed Central

Ache, Jan M.; Matheson, Thomas

2013-01-01

Summary Background Limb movements are generally driven by active muscular contractions working with and against passive forces arising in muscles and other structures. In relatively heavy limbs, the effects of gravity and inertia predominate, whereas in lighter limbs, passive forces intrinsic to the limb are of greater consequence. The roles of passive forces generated by muscles and tendons are well understood, but there has been little recognition that forces originating within joints themselves may also be important, and less still that these joint forces may be adapted through evolution to complement active muscle forces acting at the same joint. Results We examined the roles of passive joint forces in insect legs with different arrangements of antagonist muscles. We first show that passive forces modify actively generated movements of a joint across its working range, and that they can be sufficiently strong to generate completely passive movements that are faster than active movements observed in natural behaviors. We further demonstrate that some of these forces originate within the joint itself. In legs of different species adapted to different uses (walking, jumping), these passive joint forces complement the balance of strength of the antagonist muscles acting on the joint. We show that passive joint forces are stronger where they assist the weaker of two antagonist muscles. Conclusions In limbs where the dictates of a key behavior produce asymmetry in muscle forces, passive joint forces can be coadapted to provide the balance needed for the effective generation of other behaviors. PMID:23871240

Gimballed Shoulders for Friction Stir Welding

NASA Technical Reports Server (NTRS)

Carter, Robert; Lawless, Kirby

2008-01-01

In a proposed improvement of tooling for friction stir welding, gimballed shoulders would supplant shoulders that, heretofore, have been fixedly aligned with pins. The proposal is especially relevant to self-reacting friction stir welding. Some definitions of terms, recapitulated from related prior NASA Tech Briefs articles, are prerequisite to a meaningful description of the proposed improvement. In friction stir welding, one uses a tool that includes (1) a rotating shoulder on top (or front) of the workpiece and (2) a pin that rotates with the shoulder and protrudes from the shoulder into the depth of the workpiece. In conventional friction stir welding, the main axial force exerted by the tool on the workpiece is reacted through a ridged backing anvil under (behind) the workpiece. When conventional friction stir welding is augmented with an auto-adjustable pin-tool (APT) capability, the depth of penetration of the pin into the workpiece is varied in real time by a position- or forcecontrol system that extends or retracts the pin as needed to obtain the desired effect. In self-reacting (also known as self-reacted) friction stir welding as practiced heretofore, there are two shoulders: one on top (or front) and one on the bottom (or back) of the workpiece. In this case, a threaded shaft protrudes from the tip of the pin to beyond the back surface of the workpiece. The back shoulder is held axially in place against tension by a nut on the threaded shaft. Both shoulders rotate with the pin and remain aligned coaxially with the pin. The main axial force exerted on the workpiece by the tool and front shoulder is reacted through the back shoulder and the threaded shaft into the friction-stir-welding machine head, so that a backing anvil is no longer needed. A key transmits torque between the bottom shoulder and the threaded shaft, so that the bottom shoulder rotates with the shaft. This concludes the prerequisite definitions of terms.

Dominant vs. non-dominant shoulder morphology in volleyball players and associations with shoulder pain and spike speed.

PubMed

Challoumas, Dimitrios; Artemiou, Andreas; Dimitrakakis, Georgios

2017-01-01

The aims of our study were to compare the dominant (DOM) and non-dominant (NDOM) shoulders of high-level volleyball athletes and identify possible associations of shoulder adaptations with spike speed (SS) and shoulder pathology. A total of 22 male volleyball players from two teams participating in the first division of the Cypriot championship underwent clinical shoulder tests and simple measurements around their shoulder girdle joints bilaterally. SS was measured with the use of a sports speed radar. Compared with the NDOM side, the DOM scapula was more lateralised, the DOM dorsal capsule demonstrated greater laxity, the DOM dorsal muscles stretching ability was compromised, and the DOM pectoralis muscle was more lengthened. Players with present or past DOM shoulder pain demonstrated greater laxity in their DOM dorsal capsule, tightening of their DOM inferior capsule, and lower SS compared with those without shoulder pain. Dorsal capsule measurements bilaterally were significant predictors of SS. None of the shoulder measurements was associated with team roles or infraspinatus atrophy, while scapular lateralisation was more pronounced with increasing years of experience, and scapular antetilting was greater with increasing age. Adaptations of the DOM shoulder may be linked to pathology and performance. We describe simple shoulder measurements that may have the potential to predict chronic shoulder injury and become part of injury prevention programmes. Detailed biomechanical and large prospective studies are warranted to assess the validity of our findings and reach more definitive conclusions.

Rotator cuff strength in recurrent anterior shoulder instability.

PubMed

Edouard, Pascal; Degache, Francis; Beguin, Laurent; Samozino, Pierre; Gresta, Giorgio; Fayolle-Minon, Isabelle; Farizon, Frédéric; Calmels, Paul

2011-04-20

Although rotator-cuff muscle contraction plays an important role in stabilizing the glenohumeral joint, little is known about the role of these muscles in the pathophysiology of recurrent anterior instability. We intended to analyze the association between isokinetic internal rotator and external rotator muscle strength and glenohumeral joint instability in patients with recurrent anterior instability that was not previously treated surgically. We enrolled thirty-seven patients with unilateral recurrent anterior posttraumatic shoulder dislocation and eleven healthy nonathletic subjects in this controlled study. The association between internal rotator and external rotator strength and shoulder instability was analyzed by side-to-side comparisons and comparisons with a control group. Isokinetic internal rotator and external rotator strength was evaluated with a Con-Trex dynamometer, with the subject seated and the shoulder abducted 45° in the scapular plane. Tests were performed at 180°/s, 120°/s, and 60°/s in concentric mode for both sides. Peak torque normalized to body weight and external rotator to internal rotator ratio were calculated for each angular velocity. Clinical and isokinetic evaluation was done by the same rehabilitation physician. The association between shoulder instability and internal rotator and external rotator strength was associated with side-to-side differences (p < 0.05). Compared with a control group, strength values were lower on the pathological shoulder side of the patients with shoulder instability than on the healthy contralateral shoulder of control subjects at 180°/s and 120°/s (p < 0.05). The side-to-side differences were increased when the nondominant upper-extremity side was involved and were decreased when the dominant side was involved. There was no association between glenohumeral joint instability and external rotator to internal rotator ratio. Internal rotator and external rotator weakness was associated with recurrent

Knee joint forces: prediction, measurement, and significance

PubMed Central

D’Lima, Darryl D.; Fregly, Benjamin J.; Patil, Shantanu; Steklov, Nikolai; Colwell, Clifford W.

2011-01-01

Knee forces are highly significant in osteoarthritis and in the survival and function of knee arthroplasty. A large number of studies have attempted to estimate forces around the knee during various activities. Several approaches have been used to relate knee kinematics and external forces to internal joint contact forces, the most popular being inverse dynamics, forward dynamics, and static body analyses. Knee forces have also been measured in vivo after knee arthroplasty, which serves as valuable validation of computational predictions. This review summarizes the results of published studies that measured knee forces for various activities. The efficacy of various methods to alter knee force distribution, such as gait modification, orthotics, walking aids, and custom treadmills are analyzed. Current gaps in our knowledge are identified and directions for future research in this area are outlined. PMID:22468461

A Force-Velocity Relationship and Coordination Patterns in Overarm Throwing

PubMed Central

van den Tillaar, Roland; Ettema, Gertjan

2004-01-01

A force-velocity relationship in overarm throwing was determined using ball weights varying from 0.2 to 0.8 kg. Seven experienced handball players were filmed at 240 frames per second. Velocity of joints of the upper extremity and ball together with the force on the ball were derived from the data. A statistically significant negative relationship between force and maximal ball velocity, as well as between ball weight and maximal ball velocity was observed. Also, with increase of ball weight the total throwing movement time increased. No significant change in relative timing of the different joints was demonstrated, suggesting that the subjects did not change their “global ”coordination pattern (kinematics) within the tested range of ball weights. A simple model revealed that 67% of ball velocity at ball release was explained by the summation of effects from the velocity of elbow extension and internal rotation of the shoulder. With regard to the upper extremity the internal rotation of the shoulder and elbow extension are two important contributors to the total ball velocity at release. Key Points An inverse relationship between load and velocity and a linear force-velocity exists in overarm throwing with ball weights varying from 0.2 to 0.8 kg. Qualitatively, no changes in coordination pattern (relative timing) occur with increasing ball weight within the tested range of ball weights. The absolute throwing movement time increased with ball weight. Quantitatively, with regard to the upper extremity, the internal rotation of the shoulder and elbow extension are two important contributors to the total ball velocity at release. PMID:24624005

Elastic Tape Improved Shoulder Joint Position Sense in Chronic Hemiparetic Subjects: A Randomized Sham-Controlled Crossover Study.

PubMed

Santos, Gabriela Lopes Dos; Souza, Matheus Bragança; Desloovere, Kaat; Russo, Thiago Luiz

2017-01-01

Elastic tape has been widely used in clinical practice in order to improve upper limb (UL) sensibility. However, there is little evidence that supports this type of intervention in stroke patients. To verify the effect of elastic tape, applied to the paretic shoulder, on joint position sense (JPS) during abduction and flexion in subjects with chronic hemiparesis compared to sham tape (non-elastic tape). Furthermore, to verify if this potential effect is correlated to shoulder subluxation measurements and sensorimotor impairment. A crossover and sham-controlled study was conducted with post-stroke patients who were randomly allocated into two groups: 1) those who received Sham Tape (ST) first and after one month they received Elastic Tape (ET); 2) those who received Elastic Tape (ET) first and after one month they received Sham Tape (ST). The JPS was evaluated using a dynamometer. The absolute error for shoulder abduction and flexion at 30° and 60° was calculated. Sensorimotor impairment was determined by Fugl-Meyer, and shoulder subluxation was measured using a caliper. Thirteen hemiparetic subjects (average time since stroke 75.23 months) participated in the study. At baseline (before interventions), the groups were not different for abduction at 30° (p = 0.805; p = 0.951), and 60° (p = 0.509; p = 0.799), or flexion at 30° (p = 0.872; p = 0.897) and 60° (p = 0.853; p = 0.970). For the ET group, differences between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° p<0.010) and 60° (p<0.010) were observed. For the ST group, differences were also observed between pre and post-elastic tape for abduction at 30° (p<0.010) and 60° (p<0.010), and flexion at 30° (p<0.010,) and 60° (p<0.010). Potential effects were only correlated with shoulder subluxation during abduction at 30° (p = 0.001, r = -0.92) and 60° (p = 0.020, r = -0.75). Elastic tape improved shoulder JPS of subjects with chronic hemiparesis

Dynamic Wheel-Rail Forces on Mismatched Joints with Ramps

DOT National Transportation Integrated Search

2016-04-12

The discontinuity between rail ends at a joint creates : dynamic wheel-rail forces (i.e. high impact forces and wheel : unloading) that can result in a range of problems including : wear, deterioration, and early failure of the track structure, its :...

Implantable sensor technology: measuring bone and joint biomechanics of daily life in vivo

PubMed Central

2013-01-01

Stresses and strains are major factors influencing growth, remodeling and repair of musculoskeletal tissues. Therefore, knowledge of forces and deformation within bones and joints is critical to gain insight into the complex behavior of these tissues during development, aging, and response to injury and disease. Sensors have been used in vivo to measure strains in bone, intraarticular cartilage contact pressures, and forces in the spine, shoulder, hip, and knee. Implantable sensors have a high impact on several clinical applications, including fracture fixation, spine fixation, and joint arthroplasty. This review summarizes the developments in strain-measurement-based implantable sensor technology for musculoskeletal research. PMID:23369655

The effects of Navy ship ladder descent on the knee internal joint reaction forces

NASA Astrophysics Data System (ADS)

Coulter, Jonathan D.; Weinhandl, Joshua T.; Bawab, Sebastian Y.; Ringleb, Stacie I.

2017-02-01

Military populations may be at risk for developing knee osteoarthritis and other knee problems when descending a Navy ship ladder, which differs from traditional stairs due to non-overlapping treads, a larger rise and a steeper inclination angle. The purpose of this study was to develop a forward dynamic model of the descent of a Navy ship ladder to determine how this motion affects the internal knee reaction forces and how altering the hamstring/quadriceps ratio affects the internal joint reaction forces in the knee. Kinematic and kinetic data were collected from three male sailors descending a replica of a Navy ship ladder and were used as input into a model constructed in OpenSim. The peak resultant joint reaction force was 6.6 × BW, which was greater than values reported in the literature in traditional stairs. Peak compressive and anterior joint reaction forces, 4.05 × BW and 5.46 × BW, respectively, were greater than reported values for a squat, a motion similar to descending a ship ladder. The average peak vertical and anterior internal joint reaction force at the knee were 4.05 × BW and 5.46 × BW, respectively. The resultant joint reaction forces calculated from the ladder descent were greater than stair descent and squatting. Little effects were found in the joint reaction forces after adjusting the quadriceps to hamstring muscle strength ratios, possibly because these ratios might change the distribution of the contact forces across the joint, not the resultant forces.

The Effects of Posterior Rotator Cuff Cable Tears on Glenohumeral Biomechanics in a Cadaveric Model of the Throwing Shoulder

PubMed Central

Photopoulos, Christos Demetris; ElAttrache, Neal S.; Doermann, Alex; Akeda, Masaki; McGarry, Michelle H.; Lee, Thay Q.

2017-01-01

Objectives: The rotator cuff cable has been postulated to be the primary load bearing substructure of the superior part of the rotator cuff. Tears of the posterior rotator cable are frequently seen in overhead throwing athletes. Although the biomechanical significance of the anterior rotator cable has been well described, our current understanding of the relevance of the posterior cable is limited. The purpose of this study was to examine how partial-thickness tears and full-thickness tears of the posterior rotator cable would alter glenohumeral biomechanics and kinematics in cadaveric shoulder models. Methods: Eight fresh-frozen cadaveric shoulder specimens were prepared and tested. To simulate the sequence of glenohumeral positions during the throwing motion, specimens were mounted on a custom shoulder testing system with the humerus positioned at 90° of abduction (30° scapular upward rotation, 60° glenohumeral abduction) and tested at 30, 60, 90, and 120 degrees of external rotation. After a circumferential capsulotomy was performed, rotator cuff muscles were loaded based on physiologic cross-sectional area ratios, and testing for each specimen was performed on each the following three conditions: intact posterior cable, partial-thickness (50%) articular-sided posterior cable tear, and full-thickness posterior cable tear. Primary outcome measures tested for each condition under the various degrees of glenohumeral rotation were: 1) anterior and total glenohumeral translation after application of a 30N anterior force; 2) path of glenohumeral articulation; 3) glenohumeral joint force. Results: With a 30N anterior force at 120° of external rotation, there was a significant increase in anterior glenohumeral translation between intact and full-thickness tear specimens (7.28±2.00mm and 17.49±3.75mm, respectively; p<0.05). Similarly, total joint translation at 120° of external rotation significantly increased between intact and full-thickness tear specimens (10

Low rate of Propionibacterium acnes in arthritic shoulders undergoing primary total shoulder replacement surgery using a strict specimen collection technique.

PubMed

Maccioni, Cristobal B; Woodbridge, Adam B; Balestro, Jean-Christian Y; Figtree, Melanie C; Hudson, Bernard J; Cass, Benjamin; Young, Allan A

2015-08-01

Propionibacterium acnes is a recognized pathogen in postoperative shoulder infections. A recent study reported growth of P acnes in 42% of glenohumeral joints in primary shoulder arthroplasty, concluding that P acnes may cause shoulder osteoarthritis. Whether these results reflect true bacterial infection or specimen contamination is unclear. Our prospective study aimed to determine the rate of P acnes infection in arthritic shoulders using a strict specimen collection technique. We used modified Oxford protocol to collect tissue specimens from the glenohumeral joint of 32 consecutive patients undergoing primary shoulder arthroplasty. Specimens were cultured specifically for P acnes. Diagnosis of P acnes infection required 2 or more positive cultures and histopathology compatible with infection. Three of 32 patients had a positive culture for P acnes. Overall, 3.125% of specimens grew P acnes without histologic evidence of infection. There were no patients with P acnes infection. The difference in culture rates between patients with idiopathic osteoarthritis and those with a predisposing cause for osteoarthritis was not significant. We found a low rate of positive cultures for P acnes, but no P acnes infection and no difference between types of osteoarthritis. These results do not support a cause-and-effect relationship between P acnes and osteoarthritis. The differing results from previous studies are likely explained by our strict specimen collection technique, reflecting different rates of contamination rather than infection. That P acnes contamination occurs in primary shoulder arthroplasty is concerning. Further studies are needed to assess the rates of contamination in shoulder surgery, its clinical effect, and to determine optimal antibiotic prophylaxis. Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.

Simultaneous and Continuous Estimation of Shoulder and Elbow Kinematics from Surface EMG Signals

PubMed Central

Zhang, Qin; Liu, Runfeng; Chen, Wenbin; Xiong, Caihua

2017-01-01

In this paper, we present a simultaneous and continuous kinematics estimation method for multiple DoFs across shoulder and elbow joint. Although simultaneous and continuous kinematics estimation from surface electromyography (EMG) is a feasible way to achieve natural and intuitive human-machine interaction, few works investigated multi-DoF estimation across the significant joints of upper limb, shoulder and elbow joints. This paper evaluates the feasibility to estimate 4-DoF kinematics at shoulder and elbow during coordinated arm movements. Considering the potential applications of this method in exoskeleton, prosthetics and other arm rehabilitation techniques, the estimation performance is presented with different muscle activity decomposition and learning strategies. Principle component analysis (PCA) and independent component analysis (ICA) are respectively employed for EMG mode decomposition with artificial neural network (ANN) for learning the electromechanical association. Four joint angles across shoulder and elbow are simultaneously and continuously estimated from EMG in four coordinated arm movements. By using ICA (PCA) and single ANN, the average estimation accuracy 91.12% (90.23%) is obtained in 70-s intra-cross validation and 87.00% (86.30%) is obtained in 2-min inter-cross validation. This result suggests it is feasible and effective to use ICA (PCA) with single ANN for multi-joint kinematics estimation in variant application conditions. PMID:28611573

An Evolving Joint Acquisition Force

DTIC Science & Technology

2004-03-19

COVERED - 4. TITLE AND SUBTITLE An Evolving Joint Acquisition Force 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S ...Theodore Jennings 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK UNIT NUMBER 7. PERFORMING ORGANIZATION NAME( S ) AND ADDRESS(ES) U.S. Army War...College,Carlisle Barracks,Carlisle,PA,17013-5050 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING/MONITORING AGENCY NAME( S ) AND ADDRESS(ES) 10

Throwing, the Shoulder, and Human Evolution.

PubMed

Kuhn, John E

2016-01-01

Throwing with accuracy and speed is a skill unique to humans. Throwing has many advantages and the ability to throw has likely been promoted through natural selection in the evolution of humans. There are many unsolved questions regarding the anatomy of the human shoulder. The purpose of this article is to review many of these mysteries and propose that the answer to these questions can be understood if one views the shoulder as a joint that has evolved to throw.

Chronic Irreducible Anterior Dislocation of the Shoulder without Significant Functional Deficit.

PubMed

Chung, Hoejeong; Yoon, Yeo-Seung; Shin, Ji-Soo; Shin, John Junghun; Kim, Doosup

2016-09-01

Shoulder dislocation is frequently encountered by orthopedists, and closed manipulation is often sufficient to treat the injury in an acute setting. Although most dislocations are diagnosed and managed promptly, there are rare cases that are missed or neglected, leading to a chronically dislocated state of the joint. They are usually irreducible and cause considerable pain and functional disability in most affected patients, prompting the need to find a surgical method to reverse the worsening conditions caused by the dislocated joint. However, there are cases of even greater rarity in which chronic shoulder dislocations are asymptomatic with minimal functional or structural degeneration in the joint. These patients are usually left untreated, and most show good tolerance to their condition without developing disabling symptoms or significant functional loss over time. We report on one such patient who had a chronic shoulder dislocation for more than 2 years without receiving treatment.

Shoulder arthroplasty for sequelae of poliomyelitis.

PubMed

Werthel, Jean-David; Schoch, Bradley; Sperling, John W; Cofield, Robert; Elhassan, Bassem T

2016-05-01

Polio infection can often lead to orthopedic complications such as arthritis, osteoporosis, muscle weakness, skeletal deformation, and chronic instability of the joints. The purpose of this study was to assess the outcomes and associated complications of arthroplasty in shoulders with sequelae of poliomyelitis. Seven patients (average age, 70 years) were treated between 1976 and 2013 with shoulder arthroplasty for the sequelae of polio. One patient underwent reverse shoulder arthroplasty, 2 had a hemiarthroplasty, and 4 had total shoulder arthroplasty. Average follow-up was 87 months. Outcome measures included pain, range of motion, and postoperative modified Neer ratings. Overall pain scores improved from 5 to 1.6 points (on a 5-point scale) after shoulder arthroplasty. Six shoulders had no or mild pain at latest follow-up, and 6 shoulders rated the result as much better or better. Mean shoulder elevation improved from 72° to 129°, and external rotation improved from 11° to 56°. Average strength in elevation decreased from 3.9 to 3.4 postoperatively, and external rotation strength decreased from 3.9 to 3.3. This, however, did not reach significance. Evidence of muscle imbalance with radiographic instability was found in 4 shoulders that demonstrated superior subluxation, anterior subluxation, or both. This remained asymptomatic. No shoulder required revision or reoperation. Shoulder arthroplasty provides significant pain relief and improved motion in patients with sequelae of poliomyelitis. Muscle weakness may be responsible for postoperative instability, and careful selection of the patient with good upper extremity muscles must be made. Copyright © 2016 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Upper limb joint forces and moments during underwater cyclical movements.

PubMed

Lauer, Jessy; Rouard, Annie Hélène; Vilas-Boas, João Paulo

2016-10-03

Sound inverse dynamics modeling is lacking in aquatic locomotion research because of the difficulty in measuring hydrodynamic forces in dynamic conditions. Here we report the successful implementation and validation of an innovative methodology crossing new computational fluid dynamics and inverse dynamics techniques to quantify upper limb joint forces and moments while moving in water. Upper limb kinematics of seven male swimmers sculling while ballasted with 4kg was recorded through underwater motion capture. Together with body scans, segment inertial properties, and hydrodynamic resistances computed from a unique dynamic mesh algorithm capable to handle large body deformations, these data were fed into an inverse dynamics model to solve for joint kinetics. Simulation validity was assessed by comparing the impulse produced by the arms, calculated by integrating vertical forces over a stroke period, to the net theoretical impulse of buoyancy and ballast forces. A resulting gap of 1.2±3.5% provided confidence in the results. Upper limb joint load was within 5% of swimmer׳s body weight, which tends to supports the use of low-load aquatic exercises to reduce joint stress. We expect this significant methodological improvement to pave the way towards deeper insights into the mechanics of aquatic movement and the establishment of practice guidelines in rehabilitation, fitness or swimming performance. Copyright © 2016 Elsevier Ltd. All rights reserved.

Changes in Muscle and Joint Coordination in Learning to Direct Forces

PubMed Central

Hasson, Christopher J.; Caldwell, Graham E.; van Emmerik, Richard E.A.

2008-01-01

While it has been suggested that biarticular muscles have a specialized role in directing external reaction forces, it is unclear how humans learn to coordinate mono- and bi-articular muscles to perform force-directing tasks. Subjects were asked to direct pedal forces in a specified target direction during one-legged cycling. We expected that with practice, performance improvement would be associated with specific changes in joint torque patterns and mono- and bi-articular muscular coordination. Nine male subjects practiced pedaling an ergometer with only their left leg, and were instructed to always direct their applied pedal force perpendicular to the crank arm (target direction) and to maintain a constant pedaling speed. After a single practice session, the mean error between the applied and target pedal force directions decreased significantly. This improved performance was accompanied by a significant decrease in the amount of ankle angular motion and a smaller increase in knee and hip angular motion. This coincided with a re-organization of lower extremity joint torques, with a decrease in ankle plantarflexor torque and an increase in knee and hip flexor torques. Changes were seen in both mono- and bi-articular muscle activity patterns. The monoarticular muscles exhibited greater alterations, and appeared to contribute to both mechanical work and force directing. With practice, a loosening of the coupling between biarticular thigh muscle activation and joint torque co-regulation was observed. The results demonstrated that subjects were able to learn a complex and dynamic force-directing task by changing the direction of their applied pedal forces through re-organization of joint torque patterns and mono- and bi-articular muscle coordination. PMID:18405988

Changes in muscle and joint coordination in learning to direct forces.

PubMed

Hasson, Christopher J; Caldwell, Graham E; van Emmerik, Richard E A

2008-08-01

While it has been suggested that bi-articular muscles have a specialized role in directing external reaction forces, it is unclear how humans learn to coordinate mono- and bi-articular muscles to perform force-directing tasks. Participants were asked to direct pedal forces in a specified target direction during one-legged cycling. We expected that with practice, performance improvement would be associated with specific changes in joint torque patterns and mono- and bi-articular muscular coordination. Nine male participants practiced pedaling an ergometer with only their left leg, and were instructed to always direct their applied pedal force perpendicular to the crank arm (target direction) and to maintain a constant pedaling speed. After a single practice session, the mean error between the applied and target pedal force directions decreased significantly. This improved performance was accompanied by a significant decrease in the amount of ankle angular motion and a smaller increase in knee and hip angular motion. This coincided with a re-organization of lower extremity joint torques, with a decrease in ankle plantarflexor torque and an increase in knee and hip flexor torques. Changes were seen in both mono- and bi-articular muscle activity patterns. The mono-articular muscles exhibited greater alterations, and appeared to contribute to both mechanical work and force-directing. With practice, a loosening of the coupling between bi-articular thigh muscle activation and joint torque co-regulation was observed. The results demonstrated that participants were able to learn a complex and dynamic force-directing task by changing the direction of their applied pedal forces through re-organization of joint torque patterns and mono- and bi-articular muscle coordination.

Psychometric Properties of the Persian Version of the Simple Shoulder Test (SST) Questionnaire.

PubMed

Ebrahimzadeh, Mohammad H; Vahedi, Ehsan; Baradaran, Aslan; Birjandinejad, Ali; Seyyed-Hoseinian, Seyyed-Hadi; Bagheri, Farshid; Kachooei, Amir Reza

2016-10-01

To validate the Persian version of the simple shoulder test in patients with shoulder joint problems. Following Beaton`s guideline, translation and back translation was conducted. We reached to a consensus on the Persian version of SST. To test the face validity in a pilot study, the Persian SST was administered to 20 individuals with shoulder joint conditions. We enrolled 148 consecutive patients with shoulder problem to fill the Persian SST, shoulder specific measure including Oxford shoulder score (OSS) and two general measures including DASH and SF-36. To measure the test-retest reliability, 42 patients were randomly asked to fill the Persian-SST for the second time after one week. Cronbach's alpha coefficient was used to demonstrate internal consistency over the 12 items of Persian-SST. ICC for the total questionnaire was 0.61 showing good and acceptable test-retest reliability. ICC for individual items ranged from 0.32 to 0.79. The total Cronbach's alpha was 0.84 showing good internal consistency over the 12 items of the Persian-SST. Validity testing showed strong correlation between SST and OSS and DASH. The correlation with OSS was positive while with DASH scores was negative. The correlation was also good to strong with all physical and most mental subscales of the SF-36. Correlation coefficient was higher with DASH and OSS in compare to SF-36. Persian version of SST found to be valid and reliable instrument for shoulder joint pain and function assessment in Iranian population.

Determinants of shoulder and elbow flexion range: results from the San Antonio Longitudinal Study of Aging.

PubMed

Escalante, A; Lichtenstein, M J; Hazuda, H P

1999-08-01

To gain a knowledge of factors associated with impaired upper extremity range of motion (ROM) in order to understand pathways that lead to disability. Shoulder and elbow flexion range was measured in a cohort of 695 community-dwelling subjects aged 65 to 74 years. Associations between subjects' shoulder and elbow flexion ranges and their demographic and anthropometric characteristics, as well as the presence of diabetes mellitus or self-reported physician-diagnosed arthritis, were examined using multivariate regression models. The relationship between shoulder or elbow flexion range and subjects' functional reach was examined to explore the functional significance of ROM in these joints. The flexion range for the 4 joints studied was at least 120 degrees in nearly all subjects (> or = 99% of the subjects for each of the 4 joints). Multivariate models revealed significant associations between male sex, Mexican American ethnic background, the use of oral hypoglycemic drugs or insulin to treat diabetes mellitus, and a lower shoulder flexion range. A lower elbow flexion range was associated with male sex, increasing body mass index, and the use of oral hypoglycemic drugs or insulin. A higher shoulder or elbow flexion range was associated with a lower likelihood of having a short functional reach. The great majority of community-dwelling elderly have a flexion range of shoulder and elbow joints that can be considered functional. Diabetes mellitus and obesity are two potentially treatable factors associated with reduced flexion range of these two functionally important joints.

Stress perception and social indicators for low back, shoulder and joint pains in Japan: national surveys in 1995 and 2001.

PubMed

Takeuchi, Takeaki; Nakao, Mutsuhiro; Nishikitani, Mariko; Yano, Eiji

2004-07-01

This study aims to clarify the effects of stress perception and related social indicators on three major musculoskeletal symptoms: low back, shoulder, and joint pains in a Japanese population. Twenty health-related variables (stress perception and 19 social indicators) and the three symptoms were obtained from the following Japanese national surveys: the Comprehensive Survey of Living Condition of the People on Health and Welfare, the System of Social and Demographic Statistics of Japan, and the Statistical Report on Health Administration Services. The results were compared among 46 Japanese prefectures in 1995 and 2001. By factor analysis, the 19 indicators were classified into three factors of urbanization, aging and life-regularity, and individualization. The prevalence of stress perception was significantly correlated to the 8 indicators of urbanization factor. Although simple correlation analysis revealed a significant relationship of stress perception only to shoulder pain (in both years) and low back pain (in 2001), the results of multiple regression analysis showed that stress perception and some urbanization factors were significantly associated with all the three symptoms in both years exclusive of joint pain in 1995. Taking the effects of urbanization into consideration, stress perception seems to be closely related to the complaints of musculoskeletal symptoms in Japan.

Do patients with structural abnormalities of the shoulder experience pain after MR arthrography of the shoulder?

PubMed

Steurer-Dober, Isabelle; Rufibach, Kaspar; Hodler, Juerg; Saupe, Nadja; Zanetti, Marco; Fucentese, Sandro F; Pfirrmann, Christian W A

2010-09-01

To assess the pain course after intraarticular injection of a gadolinium-containing contrast material admixed with anesthetic for magnetic resonance (MR) arthrography of the shoulder in relation to internal derangements of the shoulder. Institutional review board approval and informed consent were obtained for this study. The study sample consisted of 655 consecutive patients (249 female, 406 male; median age, 54 years) referred for MR arthrography of the shoulder. Pain level was measured at baseline, directly after intraarticular injection of the gadolinium-containing contrast material admixed with anesthetic, 4 hours after injection, 1 day (18-30 hours) after injection, and 1 week (6-8 days) after injection with a visual analog scale (range, 0-10). MR arthrography was used to assess the following internal derangements: lesions of the rotator cuff tendons and long biceps tendon, adhesive capsulitis (frozen shoulder), fluid in the subacromial bursa, labral tears, and osteoarthritis of the glenohumeral joint. History of shoulder surgery was recorded. Linear regression models were calculated for the dependent variable (difference between follow-up pain and baseline pain), with the independent variable grouping adjusted for age and sex. There was no significant association between pain level over time and internal derangements of the shoulder, nor was there significant association between pain level over time in patients with a history of shoulder surgery and patients without a history of shoulder surgery. Neither internal derangements nor prior surgery have an apparent effect on the pain course after MR arthrography of the shoulder. (c) RSNA, 2010.

Counterrotating-Shoulder Mechanism for Friction Stir Welding

NASA Technical Reports Server (NTRS)

Nunes, Arthur C., Jr.

2007-01-01

A counterrotating-shoulder mechanism has been proposed as an alternative to the mechanism and fixtures used in conventional friction stir welding. The mechanism would internally react most or all of the forces and torques exerted on the workpiece, making it unnecessary to react the forces and torques through massive external fixtures. In conventional friction stir welding, a rotating pin tool is inserted into, and moved along, a weld seam. As the pin tool moves, it stirs together material from the opposite sides of the seam to form the weld. A large axial plunge force must be exerted upon the workpiece through and by the pin tool and a shoulder attached above the pin tool in order to maintain the pressure necessary for the process. The workpiece is secured on top of an anvil, which supports the workpiece against the axial plunge force and against the torque exerted by the pin tool and shoulder. The anvil and associated fixtures must be made heavy (and, therefore, are expensive) to keep the workpiece stationary. In addition, workpiece geometries must be limited to those that can be accommodated by the fixtures. The predecessor of the proposed counterrotating-shoulder mechanism is a second-generation, self-reacting tool, resembling a bobbin, that makes it possible to dispense with the heavy anvil. This tool consists essentially of a rotating pin tool with opposing shoulders. Although the opposing shoulders maintain the necessary pressure without need to externally apply or react a large plunge force, the torque exerted on the workpiece remains unreacted in the absence of a substantial external fixture. Depending on the RPM and the thickness of the workpiece, the torque can be large. The proposed mechanism (see figure) would include a spindle attached to a pin tool with a lower shoulder. The spindle would be coupled via splines to the upper one of three bevel gears in a differential drive. The middle bevel gear would be the power-input gear and would be coupled to the

Arthroscopic Findings in Anterior Shoulder Instability

PubMed Central

Hantes, Michael; Raoulis, Vasilios

2017-01-01

Background: In the last years, basic research and arthroscopic surgery, have improved our understanding of shoulder anatomy and pathology. It is a fact that arthroscopic treatment of shoulder instability has evolved considerably over the past decades. The aim of this paper is to present the variety of pathologies that should be identified and treated during shoulder arthroscopy when dealing with anterior shoulder instability cases. Methods: A review of the current literature regarding arthroscopic shoulder anatomy, anatomic variants, and arthroscopic findings in anterior shoulder instability, is presented. In addition, correlation of arthroscopic findings with physical examination and advanced imaging (CT and MRI) in order to improve our understanding in anterior shoulder instability pathology is discussed. Results: Shoulder instability represents a broad spectrum of disease and a thorough understanding of the pathoanatomy is the key for a successful treatment of the unstable shoulder. Patients can have a variety of pathologies concomitant with a traditional Bankart lesion, such as injuries of the glenoid (bony Bankart), injuries of the glenoid labrum, superiorly (SLAP) or anteroinferiorly (e.g. anterior labroligamentous periosteal sleeve avulsion, and Perthes), capsular lesions (humeral avulsion of the glenohumeral ligament), and accompanying osseous-cartilage lesions (Hill-Sachs, glenolabral articular disruption). Shoulder arthroscopy allows for a detailed visualization and a dynamic examination of all anatomic structures, identification of pathologic findings, and treatment of all concomitant lesions. Conclusion: Surgeons must be well prepared and understanding the normal anatomy of the glenohumeral joint, including its anatomic variants to seek for the possible pathologic lesions in anterior shoulder instability during shoulder arthroscopy. Patient selection criteria, improved surgical techniques, and implants available have contributed to the enhancement of

Mechanical load on the low back and shoulders during pushing and pulling of two-wheeled waste containers compared with lifting and carrying of bags and bins.

PubMed

Schibye, B; Søgaard, K; Martinsen, D; Klausen, K

2001-08-01

Compare the mechanical load on the low back and shoulders during pushing and pulling a two-wheeled container with the load during lifting and carrying the same amount of waste. Only little is known about risk factors and mechanical loads during push/pull operations. A complete 2(3) factor push/pull experiment. A two-wheeled container with 25 or 50 kg was pushed in front of and pulled behind the body by seven waste collectors. Further, the same subjects lifted and carried a paper bag and a dustbin both loaded with 7 and 25 kg. All operations were video recorded and the push/pull force was measured by means of a three-dimensional force transducer. Peak Motus and Watbak software were used for digitising and calculation of torque at L4/L5 and the shoulder joints and compression and shear forces at L4/L5. During pushing and pulling the compression at L4/L5 is from 605 to 1445 N. The extension torque at L4/L5 produced by the push/pull force is counteracted by the forward leaning of the upper body. The shear force is below 202 N in all situations. The torque at the shoulders is between 1 and 38 Nm. In the present experiments the torques at the low back and the shoulders are low during pushing and pulling. No relation exists between the size of the external force and the torque at the low back and the shoulder. Pushing and pulling are common in many workplaces and have often replaced lifting and carrying situations. This has emphasised the need for more knowledge of the internal mechanical load on the body during these activities.

Platelet-Rich Plasma for Frozen Shoulder: A Case Report.

PubMed

Aslani, Hamidreza; Nourbakhsh, Seyed Taghi; Zafarani, Zohreh; Ahmadi-Bani, Monireh; Ananloo, Mohammad Ebrahim Shahsavand; Beigy, Maani; Salehi, Shahin

2016-01-01

Frozen shoulder is a glenohumeral joint disorder that movement because of adhesion and the existence of fibrosis in the shoulder capsule. Platelet-rich plasma can produce collagen and growth factors, which increases stem cells and consequently enhances the healing. To date, there is no evidence regarding the effectiveness of platelet-rich plasma in frozen shoulder. A 45-year-old man with shoulder adhesive capsulitis volunteered for this treatment. He underwent two consecutive platelet-rich plasma injections at the seventh and eighth month after initiation of symptoms. We measured pain, function, ROM by the visual analogue scale (VAS), scores from the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and goniometer; respectively. After first injection, the patient reported 60% improvement regarding diurnal shoulder pain, and no night pain. Also, two-fold improvement for ROM and more than 70% improvement for function were reported. This study suggests the use of platelet-rich plasma in frozen shoulder to be tested in randomized trials.

[Results of shoulder isokinetic testing in volleyball players].

PubMed

Michael, J; König, D; Hessling, U; Popken, F; Eysel, P

2003-06-01

Isokinetic testing of the shoulder joint shows valuable indication to possible functional disorders and muscle imbalance. Concentric testing of several parameters using the Cybex 6000 practice unit was done by professional volleyball players performing external and internal rotation of the dominant and non-dominant shoulder at speeds of 60 degrees/s an 180 degrees/s. Sex-specific significant differences were shown which are comparable to other kind of sports.

Shoulder arthrodesis with a reconstruction plate

PubMed Central

Byeon, Hwa Kyo

2008-01-01

From 1995 to 2005, arthrodesis with a reconstruction plate was performed for eight shoulders. The average follow-up period was 44 months. The indications for shoulder arthrodesis were joint destruction as a sequel of tuberculous arthritis, malignant bone tumour, pyogenic arthritis, failed arthrodesis and paralysis of the brachial plexus. The evaluation criteria included bony union and pain. Two cases of malignant tumour required an homologous bone graft due to severe bone deficit—a fracture that occurred in the distal part of the arthrodesed shoulder after removing the plate. With the exception of these two cases, severe pain or other complications did not occur in any other case. Shoulder arthrodesis with a reconstruction plate was judged to be a useful method for glenohumeral salvage in cases without severe bone deficit. Further, additional treatment methods should be considered to prevent fracture that may occur as a result of severe bone deficit. PMID:18716728

Ultrasonographic findings of shoulder teno-muscular structures in symptomatic and asymptomatic dogs.

PubMed

Barella, Gabriele; Lodi, Matteo; Faverzani, Stefano

2017-11-14

B-mode sonographic evaluation of shoulder joint in dogs provides qualitative information concerning mainly tendon and muscles structures. Although the sonographic findings of tenomuscular lesions have been described previously, their frequency in symptomatic and asymptomatic patients has not been reported yet. Aim of the study was to describe and compare qualitative ultrasonographic findings of shoulder joint in clinically symptomatic and asymptomatic dogs and to speculate which lesions might be considered major responsible for lameness. Fifty-two dogs with shoulder lameness and 58 asymptomatic dogs (both with unremarkable radiographic findings) underwent ultrasonographic B-mode examination of the scapulohumeral joint. Lesions detected were recorded and statistically compared between groups. Significant differences between groups were observed for the number of ultrasonographic abnormalities detected and for fluid accumulation, biceps brachii tendon (BT) lesions and bone surface irregularities. Sonography was considered useful for the determination of lesions absence and for the detection of BT lesions, fluid accumulation, muscle lacerations and bone surface irregularities. The odds for symptomatic dogs were greater than for asymptomatic patients to ultrasonographically diagnose BT lesions, fluid accumulation and bone surface irregularities. Ultrasound has proven to be a useful tool in the evaluation of tenomusculoskeletal structures of shoulder in dogs with unremarkable radiographic findings. Our results suggest that ultrasonography is useful in the diagnosis of tendon abnormalities, fluid accumulation, muscle lacerations and bone surface irregularities as potential contributors to shoulder lameness in dogs.

The colonisation of the glenohumeral joint by Propionibacterium acnes is not associated with frozen shoulder but is more likely to occur after an injection into the joint.

PubMed

Booker, S J; Boyd, M; Gallacher, S; Evans, J P; Auckland, C; Kitson, J; Thomas, W; Smith, C D

2017-08-01

. acnes (OR 165, 95% CI 13.51 to 2015.24, p < 0.01). These results show a statistically significant association between subcutaneous skin P. acnes culture and P. acnes capsular culture, especially when the patient has undergone a previous injection. The results refute the hypothesis that P. acnes causes frozen shoulder. Cite this article: Bone Joint J 2017;99-B:1067-72. ©2017 The British Editorial Society of Bone & Joint Surgery.

The initial effects of a sustained glenohumeral postero-lateral glide during elevation on shoulder muscle activity: A repeated measures study on asymptomatic shoulders.

PubMed

Ribeiro, Daniel Cury; de Castro, Marcelo Peduzzi; Sole, Gisela; Vicenzino, Bill

2016-04-01

Manual therapy enhances pain-free range of motion and reduces pain levels, but its effect on shoulder muscle activity is unclear. This study aimed to assess the effects of a sustained glenohumeral postero-lateral glide during elevation on shoulder muscle activity. Thirty asymptomatic individuals participated in a repeated measures study of the electromyographic activity of the supraspinatus, infraspinatus, posterior deltoid, and middle deltoid. Participants performed four sets of 10 repetitions of shoulder scaption and abduction with and without a glide of the glenohumeral joint. Repeated-measures multivariate analysis of variance (MANOVA) was used to assess the effects of movement direction (scaption and abduction), and condition (with and without glide) (within-subject factors) on activity level of each muscle (dependent variables). Significant MANOVAs were followed-up with repeated-measures one-way analysis of variance. During shoulder scaption with glide, the supraspinatus showed a reduction of 4.1% maximal isometric voluntary contraction (MVIC) (95% CI 2.4, 5.8); and infraspinatus 1.3% MVIC (95% CI 0.5, 2.1). During shoulder abduction with a glide, supraspinatus presented a reduction of 2.5% MVIC (95% CI 1.1, 4.0), infraspinatus 2.1% MVIC (95% CI 1.0, 3.2), middle deltoid 2.2% MVIC (95% CI = 0.4, 4.1), posterior deltoid 2.1% MVIC (95% CI 1.3, 2.8). In asymptomatic individuals, sustained glide reduced shoulder muscle activity compared to control conditions. This might be useful in enhancing shoulder movement in clinical populations. Reductions in muscle activity might result from altered joint mechanics, including simply helping to lift the arm, and/or through changing afferent sensory input about the shoulder. Copyright © 2015 Elsevier Ltd. All rights reserved.

Dual-joint modeling for estimation of total knee replacement contact forces during locomotion.

PubMed

Hast, Michael W; Piazza, Stephen J

2013-02-01

Model-based estimation of in vivo contact forces arising between components of a total knee replacement is challenging because such forces depend upon accurate modeling of muscles, tendons, ligaments, contact, and multibody dynamics. Here we describe an approach to solving this problem with results that are tested by comparison to knee loads measured in vivo for a single subject and made available through the Grand Challenge Competition to Predict in vivo Tibiofemoral Loads. The approach makes use of a "dual-joint" paradigm in which the knee joint is alternately represented by (1) a ball-joint knee for inverse dynamic computation of required muscle controls and (2) a 12 degree-of-freedom (DOF) knee with elastic foundation contact at the tibiofemoral and patellofemoral articulations for forward dynamic integration. Measured external forces and kinematics were applied as a feedback controller and static optimization attempted to track measured knee flexion angles and electromyographic (EMG) activity. The resulting simulations showed excellent tracking of knee flexion (average RMS error of 2.53 deg) and EMG (muscle activations within ±10% envelopes of normalized measured EMG signals). Simulated tibiofemoral contact forces agreed qualitatively with measured contact forces, but their RMS errors were approximately 25% of the peak measured values. These results demonstrate the potential of a dual-joint modeling approach to predict joint contact forces from kinesiological data measured in the motion laboratory. It is anticipated that errors in the estimation of contact force will be reduced as more accurate subject-specific models of muscles and other soft tissues are developed.

Early motor learning changes in upper-limb dynamics and shoulder complex loading during handrim wheelchair propulsion.

PubMed

Vegter, Riemer J K; Hartog, Johanneke; de Groot, Sonja; Lamoth, Claudine J; Bekker, Michel J; van der Scheer, Jan W; van der Woude, Lucas H V; Veeger, Dirkjan H E J

2015-03-10

To propel in an energy-efficient manner, handrim wheelchair users must learn to control the bimanually applied forces onto the rims, preserving both speed and direction of locomotion. Previous studies have found an increase in mechanical efficiency due to motor learning associated with changes in propulsion technique, but it is unclear in what way the propulsion technique impacts the load on the shoulder complex. The purpose of this study was to evaluate mechanical efficiency, propulsion technique and load on the shoulder complex during the initial stage of motor learning. 15 naive able-bodied participants received 12-minutes uninstructed wheelchair practice on a motor driven treadmill, consisting of three 4-minute blocks separated by two minutes rest. Practice was performed at a fixed belt speed (v = 1.1 m/s) and constant low-intensity power output (0.2 W/kg). Energy consumption, kinematics and kinetics of propulsion technique were continuously measured. The Delft Shoulder Model was used to calculate net joint moments, muscle activity and glenohumeral reaction force. With practice mechanical efficiency increased and propulsion technique changed, reflected by a reduced push frequency and increased work per push, performed over a larger contact angle, with more tangentially applied force and reduced power losses before and after each push. Contrary to our expectations, the above mentioned propulsion technique changes were found together with an increased load on the shoulder complex reflected by higher net moments, a higher total muscle power and higher peak and mean glenohumeral reaction forces. It appears that the early stages of motor learning in handrim wheelchair propulsion are indeed associated with improved technique and efficiency due to optimization of the kinematics and dynamics of the upper extremity. This process goes at the cost of an increased muscular effort and mechanical loading of the shoulder complex. This seems to be associated with an

Design and evaluation of prosthetic shoulder controller

PubMed Central

Barton, Joseph E.; Sorkin, John D.

2015-01-01

We developed a 2-degree-of-freedom (DOF) shoulder position transducer (sensing shoulder protraction-retraction and elevation-depression) that can be used to control two of a powered prosthetic humerus' DOFs. We also developed an evaluation protocol based on Fitts' law to assess the performance of our device. The primary motivation for this work was to support development of powered prosthetic shoulder joints of a new generation of prosthetic arms for people with shoulder disarticulation and very high-level transhumeral amputation. We found that transducers that provided resistance to shoulder movement performed better than those providing no resistance. We also found that a position control scheme, where effector position is proportional to shoulder position, performed better than a velocity control scheme, where effector velocity is proportional to shoulder position. More generally, our transducer can be used to control motion along any two DOFs. It can also be used in a more general 4-DOF control scheme by sequentially controlling two DOFs at a time. The evaluation protocol has general applicability for researchers and practitioners. Researchers can employ it to compare different prosthesis designs and control schemes, while practitioners may find the evaluation protocol useful in evaluating and training people with amputation in the use of prostheses. PMID:25357185

[The gymnastics shoulder].

PubMed

Gerhardt, C; Doyscher, R; Boschert, H-P; Scheibel, M

2014-03-01

Adult gymnasts show a high prevalence of various shoulder pathologies. Due to the specific equipment used in gymnastics and the high training schedule with weekly training times up to 32 h, the shoulders of gymnasts are mostly subjected to symmetrical bilateral weight bearing. This is in contrast to overhead throwing, racket and martial arts sport forms in which the load is mainly located on the dominant side. Structural lesions of the shoulder and shoulder girdle in male gymnasts can arise due to high repetitive support and swing forces during exercises on the six specific types of apparatus and particularly the rings. These lesions particularly affect the biceps tendon anchor, the long head of the biceps tendon and the tendon of the supraspinatus muscle. Because possible pathologies can increasingly occur even in younger gymnasts, awareness of the treating physician and also the trainer should be increased. Early initiation of intensive conservative treatment and arthroscopic interventions in cases of failure of non-operative management are relevant for satisfying results. Modern arthroscopic reconstructive techniques are available for treating structural lesions. Nevertheless, in almost 30 % of the patients the occurrence of shoulder pain or the necessity for surgical interventions will prevent them from achieving the national or international level of competition. This underlines the necessity for development of prevention programs.

Shoulder joint abduction motion test bench: a new shoulder test bench for in vitro experiments with active muscle force simulation.

PubMed

Onder, Ursula; Blauth, Michael; Kralinger, Franz; Schmoelz, Werner

2012-05-30

In our society the average age is increasing, as are the number of proximal humeral head fractures. For fixation of these fractures, an increasing number of implants are available. New fixation devices should be compared biomechanically with established methods in a standardized fashion. The test bench that was designed was intended to simulate abduction motion of the humerus actively induced by muscle forces. We used three pneumatic muscles to apply forces to the tendons of the musculus supraspinatus and the bifid musculus deltoideus. Thus, it was possible to create an active abduction in the scapular plane. Two different fracture models (with and without medial support) were stabilised with an angular stable plate in sawbone models to reproduce a known clinical outcome with the newly designed test setup. The resultant force acting on the proximal humerus reached approximately 47% BW (per cent body weight), which amounted to 329.0 N (SD: 21.76). The supraspinatus reached maximum forces of 254.7 N (SD: 20.1) and the deltoid muscle 258.9 N (SD: 16.5). Fracture gap instrumentation with medial support resulted in a significantly reduced per-cycle fracture gap motion. The performance evaluation showed that the simulator produced predicable, reproducible movements with physiological muscle force magnitudes.

Kinematics of the six-degree-of-freedom force-reflecting Kraft Master

NASA Technical Reports Server (NTRS)

Williams, Robert L., II

1991-01-01

Presented here are kinematic equations for a six degree of freedom force-reflecting hand controller. The forward kinematics solution is developed and shown in simplified form. The Jacobian matrix, which uses terms from the forward kinematics solution, is derived. Both of these kinematic solutions require joint angle inputs. A calibration method is presented to determine the hand controller joint angles given the respective potentiometer readings. The kinematic relationship describing the mechanical coupling between the hand and controller shoulder and elbow joints is given. These kinematic equations may be used in an algorithm to control the hand controller as a telerobotic system component. The purpose of the hand controller is two-fold: operator commands to the telerobotic system are entered using the hand controller, and contact forces and moments from the task are reflected to the operator via the hand controller.

Using the Microsoft Kinect™ to assess 3-D shoulder kinematics during computer use.

PubMed

Xu, Xu; Robertson, Michelle; Chen, Karen B; Lin, Jia-Hua; McGorry, Raymond W

2017-11-01

Shoulder joint kinematics has been used as a representative indicator to investigate musculoskeletal symptoms among computer users for office ergonomics studies. The traditional measurement of shoulder kinematics normally requires a laboratory-based motion tracking system which limits the field studies. In the current study, a portable, low cost, and marker-less Microsoft Kinect™ sensor was examined for its feasibility on shoulder kinematics measurement during computer tasks. Eleven healthy participants performed a standardized computer task, and their shoulder kinematics data were measured by a Kinect sensor and a motion tracking system concurrently. The results indicated that placing the Kinect sensor in front of the participants would yielded a more accurate shoulder kinematics measurements then placing the Kinect sensor 15° or 30° to one side. The results also showed that the Kinect sensor had a better estimate on shoulder flexion/extension, compared with shoulder adduction/abduction and shoulder axial rotation. The RMSE of front-placed Kinect sensor on shoulder flexion/extension was less than 10° for both the right and the left shoulder. The measurement error of the front-placed Kinect sensor on the shoulder adduction/abduction was approximately 10° to 15°, and the magnitude of error is proportional to the magnitude of that joint angle. After the calibration, the RMSE on shoulder adduction/abduction were less than 10° based on an independent dataset of 5 additional participants. For shoulder axial rotation, the RMSE of front-placed Kinect sensor ranged between approximately 15° to 30°. The results of the study suggest that the Kinect sensor can provide some insight on shoulder kinematics for improving office ergonomics. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of a Hill-Sachs defect on glenohumeral translations, in situ capsular forces, and bony contact forces.

PubMed

Sekiya, Jon K; Jolly, John; Debski, Richard E

2012-02-01

Hill-Sachs defects have been associated with failed repairs for anterior shoulder instability. However, the biomechanical consequences of these defects are not well understood because of the complicated interaction between the passive soft tissue and bony stabilizers. The creation of a 25% Hill-Sachs defect would not significantly alter the glenohumeral translations but would increase the in situ forces in the glenohumeral capsule as well as the glenohumeral bony contact forces. Controlled laboratory study. A robotic/universal force-moment sensor (UFS) testing system was used to apply joint compression (22 N) and an anterior or posterior load (44 N) to cadaveric shoulders (n = 9) with the skin and deltoid removed (intact) at 3 glenohumeral joint positions (abduction/external rotation): 0°/0°, 30°/30°, and 60°/60° (corresponds to 90°/90° of shoulder abduction/external rotation). A 25% bony defect on the posterolateral humeral head (defect) was then created in the most common position of anterior shoulder dislocation (90°/90°), and the loading protocol was repeated. A nonparametric repeated-measures Friedman test with a Wilcoxon signed-rank post hoc test was performed to compare translations, in situ forces in the capsule, and bony contact forces between each state (P < .05). At 0°/0°, anterior translation significantly increased from 15.3 ± 8.2 mm to 16.6 ± 9.0 mm (P < .05) in response to an anterior load. At 30°/30°, anterior and posterior translations, respectively, significantly increased in response to both anterior (intact: 13.6 ± 7.1 mm vs defect: 14.2 ± 7 mm; P < .05) and posterior loads (intact: 15.7 ± 5.8 mm vs defect: 17.7 ± 5.1 mm; P < .05). In situ force in the capsule during anterior loading was increased in the defect state at both 60°/60° (intact: 38.9 ± 14.4 N vs defect: 43.2 ± 15.9 N; P < .05) and 30°/30° (intact: 39.6 ± 13.8 N vs defect: 45.6 ± 9.3 N; P < .05). The medial bony contact forces were also increased in the

A clamping force measurement system for monitoring the condition of bolted joints on railway track joints and points

NASA Astrophysics Data System (ADS)

Tesfa, B.; Horler, G.; Thobiani, F. Al; Gu, F.; Ball, A. D.

2012-05-01

Many industrial structures associated with railway infrastructures rely on a large number of bolted joint connections to ensure safe and reliable operation of the track and trackside furniture. Significant sums of money are spent annually to repair the damage caused by bolt failures and to maintain the integrity of bolted structures. In the UK, Network Rail (the organization responsible for rail network maintenance and safety) conducts corrective and preventive maintenance manually on 26,000 sets of points (each having approximately 30 bolted joints per set), in order to ensure operational success and safety for the travelling public. Such manual maintenance is costly, disruptive, unreliable and prone to human error. The aim of this work is to provide a means of automatically measuring the clamping force of each individual bolted joint, by means of an instrumented washer. This paper describes the development of a sensor means to be used in the washer, which satisfies the following criteria. Sense changes in the clamping force of the joint and report this fact. Provide compatibility with the large dynamic range of clamping force. Satisfy the limitations in terms of physical size. Provide the means to electronically interface with the washer. Provide a means of powering the washer in situ. Provide a solution at an acceptable cost. Specifically the paper focuses on requirements 1, 2 and 3 and presents the results that support further development of the proposed design and the realization of a pre-prototype system. In the paper, various options for the force sensing element (strain gage, capacitor, piezo-resistive) have been compared, using design optimization techniques. As a result of the evaluation, piezo-resistive sensors in concert with a proprietary force attenuation method, have been found to offer the best performance and cost trade-off The performance of the novel clamping force sensor has been evaluated experimentally and the results show that a smart washer

Occupational therapy interventions for shoulder conditions: a systematic review.

PubMed

von der Heyde, Rebecca L

2011-01-01

The objectives of this systematic review were (1) to identify, evaluate, and synthesize the research literature of relevance to occupational therapy regarding interventions for work-related shoulder conditions and (2) to interpret and apply the research literature to occupational therapy. Twenty-two studies were reviewed for this study-16 of Level I evidence, 2 of Level II evidence, and 4 of Level III evidence. In this systematic review, limited evidence from Level I studies was found to support exercise for shoulder pain; manual therapy and laser for adhesive capsulitis; conservative management of shoulder instability; early intervention without immobilization for specific, nondisplaced proximal humerus fractures; and exercise, joint mobilizations, and laser for patients with shoulder impingement. Further prospective studies are necessary for the delineation of specific surgical and therapeutic variables that facilitate positive outcomes in the treatment of patients with shoulder conditions.

The biomechanical effects of variation in the maximum forces exerted by trunk muscles on the joint forces and moments in the lumbar spine: a finite element analysis.

PubMed

Kim, K; Lee, S K; Kim, Y H

2010-10-01

The weakening of trunk muscles is known to be related to a reduction of the stabilization function provided by the muscles to the lumbar spine; therefore, strengthening deep muscles might reduce the possibility of injury and pain in the lumbar spine. In this study, the effect of variation in maximum forces of trunk muscles on the joint forces and moments in the lumbar spine was investigated. Accordingly, a three-dimensional finite element model of the lumbar spine that included the trunk muscles was used in this study. The variation in maximum forces of specific muscle groups was then modelled, and joint compressive and shear forces, as well as resultant joint moments, which were presumed to be related to spinal stabilization from a mechanical viewpoint, were analysed. The increase in resultant joint moments occurred owing to decrease in maximum forces of the multifidus, interspinales, intertransversarii, rotatores, iliocostalis, longissimus, psoas, and quadratus lumborum. In addition, joint shear forces and resultant joint moments were reduced as the maximum forces of deep muscles were increased. These results from finite element analysis indicate that the variation in maximum forces exerted by trunk muscles could affect the joint forces and joint moments in the lumbar spine.

Finding glenoid surface on scapula in 3D medical images for shoulder joint implant operation planning: 3D OCR

NASA Astrophysics Data System (ADS)

Mohammad Sadeghi, Majid; Kececi, Emin Faruk; Bilsel, Kerem; Aralasmak, Ayse

2017-03-01

Medical imaging has great importance in earlier detection, better treatment and follow-up of diseases. 3D Medical image analysis with CT Scan and MRI images has also been used to aid surgeries by enabling patient specific implant fabrication, where having a precise three dimensional model of associated body parts is essential. In this paper, a 3D image processing methodology for finding the plane on which the glenoid surface has a maximum surface area is proposed. Finding this surface is the first step in designing patient specific shoulder joint implant.

A Common Force-Sharing Pattern in Joint Action That Consists of Four People.

PubMed

Masumoto, Junya; Inui, Nobuyuki

2017-12-20

The authors examined the force-sharing patterns in a joint action performed by a group of two, three, or four people compared with a solo action. In the joint actions, 28 participants produced periodic isometric forces such that the sum of forces they produced cycled between 5% and 10% maximum voluntary contraction with the right hand at 1 Hz. In both the three- and four-person tasks, the correlation between forces produced by two of the three or four participants was negative, and the remaining one or two participants produced intermediate forces. The errors of force and interval and force variabilities were smaller in four- and three-people groups than individuals. Four- and three-people groups thus performed better than individuals.

Joint Operating Environment: The Joint Force in a Contested and Disordered World

DTIC Science & Technology

2016-07-14

spilling over borders, and creating wide-ranging international problems. The future of Science, Technology, and Engineering will see others reaching...10 Science, Technology, and Engineering and the Future Joint Force ..........................................15 Summary... Engineering – may lead to new and challenging conditions that will redefine the security environment of 2035.  Section 2: Contexts of Future Conflict

Effect of total shoulder replacements on airport security screening in the post-9/11 era.

PubMed

Dines, Joshua S; Elkousy, Hussein; Edwards, T Bradley; Gartsman, Gary M; Dines, David M

2007-01-01

There are few reports in the literature on the effect of orthopaedic implants on airport security devices and none on shoulder arthroplasty implants after September 11, 2001. Since 9/11, airport security screening devices have become more sensitive in response to the increasing threat of terrorism. Often, patients with joint implants activate the metal detectors and are subsequently subjected to more intensive screening. We assess the effects of shoulder joint implants on different airport security devices and what effect the results had on passenger travel. In this study, 154 patients who had previously undergone shoulder replacement responded to a questionnaire regarding their travel experiences after 9/11. Of these, 85 had flown during the time period studied (47 men and 38 women; mean age, 67.8 years); 79 had traveled domestically (mean, 7 flights), and 22 had taken international flights (mean, 6.1 flights). The questionnaire addressed each patient's height/weight, the number of flight segments flown (domestic and international), the number of times that a patient activated the doorway alarm/wand alarm, and the effect of a card stating that the patient had joint replacement (when applicable). On average, patients with shoulder replacement traveling domestically activated the security gate 52% of the time. The average for international travel was 42%. Of the patients who flew both domestically and internationally, there was a high correlation of activation (R = 0.54). Twenty-six patients had multiple joint implants (mean, 2.8). Multiple joint implants caused increased alarm activation (P < .001). All patients reported that their travel was delayed during the instances of security activation. There was no statistically significant effect of body mass index, height, weight, age, or sex on security device activation. Of the patients, 71% were told by their doctor that the shoulder replacement may activate security devices. Of these, 46 were given a card by their

Autologous Fat Transfer for Thumb Carpometacarpal Joint Osteoarthritis: A Prospective Study.

PubMed

Herold, Christian; Rennekampff, Hans-Oliver; Groddeck, Robert; Allert, Sixtus

2017-08-01

Most operations for carpometacarpal joint osteoarthritis of the thumb irreversibly alter or destroy the anatomy. There is a high demand for minimally invasive alternatives. The authors report the results of autologous fat transfer for treatment of thumb carpometacarpal joint osteoarthritis. In a prospective study, 50 patients with thumb carpometacarpal joint osteoarthritis were observed for 1 year after autologous fat transfer. Manual liposuction and centrifugation were performed. Pain rating according to visual analogue pain scale; objective force of pinch grip and fist closure; and Disabilities of the Arm, Shoulder, and Hand questionnaire scores before and after treatment were analyzed. The average pain in stage 2 patients preoperatively was 7.7 ± 1.3; it was 1.8 ± 1.9 after 6 months and 2.4 ± 3.1 after 12 months. Patients with stage 2 osteoarthritis demonstrated a superior benefit from this treatment compared with patients with either stage 3 or stage 4 thumb carpometacarpal joint osteoarthritis. There were similar improvements for the parameters strength and Disabilities of the Arm, Shoulder, and Hand questionnaire score. No serious adverse events were observed. Autologous fat transplantation is an appealing alternative, especially in early-stage basal joint osteoarthritis of the thumb. The low invasiveness of the procedure and early recovery of patients compared with classical procedures such as trapeziectomy, and the superior long-term results compared with classical injection therapy, make this approach feasible as a first-line therapy in early-stage basal joint osteoarthritis of the thumb. Therapeutic, IV.

Joint Force Quarterly. Issue 48, 1st Quarter 2008

DTIC Science & Technology

2008-01-01

Closure and joint basing initiatives. n Engage in the development of a broad- based, flexible, effective , and affordable joint military health care system...in a London hospital in November 2006 due to ingested alpha particles from Polonium 210 . Just the trace trail of Polonium 210 across the city and...can we adequately defend the Nation. Therefore, we will: n Determine the true health of our ground forces in terms of people, training, equipment

A Cervico-Thoraco-Lumbar Multibody Dynamic Model for the Estimation of Joint Loads and Muscle Forces.

PubMed

Khurelbaatar, Tsolmonbaatar; Kim, Kyungsoo; Hyuk Kim, Yoon

2015-11-01

Computational musculoskeletal models have been developed to predict mechanical joint loads on the human spine, such as the forces and moments applied to vertebral and facet joints and the forces that act on ligaments and muscles because of difficulties in the direct measurement of joint loads. However, many whole-spine models lack certain elements. For example, the detailed facet joints in the cervical region or the whole spine region may not be implemented. In this study, a detailed cervico-thoraco-lumbar multibody musculoskeletal model with all major ligaments, separated structures of facet contact and intervertebral disk joints, and the rib cage was developed. The model was validated by comparing the intersegmental rotations, ligament tensile forces, facet joint contact forces, compressive and shear forces on disks, and muscle forces were to those reported in previous experimental and computational studies both by region (cervical, thoracic, or lumbar regions) and for the whole model. The comparisons demonstrated that our whole spine model is consistent with in vitro and in vivo experimental studies and with computational studies. The model developed in this study can be used in further studies to better understand spine structures and injury mechanisms of spinal disorders.

[Shoulder instability and rotator cuff tear].

PubMed

Voigt, C; Lill, H

2009-01-01

A rotator cuff tear as a complication of anterior shoulder dislocation is well known in patients over 40 years old. The incidence of this accompanying injury correlates with the patient's age and the number of redislocations. The tear localization and dimension depend on the patient's age. To what extent these tears are a complication of shoulder dislocation is often unclear, as rotator cuff tears and glenohumeral instability interact. Reports on this combined injury pattern are rare, but based on the patient's age, activity level, and functional demand, therapeutic concepts have been devised. In active patients younger than 60 years and in cases of redislocation, both the rotator cuff tear and the capsule-labrum-ligament lesion should be reconstructed arthroscopically. In lesser active patients age 60 years or older, an isolated rotator cuff reconstruction is often sufficient to stabilize the glenohumeral joint. This treatment concept shows a predominantly good outcome.As a special form of anterior shoulder dislocation, a rotator cuff tear and a plexus brachialis lesion--the"terrible triad of the shoulder"--is described here.

The volleyball athlete's shoulder: biomechanical adaptations and injury associations.

PubMed

Challoumas, Dimitrios; Stavrou, Antonio; Dimitrakakis, Georgios

2017-06-01

In volleyball, the dominant shoulder of the athlete undergoes biomechanical and morphological adaptations; however, definitive conclusions about their exact nature, aetiology, purpose and associations with shoulder injury have not been reached. We present a systematic review of the existing literature describing biomechanical adaptations in the dominant shoulders of volleyball players and factors that may predispose to shoulder pain/injury. A thorough literature search via Medline, EMBASE and SCOPUS was conducted for original studies of volleyball players and 15 eligible articles were identified. Assessment of study quality was performed using the STROBE statement. The reviewed literature supports the existence of a glenohumeral internal rotation deficit (GIRD) and a possible (and less pronounced) external rotation gain in the dominant vs. the non-dominant shoulder of volleyball athletes. Unlike other overhead sports, the GIRD in volleyball athletes appears to be anatomical as a response to the repetitive overhead movements and not to be associated with shoulder pain/injury. Additionally, the dominant shoulder exhibits muscular imbalance, which appears to be a significant risk factor for shoulder pain. Strengthening of the external rotators should be used alongside shoulder stretching and joint mobilisations, core strengthening and optimisation of spike technique as part of injury management and prevention programmes.

Factors affecting the stability of reverse shoulder arthroplasty: a biomechanical study.

PubMed

Clouthier, Allison L; Hetzler, Markus A; Fedorak, Graham; Bryant, J Tim; Deluzio, Kevin J; Bicknell, Ryan T

2013-04-01

Despite the success of reverse shoulder arthroplasty (RSA) in treating patients with painful pseudoparalytic shoulders, instability is a common complication and currently the factors affecting stability are not well understood. The objective of this study was to investigate a number of factors as well as the interactions between factors to determine how they affect the stability of the prosthesis. These factors included: active arm posture (abduction and abduction plane angles), loading direction, glenosphere diameter and eccentricity, and humeral socket constraint. Force required to dislocate the joint, determined using a biomechanical shoulder simulator, was used as a measure of stability. A factorial design experiment was implemented to examine the factors and interactions. Actively increasing the abduction angle by 15° leads to a 30% increase in stability and use of an inferior-offset rather than a centered glenosphere improved stability by 17%. Use of a more constrained humeral socket also increased stability; but the effect was dependent on loading direction, with a 88% improvement for superior loading, 66% for posterior, 36% for anterior, and no change for inferior loading. Abduction plane angle and glenosphere diameter had no effect on stability. Increased glenohumeral abduction and the use of an inferior-offset glenosphere were found to increase the stability of RSA. Additionally, use of a more constrained humeral socket increased stability for anterior, posterior, and superior loading. These identified factor effects have the potential to decrease the risk of dislocation following RSA. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Influence of Muscle-Tendon Wrapping on Calculations of Joint Reaction Forces in the Equine Distal Forelimb

PubMed Central

Merritt, Jonathan S.; Davies, Helen M. S.; Burvill, Colin; Pandy, Marcus G.

2008-01-01

The equine distal forelimb is a common location of injuries related to mechanical overload. In this study, a two-dimensional model of the musculoskeletal system of the region was developed and applied to kinematic and kinetic data from walking and trotting horses. The forces in major tendons and joint reaction forces were calculated. The components of the joint reaction forces caused by wrapping of tendons around sesamoid bones were found to be of similar magnitude to the reaction forces between the long bones at each joint. This finding highlighted the importance of taking into account muscle-tendon wrapping when evaluating joint loading in the equine distal forelimb. PMID:18509485

The utility of international shoulder joint replacement registries and databases: a comparative analytic review of two hundred and sixty one thousand, four hundred and eighty four cases.

PubMed

Bayona, Carlos Eduardo Afanador; Somerson, Jeremy S; Matsen, Frederick A

2018-02-01

National registries are valuable tools for understanding the results of shoulder arthroplasty across populations. These databases provide an unselected view of shoulder joint replacement within geographical areas that cannot be obtained from case series or prospective studies. They can be particularly helpful in determining which diagnoses, patients, procedures, and prostheses have higher than expected rates of revision. In an attempt to determine the generalizability of registry data, we asked, 'how similar are the patients and procedures among the different national registries?' We analyzed national shoulder arthroplasty registries and databases accessed via Internet portals and through a PubMed literature search. Seven national/regional registries and five publications regarding national shoulder arthroplasty data were identified; these sources contained a combined total of 261,484 shoulder arthroplasty cases. The percentages of hemiarthroplasty, anatomic (aTSA) and reverse total shoulders (rTSA), the diagnoses leading to arthroplasty, the mean patient age, and the distribution of patient gender varied significantly among these different databases. This study indicates that the indications for and application of shoulder arthroplasty have important geographical variations and that these variations must be considered when comparing outcomes of shoulder arthroplasty from different locations. Without controlling for age, gender, diagnosis and procedure type, the results from one national registry may not be applicable to patients from a different location. In that national data provide the opportunity to reduce costs by identifying implants and procedures with higher failure rates, the funding of registries needs to be free of conflicts of interest.

Prediction of Knee Joint Contact Forces From External Measures Using Principal Component Prediction and Reconstruction.

PubMed

Saliba, Christopher M; Clouthier, Allison L; Brandon, Scott C E; Rainbow, Michael J; Deluzio, Kevin J

2018-05-29

Abnormal loading of the knee joint contributes to the pathogenesis of knee osteoarthritis. Gait retraining is a non-invasive intervention that aims to reduce knee loads by providing audible, visual, or haptic feedback of gait parameters. The computational expense of joint contact force prediction has limited real-time feedback to surrogate measures of the contact force, such as the knee adduction moment. We developed a method to predict knee joint contact forces using motion analysis and a statistical regression model that can be implemented in near real-time. Gait waveform variables were deconstructed using principal component analysis and a linear regression was used to predict the principal component scores of the contact force waveforms. Knee joint contact force waveforms were reconstructed using the predicted scores. We tested our method using a heterogenous population of asymptomatic controls and subjects with knee osteoarthritis. The reconstructed contact force waveforms had mean (SD) RMS differences of 0.17 (0.05) bodyweight compared to the contact forces predicted by a musculoskeletal model. Our method successfully predicted subject-specific shape features of contact force waveforms and is a potentially powerful tool in biofeedback and clinical gait analysis.

SHOULDER DISORDERS AND OCCUPATION

PubMed Central

Linaker, CH; Walker-Bone, K

2016-01-01

Shoulder pain is very common and causes substantial morbidity. Standardised classification systems based upon presumed patho-anatomical origins have proved poorly reproducible and hampered epidemiological research. Despite this, there is evidence that exposure to combinations of physical workplace strains such as overhead working, heavy lifting and forceful work as well as working in an awkward posture increase the risk of shoulder disorders. Psychosocial risk factors are also associated. There is currently little evidence to suggest that either primary prevention or treatment strategies in the workplace are very effective and more research is required, particularly around the cost-effectiveness of different strategies. PMID:26612238

Evaluation of regression-based 3-D shoulder rhythms.

PubMed

Xu, Xu; Dickerson, Clark R; Lin, Jia-Hua; McGorry, Raymond W

2016-08-01

The movements of the humerus, the clavicle, and the scapula are not completely independent. The coupled pattern of movement of these bones is called the shoulder rhythm. To date, multiple studies have focused on providing regression-based 3-D shoulder rhythms, in which the orientations of the clavicle and the scapula are estimated by the orientation of the humerus. In this study, six existing regression-based shoulder rhythms were evaluated by an independent dataset in terms of their predictability. The datasets include the measured orientations of the humerus, the clavicle, and the scapula of 14 participants over 118 different upper arm postures. The predicted orientations of the clavicle and the scapula were derived from applying those regression-based shoulder rhythms to the humerus orientation. The results indicated that none of those regression-based shoulder rhythms provides consistently more accurate results than the others. For all the joint angles and all the shoulder rhythms, the RMSE are all greater than 5°. Among those shoulder rhythms, the scapula lateral/medial rotation has the strongest correlation between the predicted and the measured angles, while the other thoracoclavicular and thoracoscapular bone orientation angles only showed a weak to moderate correlation. Since the regression-based shoulder rhythm has been adopted for shoulder biomechanical models to estimate shoulder muscle activities and structure loads, there needs to be further investigation on how the predicted error from the shoulder rhythm affects the output of the biomechanical model. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Specific Shoulder Pathoanatomy in Semiprofessional Water Polo Players

PubMed Central

Klein, Maria; Tarantino, Ignazio; Warschkow, René; Berger, Claus Joachim; Zdravkovic, Vilijam; Jost, Bernhard; Badulescu, Michael

2014-01-01

Background: Shoulders of throwing and swimming athletes are highly stressed joints that often show structural abnormalities on magnetic resonance imaging (MRI). However, while water polo players exhibit a combination of throwing and swimming movements, a specific pattern of pathological findings has not been described. Purpose: To assess specific MRI abnormalities in shoulders of elite water polo players and to compare these findings with a healthy control group. Study Design: Cross-sectional study; Level of evidence, 3. Methods: After performing a power analysis, volunteers were recruited for this study. Both shoulders of 28 semiprofessional water polo players and 15 healthy volunteers were assessed clinically (based on the Constant score) and had bilateral shoulder MRIs. The shoulders were clustered into 3 groups: 28 throwing and 28 nonthrowing shoulders of water polo athletes and 30 shoulders of healthy control subjects. Results: Twenty-eight male water polo players with an average age of 24 years and 15 healthy subjects (30 shoulders) with an average age of 31 years were examined. Compared with controls, significantly more MRI abnormalities in the water polo players' throwing shoulders could be found in the subscapularis, infraspinatus, and posterior labrum (P = .001, P = .024, and P = .041, respectively). Other structures showed no statistical differences between the 3 groups, including the supraspinatus tendon, which had abnormalities in 36% of throwing versus 32% of nonthrowing shoulders and 33% of control shoulders. All throwing shoulders showed abnormal findings in the MRI, but only 8 (29%) were symptomatic. Conclusion: The shoulders of semiprofessional water polo players demonstrated abnormalities in subscapularis and infraspinatus tendons that were not typical abnormalities for swimmers or throwing athletes. Clinical Relevance: The throwing shoulders of water polo players have specific MRI changes. Clinical symptoms do not correlate with the MRI findings

Ranges of motion after reverse shoulder arthroplasty improve significantly the first year after surgery in patients with rheumatoid arthritis.

PubMed

Tiusanen, Hannu; Sarantsin, Pjotor; Stenholm, Miika; Mattie, Ryan; Saltychev, Mikhail

2016-07-01

To evaluate the trajectory of the change in range of motion after reverse shoulder joint replacement during 3-year follow-up among patients with rheumatoid arthritis. Retrospective cohort longitudinal study of 76 shoulder replacements performed in a university clinic. The range of shoulder motion was assessed by a physiotherapist using a manual goniometer with 5-degree precision before the surgery and 1, 3, 6, 12, and 36 months postoperatively. The shapes of the regression curves suggest that the improvement or decline observed in joint motion was happening mostly during the first year after surgery. After 1 year, the trajectories become flat and they remained unchanged until the end of follow-up. After shoulder joint replacement, the range of shoulder motion showed substantial changes during the first year only. This should be taken into account when scheduling control visits, planning rehabilitation, and predicting the use of community services after the surgery.

Diagnosis of Ehlers-Danlos syndrome after a first shoulder dislocation.

PubMed

Nourissat, Geoffroy; Vigan, Marie; Hamonet, Claude; Doursounian, Levon; Deranlot, Julien

2018-01-01

Shoulder dislocation is often the first symptom of Ehlers-Danlos syndrome (EDS). Whether it occurs in early-onset EDS is unknown. In most cases, surgical failure leads to the diagnosis. We aimed to determine whether clinical symptoms can signal the presence of EDS at a first dislocation. In this retrospective study, we analyzed clinical and radiologic data for 27 patients with EDS and shoulder instability and a control population of 40 consecutive non-EDS patients undergoing surgery for an unstable shoulder. Data were collected on gender, age, single or bilateral disease, general hyperlaxity, shoulder hyperlaxity, number of dislocations or subluxations, nontraumatic onset, and pain specificity. Nerve and vascular injuries, joint disorders, and family history were recorded, and radiologic data were reported. Age <14 years, female sex, bilateral disorder, and general hyperlaxity were significantly more frequent in patients with EDS and a first dislocation than in those without EDS. Painless dislocation with pain after dislocation and concomitant nerve injury were more frequent in affected patients, as were hemostasis disorders and a family history of joint hyperlaxity. Bone lesions were not seen on radiographs. Only the hyperlaxity sign (external rotation >85°) did not differ between the groups. After a first dislocation in a young girl with global hyperlaxity but not necessarily shoulder hyperlaxity, painless atraumatic dislocation with pain after reduction can suggest EDS. Copyright © 2018. Published by Elsevier Inc.

Anterior stability of the reverse shoulder arthroplasty depending on implant configuration and rotator cuff condition.

PubMed

Pastor, Marc-Frederic; Kraemer, Manuel; Wellmann, Mathias; Hurschler, Christof; Smith, Tomas

2016-11-01

The aim of this study was to investigate the stabilizing influence of the rotator cuff as well as the importance of glenosphere and onlay configuration on the anterior stability of the reverse total shoulder replacement (RTSR). A reverse total shoulder replacement was implanted into eight human cadaveric shoulders, and biomechanical testing was performed under three conditions: after implantation of the RTSR, after additional dissection of the subscapularis tendon, and after additional dissection of the infraspinatus and teres minor tendon. Testing was performed in 30° of abduction and three rotational positions: 30° internal rotation, neutral rotation, and 30° external rotation. Furthermore, the 38-mm and 42-mm glenospheres were tested in combination with a standard and a high-mobility humeral onlay. A gradually increased force was applied to the glenohumeral joint in anterior direction until the RTSR dislocated. The 42-mm glenosphere showed superior stability compared with the 38-mm glenosphere. The standard humeral onlay required significantly higher anterior dislocation forces than the more shallow high-mobility onlay. External rotation was the most stable position. Furthermore, isolated detachment of the subscapularis and combined dissection of the infraspinatus, teres minor, and subscapularis tendon increased anterior instability. This study showed superior stability with the 42-mm glenosphere and the more conforming standard onlay. External rotation was the most stable position. Detachment of the subscapularis as well as dissection of the complete rotator cuff decreased anterior stability.

Joint range of motion after total shoulder arthroplasty with and without a continuous interscalene nerve block: a retrospective, case-control study.

PubMed

Ilfeld, Brian M; Wright, Thomas W; Enneking, F Kayser; Morey, Timothy E

2005-01-01

Although a continuous interscalene nerve block (CISB) has been shown to provide potent analgesia after major shoulder surgery, its potential effects on postoperative rehabilitation remain uninvestigated. Therefore, this retrospective case-control study was undertaken to determine the association between CISB and joint range-of-motion after total shoulder arthroplasty (TSA). The medical records for patients who underwent TSA at our institution in the previous 3 years were examined. Each patient with a CISB (cases) was matched with a patient without a CISB (controls) for the following variables: age, gender, and TSA type (primary v revision). Data collected included maximum shoulder elevation and external rotation (primary endpoints), along with pre- and postoperative pain scores. Of 134 charts reviewed, 25 cases were matched with an equal number of controls. On postoperative day 1, patients with or without a CISB achieved a median (5th-95th percentiles) of 85% (51-100) and 33% (11-56) of their surgeon-defined goal for elevation (P = .048), respectively, and attained 100% (33-100) and 17% (-81-68) for external rotation (P < .001), respectively. The median numeric rating pain score (NRS) during shoulder movement for patients with CISB was 2.0 (0.0-8.7) versus 8.5 (1.8-10.0) for patients without CISB (P < .001). Least, median, and highest resting NRS for the 24 hours after surgery were 0.0 (0.0-5.8), 1.0 (0.0-6.4), and 3.0 (0.0-9.0) for patients with CISB, respectively, versus 2.0 (0.0-7.7), 6.0 (0.3-9.6), and 8.0 (0.0-10.0) for patients without CISB (P = .030, P < .001, and P < .001 between groups, respectively). The day after TSA, a CISB is associated with increased shoulder range of motion, most likely resulting from the potent analgesia these nerve blocks provide.

Functional outcomes assessment in shoulder surgery

PubMed Central

Wylie, James D; Beckmann, James T; Granger, Erin; Tashjian, Robert Z

2014-01-01

The effective evaluation and management of orthopaedic conditions including shoulder disorders relies upon understanding the level of disability created by the disease process. Validated outcome measures are critical to the evaluation process. Traditionally, outcome measures have been physician derived objective evaluations including range of motion and radiologic evaluations. However, these measures can marginalize a patient’s perception of their disability or outcome. As a result of these limitations, patient self-reported outcomes measures have become popular over the last quarter century and are currently primary tools to evaluate outcomes of treatment. Patient reported outcomes measures can be general health related quality of life measures, health utility measures, region specific health related quality of life measures or condition specific measures. Several patients self-reported outcomes measures have been developed and validated for evaluating patients with shoulder disorders. Computer adaptive testing will likely play an important role in the arsenal of measures used to evaluate shoulder patients in the future. The purpose of this article is to review the general health related quality-of-life measures as well as the joint-specific and condition specific measures utilized in evaluating patients with shoulder conditions. Advances in computer adaptive testing as it relates to assessing dysfunction in shoulder conditions will also be reviewed. PMID:25405091

Joint torques and joint reaction forces during squatting with a forward or backward inclined Smith machine.

PubMed

Biscarini, Andrea; Botti, Fabio M; Pettorossi, Vito E

2013-02-01

We developed a biomechanical model to determine the joint torques and loadings during squatting with a backward/forward-inclined Smith machine. The Smith squat allows a large variety of body positioning (trunk tilt, foot placement, combinations of joint angles) and easy control of weight distribution between forefoot and heel. These distinctive aspects of the exercise can be managed concurrently with the equipment inclination selected to unload specific joint structures while activating specific muscle groups. A backward (forward) equipment inclination decreases (increases) knee torque, and compressive tibiofemoral and patellofemoral forces, while enhances (depresses) hip and lumbosacral torques. For small knee flexion angles, the strain-force on the posterior cruciate ligament increases (decreases) with a backward (forward) equipment inclination, whereas for large knee flexion angles, this behavior is reversed. In the 0 to 60 degree range of knee flexion angles, loads on both cruciate ligaments may be simultaneously suppressed by a 30 degree backward equipment inclination and selecting, for each value of the knee angle, specific pairs of ankle and hip angles. The anterior cruciate ligament is safely maintained unloaded by squatting with backward equipment inclination and uniform/forward foot weight distribution. The conditions for the development of anterior cruciate ligament strain forces are clearly explained.

An entropy-assisted musculoskeletal shoulder model.

PubMed

Xu, Xu; Lin, Jia-Hua; McGorry, Raymond W

2017-04-01

Optimization combined with a musculoskeletal shoulder model has been used to estimate mechanical loading of musculoskeletal elements around the shoulder. Traditionally, the objective function is to minimize the summation of the total activities of the muscles with forces, moments, and stability constraints. Such an objective function, however, tends to neglect the antagonist muscle co-contraction. In this study, an objective function including an entropy term is proposed to address muscle co-contractions. A musculoskeletal shoulder model is developed to apply the proposed objective function. To find the optimal weight for the entropy term, an experiment was conducted. In the experiment, participants generated various 3-D shoulder moments in six shoulder postures. The surface EMG of 8 shoulder muscles was measured and compared with the predicted muscle activities based on the proposed objective function using Bhattacharyya distance and concordance ratio under different weight of the entropy term. The results show that a small weight of the entropy term can improve the predictability of the model in terms of muscle activities. Such a result suggests that the concept of entropy could be helpful for further understanding the mechanism of muscle co-contractions as well as developing a shoulder biomechanical model with greater validity. Copyright © 2017 Elsevier Ltd. All rights reserved.

First-time anterior shoulder dislocations: should they be arthroscopically stabilised?

PubMed Central

Sedeek, Sedeek Mohamed; Bin Abd Razak, Hamid Rahmatullah; Ee, Gerard WW; Tan, Andrew HC

2014-01-01

The glenohumeral joint is inherently unstable because the large humeral head articulates with the small shadow glenoid fossa. Traumatic anterior dislocation of the shoulder is a relatively common athletic injury, and the high frequency of recurrent instability in young athletes after shoulder dislocation is discouraging to both the patient and the treating physician. Management of primary traumatic shoulder dislocation remains controversial. Traditionally, treatment involves initial immobilisation for 4–6 weeks, followed by functional rehabilitation. However, in view of the high recurrence rates associated with this traditional approach, there has been an escalating interest in determining whether immediate surgical intervention can lower the rate of recurrent shoulder dislocation, improving the patient’s quality of life. This review article aims to provide an overview of the nature and pathogenesis of first-time primary anterior shoulder dislocations, the widely accepted management modalities, and the efficacy of primary surgical intervention in first-time primary anterior shoulder dislocations. PMID:25631890

Influence of weak hip abductor muscles on joint contact forces during normal walking: probabilistic modeling analysis.

PubMed

Valente, Giordano; Taddei, Fulvia; Jonkers, Ilse

2013-09-03

The weakness of hip abductor muscles is related to lower-limb joint osteoarthritis, and joint overloading may increase the risk for disease progression. The relationship between muscle strength, structural joint deterioration and joint loading makes the latter an important parameter in the study of onset and follow-up of the disease. Since the relationship between hip abductor weakness and joint loading still remains an open question, the purpose of this study was to adopt a probabilistic modeling approach to give insights into how the weakness of hip abductor muscles, in the extent to which normal gait could be unaltered, affects ipsilateral joint contact forces. A generic musculoskeletal model was scaled to each healthy subject included in the study, and the maximum force-generating capacity of each hip abductor muscle in the model was perturbed to evaluate how all physiologically possible configurations of hip abductor weakness affected the joint contact forces during walking. In general, the muscular system was able to compensate for abductor weakness. The reduced force-generating capacity of the abductor muscles affected joint contact forces to a mild extent, with 50th percentile mean differences up to 0.5 BW (maximum 1.7 BW). There were greater increases in the peak knee joint loads than in loads at the hip or ankle. Gluteus medius, particularly the anterior compartment, was the abductor muscle with the most influence on hip and knee loads. Further studies should assess if these increases in joint loading may affect initiation and progression of osteoarthritis. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ten questions on prosthetic shoulder infection

PubMed Central

Pinder, Elizabeth M; Ong, Joshua CY; Bale, R Stephen

2016-01-01

Prosthetic shoulder infection can cause significant morbidity secondary to pain and stiffness. Symptoms may be present for years before diagnosis because clinical signs are often absent and inflammatory markers may be normal. An emerging common culprit, Propionibacterium acnes, is hard to culture and so prolonged incubation is necessary. A negative culture result does not always exclude infection and new synovial fluid biochemical markers such as α defensin are less sensitive than for lower limb arthroplasty. A structured approach is necessary when assessing patients for prosthetic shoulder joint infection. This includes history, examination, serum inflammatory markers, plain radiology and aspiration and/or biopsy. A classification for the likelihood of prosthetic shoulder infection has been described based on culture, pre-operative and intra-operative findings. Treatment options include antibiotic suppression, debridement with component retention, one-stage revision, two-stage revision and excision arthroplasty. Revision arthroplasty is associated with the best outcomes. PMID:27583013

Ten questions on prosthetic shoulder infection.

PubMed

Pinder, Elizabeth M; Ong, Joshua Cy; Bale, R Stephen; Trail, Ian A

2016-07-01

Prosthetic shoulder infection can cause significant morbidity secondary to pain and stiffness. Symptoms may be present for years before diagnosis because clinical signs are often absent and inflammatory markers may be normal. An emerging common culprit, Propionibacterium acnes, is hard to culture and so prolonged incubation is necessary. A negative culture result does not always exclude infection and new synovial fluid biochemical markers such as α defensin are less sensitive than for lower limb arthroplasty. A structured approach is necessary when assessing patients for prosthetic shoulder joint infection. This includes history, examination, serum inflammatory markers, plain radiology and aspiration and/or biopsy. A classification for the likelihood of prosthetic shoulder infection has been described based on culture, pre-operative and intra-operative findings. Treatment options include antibiotic suppression, debridement with component retention, one-stage revision, two-stage revision and excision arthroplasty. Revision arthroplasty is associated with the best outcomes.

Standing Joint Forces: Spearhead for Global Operational Maneuver

DTIC Science & Technology

2005-05-26

Threat,” In The War Next Time: Countering Rogue States and Terrorists 1 20 NOVEMBER 2014 Operation Roundhouse was a resounding success. While...America’s " kick -down the door" force, capable of extremely rapid deployment from CONUS to anywhere in the world to ensure aerospace access for joint

Forces and moments generated by the human arm: Variability and control

PubMed Central

Xu, Y; Terekhov, AV; Latash, ML; Zatsiorsky, VM

2012-01-01

This is an exploratory study of the accurate endpoint force vector production by the human arm in isometric conditions. We formulated three common-sense hypotheses and falsified them in the experiment. The subjects (n=10) exerted static forces on the handle in eight directions in a horizontal plane for 25 seconds. The forces were of 4 magnitude levels (10 %, 20%, 30% and 40% of individual MVC). The torsion moment on the handle (grasp moment) was not specified in the instruction. The two force components and the grasp moment were recorded, and the shoulder, elbow, and wrist joint torques were computed. The following main facts were observed: (a) While the grasp moment was not prescribed by the instruction, it was always produced. The moment magnitude and direction depended on the instructed force magnitude and direction. (b) The within-trial angular variability of the exerted force vector (angular precision) did not depend on the target force magnitude (a small negative correlation was observed). (c) Across the target force directions, the variability of the exerted force magnitude and directional variability exhibited opposite trends: In the directions where the variability of force magnitude was maximal, the directional variability was minimal and vice versa. (d) The time profiles of joint torques in the trials were always positively correlated, even for the force directions where flexion torque was produced at one joint and extension torque was produced at the other joint. (e) The correlations between the grasp moment and the wrist torque were negative across the tasks and positive within the individual trials. (f) In static serial kinematic chains, the pattern of the joint torques distribution could not be explained by an optimization cost function additive with respect to the torques. Plans for several future experiments have been suggested. PMID:23080084

Axillary artery injury secondary to inferior shoulder dislocation.

PubMed

Plaga, Brad R; Looby, Peter; Feldhaus, Steven J; Kreutzmann, Karl; Babb, Aaron

2010-11-01

Dislocation injuries of the glenohumeral joint are common in the general public and generally are corrected without complication. One serious complication with shoulder dislocations, or the subsequent reduction, is a lesion to the axillary artery. This specific complication is most frequently seen in the elderly population, where vascular structures have become less flexible. Also, these injuries are most common in association with anterior dislocations of the shoulder. To bring awareness to the possibility of axillary artery injury with inferior dislocation of the shoulder, the treatment options, and a review. We report a 15-year-old male athlete who inferiorly dislocated his shoulder during wrestling practice. The injury was reduced at the scene with manual traction and the patient was transferred to our clinic for evaluation. The patient was determined to have a pseudoaneurysm of the axillary artery, and the history and treatment of the illness are presented. Axillary artery injuries secondary to shoulder dislocations are rare, especially in the young athlete, and proper recognition and treatment offer patients a full recovery. Copyright © 2010. Published by Elsevier Inc.

Shoulder instability: impact of glenohumeral arthrotomography on treatment.

PubMed

el-Khoury, G Y; Kathol, M H; Chandler, J B; Albright, J P

1986-09-01

We used arthrotomography to study the glenoid labrum in 114 patients. Sixty-nine of the patients had anatomic instability of the shoulder (including recurrent dislocation and subluxation of the shoulder), and 45 patients had functional instability of the shoulder (denoted by chronic pain, clicking of the joint, and the sensation that an unstable condition exists without the objective signs of it). Labral tears were revealed arthrotomographically in 86% of the patients with anatomic instability, while only 40% of the patients with functional instability had labral abnormalities, and these were primarily of minor severity. Fifty-six patients (44 of whom had anatomic instability; 12, functional instability) required surgery. The surgical findings were correlated with the arthrotomographic findings, and no false-positive results were revealed. However, arthrotomography demonstrated only part of the pathologic condition of two patients. These results confirm that there is a strong correlation between labral pathologic conditions and anatomic instability of the shoulder. Arthrotomographic studies have a great impact on the selection of therapy in cases of both anatomic and functional instability of the shoulder.

Thawing frozen shoulder by steroid injection.

PubMed

Pushpasekaran, Narendran; Kumar, Narender; Chopra, R K; Borah, Diganta; Arora, Sumit

2017-01-01

Frozen shoulder is not an uncommon disorder, and steroid injection into the glenohumeral (GH) joint is one of the most well-known approaches for the frozen shoulder. However, their results have been varied with beneficial effects or no additional advantage. With the understanding about the pathological changes taking place in frozen shoulder and the biomechanics involved, we wanted to evaluate the short- and long-term efficacy of steroid injection by a novel three-site (NTS) injection technique and compare it with the single-site injection (SSI). This was a prospective study with 85 patients including all stages and randomized into two groups. SSI group received steroid injection through posterior approach. NTS group received the same dose of steroid in diluted doses at three sites (posterior capsule, subacromial and subcoracoid). Second sitting was repeated after 3 weeks. Both groups had received the same physiotherapy. The patients were evaluated by CONSTANT score at initial, 3 week, 6 week and 6 month. NTS group patients had significant pain relief and early improvement in activities of daily living ( p < 0.005). Both groups had improvement in shoulder movements but with NTS group, early near-normal scores were attained and sustained after 6 months. About 43% in SSI group could not attain near-normal levels and had relapses. The three-site approach to steroid instillation in frozen shoulder is a safe method and provides early recovery and better improvement in shoulder function with less relapses.

[Frozen shoulder. Diagnosis and therapy].

PubMed

Schultheis, A; Reichwein, F; Nebelung, W

2008-11-01

The condition of shoulder stiffness is often called adhesive capsulitis or frozen shoulder. It is regarded as a distinct clinical entity showing a benign and regular course. The major clinical feature is significant reduction in both active and passive range of motion (ROM) accompanied by stage-dependent pain, allowing for a clinical diagnosis. There are primary and secondary forms, the former having an unknown etiology and increased occurrence in patients with metabolic disorders and the latter being seen with prior injury or operation. Three stages, each lasting 4-6 months, mark the clinical course. The progression of the disease is self-limiting and may occasionally resolve in partial restitution. In the first stage ("freezing"), the shoulder continuously loses passive motion and causes worsening pain. Continuing stiffness and improvements in pain and inflammation are characteristic of the second stage ("frozen"). In the third stage ("thawing"), restriction of shoulder motion decreases, and ROM increases. Treatment should be adjusted to these stages. Recommendations include analgesics and joint injections in the first stage and physiotherapy in combination with manual therapy in the second and third stages. In cases of failure, passive exercise under interscalene block, manipulation under general anesthesia, or arthroscopic arthrolysis should be considered.

Joint Command and Control of Cyber Operations: The Joint Force Cyber Component Command (JFCCC)

DTIC Science & Technology

2012-05-04

relies so heavily on complex command and control systems and interconnectivity in general, cyber warfare has become a serious topic of interest at the...defensive cyber warfare into current and future operations and plans. In particular, Joint Task Force (JTF) Commanders must develop an optimum method to

Inter-clinician and intra-clinician reliability of force application during joint mobilization: a systematic review.

PubMed

Gorgos, Kara S; Wasylyk, Nicole T; Van Lunen, Bonnie L; Hoch, Matthew C

2014-04-01

Joint mobilizations are commonly used by clinicians to decrease pain and restore joint arthrokinematics following musculoskeletal injury. The force applied during a joint mobilization treatment is subjective to the individual clinician but may have an effect on patient outcomes. The purpose of this systematic review was to critically appraise and synthesize the studies which examined the reliability of clinicians' force application during joint mobilization. A systematic search of PubMed and EBSCO Host databases from inception to March 1, 2013 was conducted to identify studies assessing the reliability of force application during joint mobilizations. Two reviewers utilized the Quality Appraisal of Reliability Studies (QAREL) assessment tool to determine the quality of included studies. The relative reliability of the included studies was examined through intraclass correlation coefficients (ICC) to synthesize study findings. All results were collated qualitatively with a level of evidence approach. A total of seven studies met the eligibility and were included. Five studies were included that assessed inter-clinician reliability, and six studies were included that assessed intra-clinician reliability. The overall level of evidence for inter-clinician reliability was strong for poor-to-moderate reliability (ICC = -0.04 to 0.70). The overall level of evidence for intra-clinician reliability was strong for good reliability (ICC = 0.75-0.99). This systematic review indicates there is variability in force application between clinicians but individual clinicians apply forces consistently. The results of this systematic review suggest innovative instructional methods are needed to improve consistency and validate the forces applied during of joint mobilization treatments. This is particularly evident for improving the consistency of force application across clinicians. Copyright © 2014 Elsevier Ltd. All rights reserved.

Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.

PubMed

Saito, Akira; Akima, Hiroshi

2013-12-01

It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG-force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. Copyright © 2013 Elsevier Ltd. All rights reserved.

Humeral component retroversion in reverse total shoulder arthroplasty: a biomechanical study.

PubMed

Gulotta, Lawrence V; Choi, Dan; Marinello, Patrick; Knutson, Zakary; Lipman, Joseph; Wright, Timothy; Cordasco, Frank A; Craig, Edward V; Warren, Russell F

2012-09-01

Reverse total shoulder arthroplasty offers pain relief and functional improvement for patients with rotator cuff-deficient shoulders. The purpose of this study was to determine the optimal amount of humeral retroversion for this prosthesis. Six cadaveric shoulders underwent computed tomography (CT) imaging and were then dissected of soft tissues, except for their tendinous attachments. A reverse total shoulder arthroplasty was implanted in 0°, 20°, 30°, and 40° of retroversion, and the shoulders were mounted on a simulator to determine the muscle forces required to achieve 30° and 60° of scaption. CT images were converted into 3-dimensional models, and the amount of internal and external rotation was determined with computer modeling at various scaption angles. No differences were found in the forces required for 30° or 60° of scaption for any muscle, at any retroversion. With increasing retroversion, more impingement-free external rotation was obtained, with a concomitant decrease in the amount of internal rotation. Above 60°, the humerus was allowed to rotate around the glenosphere unencumbered. Increasing retroversion did not affect the muscle force requirements for scaption across the shoulder. Placing the humeral component in 0° to 20° of retroversion allows maximum internal rotation with the arm at the side, a movement that is required for daily activities. This limits external rotation with the arm at the side, but has no effect on external rotation with the arm elevated. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Hypothyroidism: Does It Cause Joint Pain?

MedlinePlus

Hypothyroidism: Does it cause joint pain? Can hypothyroidism cause joint pain? I have hypothyroidism and have been experiencing severe arthritis-like pain in my shoulders and hips. Answers from Todd B. ...

Normalized patellofemoral joint reaction force is greater in individuals with patellofemoral pain.

PubMed

Thomeer, Lucas T; Sheehan, Frances T; Jackson, Jennifer N

2017-07-26

Patellofemoral pain is a disabling, highly prevalent pathology. Altered patellofemoral contact forces are theorized to contribute to this pain. Musculoskeletal modeling has been employed to better understand the etiology of patellofemoral pain. Currently, there are no data on the effective quadriceps moment arm for individuals with patellofemoral pain, forcing researchers to apply normative values when modeling such individuals. In addition, the ratio of patellofemoral reaction force to quadriceps force is often used as a surrogate for patellofemoral joint contact force, ignoring the fact that the quadriceps efficiency can vary with pathology and intervention. Thus, the purposes of this study were to: (1) quantify the effective quadriceps moment arm in individuals with patellofemoral pain and compare this value to a control cohort and (2) develop a novel methodology for quantifying the normalized patellofemoral joint reaction force in vivo during dynamic activities. Dynamic MR data were captured as subjects with patellofemoral pain (30F/3M) cyclically flexed their knee from 10° to 40°. Data for control subjects (29F/9M) were taken from a previous study. The moment arm data acquired across a large cohort of individuals with patellofemoral pain should help advance musculoskeletal modeling. The primary finding of this study was an increased mean normalized patellofemoral reaction force of 14.9% (maximum values at a knee angle of 10°) in individuals with patellofemoral pain. Understanding changes in the normalized patellofemoral reaction force with pathology may lead to improvements in clinical decision making, and consequently treatments, by providing a more direct measure of altered patellofemoral joint forces. Copyright © 2017. Published by Elsevier Ltd.

Joint Task Force on Undergraduate Physics Programs

NASA Astrophysics Data System (ADS)

This session will focus on the guidelines and recommendations being developed by the APS/AAPT Joint Task Force on Undergraduate Physics Programs. J-TUPP is studying how undergraduate physics programs might better prepare physics majors for diverse careers. The guidelines and recommendations will focus on curricular content, flexible tracks, pedagogical methods, research experiences and internships, the development of professional skills, and enhanced advising and mentoring for all physics majors.

A novel dynamic mechanical testing technique for reverse shoulder replacements.

PubMed

Dabirrahmani, Danè; Bokor, Desmond; Appleyard, Richard

2014-04-01

In vitro mechanical testing of orthopedic implants provides information regarding their mechanical performance under simulated biomechanical conditions. Current in vitro component stability testing methods for reverse shoulder implants are based on anatomical shoulder designs, which do not capture the dynamic nature of these loads. With glenoid component loosening as one of the most prevalent modes of failure in reverse shoulder replacements, it is important to establish a testing protocol with a more realistic loading regime. This paper introduces a novel method of mechanically testing reverse shoulder implants, using more realistic load magnitudes and vectors, than is currently practiced. Using a custom made jig setup within an Instron mechanical testing system, it is possible to simulate the change in magnitude and direction of the joint load during arm abduction. This method is a step towards a more realistic testing protocol for measuring reverse shoulder implant stability.

Effect of deltoid tension and humeral version in reverse total shoulder arthroplasty: a biomechanical study.

PubMed

Henninger, Heath B; Barg, Alexej; Anderson, Andrew E; Bachus, Kent N; Tashjian, Robert Z; Burks, Robert T

2012-04-01

No clear recommendations exist regarding optimal humeral component version and deltoid tension in reverse total shoulder arthroplasty (TSA). A biomechanical shoulder simulator tested humeral versions (0°, 10°, 20° retroversion) and implant thicknesses (-3, 0, +3 mm from baseline) after reverse TSA in human cadavers. Abduction and external rotation ranges of motion as well as abduction and dislocation forces were quantified for native arms and arms implanted with 9 combinations of humeral version and implant thickness. Resting abduction angles increased significantly (up to 30°) after reverse TSA compared with native shoulders. With constant posterior cuff loads, native arms externally rotated 20°, whereas no external rotation occurred in implanted arms (20° net internal rotation). Humeral version did not affect rotational range of motion but did alter resting abduction. Abduction forces decreased 30% vs native shoulders but did not change when version or implant thickness was altered. Humeral center of rotation was shifted 17 mm medially and 12 mm inferiorly after implantation. The force required for lateral dislocation was 60% less than anterior and was not affected by implant thickness or version. Reverse TSA reduced abduction forces compared with native shoulders and resulted in limited external rotation and abduction ranges of motion. Because abduction force was reduced for all implants, the choice of humeral version and implant thickness should focus on range of motion. Lateral dislocation forces were less than anterior forces; thus, levering and inferior/posterior impingement may be a more probable basis for dislocation (laterally) than anteriorly directed forces. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

Clinical effects of leg length discrepancy through ground and joint reaction force responses: A review

NASA Astrophysics Data System (ADS)

Zabri, S. W. K. Ali; Basaruddin, K. S.; Salleh, A. F.; Rusli, W. M. R.; Daud, R.

2017-09-01

Leg length discrepancy (LLD) is caused either due to functional disorder or shortening of bone structure. This disorder could contribute to the significant effects on body weight distribution and lumbar scoliosis at the certain extend. Ground reaction force and joint reaction force are the parameters that can be used to analyze the responses in weight distribution and kinetics changes on the body joints, respectively. Hence, the purpose of this paper is to review the studies that focus on the clinical effects of LLD to the lower limb and spine through ground and joint reaction force responses that could lead to the orthopedics disorder.

Role of Tool Shoulder End Features on Friction Stir Weld Characteristics of 6082 Aluminum Alloy

NASA Astrophysics Data System (ADS)

Mugada, Krishna Kishore; Adepu, Kumar

2018-03-01

Understanding the temperature generation around the tool shoulder contact is one of the important aspects of the friction stir welding process. In the present study, the effects of various tool shoulder end feature on the temperature and mechanical properties of the 6082 aluminum alloy were investigated. The experimental results show that the axial force during the welding is considerably reduced by using tools with shoulder end features. The detailed observation revealed that around the tool shoulder contact, the amount of heat generation is higher between trialing edge (TE) to retreating side-leading edge corner (RS-LE) counter clockwise direction and lower between RS-LE to TE clockwise direction. Out of the four shoulder end featured tools, the welds produced with ridges shoulder tool resulted in superior properties with significantly lower axial force (approximately 32%) compared to plane shoulder tool.

Neuroanatomical distribution of mechanoreceptors in the human cadaveric shoulder capsule and labrum

PubMed Central

Witherspoon, Jessica W; Smirnova, Irina V; McIff, Terence E

2014-01-01

The distribution, location, and spatial arrangement of mechanoreceptors are important for neural signal conciseness and accuracy in proprioceptive information required to maintain functional joint stability. The glenohumeral joint capsule and labrum are mechanoreceptor-containing tissues for which the distribution of mechanoreceptors has not been determined despite the importance of these tissues in stabilizing the shoulder. More recently, it has been shown that damage to articular mechanoreceptors can result in proprioceptive deficits that may lead to recurrent instability. Awareness of mechanoreceptor distribution in the glenohumeral joint capsule and labrum may allow preservation of the mechanoreceptors during surgical treatment for shoulder instability, and in turn retain the joint's proprioceptive integrity. For this reason, we sought to develop a neuroanatomical map of the mechanoreceptors within the capsule and labrum. We postulated that the mechanoreceptors in these tissues are distributed in a unique pattern, with mechanoreceptor-scarce regions that may be more appropriate for surgical dissection. We determined the neuroanatomical distribution of mechanoreceptors and their associated fascicles in the capsule and labrum from eight human cadaver shoulder pairs using our improved gold chloride staining technique and light microscopy. A distribution pattern was consistently observed in the capsule and labrum from which we derived a neuroanatomical map. Both tissues demonstrated mechanoreceptor-dense and -scarce regions that may be considered during surgical treatment for instability. Capsular fascicles were located in the subsynovial layer, whereas labral fascicles were concentrated in the peri-core zone. The capsular fascicles presented as a lattice network and with a plexiform appearance. Fascicles within the labrum resembled a cable structure with the fascicles running in parallel. Our findings contribute to the neuroanatomical knowledge of the two

Bilateral ground reaction forces and joint moments for lateral sidestepping and crossover stepping tasks

PubMed Central

Kuntze, Gregor; Sellers, William I.; Mansfield, Neil

2009-01-01

Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS) and crossover stepping (XS) movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work. Key pointsGround reaction forces and joint moments during lateral stepping are smaller in magnitude than those experienced during moderate running.Force exposure in SS and XS gaits in normal play does not appear to contribute to the development of

The developing shoulder has a limited capacity to recover after a short duration of neonatal paralysis

PubMed Central

Potter, Ryan; Havlioglu, Necat; Thomopoulos, Stavros

2014-01-01

Mechanical stimuli are required for the proper development of the musculoskeletal system. Removal of muscle forces during fetal or early post-natal timepoints impairs the formation of bone, tendon, and their attachment (the enthesis). The goal of the current study was to examine the capacity of the shoulder to recover after a short duration of neonatal rotator cuff paralysis, a condition mimicking the clinical condition neonatal brachial plexus palsy. We asked if reapplication of muscle load to a transiently paralyzed muscle would allow for full recovery of tissue properties. CD-1 mice were injected with botulinum toxin A to paralyze the supraspinatus muscle from birth through 2 weeks and subsequently allowed to recover. The biomechanics of the enthesis was determined using tensile testing and the morphology of the shoulder joint was determined using micro computed tomography and histology. A recovery period of at least 10 weeks was required to achieve control properties, demonstrating a limited capacity of the shoulder to recover after only two weeks of muscle paralysis. Although care must be taken when extrapolating results from an animal model to the human condition, the results of the current study imply that treatment of neonatal brachial plexus palsy should be aggressive, as even short periods of paralysis could lead to long-term deficiencies in enthesis biomechanics and shoulder morphology. PMID:24831237

Joint Operating Environment 2035: The Joint Force in a Contested and Disordered World

DTIC Science & Technology

2016-07-14

environment. Next, Section 2 explores how the intersection and interaction of these changes might impact the character of war in the future. Finally, Section...ideas about how changes to conflict and war might impact the capabilities and operational approaches required by the future Joint Force. These...1 Colin Gray, Another Bloody Century, (2005), p. 43. 2 challenges that will impact the

Calculation of muscle loading and joint contact forces during the rock step in Irish dance.

PubMed

Shippen, James M; May, Barbara

2010-01-01

A biomechanical model for the analysis of dancers and their movements is described. The model consisted of 31 segments, 35 joints, and 539 muscles, and was animated using movement data obtained from a three-dimensional optical tracking system that recorded the motion of dancers. The model was used to calculate forces within the muscles and contact forces at the joints of the dancers in this study. Ground reaction forces were measured using force plates mounted in a sprung floor. The analysis procedure is generic and can be applied to any dance form. As an exemplar of the application process an Irish dance step, the rock, was analyzed. The maximum ground reaction force found was 4.5 times the dancer's body weight. The muscles connected to the Achilles tendon experienced a maximum force comparable to their maximal isometric strength. The contact force at the ankle joint was 14 times body weight, of which the majority of the force was due to muscle contraction. It is suggested that as the rock step produces high forces, and therefore the potential to cause injury, its use should be carefully monitored.

Biomechanics of Reverse Shoulder Arthroplasty: 
Current Concepts.

PubMed

Lorenzetti, Adam J; Stone, Geoffrey P; Simon, Peter; Frankle, Mark A

2016-01-01

The evolution of reverse shoulder arthroplasty has provided surgeons with new solutions for many complex shoulder problems. A primary goal of orthopaedics is the restoration or re-creation of functional anatomy to reduce pain and improve function, which can be accomplished by either repairing injured structures or replacing them as anatomically as possible. If reconstructible tissue is lacking or not available, which is seen in patients who have complex shoulder conditions such as an irreparable rotator cuff-deficient shoulder, cuff tear arthropathy, or severe glenoid bone loss, substantial problems may arise. Historically, hemiarthroplasty or glenoid grafting with total shoulder arthroplasty yielded inconsistent and unsatisfactory results. Underlying pathologies in patients who have an irreparable rotator cuff-deficient shoulder, cuff tear arthropathy, or severe glenoid bone loss can considerably alter the mechanical function of the shoulder and create treatment dilemmas that are difficult to overcome. A better biomechanical understanding of these pathologic adaptations has improved treatment options. In the past three decades, reverse total shoulder arthroplasty was developed to treat these complex shoulder conditions not by specifically re-creating the anatomy but by using the remaining functional tissue to improve shoulder balance. Reverse total shoulder arthroplasty has achieved reliable improvements in both pain and function. Initial implant designs lacked scientific evidence to support the design rationale, and many implants failed because surgeons did not completely understand the forces involved or the pathology being treated. Implant function and clinical results will continue to improve as surgeons' biomechanical understanding of shoulder disease and reverse shoulder arthroplasty implants increases.

Effect of shoulder model complexity in upper-body kinematics analysis of the golf swing.

PubMed

Bourgain, M; Hybois, S; Thoreux, P; Rouillon, O; Rouch, P; Sauret, C

2018-06-25

The golf swing is a complex full body movement during which the spine and shoulders are highly involved. In order to determine shoulder kinematics during this movement, multibody kinematics optimization (MKO) can be recommended to limit the effect of the soft tissue artifact and to avoid joint dislocations or bone penetration in reconstructed kinematics. Classically, in golf biomechanics research, the shoulder is represented by a 3 degrees-of-freedom model representing the glenohumeral joint. More complex and physiological models are already provided in the scientific literature. Particularly, the model used in this study was a full body model and also described motions of clavicles and scapulae. This study aimed at quantifying the effect of utilizing a more complex and physiological shoulder model when studying the golf swing. Results obtained on 20 golfers showed that a more complex and physiologically-accurate model can more efficiently track experimental markers, which resulted in differences in joint kinematics. Hence, the model with 3 degrees-of-freedom between the humerus and the thorax may be inadequate when combined with MKO and a more physiological model would be beneficial. Finally, results would also be improved through a subject-specific approach for the determination of the segment lengths. Copyright © 2018 Elsevier Ltd. All rights reserved.

Association between Propionibacterium acnes and frozen shoulder: a pilot study.

PubMed

Bunker, Tim D; Boyd, Matthew; Gallacher, Sian; Auckland, Cressida R; Kitson, Jeff; Smith, Chris D

2014-10-01

Frozen shoulder has not previously been shown to be associated with infection. The present study set out to confirm the null hypothesis that there is no relationship between infection and frozen shoulder using two modern scientific methods, extended culture and polymerase chain reaction (PCR) for bacterial nucleic acids. A prospective cohort of 10 patients undergoing arthroscopic release for stage II idiopathic frozen shoulder had two biopsies of tissue taken from the affected shoulder joint capsule at the time of surgery, along with control biopsies of subdermal fat. The biopsies and controls were examined with extended culture and PCR for microbial nucleic acid. Eight of the 10 patients had positive findings on extended culture in their shoulder capsule and, in six of these, Propionibacterium acnes was present. The findings mean that we must reject the null hypothesis that there is no relationship between infection and frozen shoulder. More studies are urgently needed to confirm or refute these findings. If they are confirmed, this could potentially lead to new and effective treatments for this common, painful and disabling condition. Could P. acnes be the Helicobacter of frozen shoulder?

Effect of reverse shoulder design philosophy on muscle moment arms.

PubMed

Hamilton, Matthew A; Diep, Phong; Roche, Chris; Flurin, Pierre Henri; Wright, Thomas W; Zuckerman, Joseph D; Routman, Howard

2015-04-01

This study analyzes the muscle moment arms of three different reverse shoulder design philosophies using a previously published method. Digital bone models of the shoulder were imported into a 3D modeling software and markers placed for the origin and insertion of relevant muscles. The anatomic model was used as a baseline for moment arm calculations. Subsequently, three different reverse shoulder designs were virtually implanted and moment arms were analyzed in abduction and external rotation. The results indicate that the lateral offset between the joint center and the axis of the humerus specific to one reverse shoulder design increased the external rotation moment arms of the posterior deltoid relative to the other reverse shoulder designs. The other muscles analyzed demonstrated differences in the moment arms, but none of the differences reached statistical significance. This study demonstrated how the combination of variables making up different reverse shoulder designs can affect the moment arms of the muscles in different and statistically significant ways. The role of humeral offset in reverse shoulder design has not been previously reported and could have an impact on external rotation and stability achieved post-operatively. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Association between Propionibacterium acnes and frozen shoulder: a pilot study

PubMed Central

Bunker, Tim D; Gallacher, Sian; Auckland, Cressida R; Kitson, Jeff; Smith, Chris D

2014-01-01

Background Frozen shoulder has not previously been shown to be associated with infection. The present study set out to confirm the null hypothesis that there is no relationship between infection and frozen shoulder using two modern scientific methods, extended culture and polymerase chain reaction (PCR) for bacterial nucleic acids. Methods A prospective cohort of 10 patients undergoing arthroscopic release for stage II idiopathic frozen shoulder had two biopsies of tissue taken from the affected shoulder joint capsule at the time of surgery, along with control biopsies of subdermal fat. The biopsies and controls were examined with extended culture and PCR for microbial nucleic acid. Results Eight of the 10 patients had positive findings on extended culture in their shoulder capsule and, in six of these, Propionibacterium acnes was present. Conclusions The findings mean that we must reject the null hypothesis that there is no relationship between infection and frozen shoulder. More studies are urgently needed to confirm or refute these findings. If they are confirmed, this could potentially lead to new and effective treatments for this common, painful and disabling condition. Could P. acnes be the Helicobacter of frozen shoulder? PMID:27582943

Upper limb joint motion of two different user groups during manual wheelchair propulsion

NASA Astrophysics Data System (ADS)

Hwang, Seonhong; Kim, Seunghyeon; Son, Jongsang; Lee, Jinbok; Kim, Youngho

2013-02-01

Manual wheelchair users have a high risk of injury to the upper extremities. Recent studies have focused on kinematic and kinetic analyses of manual wheelchair propulsion in order to understand the physical demands on wheelchair users. The purpose of this study was to investigate upper limb joint motion by using a motion capture system and a dynamometer with two different groups of wheelchair users propelling their wheelchairs at different speeds under different load conditions. The variations in the contact time, release time, and linear velocity of the experienced group were all larger than they were in the novice group. The propulsion angles of the experienced users were larger than those of the novices under all conditions. The variances in the propulsion force (both radial and tangential) of the experienced users were larger than those of the novices. The shoulder joint moment had the largest variance with the conditions, followed by the wrist joint moment and the elbow joint moment. The variance of the maximum shoulder joint moment was over four times the variance of the maximum wrist joint moment and eight times the maximum elbow joint moment. The maximum joint moments increased significantly as the speed and load increased in both groups. Quick and significant manipulation ability based on environmental changes is considered an important factor in efficient propulsion. This efficiency was confirmed from the propulsion power results. Sophisticated strategies for efficient manual wheelchair propulsion could be understood by observation of the physical responses of each upper limb joint to changes in load and speed. We expect that the findings of this study will be utilized for designing a rehabilitation program to reduce injuries.

Don't aim too high: Avoiding shoulder injury related to vaccine administration.

PubMed

Cross, Gail B; Moghaddas, Jason; Buttery, Jim; Ayoub, Sally; Korman, Tony M

2016-05-01

Shoulder injury related to vaccine administration (SIRVA) is a previously described phenomenon that is the result of improper vaccine delivery. Appropriate injection technique for administration of intramuscular vaccinations can reduce the risk of shoulder injury. In this article, we describe the cases of two patients who developed SIRVA. A literature review was conducted to find and describe other cases of shoulder injury that developed post-vaccination. SIRVA has previously been described in the world literature. Seventeen cases in women and five cases in men were found. Pain and reduction in the range of movement within a few hours of vaccination were cardinal signs of a shoulder injury. This included injuries to the soft tissues of the shoulder as well as injuries to bone and joint. SIRVA can be avoided with correct vaccination technique as described.

Natural History of Anterior Shoulder Instability.

PubMed

Carpinteiro, Eduardo Palma; Barros, Andre Aires

2017-01-01

The shoulder is the most complex joint in the body. The large freedom of motion in this joint is the main cause of instability. Instability varies in its degree, direction, etiology and volition and there is a large spectrum of conditions. Based on literature research and also in our own experience, we propose to elucidate the reader about the natural history of instability and its importance for the appropriate management of this pathology, by answering the following questions: What happens in the shoulder after the first dislocation? Which structures suffer damage? Who are the patients at higher risk of recurrence? How does the disease evolve without treatment? Will surgical treatment avoid future negative outcomes and prevent degenerative joint disease? Who should we treat and when? 80% of anterior-inferior dislocations occur in young patients. Recurrent instability is common and multiple dislocations are the rule. Instability is influenced by a large number of variables, including age of onset, activity profile, number of episodes,delay between first episode and surgical treatment. Understanding the disease and its natural evolution is determinant to decide the treatment in order to obtain the best outcome. It is crucial to identify the risk factors for recurrence. Delay in surgical treatment, when indicated, leads to worse results. Surgical technique should address the type and severity of both soft tissue and bone lesions, when present.

Estimation of ground reaction forces and joint moments on the basis on plantar pressure insoles and wearable sensors for joint angle measurement.

PubMed

Ostaszewski, Michal; Pauk, Jolanta

2018-05-16

Gait analysis is a useful tool medical staff use to support clinical decision making. There is still an urgent need to develop low-cost and unobtrusive mobile health monitoring systems. The goal of this study was twofold. Firstly, a wearable sensor system composed of plantar pressure insoles and wearable sensors for joint angle measurement was developed. Secondly, the accuracy of the system in the measurement of ground reaction forces and joint moments was examined. The measurements included joint angles and plantar pressure distribution. To validate the wearable sensor system and examine the effectiveness of the proposed method for gait analysis, an experimental study on ten volunteer subjects was conducted. The accuracy of measurement of ground reaction forces and joint moments was validated against the results obtained from a reference motion capture system. Ground reaction forces and joint moments measured by the wearable sensor system showed a root mean square error of 1% for min. GRF and 27.3% for knee extension moment. The correlation coefficient was over 0.9, in comparison with the stationary motion capture system. The study suggests that the wearable sensor system could be recommended both for research and clinical applications outside a typical gait laboratory.

The effect of the arthroscopic augmentation of the subscapularis tendon on shoulder instability and range of motion: A biomechanical study.

PubMed

Schröter, S; Krämer, M; Welke, B; Hurschler, C; Russo, R; Herbst, M; Stöckle, U; Ateschrang, A; Maiotti, M

2016-10-01

Anterior shoulder dislocation is common. The treatment of recurrence with glenoid bone defect is still considered controversial. A new arthroscopic subscapularis augmentation has recently been described that functions to decrease the anterior translation of the humeral head. The purpose of the presented study was to examine the biomechanical effect on glenohumeral joint motion and stability. Eight fresh frozen cadaver shoulders were studied by use of a force guided industrial robot fitted with a six-component force-moment sensor to which the humerus was attached. The testing protocol includes measurement of glenohumeral translation in the anterior, anterior-inferior and inferior directions at 0°, 30° and 60° of glenohumeral abduction, respectively, with a passive humerus load of 30N in the testing direction. The maximum possible external rotation was measured at each abduction angle applying a moment of 1Nm. Each specimen was measured in a physiologic state, as well as after Bankart lesion with an anterior bone defect of 15-20% of the glenoid, after arthroscopic subscapularis augmentation and after Bankart repair. The arthroscopic subscapularis augmentation decreased the anterior and anterior-inferior translation. The Bankart repair did not restore the mechanical stability compared to the physiologic shoulder group. External rotation was decreased after arthroscopic subscapularis augmentation compared to the physiologic state, however, the limitation of external rotation was decreased at 60° abduction. The arthroscopic subscapularis augmentation investigated herein was observed to restore shoulder stability in an experimental model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Knee Joint Loads and Surrounding Muscle Forces during Stair Ascent in Patients with Total Knee Replacement

PubMed Central

Rasnick, Robert; Standifird, Tyler; Reinbolt, Jeffrey A.; Cates, Harold E.

2016-01-01

Total knee replacement (TKR) is commonly used to correct end-stage knee osteoarthritis. Unfortunately, difficulty with stair climbing often persists and prolongs the challenges of TKR patents. Complete understanding of loading at the knee is of great interest in order to aid patient populations, implant manufacturers, rehabilitation, and future healthcare research. Musculoskeletal modeling and simulation approximates joint loading and corresponding muscle forces during a movement. The purpose of this study was to determine if knee joint loadings following TKR are recovered to the level of healthy individuals, and determine the differences in muscle forces causing those loadings. Data from five healthy and five TKR patients were selected for musculoskeletal simulation. Variables of interest included knee joint reaction forces (JRF) and the corresponding muscle forces. A paired samples t-test was used to detect differences between groups for each variable of interest (p<0.05). No differences were observed for peak joint compressive forces between groups. Some muscle force compensatory strategies appear to be present in both the loading and push-off phases. Evidence from knee extension moment and muscle forces during the loading response phase indicates the presence of deficits in TKR in quadriceps muscle force production during stair ascent. This result combined with greater flexor muscle forces resulted in similar compressive JRF during loading response between groups. PMID:27258086

Reproducibility of manual pressure force on provocation of the sacroiliac joint.

PubMed

Levin, U; Nilsson-Wikmar, L; Stenström, C H; Lundeberg, T

1998-01-01

Previous studies of pain-provocation sacroiliac (SI) joint tests have revealed conflicting results. The aim of the present study was to evaluate the intra- and inter-test reliability of pressure force applied during distraction test, compression test and pressure on the apex sacralis. Seventeen physiotherapists (PTs), median age 43 years and median clinical experience 11 years, all experienced in musculoskeletal evaluation and therapy, participated in the study. Each PT performed each test on the same healthy volunteer for 20 s, on three separate occasions, at intervals of one week using a specially constructed examination table which registered pressure force. The PTs were capable of maintaining a relatively constant pressure force for 20 s. The intra-test reliability was acceptable even though there were individual differences on different occasions between those PTs who used the SI joint tests often and those who seldom or never used them. The inter-test reliability was insufficient. The findings indicate the advantage of registering pressure force as a complement for standardized methods for pain-provoking tests and when learning provocation tests, since individual variability was considerable.

Impact of movement training on upper limb motor strategies in persons with shoulder impingement syndrome

PubMed Central

Roy, Jean-Sébastien; Moffet, Hélène; McFadyen, Bradford J; Lirette, Richard

2009-01-01

Background Movement deficits, such as changes in the magnitude of scapulohumeral and scapulathoracic muscle activations or perturbations in the kinematics of the glenohumeral, sternoclavicular and scapulothoracic joints, have been observed in people with shoulder impingement syndrome. Movement training has been suggested as a mean to contribute to the improvement of the motor performance in persons with musculoskeletal impairments. However, the impact of movement training on the movement deficits of persons with shoulder impingement syndrome is still unknown. The aim of this study was to evaluate the short-term effects of supervised movement training with feedback on the motor strategies of persons with shoulder impingement syndrome. Methods Thirty-three subjects with shoulder impingement were recruited. They were involved in two visits, one day apart. During the first visit, supervised movement training with feedback was performed. The upper limb motor strategies were evaluated before, during, immediately after and 24 hours after movement training. They were characterized during reaching movements in the frontal plane by EMG activity of seven shoulder muscles and total excursion and final position of the wrist, elbow, shoulder, clavicle and trunk. Movement training consisted of reaching movements performed under the supervision of a physiotherapist who gave feedback aimed at restoring shoulder movements. One-way repeated measures ANOVAs were run to analyze the effect of movement training. Results During, immediately after and 24 hours after movement training with feedback, the EMG activity was significantly decreased compared to the baseline level. For the kinematics, total joint excursion of the trunk and final joint position of the trunk, shoulder and clavicle were significantly improved during and immediately after training compared to baseline. Twenty-four hours after supervised movement training, the kinematics of trunk, shoulder and clavicle were back to the

Trunk and Shoulder Kinematic and Kinetic and Electromyographic Adaptations to Slope Increase during Motorized Treadmill Propulsion among Manual Wheelchair Users with a Spinal Cord Injury

PubMed Central

Champagne, Audrey

2015-01-01

The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments. PMID:25793200

Trunk and shoulder kinematic and kinetic and electromyographic adaptations to slope increase during motorized treadmill propulsion among manual wheelchair users with a spinal cord injury.

PubMed

Gagnon, Dany; Babineau, Annie-Claude; Champagne, Audrey; Desroches, Guillaume; Aissaoui, Rachid

2015-01-01

The main objective was to quantify the effects of five different slopes on trunk and shoulder kinematics as well as shoulder kinetic and muscular demands during manual wheelchair (MWC) propulsion on a motorized treadmill. Eighteen participants with spinal cord injury propelled their MWC at a self-selected constant speed on a motorized treadmill set at different slopes (0°, 2.7°, 3.6°, 4.8°, and 7.1°). Trunk and upper limb movements were recorded with a motion analysis system. Net shoulder joint moments were computed with the forces applied to the handrims measured with an instrumented wheel. To quantify muscular demand, the electromyographic activity (EMG) of the pectoralis major (clavicular and sternal portions) and deltoid (anterior and posterior fibers) was recorded during the experimental tasks and normalized against maximum EMG values obtained during static contractions. Overall, forward trunk flexion and shoulder flexion increased as the slope became steeper, whereas shoulder flexion, adduction, and internal rotation moments along with the muscular demand also increased as the slope became steeper. The results confirm that forward trunk flexion and shoulder flexion movement amplitudes, along with shoulder mechanical and muscular demands, generally increase when the slope of the treadmill increases despite some similarities between the 2.7° to 3.6° and 3.6° to 4.8° slope increments.

Effect of changes of femoral offset on abductor and joint reaction forces in total hip arthroplasty.

PubMed

Rüdiger, Hannes A; Guillemin, Maïka; Latypova, Adeliya; Terrier, Alexandre

2017-11-01

Anatomical reconstruction in total hip arthroplasty (THA) allows for physiological muscle function, good functional outcome and implant longevity. Quantitative data on the effect of a loss or gain of femoral offset (FO) are scarce. The aim of this study was to quantitatively describe the effect of FO changes on abductor moment arms, muscle and joint reactions forces. THA was virtually performed on 3D models built from preoperative CT scans of 15 patients undergoing THA. Virtual THA was performed with a perfectly anatomical reconstruction, a loss of 20% of FO (-FO), and a gain of 20% of FO (+FO). These models were combined with a generic musculoskeletal model (OpenSim) to predict moment arms, muscle and joint reaction forces during normal gait cycles. In average, with -FO reconstructions, muscle moment arms decreased, while muscle and hip forces increased significantly (p < 0.001). We observed the opposite with +FO reconstructions. Gluteus medius was more affected than gluteus minimus. -FO had more effect than +FO. A change of 20% of FO induced an average change 8% of abductor moment arms, 16% of their forces, and 6% of the joint reaction force. To our knowledge, this is the first report providing quantitative data on the effect of FO changes on muscle and joint forces during normal gait. A decrease of FO necessitates an increase of abductor muscle force to maintain normal gait, which in turn increases the joint reaction force. This effect underscores the importance of an accurate reconstruction of the femoral offset.

Anterior deltoid deficiency in reverse total shoulder replacement: a biomechanical study with cadavers.

PubMed

Gulotta, L V; Choi, D; Marinello, P; Wright, T; Cordasco, F A; Craig, E V; Warren, R F

2012-12-01

Reverse total shoulder replacement (RTSR) depends on adequate deltoid function for a successful outcome. However, the anterior deltoid and/or axillary nerve may be damaged due to prior procedures or injury. The purpose of this study was to determine the compensatory muscle forces required for scapular plane elevation following RTSR when the anterior deltoid is deficient. The soft tissues were removed from six cadaver shoulders, except for tendon attachments. After implantation of the RTSR, the shoulders were mounted on a custom-made shoulder simulator to determine the mean force in each muscle required to achieve 30° and 60° of scapular plane elevation. Two conditions were tested: 1) Control with an absent supraspinatus and infraspinatus; and 2) Control with anterior deltoid deficiency. Anterior deltoid deficiency resulted in a mean increase of 195% in subscapularis force at 30° when compared with the control (p = 0.02). At 60°, the subscapularis force increased a mean of 82% (p < 0.001) and the middle deltoid force increased a mean of 26% (p = 0.04). Scapular plane elevation may still be possible following an RTSR in the setting of anterior deltoid deficiency. When the anterior deltoid is deficient, there is a compensatory increase in the force required by the subscapularis and middle deltoid. Attempts to preserve the subscapularis, if present, might maximise post-operative function.

Finite element models of the human shoulder complex: a review of their clinical implications and modelling techniques.

PubMed

Zheng, Manxu; Zou, Zhenmin; Bartolo, Paulo Jorge Da Silva; Peach, Chris; Ren, Lei

2017-02-01

The human shoulder is a complicated musculoskeletal structure and is a perfect compromise between mobility and stability. The objective of this paper is to provide a thorough review of previous finite element (FE) studies in biomechanics of the human shoulder complex. Those FE studies to investigate shoulder biomechanics have been reviewed according to the physiological and clinical problems addressed: glenohumeral joint stability, rotator cuff tears, joint capsular and labral defects and shoulder arthroplasty. The major findings, limitations, potential clinical applications and modelling techniques of those FE studies are critically discussed. The main challenges faced in order to accurately represent the realistic physiological functions of the shoulder mechanism in FE simulations involve (1) subject-specific representation of the anisotropic nonhomogeneous material properties of the shoulder tissues in both healthy and pathological conditions; (2) definition of boundary and loading conditions based on individualised physiological data; (3) more comprehensive modelling describing the whole shoulder complex including appropriate three-dimensional (3D) representation of all major shoulder hard tissues and soft tissues and their delicate interactions; (4) rigorous in vivo experimental validation of FE simulation results. Fully validated shoulder FE models would greatly enhance our understanding of the aetiology of shoulder disorders, and hence facilitate the development of more efficient clinical diagnoses, non-surgical and surgical treatments, as well as shoulder orthotics and prosthetics. © 2016 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd. © 2016 The Authors. International Journal for Numerical Methods in Biomedical Engineering published by John Wiley & Sons Ltd.

Reverse total shoulder arthroplasty: research models

PubMed Central

PETRILLO, STEFANO; LONGO, UMILE GIUSEPPE; GULOTTA, LAWRENCE V.; BERTON, ALESSANDRA; KONTAXIS, ANDREAS; WRIGHT, TIMOTHY; DENARO, VINCENZO

2016-01-01

Purpose the past decade has seen a considerable increase in the use of research models to study reverse total shoulder arthroplasty (RTSA). Nevertheless, none of these models has been shown to completely reflect real in vivo conditions. Methods we performed a systematic review of the literature matching the following key words: “reverse total shoulder arthroplasty” or “reverse total shoulder replacement” or “reverse total shoulder prosthesis” and “research models” or “biomechanical models” or “physical simulators” or “virtual simulators”. The following databases were screened: Medline, Google Scholar, EMBASE, CINAHIL and Ovid. We identified and included all articles reporting research models of any kind, such as physical or virtual simulators, in which RTSA and the glenohumeral joint were reproduced. Results computer models and cadaveric models are the most commonly used, and they were shown to be reliable in simulating in vivo conditions. Bone substitute models have been used in a few studies. Mechanical testing machines provided useful information on stability factors in RTSA. Conclusion because of the limitations of each individual model, additional research is required to develop a research model of RTSA that may reduce the limitations of those presently available, and increase the reproducibility of this technique in the clinical setting. PMID:28217660

Shoulder pain and jerk during recovery phase of manual wheelchair propulsion.

PubMed

Jayaraman, Chandrasekaran; Beck, Carolyn L; Sosnoff, Jacob J

2015-11-05

Repetitive loading of the upper limb due to wheelchair propulsion plays a leading role in the development of shoulder pain in manual wheelchair users (mWCUs). There has been minimal inquiry on understanding wheelchair propulsion kinematics from a human movement ergonomics perspective. This investigation employs an ergonomic metric, jerk, to characterize the recovery phase kinematics of two recommended manual wheelchair propulsion patterns: semi-circular and the double loop. Further it examines if jerk is related to shoulder pain in mWCUs. Data from 22 experienced adult mWCUs was analyzed for this study (semi-circular: n=12 (pain/without-pain:6/6); double-loop: n=10 (pain/without-pain:4/6)). Participants propelled their own wheelchair fitted with SMARTWheels on a roller dynamometer at 1.1 m/s for 3 min. Kinematic and kinetic data of the upper limbs were recorded. Three dimensional absolute jerk experienced at the shoulder, elbow and wrist joint during the recovery phase of wheelchair propulsion were computed. Two-way ANOVAs were conducted with the recovery pattern type and shoulder pain as between group factors. (1) Individuals using a semi-circular pattern experienced lower jerk at their arm joints than those using a double loop pattern (P<0.05, η(2)=0.32)wrist;(P=0.05, η(2)=0.19)elbow;(P<0.05, η(2)=0.34)shoulder and (2) individuals with shoulder pain had lower peak jerk magnitude during the recovery phase (P≤0.05, η(2)=0.36)wrist;(P≤0.05, η(2)=0.30)elbow;(P≤0.05, η(2)=0.31)shoulder. Jerk during wheelchair propulsion was able to distinguish between pattern types (semi-circular and double loop) and the presence of shoulder pain. Jerk provides novel insights into wheelchair propulsion kinematics and in the future it may be beneficial to incorporate jerk based metric into rehabilitation practice. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shoulder pain and jerk during recovery phase of manual wheelchair propulsion

PubMed Central

Jayaraman, Chandrasekaran; Beck, Carolyn L; Sosnoff, Jacob J.

2015-01-01

Repetitive loading of the upper limb due to wheelchair propulsion plays a leading role in the development of shoulder pain in manual wheelchair users (mWCUs). There has been minimal inquiry on understanding wheelchair propulsion kinematics from a human movement ergonomics perspective. This investigation employs an ergonomic metric, jerk, to characterize the recovery phase kinematics of two recommended manual wheelchair propulsion patterns: semi-circular and the double loop. Further it examines if jerk is related to shoulder pain in mWCUs. Data from 22 experienced adult mWCUs was analyzed for this study (semi-circular: n=12 (pain/without-pain:6/6); double-loop: n=10 (pain/without-pain:4/6)). Participants propelled their own wheelchair fitted with SMARTWheels on a roller dynamometer at 1.1 m/s for 3 minutes. Kinematic and kinetic data of the upper limbs were recorded. Three dimensional absolute jerk experienced at the shoulder, elbow and wrist joint during the recovery phase of wheelchair propulsion were computed. Two-way ANOVAs were conducted with the recovery pattern type and shoulder pain as between group factors. Findings (1) Individuals using a semi-circular pattern experienced lower jerk at their arm joints than those using a double loop pattern (P<0.05, η2=0.32)wrist; (P=0.05, η2=0.19)elbow; (P<0.05, η2=0.34)shoulder and (2) individuals with shoulder pain had lower peak jerk magnitude during the recovery phase (P≤0.05, η2=0.36)wrist; (P≤0.05, η2=0.30)elbow; (P≤0.05, η2=0.31)shoulder. Conclusions Jerk during wheelchair propulsion was able to distinguish between pattern types (semi-circular and double loop) and the presence of shoulder pain. Jerk provides novel insights into wheelchair propulsion kinematics and in the future it may be beneficial to incorporate jerk based metric into rehabilitation practice. PMID:26472307

Enhancing Friction Stir Weldability of 6061-T6 Al and AZ31B Mg Alloys Assisted by External Non-rotational Shoulder

NASA Astrophysics Data System (ADS)

Ji, Shude; Huang, Ruofei; Meng, Xiangchen; Zhang, Liguo; Huang, Yongxian

2017-05-01

In order to increase cooling rate and then reduce the amounts of intermetallic compounds, external non-rotational shoulder tool system derived from traditional tool in friction stir welding was used to join dissimilar Al and Mg alloys. In this study, based on the external non-rotational shoulder, the weldability of Al and Mg alloys was significantly improved. The non-rotational shoulder tool is propitious to make more materials into weld, increase cooling rate and then reduce material adhesion of rotational pin, obtaining sound joint with smaller flashes and smooth surface. Importantly, the thickness of intermetallic compounds layer is reduced compared with traditional tool. Meanwhile, hardness values of dissimilar joint present uneven distribution, resulting from complex intercalated structures in nugget zone (NZ) featured by intermetallic compound layers and fine recrystallized Mg and Al grains. Compared with traditional tool, non-rotational shoulder is beneficial to higher tensile properties of joint. Due to the intermetallic compound layer formed in the interface of Al-Mg, the welding joint easily fractures at the NZ, presenting the typical brittle fracture mode.

Glenoid wear after shoulder hemiarthroplasty: quantitative radiographic analysis.

PubMed

Parsons, I M; Millett, Peter J; Warner, Jon J P

2004-04-01

Symptomatic glenoid arthrosis may limit the long-term success of shoulder hemiarthroplasty in patients who are young and functionally demanding. The principal objective of the current study was to quantify glenoid wear after proximal humeral replacement in young, active subjects. Eight patients, ages 21 to 60 years (mean, 45 years), met inclusion criteria. The mean followup was 43 months. Functional scores for the cohort averaged 60% of age and gender-adjusted healthy subjects (range, 28%-84%). Glenohumeral joint space was measured on serial axillary radiographs using a Microscribe 3-DX digitizing device (measurement accuracy, 0.23 mm). Progressive glenoid wear was found in all eight patients. The mean decrease was 2 mm (range, 1.3-2.8 mm), a 68% decrease in glenohumeral joint space. Glenoid cartilage wear also was correlated with Constant and Murley scores. Patients with residual joint spaces less than 1 mm had a mean score of 50%, compared with a score of 71% for patients with joint spaces greater than 1 mm. There were no correlations between wear and mechanism of injury, duration of symptoms, and prior surgery. This study suggests that glenoid cartilage erosion can be expected routinely after humeral head replacement in young, active individuals, and that such wear may adversely affect function or necessitate conversion to total shoulder arthroplasty.

Online resources for shoulder instability: what are patients reading?

PubMed

Garcia, Grant H; Taylor, Samuel A; Dy, Christopher J; Christ, Alexander; Patel, Ronak M; Dines, Joshua S

2014-10-15

Evaluations of the medical literature suggest that many online sites provide poor-quality information. The purpose of our study was to investigate the value of online resources for patient education about shoulder instability. Three search terms ("shoulder instability," "loose shoulder," and "shoulder dislocation") were entered into three Internet search engines. Three orthopaedic residents independently gauged the quality and accuracy of the information with use of a set of predetermined scoring criteria, in addition to noting whether or not four potential surgery options were mentioned. The readability of the web sites was evaluated with use of the Flesch-Kincaid score. Eighty-two unique web sites were evaluated. Quality and accuracy were significantly higher with use of the term "shoulder instability" compared with the term "loose shoulder" (quality, p < 0.001; accuracy, p = 0.001). However, the reading level was significantly more advanced for the "shoulder instability" web sites (p < 0.001). Quality was significantly higher on web sites with reading levels above the eighth grade level (p = 0.001) (88% of web sites). Only twenty-three sites (28%) mentioned surgical options for shoulder instability, and of these, only eight mentioned thermal capsulorrhaphy as a primary treatment. Online information regarding shoulder instability is often inaccurate and/or at an inappropriately high reading level. The quality of information is highly dependent on the specific search term used. Clinicians need to be aware of the information that is available online and should help direct patients to proper sites and guide Internet search terms. Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.

Correlations between Angular Velocities in Selected Joints and Velocity of Table Tennis Racket during Topspin Forehand and Backhand.

PubMed

Bańkosz, Ziemowit; Winiarski, Sławomir

2018-06-01

The aim of this study was to determine the correlations between angular velocities in individual joints and racket velocity for different topspin forehand and backhand strokes in table tennis. Ten elite female table tennis players participated, presenting different kinds of topspin forehands and backhands - after a no-spin ball (FH1, BH1), after a backspin ball (FH2, BH2) and "heavy" topspin (FH3, BH3). Range of motion was measured with the BTS Smart-E (BTS Bioengineering, Milan, Italy) motion analysis system with a specially developed marker placement protocol for the upper body parts and an acoustic sensor attached to the racket to identify ball-racket contact. In forehand strokes angular velocities of internal arm rotation and adduction in shoulder joint correlated with racket velocity. Racket velocity was correlated with angular velocities (hip extension on the playing side; hip flexion on the opposite side; ankle flexion) in the case of a topspin forehand performed with maximal force -"heavy" topspin (FH3). In backhand strokes the velocities of arm abduction and shoulder girdle rotation towards the playing side correlated with racket velocity. The angular velocity of internal arm rotation and adduction in shoulder joint may be important components of a coordinated stroke, whilst angular velocity can substantially affect the racket speed when one is changing the type of stroke.

Effect of shoulder taping on maximum shoulder external and internal rotation range in uninjured and previously injured overhead athletes during a seated throw.

PubMed

McConnell, Jenny; Donnelly, Cyril; Hamner, Samuel; Dunne, James; Besier, Thor

2011-09-01

The purpose of our study was to investigate whether shoulder taping affects shoulder kinematics in injured and previously injured overhead athletes during a seated throw. Twenty-six overhead college athletes threw a handball three times with and without tape, while seated on a chair. An 8-camera Vicon Motion Capture system recorded markers placed on the upper limb and trunk during each of the throwing conditions. Scaled musculoskeletal models of the upper limb were created using OpenSim and inverse kinematics used to obtain relevant joint angles. Shoulder taping had no main effect on external (ER) and internal (IR) rotation range (ROM) of the shoulder, but a significant interaction effect was found (p = 0.003 and 0.02, respectively), depending on previous injury status, whereby both the ER and IR ROM of the shoulder in the group of previously injured athletes decreased when taped (143-138° and 54-51°, respectively), but increased in the group who had never been injured (131-135° and 42-44°, respectively). Maximum abduction range and ball velocity were not affected by the application of shoulder taping, regardless of previous injury status. Thus, application of shoulder taping has a differential effect on maximum shoulder ER and IR ROM during throwing depending on previous injury status. These findings have implications for returning athletes to sport after injury and for screening athletes at risk of injury. Copyright © 2011 Orthopaedic Research Society.

The biomechanical effect of clavicular shortening on shoulder muscle function, a simulation study.

PubMed

Hillen, Robert J; Bolsterlee, Bart; Veeger, Dirkjan H E J

2016-08-01

Malunion of the clavicle with shortening after mid shaft fractures can give rise to long-term residual complaints. The cause of these complaints is as yet unclear. In this study we analysed data of an earlier experimental cadaveric study on changes of shoulder biomechanics with progressive shortening of the clavicle. The data was used in a musculoskeletal computer model to examine the effect of clavicle shortening on muscle function, expressed as maximal muscle moments for abduction and internal rotation. Clavicle shortening results in changes of maximal muscle moments around the shoulder girdle. The mean values at 3.6cm of shortening of maximal muscle moment changes are 16% decreased around the sterno-clavicular joint decreased for both ab- and adduction, 37% increased around the acromion-clavicular joint for adduction and 32% decrease for internal rotation around the gleno-humeral joint in resting position. Shortening of the clavicle affects muscle function in the shoulder in a computer model. This may explain for the residual complaints after short malunion with shortening. Basic Science Study. Biomechanics. Cadaveric data and computer model. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of Prosthetic Mismatch and Subscapularis Tear on Glenohumeral Contact Patterns in Total Shoulder Arthroplasty: A Numerical Musculoskeletal Analysis.

PubMed

Sins, Lauranne; Tétreault, Patrice; Nuño, Natalia; Hagemeister, Nicola

2016-12-01

Prosthetic components' mismatch and subscapularis (SC) tear are determining factors for glenoid failure complication in nonconforming total shoulder arthroplasty (NC-TSA). Risk factors are linked to glenoid prosthetic loading. However, the mechanisms underlying the clinical observations remain unclear. This study assessed the combined impact of mismatch and subscapularis tear on glenoid loading. It was assumed that adequate glenoid loading was associated with minimal, but non-null, humeral head translations and contact pressure, as well as with maximal glenoid contact area, and that the center of pressure (COP) on the glenoid would have a centered displacement pattern. A numerical model was used to achieve two objectives. The first was to verify whether an optimum mismatch existed, for which failure risk would be minimal. The second was to explore the effect of subscapularis tear on the position of applied forces on the glenoid. A shoulder AnyBody musculoskeletal model was adapted to the arthroplasty context by introducing humeral head translations and contact between implants. Ten simulations were computed to compare combinations of varying mismatches (1.4 mm, 3.4 mm, 6.4 mm, 8.6 mm, and 9 mm) with two shoulder conditions (intact-muscle or subscapularis tear). Humeral head translations, center-of-pressure, contact area, contact pressure, and glenohumeral joint contact forces were numerically estimated. Mismatches between 3.4 mm and 6.4 mm were associated with the most minimal humeral translations and contact pressure, as well as with maximal contact area. Center of pressure displacement pattern differed according to shoulder condition, with an outward anterior tendency in presence of tear.

Range of motion and isometric strength of shoulder joints of team handball athletes during the playing season, Part II: changes after midseason.

PubMed

Fieseler, Georg; Jungermann, Philipp; Koke, Alexander; Irlenbusch, Lars; Delank, Karl-Stefan; Schwesig, Rene

2015-03-01

Our objective was to investigate the influence of workload and consecutive changes on active range of motion and isometric strength of team handball athletes' throwing shoulders (TSs) because the available data are insufficient. In a longitudinal investigation, 31 professional male handball athletes underwent a clinical shoulder examination. Athletes were examined at the beginning (week 0), at the end (week 6) of the preseasonal training, and at the end of the half-season (week 22) on both shoulders to determine isometric rotational strength (hand held dynamometer) and active range of motion (goniometer). This analysis demonstrates the results subsequently from week 6 to week 22 and from week 0 to week 22. The glenohumeral internal rotation (IR) deficit (GIRD), external rotation (ER) gain, and ER at the TS increased significantly (P < .05, η(2) > 0.10, d > 0.30) in the first sequence (week 6 to week 22) but not significantly from week 0 to week 22. The total range of motion remained stable, and IR changed but not significantly. There was no influence on IR, ER, and total range of motion at the non-TS. The isometric strength of the TS and non-TS IR did not change. The isometric strength in ER significantly increased bilaterally during the investigation period. Our data verify changes and influences, such as an increasing GIRD, at the overhead TS joint in accordance with the workload during team handball season. ER gain did improve after the half-season period but did not fully compensate the GIRD at the TS. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.