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At least 937 records · Page 52Linked to original sources
PubMed2002

Trabecular microstructure and surface changes in the greater tuberosity in rotator cuff tears.

OBJECTIVE: When planning surgery in patients with rotator cuff tear, strength of bone at the tendon insertion and trabecular bone structure in the greater tuberosity are usually taken into consideration. We investigated radiographic changes in bone structure of the greater tuberosity in rotator cuff tears. DESIGN: Twenty-two human cadaveric shoulders from subjects ranging from 55 to 75 years of age were obtained. The integrity of the rotator cuff was examined by sonography to determine if it is intact without any tear, or torn partially or completely. The humeral head was sectioned in 3 mm thick coronal slab sections and microradiographed. After digitization of the microradiographs and imaging processing with in-house semi-automated image processing software tools developed using software interfaces on a Sun workstation, the trabecular histomorphometrical structural parameters and connectivity in the greater tuberosity were quantified. The degenerative changes on the surface of the greater tuberosity were interpreted blindly by 2 independent readers. RESULTS: Among the 22 shoulder specimens, the rotator cuff was found intact in 10 shoulders, partially in 7 and fully torn in 5. Statistically significant loss in apparent trabecular bone volume fraction, number of trabecular nodes, and number of trabecular branches, and a statistically significant increase in apparent trabecular separation and number of trabecular free ends were found in the greater tuberosity of the shoulders with tears. The loss was greater in association with full tear than in partial tear. Thickening of the cortical margin of the enthesis, irregularity of its surface, and calcification beyond the tidemark were observed in 2 (20%) shoulders with intact rotator cuff, in 6 (86%) shoulders with partial tear, and in 5 (100%) shoulders with full tear. CONCLUSIONS: Rotator cuff tears are associated with degenerative changes on the bone surface and with disuse osteopenia of the greater tuberosity. Aging, degenerative enthesopathy of the supraspinatus tendon, and rotator cuff tears appear closely related.

Aged↗
PubMed2005

Adhesive capsulitis: sonographic changes in the rotator cuff interval with arthroscopic correlation.

OBJECTIVE: To evaluate the sonographic findings of the rotator interval in patients with clinical evidence of adhesive capsulitis immediately prior to arthroscopy. DESIGN AND PATIENTS: We prospectively compared 30 patients with clinically diagnosed adhesive capsulitis (20 females, 10 males, mean age 50 years) with a control population of 10 normal volunteers and 100 patients with a clinical suspicion of rotator cuff tears. Grey-scale and colour Doppler sonography of the rotator interval were used. RESULTS: Twenty-six patients (87%) demonstrated hypoechoic echotexture and increased vascularity within the rotator interval, all of whom had had symptoms for less than 1 year. Three patients had hypoechoic echotexture but no increase in vascularity, and one patient had a normal sonographic appearance. All patients were shown to have fibrovascular inflammatory soft-tissue changes in the rotator interval at arthroscopy commensurate with adhesive capsulitis. None of the volunteers or the patients with a clinical diagnosis of rotator cuff tear showed such changes. CONCLUSIONS: Sonography can provide an early accurate diagnosis of adhesive capsulitis by assessing the rotator interval for hypoechoic vascular soft tissue.

Adult↗
PubMed1996

Evaluation of post-exercise magnetic resonance images of the rotator cuff.

OBJECTIVE: To examine the effect of strenuous exercise on the magnetic resonance imaging (MRI) characteristics of the rotator cuff tendon. A second objective was to define an optimal time to image the rotator cuff and possibly eliminate exercise-induced false positives. DESIGN AND PATIENTS: Five male subjects from 24 to 38 years old with normal rotator cuffs by history, physical examination, and screening MRI underwent a rotator cuff exercise session on the Biodex System 2 (Biodex, Shirley, New York). The exercise sessions were followed by sequential MRI scans of the exercised shoulder. These were performed immediately and at 8 h and 24 h after exercise. RESULTS AND CONCLUSIONS: The rotator cuff tendon and subacromial-subdeltoid bursal signal remained unchanged from the pre-exercise through the 24-h post-exercise scans. The rotator cuff muscle signal was increased in five of five subjects on the immediate post-exercise fat-suppressed T2-weighted images. This signal returned to baseline by the 8-h scan. Positive findings of rotator cuff pathology on MRI after strenuous athletic activity should not be discounted as normal exercise-induced changes. Also, diagnostic MRI scanning may take place after a practice session without an increased risk of false positives.

Adult↗
PubMed1998

The rotational angle in osteoarthritic knees.

The angle of rotation of the knee joint during weight-bearing in osteoarthritic knees has not been fully determined. The authors aimed to examine the nature and extent of rotation during weight-bearing by means of ultrasonic investigation. There was a highly significant correlation between the rotational angle measured by ultrasound and that determined by CT. The dynamic rotatory movement during weight-bearing was measured in 107 osteoarthritic and 40 control knees. At 20 degrees of flexion the internal rotation of the early grade I osteoarthritic knees (-1.6 degrees) was significantly less than that of the control knees (-4.8 degrees, P = 0.004). This abnormality was the initial pathological rotational change in osteoarthritis of the knee joint. The external rotation at maximal extension and the rotation of the screw-home movement proportionately decreased with progression of medial compartment osteoarthritis. By virtue of these observations we have clarified the dynamic rotatory movement in osteoarthritic knees during weight-bearing.

Adult↗
PubMed1981

An approach to rotational relapse.

The tendency of rotated teeth to relapse after treatment following retention is partially because of the supra-alveolar fibers which are stretched during rotational correction. Early treatment, overrotation, a long retention period, and proper contouring of contact points have been used to reduce relapse. With several surgical methods, it has been shown that releasing the tension in the periodontal fibers by severing the supracrestal and transseptal fibers significantly reduced relapse tendencies following rotation. This study was designed to test a simple surgical method (Vanarsdall) and to examine the effect of transsecting supra-alveolar fibers in orthodontically rotated teeth. Twelve cases in which a tooth and its antimere were rotated in excess of 10 degrees prior to orthodontic treatment were chosen for this study. One of the two rotated teeth was chosen for the gingival fibrotomy, while its antimere was retained by conventional orthodontic means and served as a control. The incision was made at a 45-degree angle to the long axis of the tooth, on the labial and lingual aspects of each tooth, 2 months prior to debanding. A significant decrease in the amount of relapse up to 30 days following removal of appliances in the fibrotomy group as compared to the control group (0.42 degrees and 5.75 degrees, respectively) suggests that the procedure be considered for overcoming rotational relapse.

Gingivoplasty↗
PubMed1988

The comparative influence of substituted phenols (especially chlorophenols) on yeast cells assayed by electro-rotation and other methods.

The toxicity of 31 phenols was studied by electro-rotation of yeast cells. Control yeast cells show both anti-field and co-field rotation, depending upon the field frequency applied. After treatment with supra-threshold amounts of phenols the anti-field rotation is weakened or abolished and a stronger co-field rotation can be seen. The proportion of cells showing the co-field rotation was found to be a sensitive measure of toxicity. Doses of 2.2 mumol/l of pentachlorophenol, or of 0.3 mumol/l of pentabromophenol were detectable after 3 h incubation at pH 4.0. At a given pH, the toxicity of the chlorophenols correlated extremely well with their octanol:water partition coefficients (Pow). The complete set of phenols showed fair overall correlation with Pow, but less good correlation with their acidity constants (pKa). In particular the toxicity of a given phenol was less than predicted from its pKa if the incubation pH was higher than the pKa. Biochemical assays on 23 of the phenols showed that the rotational sensitivity runs closely parallel to the sensitivities of cell growth rate and of the plasmamembrane ATPase, but less closely to the inhibition of purine incorporation. It appears that the electro-rotation method provides a useful and rapid test for the presence of organic ecotoxins. The test enables us to distinguish differences between single cells, and is comparable in sensitivity to biochemical tests that use vesicles or homogenates derived from a cell population.

Acids↗
PubMed1991

Antibodies against the 53 kDa glycoprotein inhibit the rotational dynamics of both the 53 kDa glycoprotein and the Ca(2+)-ATPase in the sarcoplasmic reticulum membrane.

The purpose of this study is to better define the relationship of the 53 kDa glycoprotein (GP-53) of the sarcoplasmic reticulum (SR) to other SR proteins. Towards that end the effects of antibodies against GP-53 on the rotational dynamics of maleimide spin-labeled proteins of SR of rabbit skeletal muscle were investigated. The labeling protocol used in this study provided 1.6 +/- 0.3 moles spin label incorporated per 10(5) g SR protein. Labeling specificity studies indicated that nearly 70% of the label bound specifically to the Ca(2+)-ATPase, with the remainder bound to GP-53. Using saturation-transfer electron paramagnetic resonance (ST-EPR), it was determined that the rotational mobility (i.e., the rate of rotation) of the spin-labeled SR proteins decreased greater than 5-fold upon preincubation of MSL-SR with an antiserum against the GP-53, while preincubation of MSL-SR with preimmune serum had no effect. Preincubation of MSL-SR with a monoclonal antibody against the GP-53 produced a 4-fold decrease in the rotational mobility of the MSL-SR proteins compared to control measurements. Further, these effects showed a marked calcium dependence: the decrease in the rotational mobility of the MSL-SR proteins preincubated with anti-GP-53 antibodies in 500 microM Ca2+ was 3-6-fold greater than that of MSL-SR preincubated with antibodies in 5 mM EGTA. While MSL was bound to both Ca(2+)-ATPase and GP-53, model calculations indicated that the decreases observed in the rotational mobility of the MSL-SR proteins caused by the anti-GP-53 monoclonal antibodies were too large to be accounted for by effects on GP-53 alone. The calculations suggest that the rotational rate of Ca(2+)-ATPase was also diminished by anti-GP-53 monoclonal antibodies, indicating an interaction between GP-53 and Ca(2+)-ATPase in the SR membrane.

Antibodies, Monoclonal↗
PubMed1987

Dependence of cat vestibulo-ocular reflex direction adaptation on animal orientation during adaptation and rotation in darkness.

Four series of experiments investigated how adaptive changes in direction of the cat's vestibulo-ocular reflex (VOR) vary with position of the animal during adaptive training and postadaptive testing. In all experiments VOR was measured electrooculographically during rotations about earth-horizontal and vertical axes in the dark before and after 2 h of adaptation in which 0.25 Hz sinusoidal whole body rotation about a horizontal/vertical axis was paired with synchronous 0.25 Hz rotation of a visual pattern about a vertical/horizontal axis, respectively. In upright sagittal (US) experiments, coupling of pitch rotation with visual pattern rotation about an earth vertical axis yielded an adaptive horizontal VOR response to pitch rotation whose gain had a local maximum at 0.25-0.5 Hz plus a sustained rise for frequencies below 0.1 Hz. When post-tests were done with the animal rolled 90 degrees onto its side and rotated about the earth vertical axis (pitch relative to the cat), the low frequency rise was eliminated and the 0.25 Hz peak was reduced. In on side sagittal (SS) experiments, where training was done in the latter (on side) position, training produced only the 0.25 Hz peak without the low frequency rise, indicating that the rise is due to coupling of otolith input to horizontal VOR. Again the 0.25 Hz peak was reduced when testing was done with the cat oriented 90 degrees from the training position (in the US position). This indicates that the cross-coupled canal-ocular reflex response is modulated or gated by the position of the animal with respect to gravity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Ocular↗
PubMed1989

The human torsional vestibulo-ocular reflex during rotation about an earth-vertical axis.

Using the magnetic search coil technique, we have measured the gain and time constant (Tvor) of the torsional vestibulo-ocular reflex (VOR) in 4 subjects who were rotated about an earth-vertical axis with their necks extended and faces supine. Following a 1-min period of rotation in darkness at 50 degrees/s, the post-rotational response to a velocity off-step had a group mean gain of 0.43 and Tvor of 3.7 s. Following a 1-min period of rotation in the light at 50 degrees/s, the post-rotational response in darkness had a group mean gain of 0.29 and Tvor of 4.1 s. Following rotation in darkness with the neck flexed and head prone, the post-rotational response, measured in two subjects, had a mean gain of 0.39 and Tvor of 5.7 s. Similar results were obtained with 100 degrees/s stimuli. In all subjects, the gain and Tvor of the torsional VOR were smaller than corresponding values for their horizontal VOR; these smaller values can be related to the different visual demands made of the torsional VOR.

Adult↗
PubMed1995

The cannabinoid agonists WIN 55,212-2 and CP 55,940 attenuate rotational behavior induced by a dopamine D1 but not a D2 agonist in rats with unilateral lesions of the nigrostriatal pathway.

The effect of cannabinoid receptor stimulation on rotational behavior induced by a dopamine D1 and a D2 agonist was studied in rats with unilateral 6-hydroxydopamine-induced lesions of the dopaminergic nigrostriatal pathway. The cannabinoid agonists WIN 55,212-2 (2.5 mg/kg) and CP 55,940 (0.1 mg/kg) both markedly attenuated contralateral rotation induced by the D1 agonist SKF 38393 (1.5 mg/kg). In contrast, WIN 55,212-2 and CP 55,940 did not alter rotation elicited by the D2 agonist quinpirole (0.1 mg/kg). Doses of WIN 55,212-2 and CP 55,940 that attenuated D1-mediated rotation did not produce catalepsy in intact rats or in rats with 6-hydroxydopamine-induced lesions, indicating that the reduction in rotation produced by the cannabinoids was not due to a generalized motor impairment. In addition, the effective dose of WIN 55,212-2, but not CP 55,940, produced only a slight increase in ipsilateral rotation when administered alone, making it improbable that this ipsilateral tendency accounts for the reduction in D1-mediated contralateral rotation. These results suggest a preferential interaction between cannabinoid receptor stimulation and dopamine D1 receptor-mediated behavior.

Animals↗
PubMed1992

Rotational behavior as a classically conditioned response to pentobarbital administration.

Pentobarbital stimulus control of rotational behavior was investigated in rats with unilateral 6-hydroxydopamine lesions of substantia nigra. In conditioning trials, lesioned rats were injected simultaneously with 10 mg/kg pentobarbital and 0.05 mg/kg apomorphine and their rotational (circling) behavior observed and counted. Subsequent to three consecutive daily conditioning sessions, animals were re-introduced to the rotation environment and tested with saline or pentobarbital. Pentobarbital, but not saline, administration was followed by a brief epoch of rapid contralateral rotation. After additional conditioning trials in which pentobarbital and apomorphine administration were paired, test sessions with 1 g/kg ethanol and with 10 mg/kg chlordiazepoxide were conducted. Most animals did not rotate in response to ethanol administration and most did rotate in response to chlordiazepoxide. Finally, in order to determine the persistence of the conditioned effect, animals were tested with pentobarbital 15 weeks after their last conditioning session and were found to rotate actively in response.

Animals↗
PubMed1989

Identification of knee joint models for varus-valgus and internal-external rotations: snow skiing experiments.

Sprains at the knee are the most frequent of the severe injuries occurring during alpine snow skiing. This paper discusses the development of analytical models describing rotations across the knee joint caused by varus-valgus and internal-external moments applied at the foot during skiing. Identification of an ARMAX model requires simultaneous measurements of the rotations across the knee and the moments at the foot during skiing. As the models only relate the measured input (moment) and output (rotation) data, they also identify components of apparent rotation resulting from imperfect fixation of the rotation measuring instrument on the test subject and resulting from other inputs. The models identified for all subjects are of order four or five for both varus-valgus and internal-external rotation, and they describe modes with oscillatory and exponentially decaying components. Application of the models to prediction of rotation across the knee from the measured moment at the foot is illustrated by example. A new, and virtually mechanically uncoupled, six degrees-of-freedom, strain gauge dynamometer is developed to record the moments at the foot during skiing. The concept of the dynamometer design has general application.

Humans↗
PubMed1994

A three-dimensional kinematic method for determining the effectiveness of arm segment rotations in producing racquet-head speed.

The contribution that a segment's anatomical rotations make to racquet-head speed depends on both the segment's angular velocity and the instantaneous position of the head of the racquet with respect to the segment's axes of rotation. Any analysis of racquet swing technique that does not consider both of these factors simultaneously is, at best, incomplete. With this in mind, a three-dimensional kinematic method was developed to determine the effectiveness of the anatomical rotations of the upper arm, forearm, and hand in producing racquet-head speed. The method entailed developing a system of vector equations for three-dimensional upper limb rotations that used displacement histories of 10 selected landmarks as input. The required three-dimensional displacement histories were obtained using three cine cameras and the DLT approach. To test the diagnostic capabilities of the method, a tennis serve was selected for analysis. For the player and serve analyzed, the greatest contribution to racquet-head speed at impact was produced by internal rotation of the upper arm (8 m s-1). Forearm pronation, although exhibiting the fastest rotation at impact (24 rad s-1), ranked only fourth in terms of its contribution (4 m s-1) to racquet-head speed. To test the performance of the method, a comparison was made between the racquet-head speed measured directly from film and the racquet-head speed computed by summing all of the individual segment contributions to speed commencing at the start of forward swing and ending at ball contact. The results indicate that the method can successfully determine the individual contributions that the different anatomical rotational velocities of the arm segments make to the measured instantaneous racquet-head speed.

Algorithms↗
PubMed1986

Transient contralateral rotation following unilateral substantia nigra lesion reflects susceptibility of the nigrostriatal system to exhaustion by amphetamine.

Following unilateral 6-OHDA induced SN lesion, a transient period of contralateral rotation has been reported to precede the predominant ipsilateral circling. In order to clarify the nature of this initial contralateral rotation we examined the effect of the duration of recovery period after the lesion, on amphetamine-induced rotational behavior. Three days post lesion, most rats circled predominantly contralaterally to the lesion. Such contralateral rotation may result from either degeneration-induced breakdown of the DA pool, or lesion-induced increase of DA turnover in the spared neurons. A substantial degree of contralateral preference was still evident when amphetamine was administered for the first time 24 days after lesioning, indicating involvement of spared cells in the contralateral rotation. However, regardless of the duration of recovery (and irrespective of either lesion volume, amphetamine dose, or post-lesion motor exercise), amphetamine-induced rotation tended to become gradually more ipsilateral as the observation session progressed, and all rats circled ipsilaterally to the lesion in response to further amphetamine injections. These findings suggest that amphetamine has an irreversible effect on the post-lesion DA pool contributing to contralateral rotation.

Amphetamine↗
PubMed1992

Strain and sex differences in amphetamine-induced rotation.

Studies of rotational behavior in female rats have investigated Fischer, Sprague-Dawley, Madison, WI, and Holtzman strains. The present study of amphetamine-induced rotational preference looked at the most widely used of the pigmented strains, Long-Evans hooded rats, examining rotation in females and comparing rotational magnitude and direction to males of the same strain. We corroborate in Long-Evans animals the greater rotation of females, but our findings oppose the right-sided female and left-sided male rotational preferences reported in earlier studies. Only female rats in this experiment had a significant directional bias, and it was to the left. This result strongly points to the importance of strain in the lateralization expressed by rotation.

Amphetamine↗
PubMed2006

Does tibial rotation correlate with femoral anteversion? Implications for hip arthroplasty.

The aim of the study was to assess the magnitude and variability of rotation of ipsilateral femur and tibia and to identify the existence of rotational correlations. Femoral rotation (FR) and tibial rotation (TR) were measured with computed tomography in 151 consecutive patients when total hip arthroplasty was planned. Median FR was 14 degrees (range, -23 degrees to 91 degrees ) and median TR was 38 degrees (range, 15 degrees -76 degrees ). Femoral rotation was significantly higher in females, in left femora, in the presence of secondary osteoarthritis, and in hip dysplasia. Tibial rotation was significantly higher in females. Femoral rotation and TR positively correlated (r = 0.2963, P = .0001). The magnitude of TR and FR was found to be dependent on each other. Disregarding the variability and magnitude of TR may result in asymmetrical foot positioning after correction of FR during total hip arthroplasty.

Adult↗
PubMed2006

Gender differences in quality of life and extent of rotator cuff pathology.

PURPOSE: The purpose of this study was to investigate the effect of age and gender on functional and emotional status and extent of rotator cuff and associated pathology in patients undergoing arthroscopic surgery. TYPE OF STUDY: Historical cohort study. METHODS: This study involved 279 patients who underwent rotator cuff decompression or rotator cuff repair and for whom scores for the 5 domains of a preoperative rotator cuff outcome measure were available. Arthroscopic examination was used to identify the extent of pathology in the rotator cuff, biceps tendon, and superior labrum. RESULTS: Over a period of 3 years, 108 women and 171 men underwent surgery. There was a statistically significant difference in the domain of emotions (P = .024) for men and women. The levels of symptoms (P = .020), difficulty with performing sports and recreational activities (P = .043), and emotions (P = .001) were significantly different between individuals under 55 years of age and those 55 and older, with older patients reporting less difficulty. In terms of extent of pathology, the chi-square analysis showed a statistically significant difference in the incidence of full-thickness tears (P < .0001) between different age groups and SLAP lesions types II to IV (P = .009) between men and women. CONCLUSIONS: Female candidates for rotator cuff-related surgeries report more emotional difficulties. Older age group appear to have less functional and emotional disability despite an increase in the prevalence of major rotator cuff pathology. Gender and age have important roles on quality of life and extent of shoulder pathology. LEVEL OF EVIDENCE: Level II, investigating the outcome of disease.

Age Factors↗
PubMed2006

Concomitant rotator cuff and capsuloligamentous lesions of the shoulder: a cadaver study.

PURPOSE: Rotator cuff lesions have not yet been evaluated in association with capsuloligamentous lesions in an otherwise intact shoulder model. Our hypothesis was that less extensive capsuloligamentous lesions are necessary to allow dislocation in the presence of rotator cuff lesions. METHODS: The supraspinatus and infraspinatus, or the subscapularis, or all 3 tendons were carefully detached from their insertion without damage to the underlying capsule. Adjacent combinations of 4 zones of the capsuloligamentous complex were then sequentially detached from the glenoid or from the humerus in 80 cadaver shoulders. Stability was tested before and after each resection step; this included testing of inferior stability with a sulcus test, and of anterior stability with a drawer test and with an apprehension maneuver. Findings from these specimens were statistically compared with those from the same types of tests in specimens with intact rotator cuffs. RESULTS: Subluxation during the drawer and sulcus tests is already reached after the tendon lesion has been created, or after only 1 ligamentous zone has been cut. In the presence of a tendon lesion, at least 1 less cutting step is necessary for dislocation to occur in the apprehension position. There is a difference, however, between glenoid- and humerus-based lesions. CONCLUSIONS: The humeral head dislocates easily with less extensive capsuloligamentous lesions when rotator cuff lesions are present. In the present experimental model, passive stabilization provided by the rotator cuff appears more easily disrupted when associated with ligamentous lesions on the humeral side than with lesions on the glenoid side. This may be so because interdigitation of the cuff tendons with each other and with the capsule through the rotator cable is maintained with glenoid-sided lesions. CLINICAL RELEVANCE: Rotator cuff lesions destabilize the glenohumeral joint. This effect is less pronounced when cuff tendons continue to interact with underlying capsuloligamentous structures. This finding may be relevant for small cuff tears and for partial cuff tears, especially those seen after dislocation.

Aged↗