Luxatio erecta of bilateral shoulders.
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Aged↗
Biomedical subjects
E Itoi
Publications and source records attributed to E Itoi.
Function of the 3 portions of the inferior glenohumeral ligament: a cadaveric study.
The stabilizing function of the inferior glenohumeral ligament of the anterior band and posterior band has been investigated, but little is known about the function of the axillary pouch. The strain of the 3 portions of the inferior glenohumeral ligament in 17 fresh-frozen cadaveric shoulders was measured with use of linear transducers. The measurements were performed under the following conditions: 0 degrees, 30 degrees, 45 degrees, and 60 degrees of glenohumeral elevation in the coronal, scapular, and sagittal planes and internal to external rotations in 10 degrees increments. The anterior band and axillary pouch showed significant strain increases when the arm was elevated and externally rotated in the coronal and scapular planes but no increase in the sagittal plane. The posterior band showed no strain in the coronal and scapular planes, but a significant strain increase with the arm elevated and internally rotated in the sagittal plane. We conclude that the anterior band and axillary pouch, which showed the greatest strain in abduction and external rotation, are anterior stabilizers, whereas the posterior band, which showed the greatest strain in flexion and internal rotation, is a posterior stabilizer. We recommend that the 6 o'clock position be firmly repaired during the Bankart procedure.
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Correlation of back extensor strength with thoracic kyphosis and lumbar lordosis in estrogen-deficient women.
Aging and osteoporosis have been associated with skeletal changes. Back extensor strengthening exercises are highly recommended for management of back pain, especially back pain related to osteoporosis. To our knowledge, the correlation of thoracic kyphosis, lumbar lordosis, and sacral inclination with back extensor strength, physical activity, and bone mineral density has not been critically studied in healthy, active, estrogen-deficient women. In a study of 65 such women (ages 48-65 yr), back extensor strength, bone mineral density, and physical activity score were evaluated and measured. These factors were then correlated with radiographic factors: (1) vertebral body ratios (anterior/posterior height) calculated for each vertebra from T-4 through L-5; (2) kyphosis index determined by adding the anterior heights of each vertebral body, T-4 through T-12, and then dividing the total by the corresponding sum of the posterior heights of each vertebral body; (3) thoracic kyphosis; (4) lumbar lordosis; and (5) sacral inclination. Back extensor strength had a significant negative correlation with thoracic kyphosis (r = -0.30, P = 0.019) and a positive correlation with lumbar lordosis (r = 0.26, P = 0.048) and sacral inclination (r = 0.34, P = 0.009). However, bone mineral density and physical activity score did not show any significant correlations with the radiographic factors. The results indicate that the stronger the back extensor, the smaller the thoracic kyphosis and the larger the lumbar lordosis and sacral inclination. We conclude that back extensor strength is an important determinant of posture in healthy women. However, prescribing back extensor strengthening exercises alone may also increase lumbar lordosis, which is not desirable.
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Range of motion after Bankart repair. Vertical compared with horizontal capsulotomy.
We studied the range of shoulder motion of patients who underwent vertical as compared with horizontal capsulotomies during open Bankart repair for recurrent anterior dislocations of the shoulder. A vertical capsulotomy was used in 10 shoulders and a horizontal capsulotomy was used in 14 shoulders. Except for the method of capsulotomy, the surgical procedure and postoperative rehabilitation were the same. The range of motion was measured at 1.5, 2, 3, 4, 5, 6, 9, and 12 months after the surgery, and at the final follow-up (average, 49 months for the vertical and 26 months for the horizontal group). No dislocations recurred, and the anterior apprehension test was negative in all of the patients in both groups. External rotation in abduction was greater in the horizontal group than in the vertical group; the differences were significantly greater at 9 months and 12 months after surgery and at the final follow-up. External rotation in adduction, flexion, and internal rotation were not significantly different between the groups. We conclude that Bankart repair through a horizontal capsulotomy preserves a better range of external rotation in abduction than does a vertical approach.
Adolescent↗
Superior labral strain during the throwing motion. A cadaveric study.
We studied the strain on the superior labrum of 10 fresh-frozen cadaveric shoulders with the arm in simulated positions of a pitching motion. We used linear transducers to measure the strain in both the anterior and posterior superior labrum with the arm in various planes and rotations simulating the motions of pitching: early cocking, late cocking, acceleration, deceleration, and follow-through. Predetermined loads, according to the percent of maximum voluntary contraction of the biceps muscle during each phase of pitching, were calculated and applied to the long head of the biceps tendon using a spring device. Only during the late cocking phase, when the arm was in maximal external rotation, was the increase in strain statistically significant for the anterior and posterior portions and the strain on the posterior portion significantly greater than that on the anterior portion of the labrum. The increased strain in the posterior portion may be due to the anatomic orientation of the long head of the biceps tendon at the superior labrum. The increased strain in the late cocking phase may contribute to the detachment of the labrum with the eccentric contraction of the biceps muscle that occurs with rapid extension of the elbow.
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Effect of superior capsule and coracohumeral ligament release on strain in the repaired rotator cuff tendon. A cadaveric study.
Twelve cadaveric shoulders were used to determine the effects of release of the superior capsule and the coracohumeral ligament on the strain in the repaired rotator cuff tendon. A rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force. The strain in the repaired tendon was measured with use of linear transducers with the arm in 50 different positions. Release of either the superior capsule or the coracohumeral ligament diminished the tension of the repaired rotator cuff by an average of 25% with the arm in adduction. Release of both of these structures further reduced the tension by an average of 44% in adduction and 43% to 60% with the arm in 15 degrees of elevation. The maximum reduction of tension in the repaired rotator cuff occurred when both the superior capsule and coracohumeral ligament were divided and when the arm was positioned in adduction and in 60 degrees of external rotation. Release of the coracohumeral ligament is equally as efficient as releasing the superior capsule in reducing the strain of the repaired rotator cuff. Releasing both structures seems to be desirable when releasing one structure or the other is not sufficient.
Aged↗
Effect of arm elevation and rotation on the strain in the repaired rotator cuff tendon. A cadaveric study.
In 14 cadaveric shoulders, a rotator cuff tear (2 cm wide and 1.5 cm long) was created and repaired under a 3-kg tensile force with the arm in adduction. Strain on the repaired tendon was measured at 0 degrees, 15 degrees, 30 degrees, and 45 degrees of elevation in the sagittal, scapular, and coronal planes and from 60 degrees of internal rotation to 60 degrees of external rotation. The strain in all of the planes decreased significantly with the arm elevated more than 30 degrees. With 30 degrees of elevation in the scapular and coronal planes, the strain increased in internal rotation and decreased in external rotation. In all of the positions measured, the strain in the sagittal plane was significantly greater than in the other planes. We concluded that more than 30 degrees of elevation in the coronal or scapular plane and rotation ranging from 0 degrees to 60 degrees of external rotation compose the safe range of motion after repair of the rotator cuff.
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Contribution of axial arm rotation to humeral head translation.
The contribution of axial arm rotation to translation of the humeral head with the arm in the hanging position was examined using nine fresh-frozen cadaveric shoulders. Three standard clinical tests were simulated: anterior and posterior translation and sulcus tests. In both the anterior translation and sulcus tests, anterior and inferior displacements were significantly restricted in internal rotation but not in neutral and external rotation. In the posterior translation test, no significant differences in displacement could be observed in internal, neutral, or external rotation. Since anterior and inferior translations of the humeral head were significantly affected by the rotation of the arm, we recommend that the anterior translation and sulcus tests be performed in various rotations.
Adult↗
Which is more useful, the "full can test" or the "empty can test," in detecting the torn supraspinatus tendon?
The purpose of this study was to determine the clinical usefulness of the full can and empty can tests for determining the presence of a torn supraspinatus tendon. The two tests were performed in 143 shoulders of 136 consecutive patients. In each test, the muscle strength was determined by manual muscle testing, and the presence of pain during the maneuver was recorded. We interpreted the tests as positive when there was 1) pain, 2) muscle weakness, or 3) pain or muscle weakness or both. Shoulders were examined by high-resolution magnetic resonance imaging with 95% accuracy for full-thickness rotator cuff tears. There were 35 shoulders with full-thickness tears of the supraspinatus tendon. The accuracy of the tests was the greatest when muscle weakness was interpreted as indicating a torn supraspinatus tendon in both the full can test (75% accurate) and the empty can test (70% accurate). However, there was no significant difference between the accuracy of the tests when this criterion was used. Pain was observed in 62 shoulders (43%) during the full can test and in 71 shoulders (50%) during the empty can test, but the difference was not statistically significant. Muscle weakness should be interpreted as indicative of supraspinatus tendon tear. Using this indicator, both tests are equivalent in terms of accuracy, but considering pain provocation, the full can test may be more beneficial in the clinical setting.
Adolescent↗
Prediction of muscle force involved in shoulder internal rotation.
The estimation of shoulder muscle force is important to understand the mechanism of rotator cuff injury. In general, mean parameter values are used as input for computational models. However, anatomic and biomechanical parameters vary widely among people. The purpose of this study was to evaluate shoulder muscle forces predicted by an electromyography-driven muscle model given neuromuscular parameters generated by Monte Carlo simulation. Normal distributions were used to model muscle moment arms; electromyographic and muscle physiological cross-sectional area data were modeled with log-normal distributions. Eight muscles were included in the model. Muscle force and joint moment were predicted on the basis of the simulated parameters. The results showed that the subscapularis and pectoralis major were substantial actuators for shoulder internal rotation. During maximum voluntary contraction the median of the muscle forces of the subscapularis and the pectoralis major were 1030 N and 462 N, respectively. This study demonstrated that the Monte Carlo method could be used for muscle force prediction by integrating population variability of physiological parameter into a biomechanical muscle model.
Biomechanical Phenomena↗
Isokinetic external rotation strength of shoulder : correlation with age and muscle size.
The purpose of this study was to determine the correlation between quantitative (cross sectional areas) evaluation of the posterior cuff muscles and mechanical strength in asymptomatic shoulders with special reference to aging. The cross-sectional area of the combined infraspinatus and teres minor muscles were measured, in the sagittal oblique magnetic resonance images, in eighty-one patients with a mean age of 44.06 years (range 19 - 74). These areas were correlated with the measured isokinetic strength in external rotation at angular velocities of 60 deg/s and 180 deg/s using Cybex 770 NORM. The results show that there was a gradual decrease in size of the muscles as the age of the individual increases. A strong correlation was found between aging and combined cross-sectional area and peak torque as well. The correlation between combined cross-sectional area and peak torques at both angular velocities were less strong. Further, the correlation between the peak torque/cross-sectional area ratio with aging was also less significant, which may imply that the decrease in the muscle strength was greater than the change in muscle area. Our results suggest that there may be other qualitative and biochemical factors that may determine the true strength of the muscles in the aged population.
Adult↗
Dual phased array coils for high-resolution MRI of the shoulder.
We connected two 3-inch coils to a dual phased array receiver system and sandwiched the shoulder between the two coils. To obtain a quantitative assessment of the improved SNR, we imaged a phantom with both the dual phased array coils and the standard shoulder coil. SNR as a function of distance from the coils was computed by the National Electrical Manufacturers Association (NEMA) standard. At the expected depth of the humeral head, the SNR of the phased array coils on single excitation was 1.42 times that of the standard shoulder coil on two excitations. The higher quality of the images on single excitation shortened the imaging procedure. The dual phased array coils realized the minimum FOV: 8 cm with a pixel of 0.31 x 0.41 mm. The dual phased array coils achieved high spatial resolution images of the shoulder with significantly shorter imaging times.
Adult↗
Comparison of fast spin-echo and conventional spin-echo sequences in the MR diagnosis of rotator cuff tears.
The fast spin-echo (FSE) technique has been a successful alternative to conventional spin-echo (CSE) imaging in the brain, spine, and pelvis, but not in the knee. This study evaluated the performance of the FSE technique in comparison with the established CSE technique as a reference standard. Oblique coronal images of 30 shoulders were obtained by both FSE and CSE techniques. The FSE images were compared with CSE images in terms of blurring and motion artifact, fat signal intensity, structural conspicuity, and visualization of joint effusion and rotator cuff tears. We imaged 30 consecutive patients with suspected rotator cuff tears who were referred for MR examination. FSE images often were worse in blurring and motion artifact than CSE images. FSE images showed higher fat signal intensity, but visualized structural conspicuity, joint effusion, and rotator cuff tear as well as CSE images. Our results suggest that the FSE technique is not equal to the CSE technique but can be used for the diagnosis of rotator cuff tears.
Adolescent↗