Introduction Kinematic and electromyography (EMG) studies concerning internal rotation (IR) of the shoulder are limited. This study investigated the kinematic components and EMG activity of the rotator cuff muscles during IR at the side (IRs), IR at 90 ° of abduction (IRa), and IR to the posterior (IRp). Methods Ten healthy young men attended this study. The angles of IR, extension, and abduction of the humerothoracic joint, and angles of scapular IR, anterior tilt, and upward rotation were measured using a three-dimensional (3-D) motion analyzer. EMG activities in the 4 rotator cuff muscles were simultaneously recorded using synchronized 3-D motion analysis. Results The maximum IR angles were 56.6°, 72.4°, and 31.6° in IRs, IRa, and IRp, respectively. The maximum extension angle was 34.1° in IRp, and the maximum abduction angles were 1.4°, 87.4°, and 24.1° in IRs, IRa, and IRp, respectively. The EMG activity patterns of the rotator cuff muscles differed across the 3 IR types. %IEMGs of the subscapularis in IRs were approximately 20%, gradually increased up to 18.2% in IRa, and greatly increased to 29.8% at maximum IRp. %IEMGs of the supraspinatus were constant during the 3 movements, and EMG activities of the infraspinatus and teres minor decreased preceding IRa, whereas those increased up to maximum IRp. Discussion The rotation axes of IRs and IRa are constant, but that of IRp always changes. Our results show that the internal rotation angles for IRs and IRa are nearly identical to those reported previously. In contrast, the rotation angle for IRp differs from those in the current reports. EMG analysis of the 3 types of IR movements reveals different muscle activity patterns. Conclusion Kinematic and EMG analyses revealed that the three types of IR completely differ. The total IR angles in the humerothoracic joint increased in the order IRa > IRs > IRp. The highest activity of the subscapularis was observed in IRp. The internal rotation angle is the smallest, and the internal rotation movement of the IRp is completed in the early phase of the movement. The joint structure itself is presumed to limit the internal rotation movement of the IRp.

Background:Glenohumeral adduction restriction (AR), which is found in rotator cuff tears, is also observed in frozen shoulder (FS). AR was examined using an adduction test and treated through adduction manipulation. We aimed to compare the incidence and severity of AR and investigate clinical characteristics and outcomes of the freezing and frozen phases. Methods:Two hundred sixteen patients with FS were enrolled in this study; consequently, 120 were classified into the freezing phase (mean age 58 years, 37 men) and 56 into the frozen phase (mean age 55.4 years, 29 men). Using the adduction test, the patients in 2 phases were divided into 2 groups, with and without AR. The glenohumeral adduction angle (GAA) was measured radiographically. Treatments in the freezing phase were physiotherapy and/or adduction manipulation and joint manipulation and physiotherapy for the frozen phase. We recorded the visual analog scale of pain severity, EuroQol-visual analog scale, flexion, abduction, external rotation (ER), internal rotation, and American Shoulder and Elbow Surgeons and Constant scores at the baseline and at the 1-, 3-, 6-, 12-, and 24-month follow-ups. Results:Seventy-five of 120 patients in the freezing phase were divided into group 1 without AR and 45 into group 2 with AR. Eight of 56 patients in the frozen phase were classified into group 3 without AR and 48 into group 4 with AR. AR was identified in 37.5% of patients in the freezing phase and 85.7% in the frozen phase. The mean GAA decreased from the freezing (-3.0°) to the frozen phases (-18.3°). GAA was positively correlated with ER. The treatment duration in group 1 (5.2 M) was shorter than in group 2 (7.4 M), and the percentage of transition to joint manipulation in group 1 (5.3%) was lower than in group 2 (17.8%). Complete rupture of intra-articular soft tissues was observed in group 4 but not in group 3 with magnetic resonance imaging. Clinical items, except for ER in the freezing phase (group 1 vs. 2) and frozen phase (group 3 vs. 4), were not significantly different from those at the initial visit to the 24-month follow-up appointment. Conclusion:The incidence and severity of AR increase from the freezing phase to the frozen phase. AR correlating with ER reflects the progression of intra-articular lesions, which prolongs the treatment duration and increases the joint manipulation rate in the freezing phase. Negative AR in the frozen phase suggests mild intra-articular pathologies.

Despite the latest knowledge, the coracohumeral ligament has been inconsistently understood in terms of its expansion. The reason for this is the ambiguous definition of the term ligament. This study aimed to anatomically investigate the posterior extension of the coracohumeral ligament, including loose connective tissues. The current study used nine embalmed shoulders harvested from seven embalmed cadavers under the IRB agreement. We macroscopically observed four shoulders to analyze the connective tissues from the posterior part of the coracoid process to the superficial and deep layers of the supraspinatus tendon.

Background: Frozen shoulder (FS) is a common disorder causing shoulder pain and limited motion. Magnetic resonance imaging (MRI) is expected to help diagnose FS and realize the disease stage if stage-specific features are present. We aimed to survey stage-related MRI findings of FS in the literature. Methods: MEDLINE, SCOPUS, and Google Scholar databases were searched with search terms ''frozen shoulder'' or ''adhesive capsulitis'' combined with ''magnetic resonance imaging.'' Studies that discussed MRI findings in relation to FS stages were retrieved. The course of FS was divided into stages 1 to 4 according to Hannafin and Chiaia. Results: Two of the noncontrast-enhanced MRI findings were stage-related. T2 signal hyperintensity of the joint capsule was more frequent in stages 1 and 2. The axillary capsule thickness was greater in stages 1 and 2. However, these findings were also seen in the later stages to a lesser degree. Effusion around the long head of biceps, subcoracoid fat obliteration, and coracohumeral ligament thickening were common in FS but their relation to the stages was not evident. Signal enhancement on contrast-enhanced MRI was not consistently linked to stages. Conclusion: T2 signal hyperintensity and axillary capsule thickening are characteristic of the early stages of FS, although MRI alone cannot completely define the disease stage.

Frozen shoulder (FS) is a common disorder characterized by spontaneous onset of shoulder pain accompanied by progressive loss of range-of-motions. The cause of FS is still unclear, and radical therapy has not been established. With the final aim of preventing or curing FS at an earlier stage, we reviewed the pathological and biological features of this disease. Many studies indicate that the main pathology of FS is inflammation initially and fibrosis later. There are inflammatory cytokines, immune cells, fibrotic growth factors, and type-III collagen in the synovium and the joint capsule. The immune cell landscape switches from the macrophages to T cells. Activated fibroblasts seem to regulate the inflammatory and fibrotic processes. The imbalance between matrix metalloproteinases and tissue inhibitors of metalloproteases might promote fibrosis. Additionally, advanced glycation end-products are noted in the FS synovium. Diabetes mellitus and hypothyroidism are closely related to the development of FS. In terms of nonsurgical treatment, oral or intra-articular glucocorticoids are the only drugs that provide early benefit. Some other anti-inflammatory or antifibrotic drugs may potentially control the FS, but have not been proven effective in the clinical setting. Future studies should be targeted to develop steroid-sparing agents that inhibit biological events in FS.

Background:Frozen shoulder (FS) is a pathological condition that involves a painful and stiff shoulder joint, most commonly in people aged 40-60 years. Most literature supports treatment with physical therapy (PT), although some studies have demonstrated years of continuing pain and functional deficits. Manipulation under anesthesia is effective at eliminating the contracture of intra-articular lesions for refractory FS. This study aimed to compare whether manipulation under anesthesia or PT is a more effective treatment in refractory FS.Methods:This study was a prospective observational study. A total of 102 patients with refractory FS were enrolled in this study in the medical records, all of whom had severe and multidirectional loss of motion and thickening of the joint capsule and coracohumeral ligament on magnetic resonance imaging. Fifty-one patients were in the manipulation under brachial plexus block (MUB) group (34 females, median age: 57 years), and 51 patients were in the PT group (34 females, median age: 59 years). The MUB procedure consisted of the conventional method with additional adduction manipulation, in which one examiner initially abducted the shoulder joint as much as possible. We recorded the visual analog scale, shoulder range of motion, and American Shoulder and Elbow Surgeons and Constant Scores at the initial baseline visit and at the 1-, 3-, 6-, and 12-month follow-ups. The total cost was calculated from the medical records, and cost-effectiveness was evaluated using quality-adjusted life year and incremental cost-effectiveness ratio.Results:Visual analog scale (P < .001), range of motion (P < .001), and American Shoulder and Elbow Surgeons and Constant Scores (P < .001) in the MUB group were significantly superior to those in the PT group at 1, 3, 6, and 12 months after treatment. The median cost and total quality-adjusted life year in the MUB and PT groups were $1375 versus $2751 and 2.95 versus 2.68, respectively, and the cost-effectiveness ratio between the MUB and PT groups was calculated as -$560.Conclusions:The new MUB procedure provides a shorter treatment period, better clinical outcomes, and higher cost-effectiveness in patients with refractory FS compared to PT.

Background: Atraumatic rotator cuff tears (ARCTs) are frequently concomitant with adduction restriction of the glenohumeral joint (GHJ). Adduction manipulation (AM) removes the restriction and relieves pain. The present study aimed to investigate the clinical efficacy of AM versus physiotherapy (PT) in ARCTs. Methods: Eighty-eight patients with adduction restriction were allocated to the AM and PT groups (n = 44 per group). The glenohumeral adduction angle (GAA) was calculated using X-rays at the first and last follow-up appointments. We recorded pain severity (visual analog scale, VAS), flexion, abduction, external rotation (ER), internal rotation (IR), and American Shoulder and Elbow Society (ASES) and Constant scores at baseline and at 1-, 3-, 6-, and 12- month follow-ups. Results: Forty-three patients (23 males, average age 71.3 years) in the AM group and 41 (16 males, average age 70.7 years) in the PT group were consequently analyzed. At the 1-month follow-up, VAS, shoulder motion except ER, ASES and Constant scores were much better in the AM group than in the PT group, whereas those in the PT group improved gradually up to 12 months. At the final follow-up, flexion, abduction, and Constant score were significantly better in the AM group than in the PT group. The GAA at the initial and final examinations was −21.6° and −3.2°, respectively, in the AM group, and −21.1° and −14.4°, respectively, in the PT group. Conclusions: The AM procedure, which had better clinical efficacy than PT, is recommended as the first conservative treatment option for ARCTs.

Background: Extension of the elbow joint is maintained during shoulder flexion. In contrast, the arm starts from the flexed position of the elbow joint and the joint gradually extends during reaching elevation. Objectives: This study aimed to compare the kinematic elements and electromyographic (EMG) activities of the rotator cuff muscles between flexion and reaching elevation. Methods: The study included 10 healthy young men. (average age, 21.5 ± 3.4 years), and measurements were performed on their dominant arms. A three-dimensional motion analyzer was used to record the following elements during shoulder flexion and reaching elevation: the angles of glenohumeral joint elevation and scapular upward rotation, scapulohumeral rhythm, external rotation of the humerus, and glenohumeral plane shifting from the coronal plane. The EMG activities in the supraspinatus, infraspinatus, subscapularis, and teres minor were recorded simultaneously. Results: The plane of reaching elevation was retained at 60° from the coronal plane. The glenohumeral planes (P < 0 .01) and the external rotation angles of the humerus below 90° of elevation (P < 0.05) were significantly different between both the motions. The EMG activities in the supraspinatus (P < .01), infraspinatus (P < 0.05), and teres minor (P < 0.01) were significantly lower while reaching elevation than those during flexion. Conclusion: The motion plane at 60° from the coronal plane, movement of the humeral external rotation, and EMG activities of the rotator cuff muscles were different during reaching elevation and shoulder flexion.

BACKGROUND:The pathophysiology of atraumatic rotator cuff tears (ATTs) has not been fully understood. Adduction restriction of the glenohumeral joint can cause pain and disability in patients with ATTs. We aimed to use our adduction test (pushing the humerus toward the side in the coronal plane with scapular fixation) to fluoroscopically measure the glenohumeral adduction angle (GAA) and to assess the effectiveness of adduction manipulation.MATERIALS AND METHODS:Fifty-five patients with ATTs were included in the study. The GAAs of the patients vs. healthy subjects without ATTs were measured fluoroscopically and compared. During the test, patients showed restriction and expressed pain. The visual analog scale (VAS) score, passive range of motion (ROM), and the American Shoulder and Elbow Surgeons score at the initial visit were compared with those after adduction manipulation.RESULTS:Of the patients, 41 (75%) had positive adduction test results. A higher percentage of positive adduction test results was observed in smaller tears. The average GAA was -21.4° on the affected side, which was smaller than that on the unaffected side, at -2.8° (P < .001), and that in healthy subjects, at 4.8° (P < .001). After manipulation, the GAA was -0.8° (P < .001) and the VAS score, the American Shoulder and Elbow Surgeons score, and all ROM values significantly improved up to the level on the unaffected side.CONCLUSION:Adduction restriction of the glenohumeral joint was identified in 75% of all the patients with ATTs. Adduction manipulation significantly reduces the VAS score and restores the ROM. Adduction restriction is considered a crucial pathophysiology of ATTs.

Background: In acromioclavicular joint (ACJ) separations, patient characteristics determine the indications for surgery. However, in Japan, classification methods used to assess the severity of ACJ separations differ between institutions, and even within a classification method, different interpretations can lead to different assessments of severity. Therefore, in this study, we conducted an email survey of Japan Shoulder Society (JSS) members regarding their assessment methods for ACJ separation severity. Methods: A questionnaire about methods for assessing the severity of ACJ separations was emailed to JSS members (1655) including 59 JSS councilors. The survey focused on diagnostic imaging methods, classifications of severity assessments, and methods of assessing severity. Results: In total, 183 responses were received. All respondents used an anteroposterior view of the ACJ. Severity assessments were classified by the Tossy classification (57 respondents), Rockwood classification (141 respondents), and other classifications (7 respondents) including duplication. Of the 141 respondents using the Rockwood classification, 119 diagnosed type III as ACJ dislocation when the inferior clavicle border translated above the superior acromial border, whereas 56 used the coracoclavicular distance. However, to diagnose type V, 118 respondents used the coracoclavicular distance whereas 38 used palpation. To diagnose type IV, 57 respondents considered all cases in which the clavicle translated posterior to the acromion, even when vertical ACJ dislocation occurred simultaneously. However, 88 respondents did so in the presence of posterior clavicle displacement and ACJ subluxation. Conclusion: The Rockwood classification is commonly used for severity assessments in Japan; however, there is some disagreement regarding the assessment for the diagnosis of type IV. Methods to diagnose both superior and posterior translation of the clavicle need further debate.

BACKGROUND:Treatment options for acromioclavicular joint (ACJ) separations are highly dependent on severity, as well as the patient's background. Furthermore, some patients can be switched from conservative to surgical treatment. In this study, we conducted a mail-based questionnaire survey of members of the Japan Shoulder Society on the administration of treatments for ACJ separations.METHODS:A questionnaire survey with 5 categories was mailed to all 1655 members of the Japan Shoulder Society (including 59 councilors): initial treatment, whether surgery was performed, indications for surgery based on severity, switching from conservative to surgical treatment, and surgical methods.RESULTS:Altogether, 183 members, including 56 councilors, responded. Regarding the initial treatment, 17 respondents opted for treatment without immobilization or fixation and 166 opted for immobilization or fixation. Of the members, 11 opted for only conservative treatment whereas 172 chose surgery depending on the case; of the latter, 9 considered it for patients with a Rockwood classification of type 2 or higher; 120, for patients with type 3 or higher; and 172, for patients with types 4-6. Furthermore, 75 of 172 members had experience switching to surgical treatment during conservative treatment. For 64 of 172 members, the modified Cadenat method was the most common surgical method.CONCLUSIONS:Only 11 members opted for conservative treatment of ACJ separations, and approximately 95% of physicians chose surgery. Furthermore, >70% of physicians considered surgery for an injury classified as type 3 or higher, and 37% of members performed the modified Cadenat method. However, the popularization of arthroscopic surgery may affect the selection of surgical methods in the future.

Background: Primary frozen shoulder has unknown etiology and significant restriction of active and passive motion. The distinction between frozen shoulder and stiff shoulder has been unclear. Therefore, the purposes of this study were to perform a survey regarding definition and classification of frozen shoulder proposed by the American Academy of Orthopedic Surgeons (AAOS) among the members of the Japan Shoulder Society (JSS) and to compare the results with those obtained among the members of the American Shoulder and Elbow Surgeons (ASES). Methods: The Scientific Research Project Committee of the JSS prepared the questionnaire for frozen shoulder and stiff shoulder. Surveys were sent by e-mail on Jan 14, 2016 to JSS registered members and the response dead-line was set on March 13, 2016. Results: The number of respondents was 230, including all directors, councilors, and senior doctors. Agreement with the definition of primary frozen shoulder was 67%, the classification of primary or secondary frozen shoulder was 53%, and the 3 divisions of secondary frozen shoulder was 53%. Diagnostic terms for the cases of shoulder stiffness with unknown etiology were as follows: frozen shoulder (31%), stiff shoulder (22%), periarthritis scapulohumeralis (16%), so called "Gojukata" in Japan, which means shoulder problems in their fifties (16%), idiopathic frozen shoulder (6%), primary frozen shoulder (4%), adhesive capsulitis (3%), others (2%). Conclusion: The survey shows lower rates of agreement among the JSS members than the ASES members for the definition of primary frozen shoulder, the classification of primary and secondary frozen shoulder, and the divisions of secondary frozen shoulder. To avoid confusion between stiff shoulder and frozen shoulder, the committee agrees to the ISAKOS recommendation that the term "frozen shoulder" should be used exclusively for primary idiopathic stiff shoulder. (c) 2019 The Japanese Orthopaedic Association. Published by Elsevier B.V. All rights reserved.

Background:Little consensus has been achieved on conservative treatments in patients with Rotator Cuff Tears (RCTs).Objective:To determine whether anatomical severities of RCTs were poor prognostic factors in conservative treatments.Method:This study included 102 shoulders with atraumatic RCTs diagnosed by magnetic resonance imaging. Partial-thickness tears were identified in 15 shoulders and full-thickness tears in 87 shoulders. Three patients had a concomitant subscapularis (SSC) tendon tear. All patients were treated conservatively with the administration of non-steroidal anti-inflammatory drugs and physical therapy. The visual analog scale (VAS), Constant scores, and active range of motion were evaluated as clinical outcomes. Pearson’s chi-square test and Student’s t test, Mann-Whitney U test, one-way analysis of variance (ANOVA), or Kruskal-Wallis test was performed to compare the participant’s characteristics and clinical data. Treatment effectiveness among the tear size groups and with/without SSC tear groups was assessed using a two-factor repeated measures ANOVA.Results:Larger tears were associated with less improvement in VAS (p = 0.032). At the initial and final visits, larger tears showed lower constant scores (p = 0.014 and p < 0.001, respectively) and restricted forward elevation (FE) (p = 0.042 and p = 0.013, respectively). Shoulders with SSC tear showed higher VAS, lower constant scores, and lower FE at the final visit (p = 0.002, p = 0.001, and p=0.019, respectively). Patients with SSC tear underwent surgery more frequently than those without tear (p < 0.001).Conclusion:Larger RCTs and concomitant SSC tear are poor prognostic factors for the conservative treatment of atraumatic RCTs.

Rotator cuff disease is one of the most prevalent shoulder disabilities especially in the elderly population. Tear progression is significantly greater in the symptomatic patients than in the asymptomatic ones. From these aspects, shoulder surgeons interpret surgical indications and counsel patients regarding the risk of non-operative treatments. However, there were a few reports that pain and duration of symptoms were not strongly associated with severity of rotator cuff tears, and non-operative management with physical therapy was effective. There have remained controversies for the treatment of rotator cuff tears.A 59-year-old man with a sedentary work life experienced right shoulder pain with abduction at night. However, the pain kept worsening after two months, and he finally visited our clinic three months after the onset of pain. Magnetic resonance imaging in the coronal and axial planes showed effusion around the subacromial and subcoracoid bursae and joint-side tear of the supraspinatus tendon. A range of motion in the right shoulder was severely restricted at the initial visit of our clinic. After sufficient rehabilitation, the symptoms were not changed and an arthroscopic rotator cuff repair was scheduled. However, during waiting for surgery, he felt something popped in the right shoulder while wearing a jacket. Immediately after this, pain during motion and at night decreased, and he experienced no difficulty with activities of daily living and the surgery was cancelled. This is the first case with a recovery of range of motion and a decrease in pain after progression of a supraspinatus tendon tear.

Why some rotator cuff tears are asymptomatic is not well-understood. We measured the glenohumeral adduction angle (GAA) with scapular fixation and proved that patients with shoulder stiffness and/or rotator cuff tear usually had abduction contracture. Our study aimed to (1) check the frequency of abduction contracture, (2) measure GAA, and (3) evaluate the result of adduction manipulation among patients with symptomatic rotator cuff tear.

Background: A thickened coracohumeral ligament is a highly specific manifestation of, and primary restraint against external rotation in frozen shoulders. Objective: The purpose of this study was to evaluate the effects of complete arthroscopic coracohumeral ligament release on range of motion in frozen shoulder. Methods: Fifty-two consecutive shoulders in 52 patients were treated between April 2015 and June 2016. To evaluate solely glenohumeral range of motion, the scapula was fixed by an examiner with one hand (without palpating scapular motion), and range of motion was measured using a goniometer. For the first step, arthroscopic pancapsular release was performed in a beach-chair position with (Group 1) or without (Group 2) complete coracohumeral ligament release. For the final step, the remaining coracohumeral ligaments in Group 2 were released and the ranges of motion were compared to those in Group 1. Results: The average age of the patients was significantly higher in Group 1, but there were no significant differences between the two groups with respect to sex, affected side, preoperative range of motion, or American Shoulder and Elbow Society Score. Abduction, external rotation at adduction, and external and internal rotations at 90° of flexion in Group 1 were significantly greater than those in Group 2. After the additional release of the remaining coracohumeral ligaments in Group 2, all ranges of motion were significantly recovered and there was no significant difference between the groups. Conclusion: Complete coracohumeral ligament release is a recommended intraoperative procedure for regaining full range of motion in frozen shoulders.

To respond to the numerous demands for exhaust manifold systems in automobiles, two types of Cu-containing ferritic stainless steel sheet have been developed in this study. Based on the fundamental researches on Cu precipitation strengthening during the thermal fatigue process, new heat-resistant ferritic stainless steels named NSSC 429NF and NSSC 448EM have been developed. In addition, a new Type 444 ferritic grade, namely, NSSC 190EM, with excellent formability has been successfully produced. This sheet has both a superior heat resistance and a high flexibility for the stamping process.

Purpose: This study examined the effectiveness of manipulation under ultrasound-guided brachial plexus block in patients with recalcitrant idiopathic frozen shoulder and diabetic secondary frozen shoulder (diabetic frozen shoulder). Methods: Forty-four idiopathic frozen shoulders and 10 diabetic frozen shoulders with failed conservative treatment for at least 3 months were included in this study. The manipulation was performed under ultrasound-guided brachial plexus block and visual analogue scale, range of motion, and Constant scores were measured before manipulation and at the last follow-up examination. Results: No major complications were observed during the procedure. Sufficient improvement was not obtained in two patients during the procedure and to avoid complications, the procedure was discontinued and subsequently arthroscopic capsular release was performed. Visual analogue scale, range of motion towards all directions, and Constant scores were significantly improved after the manipulation in both the idiopathic frozen shoulder and diabetic frozen shoulder groups, however the diabetic group showed inferior results compared with those of the idiopathic group. Conclusion: This manipulation was effective and shortened the duration of symptoms in most of the idiopathic and diabetic frozen shoulders without major complications during the procedure. Diabetic frozen shoulder showed inferior clinical results and difficulty in recovery in range of motion, which indicated that diabetic frozen shoulder should be discussed as a different entity.

Arthroscopic pancapsular release has been recommended for recalcitrant frozen shoulder, but regaining range of motion has not been sufficient compared with the unaffected side. There is no consensus about the reasons for these remaining restrictions in range of motion, but residual capsular or connective tissue must be considered a candidate. A thickened coracohumeral ligament at the rotator interval has been reported as one of the most specific manifestations of frozen shoulder. It covers wider portions of the subscapularis tendon, supraspinatus tendon, and infraspinatus tendon than previously reported. We describe an arthroscopic surgical technique for the release of the entire coracohumeral ligament including the subscapularis and supraspinatus portions and the release of the inferior and posterior parts of the glenohumeral ligament using the 7-o'clock portal. These procedures are essential and reliable methods to release the entire joint capsule to regain full range of motion for frozen shoulder.