Sonographic features of dialysis-related amyloidosis of the shoulder.
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This study evaluated the diagnostic role of ultrasonography in dialysis-related amyloidosis in shoulders of chronically hemodialyzed patients. Fourteen shoulders of 12 long-term hemodialysis patients were examined. All patients had been on dialysis for at least 10 years. All patients had varying degrees of pain and limitations of movement in the studied shoulders. Dialysis-related amyloidosis was the presumed diagnosis in all patients. Any patient with a history of any disease, other than dialysis-related amyloidosis, capable of producing a pathologic shoulder condition was excluded. The following parameters were studied: supraspinatus and biceps tendon thickness, tendon tears, synovial thickening, and the presence of hypoechoic material around tendons and within bursae. All shoulders had a nonhomogeneous thickening, greater than 7 mm, of the supraspinatus tendon. Seven shoulders (50%) had abnormal thickening of the biceps tendon (4 mm or greater), and two shoulders had abnormal thickening of the subscapularis tendon. Hypoechoic deposits were seen in the subdeltoid bursae and biceps sheaths in five and six shoulders, respectively. Three shoulders showed partial tears of the supraspinatus tendon, one shoulder showed a tear in the biceps tendon, and one shoulder had a tear in the subscapularis tendon. Ultrasonography is an excellent imaging modality in diagnosing the presence of dialysis-related amyloidosis in symptomatic shoulders of long-term hemodialysis patients, without having to resort to invasive procedures. The results of previous studies have been confirmed and new ultrasonographic findings described. Of particular interest is the involvement of the subscapularis tendon in dialysis-related amyloidosis. Repeat ultrasonography can become an important way to follow-up progression of shoulder dialysis-related amyloidosis in hemodialyzed patients. (+info)
Kinematic coordinates in which motor cortical cells encode movement direction.
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During goal-directed reaching in primates, a sensorimotor transformation generates a dynamical pattern of muscle activation. Within the context of this sensorimotor transformation, a fundamental question concerns the coordinate systems in which individual cells in the primary motor cortex (MI) encode movement direction. This article develops a mathematical framework that computes, as a function of the coordinate system in which an individual cell is hypothesized to operate, the spatial preferred direction (pd) of that cell as the arm configuration and hand location vary. Three coordinate systems are explicitly modeled: Cartesian spatial, shoulder-centered, and joint angle. The computed patterns of spatial pds are distinct for each of these three coordinate systems, and experimental approaches are described that can capitalize on these differences to compare the empirical adequacy of each coordinate hypothesis. One particular experiment involving curved motion was analyzed from this perspective. Out of the three coordinate systems tested, the assumption of joint angle coordinates best explained the observed cellular response properties. The mathematical framework developed in this paper can also be used to design new experiments that are capable of disambiguating between a given set of specified coordinate hypotheses. (+info)
Kinematic strategies for upper arm-forearm coordination in three dimensions.
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This study addressed the question of how the three-dimensional (3-D) control strategy for the upper arm depends on what the forearm is doing. Subjects were instructed to point a laser-attached in line with the upper arm-toward various visual targets, such that two-dimensional (2-D) pointing directions of the upper arm were held constant across different tasks. For each such task, subjects maintained one of several static upper arm-forearm configurations, i. e., each with a set elbow angle and forearm orientation. Upper arm, forearm, and eye orientations were measured with the use of 3-D search coils. The results confirmed that Donders' law (a behavioral restriction of 3-D orientation vectors to a 2-D "surface") does not hold across all pointing tasks, i.e., for a given pointing target, upper arm torsion varied widely. However, for any one static elbow configuration, torsional variance was considerably reduced and was independent of previous arm position, resulting in a thin, Donders-like surface of orientation vectors. More importantly, the shape of this surface (which describes upper arm torsion as a function of its 2-D pointing direction) depended on both elbow angle and forearm orientation. For pointing with the arm fully extended or with the elbow flexed in the horizontal plane, a Listing's-law-like strategy was observed, minimizing shoulder rotations to and from center at the cost of position-dependent tilts in the forearm. In contrast, when the arm was bent in the vertical plane, the surface of best fit showed a Fick-like twist that increased continuously as a function of static elbow flexion, thereby reducing position-dependent tilts of the forearm with respect to gravity. In each case, the torsional variance from these surfaces remained constant, suggesting that Donders' law was obeyed equally well for each task condition. Further experiments established that these kinematic rules were independent of gaze direction and eye orientation, suggesting that Donders' law of the arm does not coordinate with Listing's law for the eye. These results revive the idea that Donders' law is an important governing principle for the control of arm movements but also suggest that its various forms may only be limited manifestations of a more general set of context-dependent kinematic rules. We propose that these rules are implemented by neural velocity commands arising as a function of initial arm orientation and desired pointing direction, calculated such that the torsional orientation of the upper arm is implicitly coordinated with desired forearm posture. (+info)
End-range mobilization techniques in adhesive capsulitis of the shoulder joint: A multiple-subject case report.
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BACKGROUND AND PURPOSE: The purpose of this case report is to describe the use of end-range mobilization techniques in the management of patients with adhesive capsulitis. CASE DESCRIPTION: Four men and 3 women (mean age=50.2 years, SD=6.0, range=41-65) with adhesive capsulitis of the glenohumeral joint (mean disease duration=8.4 months, SD=3.3, range=3-12) were treated with end-range mobilization techniques, twice a week for 3 months. Indexes of pain, joint mobility, and function were measured by the same observer before treatment, after 3 months of treatment, and at the time of a 9-month follow-up. In addition, arthrographic assessment of joint capacity (ie, the amount of fluid the joint can contain) and measurement of range of motion of glenohumeral abduction on a plain radiograph were conducted initially and after 3 months of treatment. OUTCOMES: After 3 months of treatment, there were increases in active range of motion. Mean abduction increased from 91 degrees (SD=16, range=70-120) to 151 degrees (SD=22, range=110-170), mean flexion in the sagittal plane increased from 113 degrees (SD=17, range=90-145) to 147 degrees (SD=18, range=115-175), and mean lateral rotation increased from 13 degrees (SD=13, range=0-40) to 31 degrees (SD=11, range=15-50). There were also increases in passive range of motion: Mean abduction increased from 96 degrees (SD=18, range=70-125) to 159 degrees (SD=24, range 110-180), mean flexion in the sagittal plane increased from 120 degrees (SD=16, range=95-145) to 154 degrees (SD=19, range=120-180), and mean lateral rotation increased from 21 degrees (SD=11, range=10-45) to 41 degrees (SD=8, range=35-55). The mean capacity of the glenohumeral joint capsule (its ability to contain fluid) increased from 10 cc (SD=3, range=6-15) to 15 cc (SD=3, range=10-20). Four patients rated their improvement in shoulder function as excellent, 2 patients rated it as good, and 1 patient rated it as moderate. All patients maintained their gain in joint mobility at the 9-month follow-up. DISCUSSION: There seems to be a role for intensive mobilization techniques in the treatment of adhesive capsulitis. Controlled studies regarding the effectiveness of end-range mobilization techniques in the treatment of adhesive capsulitis are warranted. (+info)
The relationship of age, gender, and degenerative changes observed on radiographs of the shoulder in asymptomatic individuals.
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Radiographs of the shoulders of 84 asymptomatic individuals aged between 40 and 83 years were evaluated to determine changes in 23 specific areas. Two fellowship-trained orthopaedic radiologists graded each area on a scale of 0 to II (normal 0, mild changes I, advanced changes II). Logistic regression analysis indicated age to be a significant predictor of change (p < 0.05) for sclerosis of the medial acromion and lateral clavicle, the presence of subchondral cysts in the acromion, formation of osteophytes at the inferior acromion and clavicle, and narrowing and degeneration of the acromioclavicular joint. Gender was not a significant predictor (p > 0.05) for radiological changes. Student's t-test determined significance (p < 0.05) between age and the presence of medial acromial and lateral clavicular sclerosis, subchondral acromial cysts, inferior acromial and clavicular osteophytes, and degeneration of the acromioclavicular joint. Radiological analysis in conditions such as subacromial impingement, pathology of the rotator cuff, and acromioclavicular degeneration should be interpreted in the context of the symptoms and normal age-related changes. (+info)
Effect of long-duration spaceflight on postural control during self-generated perturbations.
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This report is the first systematic evaluation of the effects of prolonged weightlessness on the bipedal postural control processes during self-generated perturbations produced by voluntary upper limb movements. Spaceflight impacts humans in a variety of ways, one of which is compromised postflight postural control. We examined the neuromuscular activation characteristics and center of pressure (COP) motion associated with arm movement of eight subjects who experienced long-duration spaceflight (3--6 mo) aboard the Mir space station. Surface electromyography, arm acceleration, and COP motion were collected while astronauts performed rapid unilateral shoulder flexions before and after spaceflight. Subjects generally displayed compromised postural control after flight, as evidenced by modified COP peak-to-peak anterior-posterior and mediolateral excursion, and pathlength relative to preflight values. These changes were associated with disrupted neuromuscular activation characteristics, particularly after the completion of arm acceleration (i.e., when subjects were attempting to maintain upright posture in response to self-generated perturbations). These findings suggest that, although the subjects were able to assemble coordination modes that enabled them to generate rapid arm movements, the subtle control necessary to maintain bipedal equilibrium evident in their preflight performance is compromised after long-duration spaceflight. (+info)
Measurement of scapular asymetry and assessment of shoulder dysfunction using the Lateral Scapular Slide Test: a reliability and validity study.
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BACKGROUND AND PURPOSE: The Lateral Scapular Slide Test (LSST) is used to determine scapular position with the arm abducted 0, 45, and 90 degrees in the coronal plane. Assessment of scapular position is based on the derived difference measurement of bilateral scapular distances. The purpose of this study was to assess the reliability of measurements obtained using the LSST and whether they could be used to identify people with and without shoulder impairments. Subjects. Forty-six subjects ranging in age from 18 to 65 years (X=30.0, SD=11.1) participated in this study. One group consisted of 20 subjects being treated for shoulder impairments, and one group consisted of 26 subjects without shoulder impairments. METHODS: Two measurements in each test position were obtained bilaterally. From the bilateral measurements, we derived the difference measurement. Intraclass correlation coefficients (ICC [1,1]) and the standard error of measurement (SEM) were calculated for intrarater and interrater reliability of the difference in side-to-side measures of scapular distance. Sensitivity and specificity of the LSST for classifying subjects with and without shoulder impairments were also determined. RESULTS: The ICCs for intrarater reliability were .75, .77, and .80 and .52, .66, and .62, respectively, for subjects without and with shoulder impairments in 0, 45, and 90 degrees of abduction. The ICCs for interrater reliability were .67, .43, and .74 and .79, .45, and .57, respectively, for subjects without and with shoulder impairments in 0,45 and 90 degrees of abduction. The SEMs ranged from 0.57 to 0.86 cm for intrarater reliability and from 0.79 to 1.20 cm for interrater reliability. Using the criterion of greater than 1.0 cm difference, sensitivity and specificity were 35% and 48%, 41% and 54%, and 43% and 56%, respectively, for 0, 45, and 90 degrees of abduction. Sensitivity and specificity based on the criterion of greater than 1.5 cm difference were 28% and 53%, 50% and 58%, and 34% and 52%, respectively, for the 3 scapular positions. CONCLUSION AND DISCUSSION: Our results suggest that measurements of scapular positioning based on the difference in side-to-side scapular distance measures are not reliable. Furthermore, the results suggest that sensitivity and specificity of the LSST measurements are poor and that the LSST should not be used to identify people with and without shoulder dysfunction. (+info)
Bone destruction, upward migration, and medialisation of rheumatoid shoulder: a 15 year follow up study.
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OBJECTIVE: To evaluate bone destruction, upward migration, and medialisation of the glenohumeral (GH) joint in a cohort of 74 patients with seropositive and erosive rheumatoid arthritis followed up prospectively. METHODS: At the 15 year follow up 148 shoulders were radiographed by a standard method. Bone destruction in the GH joint was examined from the radiographs by four methods, of which three measured the migration and one the remodelling of the humeral head. The distances from the greater tuberosity of the humeral head to the coracoid process (medialisation distance (MD)) and to the articular surface of the humeral head (GA) have been previously developed to evaluate the preoperative offsets of the arthritic GH joint. Medial displacement index (MI) and upward migration index (UI) have been recently developed to evaluate the destructive pattern of the rheumatoid GH joint. Destruction of the GH joints was assessed by the Larsen method on a scale of 0 to 5. The relation between the measurements and the grade of destruction of the GH joints was examined. UI was compared with our previous measurements of the subacromial space. RESULTS: Both the MI and the UI had a negative correlation with the GH joint destruction (Larsen grade), r=-0.49 (95% CI -0.36 to -0.60) and r=-0.58 (95% CI -0.46 to -0.68). The UI correlated significantly with the subacromial space, r=0.90 (95% CI 0.86 to 0.93). The mean MI and UI measurements of the non-affected joints were within the reported normal variation. The mean MD collapsed between Larsen grades 4 (83.0 mm) and 5 (65.5 mm). The morphology of the humeral head began to flatten and erode from the grade 3 onwards and medial head destruction was detected at grade 5. CONCLUSIONS: Medialisation seems to be preceded by upward migration of the humeral head, indicating rotator cuff damage. Symptomatic Larsen grade 3 shoulders should be intensively followed up by clinical and radiological means. If a total shoulder arthroplasty is considered, an orthopaedic consultation is worthwhile at a sufficiently early stage (Larsen 3 and 4), when soft tissue structures responsible for function are still in proper condition and timing of the operative procedure can be well planned. (+info)