Effects of elevation on shoulder joint motion: comparison of dynamic and static conditions.

BACKGROUND: Although visual examination and palpation are used to assess shoulder motion in clinical practice, there is no consensus on shoulder motion under dynamic and static conditions. This study aimed to compare shoulder joint motion under dynamic and static conditions. METHODS: The dominant arm of 14 healthy adult males was investigated. Electromagnetic sensors attached to the scapular, thorax, and humerus were used to measure three-dimensional shoulder joint motion under dynamic and static elevation conditions and compare scapular upward rotation and glenohumeral joint elevation in different elevation planes and angles. RESULTS: At 120° of elevation in the scapular and coronal planes, the scapular upward rotation angle was higher in the static condition and the glenohumeral joint elevation angle was higher in the dynamic condition (P<0.05). In scapular plane and coronal plane elevation 90°- 120°, the angular change in scapular upward rotation was higher in the static condition and the angular change in scapulohumeral joint elevation was higher in the dynamic condition (P<0.05). No differences were found in shoulder joint motion in the sagittal plane elevation between the dynamic and static conditions. No interaction effects were found between elevation condition and elevation angle in all elevation planes. CONCLUSIONS: Differences in shoulder joint motion should be noted when assessing shoulder joint motion in different dynamic and static conditions. Level of evidence: Level III, diagnostic cross-sectional study.

Clinical results of conservative management in patients with full-thickness rotator cuff tear: a meta-analysis.

BACKGROUND: Several systematic reviews have reported on the conservative treatment of full-thickness rotator cuff tears; however, clinical results of this treatment still remain determined. METHODS: PubMed, Cochrane Library, PEDro, and CINAHL databases were systematically searched for randomized clinical trials and observational studies. Two independent researchers reviewed a total of 2,981 articles, 28 of which met the criteria for inclusion in the study. Clinical outcome measures included Constant score, visual analog scale score for pain, range of motion, and short-form 36 questionnaires. The meta-analysis used a linear mixed model weighted with the variance of the estimate. RESULTS: The meta-analysis showed a significant improvement after surgery. Pain score is 26.2 mm (1 month) to 26.4 mm (3 months), and 24.8 mm (12 months) (P<0.05); active abduction: 153.2º (2 months), 159.0º (6 months), 168.1º (12 months) (P<0.05); Constant score: 67.8 points (2 months) to 77.2 points (12 months) (P<0.05); short-form 36 questionnaires "vitality" section: 57.0 points (6 months) to 70.0 points (12 months) (P<0.05). CONCLUSIONS: Our data confirmed the effectiveness of conservative treatment in patients with full-thickness rotator cuff tears 12 months post-intervention. The results suggest that conservative treatment for patients with full-thickness rotator cuff tears should be the first line of treatment before considering surgery.

Usefulness of Shoulder36 in rotator cuff tears: Comparison with Simple Shoulder Test.

BACKGROUND: In patients with rotator cuff tears, Shoulder36 (Sh36) was compared to the Simple Shoulder Test (SST) to determine a broader use of Sh36 worldwide. METHODS: Sh36, SST, "Constant score," and the Japanese Orthopaedic Association score (JOA) were used to evaluate 230 patients (male, 116; female, 114) during the first visit, analyzed by staff blinded to the study. Pearson's correlation coefficient was used for the statistical analysis. RESULTS: The correlation coefficient between the Constant score and each domain in Sh36 was as follows: r = 0.68 (vs. pain, p < 0.01); r = 0.69 (vs. range of motion, p < 0.01); r = 0.74 (vs. muscle strength, p < 0.01); r = 0.62 (vs. general health, p < 0.01); r = 0.66 (vs. ability of daily living, p < 0.01); and r = 0.65 (vs. ability for sports, p < 0.01). The correlation coefficient between the JOA and each domain in Sh36 was as follows: r = 0.76 (vs. pain, p < 0.01); r = 0.73 (vs. range of motion, p < 0.01); r = 0.78 (vs. muscle strength, p < 0.01); r = 0.68 (vs. general health, p < 0.01); r = 0.71 (vs. ability of daily living, p < 0.01); and r = 0.70 (vs. ability for sports, p < 0.01). The correlation coefficient between the SST and each domain in Sh36 was as follows: r = 0.73 (vs. pain, p < 0.01); r = 0.70 (vs. range of motion, p < 0.01); r = 0.75 (vs. muscle strength, p < 0.01); r = 0.67 (vs. general health, p < 0.01); r = 0.69 (vs. ability of daily living, p < 0.01); and r = 0.64 (vs. ability for sports, p < 0.01). CONCLUSION: A strong association exists between the SST and each domain in the Sh36, in patients with rotator cuff tears ( r = 0.64-0.73), suggesting the usefulness of Sh36 for patient-based scoring.

Factors Affecting Return to Work in Patients Undergoing Arthroscopic Rotator Cuff Repair.

OBJECTIVE: Although clinical outcomes after arthroscopic rotator cuff repair are generally favorable, postoperative return to work is also an important issue. This study aimed to assess clinical outcomes and clarify the factors affecting return to work in patients who had undergone arthroscopic rotator cuff repair. METHODS: In total, 63 patients who had undergone arthroscopic rotator cuff repair were included in this study. Clinical assessment was performed using Japanese Orthopaedic Association (JOA) scores, along with measurements of pain, range of motion, muscle strength, cuff integrity, and fatty infiltration. Depending on their return-to-work status at the final follow-up, subjects were assigned to either the complete return group (the patient returned to work) or the incomplete return group (the patient had quit or had changed their occupation at final follow-up). Various clinical parameters affecting the return to work outcome were examined through univariate and multivariate analyses. RESULTS: Of the 63 subjects, 42 belonged to the complete return group and 21 belonged to the incomplete return group. Therefore, the working capability recovery rate following arthroscopic rotator cuff repair was 66.7%. Both groups showed significant improvement from their preoperative status, but there were statistically significant differences in JOA scores between the groups at 9 and 12 months postoperatively (P <0.01). Multivariate stepwise logistic regression analysis showed that heavy work and female sex were significantly adversely associated with return to work (P <0.05). CONCLUSION: The working capability recovery rate following arthroscopic rotator cuff repair was 66.7%, and the preoperative factors affecting recovery of working capability were heavy work and female sex.

Influence of Brassiere Wearing on Shoulder Kinematics.

OBJECTIVE: Gender differences in scapular kinematics during arm elevation have been reported. Because women wear brassieres (bras) daily, their scapular motion may be restricted by the garment; however, the influence of bra wearing on this motion has not been reported. Therefore, using a three-dimensional electromagnetic tracking device, we investigated the influence of bra wearing on shoulder kinematics during arm elevation. METHODS: The subjects were 19 healthy women, and the shoulder on the dominant side was evaluated. Subjects performed scapular plane arm elevation while wearing or not wearing bras. Kinematic data were recorded using an electromagnetic tracking device. The glenohumeral elevation angle, scapular upward and internal rotation angles, and the posterior tilt angle were determined from the recorded data. The angles were calculated at 20°-120° arm elevation, and the data were compared between the two conditions. RESULTS: The scapular upward and internal rotation angles and the posterior tilt angle were significantly smaller with the subjects wearing bras than not wearing bras. In contrast, the glenohumeral elevation angle was significantly greater when bras were warn. CONCLUSIONS: Bra wearing may influence shoulder kinematics. Consequently, great care should be taken to account for this factor during the evaluation of kinematics in female subjects.

Cut-off values of the Japanese Orthopaedic Association score corresponding to Constant scores for evaluating outcomes in rotator cuff tear.

PURPOSE: To clarify the cut-off value of the Japanese Orthopaedic Association (JOA) score corresponding to rotator cuff tear outcome as evaluated by the Constant score. METHODS: The subjects were 230 patients with rotator cuff tear. The Constant and JOA scores on the first examination in our hospital were evaluated. After investigation of the correlation between the Constant and JOA scores, the cut-off JOA score was calculated, corresponding to excellent, good and fair outcomes as evaluated by the Constant score. RESULTS: The Constant and JOA scores on the first examination were 49.64 ± 12.84 and 72.52 ± 12.84, respectively, with a strong correlation ( r = 0.87, p < 0.01). Receiver operating characteristic analysis revealed that the cut-off JOA score was 87.0 for excellent outcome (area under the curve, AUC: 0.93; sensitivity: 100%; specificity: 88.6%; p < 0.01), 84.0 for good outcome (AUC: 0.94; sensitivity: 100%; specificity: 83.4%; p < 0.01) and 78.0 for fair outcome (AUC: 0.88; sensitivity: 100%; specificity: 71.3%; p < 0.01). CONCLUSIONS: In patients with rotator cuff tear, good outcome as judged by a Constant score of ≥80 corresponds to a JOA score cut-off of 84.0. Judgement of the treatment outcomes and evaluation of the surgical method may be more accurate when using clear cut-off values for the scoring system employed, such as those determined in our study.

Analysis of scapular kinematics during active and passive arm elevation.

[Purpose] Early postoperative passive motion exercise after arthroscopic rotator cuff repair remains controversial. To better understand this issue, this study was aimed at evaluating scapular kinematics and muscle activities during passive arm elevation in healthy subjects. [Subjects and Methods] The dominant shoulders of 27 healthy subjects were examined. Electromagnetic sensors attached to the scapula, thorax, and humerus were used to determine three-dimensional scapular kinematics during active arm elevation with or without external loads and passive arm elevation. Simultaneously, the activities of seven shoulder muscles were recorded with surface and intramuscular fine-wire electrodes. [Results] Compared with active arm elevation, passive elevation between 30° and 100° significantly decreased the scapular upward rotation and increased the glenohumeral elevation angle. However, no significant differences in scapular posterior tilt and external rotation were observed between active and passive arm elevation, and scapular plane kinematics were not affected by muscle activity. [Conclusion] Unlike active motion with or without an external load, passive arm elevation significantly decreased the scapular upward rotation and significantly increased the mid-range glenohumeral elevation. These data, which suggest that passive arm elevation should be avoided during the early postoperative period, may expand the understanding of rehabilitation after arthroscopic rotator cuff repair.

Effect of external load on scapular upward rotation during arm elevation: the knot concept.

BACKGROUND: Failure of the scapulohumeral rhythm (SHR) is observed in patients with shoulder joint dysfunction. The SHR reportedly has a 2:1 ratio during scapular upward rotation with arm elevation. However, three-dimensional scapular motion analysis has indicated variations in this ratio according to the arm elevation angle. We observed 2 distinct patterns: the scapular upward rotation decreased after knot formation (type I) or increased after knot formation (type II) during arm elevation. In the present study, we aimed to identify the knot and investigate the influence of varying external loads on this kinesiological change point. METHODS: We evaluated 35 healthy adult men (35 dominant-side shoulders) with a mean age of 20 ± 1.7 years (mean height: 172 ± 6.4 cm, mean weight: 65.7 ± 5.8 kg). Participants performed scapular plane elevation with no load or with an external load (1-5 kg) while sitting on a chair. The measured scapular upward rotation values were interpolated using the spline function and fitted to line graphs, and the change in these values was compared for various loads. RESULTS: The estimated knot angles (standard error) in the no load condition, and with external loads of 1, 2, 3, 4, and 5 kg were 83.5 (2.9°), 81.2 (2.9°), 81.0 (2.9°), 76.1 (2.9°), 73.4 (3.1°), and 75.8 (3.1°), respectively. No significant difference was noted in the knot position at 1-2 kg (vs. unloaded), although the knot was significantly lower at 3-5 kg (3 kg: p = 0.01, 4 kg: p = 0.001, and 5 kg: p = 0.02). Moreover, we observed that participants either exhibited increased or decreased upward rotational momentum after knot formation. CONCLUSION: Our results confirm that the kinesiological change point (the knot) during scapular upward rotation occurred at lower angles in cases of increasing external loads.

Effects of sex differences on scapular motion during arm elevation.

INTRODUCTION: Scapular motion during arm elevation is frequently evaluated in patients with shoulder disorders because it provides clinically useful information. With the development of measurement devices and improvement in accuracy, comparisons under various conditions have recently been reported. However, in most of these reports, the subjects examined were limited to males, or a mixed population of males and females. Only a few reports have described sex differences. In the current study, we performed three-dimensional dynamic analysis of arm elevation and investigated whether there is a sex difference in scapular motion. METHODS: Subjects included 18 healthy adult males (18 shoulders) and 19 healthy adult females (19 shoulders). Thirty-seven shoulders were on the dominant side. The age range was 20.5 ± 0.03 years. Subjects performed scapular plane arm elevation, and kinematic data were recorded using an electromagnetic tracking device. Scapular upward rotation and internal rotation angles and the posterior tilt angle accompanying arm elevation were calculated from recorded data. Changes in each angle during scapular motion were recorded according to sex. RESULTS: There were sex differences in scapular upward rotation and internal rotation angles. The upward rotation angle was significantly greater in males, whereas the internal rotation angle was significantly greater in females. No sex differences were noted in the scapular posterior tilt angle. DISCUSSION: Findings of this study may serve as basic data for scapular motion during scapular plane elevation in healthy males and females. In addition, it is necessary to evaluate and treat the shoulder while taking sex differences in scapular movement into consideration.

Electromyographic study of rotator cuff muscle activity during full and empty can tests.

The empty can (EC) and full can (FC) tests are used as diagnostic tools for patients with rotator cuff disease. However, recently concerns have been raised that these tests do not selectively activate the muscle. Therefore, the purpose of this study was to evaluate the rotator cuff muscle activation levels during the EC and FC tests in various positions using electromyography. Twelve healthy, right-handed men without shoulder complaints (mean age: 26.1 years, range: 23-35 years) were included. The tests were performed isometrically with the shoulder elevated at 45° and 90° in the sagittal, scapular, and coronal planes, either in the thumb-up (FC test) or thumb-down (EC test) positions. During these positions, the electromyographic signal was recorded simultaneously from the four shoulder muscles using a combination of surface and intramuscular fine-wire electrodes. The average activation of the supraspinatus and subscapularis was greater during the EC test than during the FC test and in the scapular and coronal planes than in the sagittal plane at 90°. For the infraspinatus, there were no significant differences in any positions between the two tests. Thus, the rotator cuff muscles are influenced by arm position and the elevation plane during the EC and FC tests.