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Background and Objectives: This study aimed to compare capsular volume in patients with shoulder instability to that in control subjects without instability using magnetic resonance (MR) arthrography. The objective was to develop a reliable screening method with which to assess shoulder volume. Materials and Methods: In 21 patients with atraumatic shoulder instability and 21 controls, thin-slice 3D volumetric MR arthrography sequences were obtained. MR arthrography images were uploaded to 3D reconstruction, and 3D images were generated. From the 3D reconstructed images, volumetric measurements of rotator interval (RI), anterior and posterior capsular (AC, PC) recesses, biceps tendon sheath (BS), axillary recess (AR), and total glenohumeral joint (TGJ) were performed. Individuals with any extra-articular contrast leakage were also recorded. Results: A retrospective study analyzed a patient group of 21 individuals with shoulder instability (mean age 29.52 ± 12.83 years) and a control group of 21 individuals without instability (mean age 35.71 ± 12.77 years). No statistically significant differences were identified between the groups with regard to age, gender, or side distribution. The mean total joint volume was significantly higher in the instability group (29.85 ± 6.40 cm3) compared to the control group (23.15 ± 3.48 cm3, p = 0.0001). Additionally, the mean volumes of the RI, AC, PC, BS, and AR were all significantly greater in the patient group compared to the control group. Conclusions: 3D volumetric MR arthrographic measurements of the shoulder joint capacity can provide valuable insights for clinical follow-up and guide surgical treatment decisions in cases of atraumatic shoulder instability. [ABSTRACT FROM AUTHOR]

As capsule elongation is assumed to weaken the static stability of the shoulder joint, the purpose of this biomechanical study was to demonstrate that capsule elongation occurs immediately after a first-time shoulder dislocation and not just after recurrent dislocation events. We hypothesize an increment in joint clearance due to joint capsule elongation after a first-time dislocation. An experimental in-vitro study was conducted on 6 paired fresh frozen human shoulders (4 females; 2 males; 12 specimen) with a mean age of 80 (Range 67–89) years. The shoulder joint with the articular capsule was exposed and an inferior static tension force of 2.5 N was applied to the humerus prior to dislocation. Next, the humeral head was dislocated and was then immediately reduced back into the start position. The joint gap as well as joint capsule deformation was assessed using optical techniques. The radiographic joint gap increased from 13.7 ± 6.9 mm (prior to dislocation) to 18.1 ± 6.5 mm (post dislocation) (p <.001). The increase in joint clearance was 4.4 mm. The joint capsule elongated from 5.9 ± 0.005 % (prior to dislocation) to 9.4 ± 0.007 % (post dislocation) (p <.001). The mean increase in joint capsule elongation was 3.5 %. Capsule elongation was observed immediately after a simulated first-time shoulder dislocation in an in-vitro model of elderly human cadavers. It might therefore not only be a phenomenon of recurrent dislocation events. [ABSTRACT FROM AUTHOR]

Background and Objectives: This study aimed to compare capsular volume in patients with shoulder instability to that in control subjects without instability using magnetic resonance (MR) arthrography. The objective was to develop a reliable screening method with which to assess shoulder volume. Materials and Methods: In 21 patients with atraumatic shoulder instability and 21 controls, thin-slice 3D volumetric MR arthrography sequences were obtained. MR arthrography images were uploaded to 3D reconstruction, and 3D images were generated. From the 3D reconstructed images, volumetric measurements of rotator interval (RI), anterior and posterior capsular (AC, PC) recesses, biceps tendon sheath (BS), axillary recess (AR), and total glenohumeral joint (TGJ) were performed. Individuals with any extra-articular contrast leakage were also recorded. Results: A retrospective study analyzed a patient group of 21 individuals with shoulder instability (mean age 29.52 ± 12.83 years) and a control group of 21 individuals without instability (mean age 35.71 ± 12.77 years). No statistically significant differences were identified between the groups with regard to age, gender, or side distribution. The mean total joint volume was significantly higher in the instability group (29.85 ± 6.40 cm3) compared to the control group (23.15 ± 3.48 cm3, p = 0.0001). Additionally, the mean volumes of the RI, AC, PC, BS, and AR were all significantly greater in the patient group compared to the control group. Conclusions: 3D volumetric MR arthrographic measurements of the shoulder joint capacity can provide valuable insights for clinical follow-up and guide surgical treatment decisions in cases of atraumatic shoulder instability.

Background: Advanced glycation end products (AGEs) are compounds formed due to aging and diabetes mellitus (DM). They activate NADPH oxidase (NOX) by binding to their receptors, thereby increasing the production of reactive oxygen species (ROS), which cause oxidative stress. In this study, we investigated the effects of AGEs on the tissues of the shoulder joint (such as rotator cuff synovium, and capsule) in patients with DM having rotator cuff tears. Methods: This study included eight patients with DM who underwent surgical treatment for rotator cuff tears with contracture. The rotator cuff, synovium, and joint capsule were harvested at the time of surgery and evaluated by hematoxylin-eosin staining. Furthermore, immunostaining was used for evaluating AGEs and receptor for AGEs (RAGE), cell activity, ROS, and apoptosis. Quantitative real-time polymerase chain reaction (qPCR) was employed for the cellular evaluation of NOX, interleukins, RAGE, and collagen. Results: The AGEs and RAGE staining as well as the ratio of ROS and apoptosis were in the following order: rotator cuff > joint capsule > synovium. In contrast, the cellular activity was significantly higher in the synovium than in the other regions. The type I collagen expression (as shown by qPCR) as well as the RAGE and NOX expressions were as follows: rotator cuff > joint capsule > synovium. Conversely, the expression of inflammatory cytokines (i.e., IL-6 and IL-1β) was higher in the synovium than in the other regions. Conclusions: Our study is among the first to evaluate the effects of AGEs on each tissue of the shoulder joint in patients with DM having rotator cuff tears and contractures. The accumulation of AGEs in each tissue of the shoulder joint could reveal the locations affected by DM, which can lead to a better understanding of the pathophysiology of DM-related shoulder diseases. [ABSTRACT FROM AUTHOR]

Abstract Background Most degenerative rotator cuff tears (RCTs) are associated with a limited range of motion (ROM) of the shoulder joint. Additionally, patients with diabetes mellitus (DM) show a higher frequency of limited ROM. Recently, advanced glycation end products (AGEs) of proteins have been observed to cause tissue fibrosis, primarily through abnormal collagen cross-linking and oxidative stress. In this study, we investigated the effect of AGEs on ROM limitation in the shoulder capsule and its relationship with DM in the patients with RCTs. Methods Sixteen patients (eight in the DM and non-DM groups) who underwent arthroscopic surgery for RCT with limited shoulder ROM were included in this study. AGE-related pathologies in both groups were compared, and the relationship between AGE accumulation and shoulder joint ROM was evaluated. Shoulder capsule tissue was harvested and subjected to histological and in vitro evaluation. Results The DM group displayed high levels of AGEs and reactive oxygen species (ROS), and reduced cell viability. There was a significant positive correlation between ROS expression, apoptosis, and preoperative hemoglobin A1c. ROS expression, apoptosis, and ROM of the shoulder joint showed a negative correlation. The NADPH oxidase (NOX) expression and collagen III/I ratio were significantly higher in the DM group than in the non-DM group. Conclusions The DM group showed significant AGEs deposition in the shoulder capsule. Additionally, there was a significant association between AGEs and ROM limitation. Collectively, the findings suggest that the oxidative stress induced by AGEs deposition, which leads to fibrosis and local inflammation, might contribute to the limited ROM of the shoulder joint in patients with RCTs accompanied by DM.

BackgroundAdhesive capsulitis (AC) is a type of arthritis that causes shoulder joint pain, stiffness, and limited mobility. The pathogenesis of AC is still controversial. This study aims to explore the role of immune related factors in the occurrence and development of AC.MethodsThe AC dataset was downloaded from Gene Expression Omnibus (GEO) data repository. Differentially expressed immune-related genes (DEIRGs) were obtained based on R package “DESeq2” and Immport database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to explore the functional correlation of DEIRGs. MCC method and Least Absolute Shrinkage and Selection Operator (LASSO) regression were conducted to identify the hub genes. The immune cell infiltration in shoulder joint capsule between AC and control was evaluated by CIBERSORTx, and the relationship between hub genes and infiltrating immune cells was analyzed by Spearman’s rank correlation. Finally, potential small molecule drugs for AC were screened by the Connectivity Map database (CMap) and further verified by molecular docking.ResultsA total of 137 DEIRGs and eight significantly different types of infiltrating immune cells (M0 macrophages, M1 macrophages, regulatory T cells, Tfh cells, monocytes, activated NK cells, memory resting CD4+T cells and resting dendritic cells) were screened between AC and control tissues. MMP9, FOS, SOCS3, and EGF were identified as potential targets for AC. MMP9 was negatively correlated with memory resting CD4+T cells and activated NK cells, but positively correlated with M0 macrophages. SOCS3 was positively correlated with M1 macrophages. FOS was positively correlated with M1 macrophages. EGF was positively correlated with monocytes. Additionally, dactolisib (ranked first) was identified as a potential small-molecule drug for the targeted therapy of AC.ConclusionsThis is the first study on immune cell infiltration analysis in AC, and these findings may provide a new idea for the diagnosis and treatment of AC.

Background: Most degenerative rotator cuff tears (RCTs) are associated with a limited range of motion (ROM) of the shoulder joint. Additionally, patients with diabetes mellitus (DM) show a higher frequency of limited ROM. Recently, advanced glycation end products (AGEs) of proteins have been observed to cause tissue fibrosis, primarily through abnormal collagen cross-linking and oxidative stress. In this study, we investigated the effect of AGEs on ROM limitation in the shoulder capsule and its relationship with DM in the patients with RCTs.Methods: Sixteen patients (eight in the DM and non-DM groups) who underwent arthroscopic surgery for RCT with limited shoulder ROM were included in this study. AGE-related pathologies in both groups were compared, and the relationship between AGE accumulation and shoulder joint ROM was evaluated. Shoulder capsule tissue was harvested and subjected to histological and in vitro evaluation.Results: The DM group displayed high levels of AGEs and reactive oxygen species (ROS), and reduced cell viability. There was a significant positive correlation between ROS expression, apoptosis, and preoperative hemoglobin A1c. ROS expression, apoptosis, and ROM of the shoulder joint showed a negative correlation. The NADPH oxidase (NOX) expression and collagen III/I ratio were significantly higher in the DM group than in the non-DM group.Conclusions: The DM group showed significant AGEs deposition in the shoulder capsule. Additionally, there was a significant association between AGEs and ROM limitation. Collectively, the findings suggest that the oxidative stress induced by AGEs deposition, which leads to fibrosis and local inflammation, might contribute to the limited ROM of the shoulder joint in patients with RCTs accompanied by DM. [ABSTRACT FROM AUTHOR]

The author reflects on developments in orthopaedic sports medicine as of February 2021, particularly the use of superior capsular reconstruction (SCR) for shoulder with damaged rotator cuffs that cannot be cured with primary repair. Topics include key role played by the superior capsule, the use of supraspinatus and infraspinatus insertions, and studies on the results of autograft SCR.

Background: Partial-thickness rotator cuff tears are common shoulder injuries in baseball players. For some tears, the symptoms can be relieved through physical therapy or debridement without rotator cuff repair. Purpose: To assess whether partial-thickness rotator cuff tear by itself causes shoulder pain and muscle weakness in baseball players. Study Design: Cross-sectional study; Level of evidence, 3. Methods: We studied 87 university baseball players (age, 19.5 ± 0.8 years; baseball career, 11.5 ± 1.6 years). All data were obtained during a full-participation annual medical check in 1 team. Rotator cuff tendons were examined ultrasonographically and allocated to 4 groups: (1) no tear, (2) supraspinatus tendon tear, (3) infraspinatus tendon tear, and (4) both supraspinatus and infraspinatus tendon tears. Current shoulder pain and shoulder muscle strength (dominant/nondominant) in abduction, external rotation, and internal rotation were compared by using chi-square and t tests. All players could play baseball with or without shoulder pain in this study. Results: Of the 87 players, 41 (47%) had articular-sided partial-thickness rotator cuff tears diagnosed on ultrasonography; the remaining 46 athletes were tear-free. Of the 41 affected patients, 19 had tears in the supraspinatus, 13 in the infraspinatus, and 9 in both the supraspinatus and infraspinatus tendons. Tear depth (mean ± SD) was 4.6 ± 2.3 mm in the supraspinatus and 6.2 ± 3.6 mm in the infraspinatus. Neither the rate of shoulder pain nor muscle strength differed significantly among the 4 groups (P =.96 and P =.15-.70, respectively). Conclusion: Articular-sided partial-thickness rotator cuff tear—by itself—did not cause shoulder pain and muscle weakness in university baseball players. Most so-called articular-sided partial-thickness rotator cuff tears may not be pathologic tendon tears. [ABSTRACT FROM AUTHOR]

Purpose: Superior capsular reconstruction (SCR) has gained attention as a potential treatment option for those with massive irreparable rotator cuff tears without significant arthritis. The aim of this systematic review is to review and evaluate the current sources and quality of SCR literature as well as reported outcomes. Methods: Three databases (PubMed, Ovid [MEDLINE], and EMBASE) were searched independently and in duplicate to systematically screen the literature. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) checklist guided the reporting and data abstraction. The results are presented in a narrative summary fashion using descriptive statistics. Results: Overall, 58 studies were identified, including 304 different patients. There was a rapid increase in the number of publications observed over the past 3 years, with the most dramatic single-year increase noted from 2017 to 2018 (175% increase). There are no level 1 studies, and 95% of the included studies were level 4 and 5 evidence. Comparing pre-operative to post-operative pooled-weighted mean outcome scores, the American Shoulder and Elbow Surgeons score improved from 44.2 to 84.8, the Visual Analogue Scale from 5.0 to 1.5, and acromiohumeral distance from 6.5 to 8.4 mm, respectively. Range of motion in forward elevation also improved from 111° to 152°. Among studies reporting, the complication rate was 13.4% with a revision surgery rate of 4.3%. Conclusion: Over the past 3 years there has been considerable growth in the number of publications of publications related to SCR. Despite a lack of high-quality clinical evidence, preliminary available evidence does suggest promising results both functionally and radiographically. There is a need for future higher-quality research such as large randomized controlled trials to improve our current understanding of the benefits of SCR. [ABSTRACT FROM AUTHOR]

Frozen Shoulder remains one of the most misunderstood pathologies to affect the shoulder joint. Frozen Shoulder is characterised by pain, loss of active and passive range of motion especially in flexion and external rotation with normal radiological findings undergoing three stages of presentation: initial pain, stiffness and near full resolution with time. Current treatment options include manual physiotherapy techniques, injection therapy, manipulation under anaesthetic and surgical release of shoulder capsule. Presently there remains a paucity of significant research supporting the sole use of any of these techniques in the treatment of frozen shoulder. Future studies should incorporate larger subject populations with closely related symptoms and be multicentred across a larger geographical area. [ABSTRACT FROM AUTHOR]

Background: Adhesive capsulitis (AC) is a type of arthritis that causes shoulder joint pain, stiffness, and limited mobility. The pathogenesis of AC is still controversial. This study aims to explore the role of immune related factors in the occurrence and development of AC., Methods: The AC dataset was downloaded from Gene Expression Omnibus (GEO) data repository. Differentially expressed immune-related genes (DEIRGs) were obtained based on R package "DESeq2" and Immport database. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were performed to explore the functional correlation of DEIRGs. MCC method and Least Absolute Shrinkage and Selection Operator (LASSO) regression were conducted to identify the hub genes. The immune cell infiltration in shoulder joint capsule between AC and control was evaluated by CIBERSORTx, and the relationship between hub genes and infiltrating immune cells was analyzed by Spearman's rank correlation. Finally, potential small molecule drugs for AC were screened by the Connectivity Map database (CMap) and further verified by molecular docking., Results: A total of 137 DEIRGs and eight significantly different types of infiltrating immune cells (M0 macrophages, M1 macrophages, regulatory T cells, Tfh cells, monocytes, activated NK cells, memory resting CD4+T cells and resting dendritic cells) were screened between AC and control tissues. MMP9, FOS, SOCS3, and EGF were identified as potential targets for AC. MMP9 was negatively correlated with memory resting CD4+T cells and activated NK cells, but positively correlated with M0 macrophages. SOCS3 was positively correlated with M1 macrophages. FOS was positively correlated with M1 macrophages. EGF was positively correlated with monocytes. Additionally, dactolisib (ranked first) was identified as a potential small-molecule drug for the targeted therapy of AC., Conclusions: This is the first study on immune cell infiltration analysis in AC, and these findings may provide a new idea for the diagnosis and treatment of AC., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Liu, Yu, Deng, Zhao, Zeng, Li and Fu.)

Background Tearing of the anterior capsule of the shoulder is a rare but debilitating injury for throwing athletes. However, there is very little in the literature to guide its diagnosis and treatment. In this case series, we outline our experience with anterior capsular tears of the shoulder in professional baseball players. Methods Five professional baseball players were diagnosed with midsubstance tears of their anterior capsule. A trial of rest and rehabilitation failed in all patients, and they eventually underwent surgery. These patients were retrospectively reviewed. The presenting symptoms and findings were documented, and outcomes were assessed by the player's ability to return to play. Results The mean age was 33.5 years (range, 31-37 years), and all patients presented with anterior shoulder pain and the inability to throw. No patient had an acute traumatic injury. Magnetic resonance imaging provided the correct diagnosis in 4 patients, and the diagnosis was made with diagnostic arthroscopy in the fifth. Three underwent arthroscopic repair, and 2 underwent open repair of the anterior capsule. Of the 5 players, 4 (80%) returned to their preinjury level by a mean of 13.3 months (range, 8-18 months). Conclusions Anterior capsular tears can occur in older throwing athletes. Surgical repair, whether arthroscopic or open, can yield good results in most patients. [ABSTRACT FROM AUTHOR]

Background: Although increased capsular volume has been implicated in shoulder instability, there is a paucity of clinical evidence to quantify the size of the capsule with specific instability conditions of the shoulder. Hypothesis: Shoulder capsular area, as measured by magnetic resonance arthrography, is increased with specific patterns of shoulder instability. Study Design: Cross-sectional study; Level of evidence, 4. Methods: During an 8-month period, all patients with a diagnosis of anterior (n = 19), posterior (n = 14), or multidirectional (n = 13) instability of the shoulder and who were assessed with a magnetic resonance arthrogram were reviewed. A group of 10 control patients without clinical instability were also identified. The magnetic resonance arthrograms of all groups were randomly mixed, and 5 reviewers recorded measures of capsular length and area and determined labral abnormalities. The magnetic resonance arthrogram measurements were compared between groups, and interobserver agreement was determined. Results: The cross-sectional area of the capsule was increased in patients with posterior (P = .017) or multidirectional instability (P = .02 1) versus controls, but not in patients with anterior instability. Additionally, the posteroinferior cross-sectional area was increased in patients with posterior (P = .001), multidirectional (P = .003), and anterior (P = .008) instability. In patients with a posterior labral tear, the mean axial (P = .043) and mean posteroinferior sagittal cross-sectional area (P = .011) was increased, but there were no differences in cross-sectional area for those with an anterior labral tear. The overall interobserver reliability was very good (correlation coefficient range, 0.68-0.94). Conclusion: Our results reinforce the concept that capsular elongation and laxity, either preexisting or acquired, play a role in certain instability conditions of the shoulder. Additional work is needed to determine how to correlate surgical decision making with the cross-sectional area measurements demonstrated in this study. [ABSTRACT FROM AUTHOR]

Purpose: To determine the biomechanical strength properties of suture capsulolabral plication to an intact labrum versus glenoid bone anchor fixation. Methods: Fourteen paired fresh frozen shoulders with intact glenoid labrum and mean age of 43.3 ± 11.1 were randomized to capsular plication in the anteroinferior and posteroinferior quadrants using either two suture-anchor fixation versus suture fixation to an intact labrum. The construct was then preconditioned at 10 N for 10 cycles (1 Hz), and then loaded to failure at 3 mm per minute. Results: There was no statistical difference in ultimate load to failure between the suture anchor (304.3 ± 92.8 N) and the intact labrum (285.6 ± 66.7 N) groups. The suture anchor group demonstrated significantly less mean displacement (2.15 ± 1.1 mm) than suture plication (3.43 ± 1.38 mm; P = .007) at failure. There were no statistical differences of labrum strength and stiffness between the anteroinferior and posteroinferior quadrants. Conclusions: An intact labrum provides similar fixation strength to a glenoid anchor; however, the labrum displacement was higher with plication alone. There were no strength differences between the anteroinferior and posteroinferior labrum. However, displacement of up to 1.5 mm may be expected without the use of glenoid anchors. Clinical Relevance: The intact posteroinferior or anteroinferior labrum provides similar fixation strength to a glenoid anchor; however, the labrum displacement is higher versus plication alone. [Copyright &y& Elsevier]

Background: Being able to predict recurrence after the treatment of shoulder instability would be helpful in planning the appropriate treatment., Purpose: To define the multiple subscapularis tendon sign (MSTS) as a novel anatomic variant and a possible risk factor for the recurrence of shoulder instability after anterior stabilization and to evaluate it, together with the other risk factors as described in the literature., Study Design: Case-control study; Level of evidence, 3., Methods: A total of 87 patients met the study criteria and underwent arthroscopic stabilization for anterior shoulder instability. The MSTS was evaluated in this study group. Age, sex, hand dominance, number of preoperative shoulder dislocations, history of overhead or contact sports participation, type of labral lesion, number of anchors used in surgery, presence of the drive-through sign, presence of the MSTS, Oxford Shoulder Score results, and the association of these parameters with recurrence were assessed. The mean follow-up time was 81.0 ± 27.9 months (range, 48-139 months)., Results: Nine (10.3%) patients experienced recurrent instability. The presence of the MSTS ( P = .009), existence of an anterior labroligamentous periosteal sleeve avulsion (ALPSA) lesion ( P = .04), and history of overhead or contact sports participation ( P = .04) were significant risk factors for recurrence. The recurrence rates were as follows: 30.7% with the MSTS; 40% with the MSTS and an ALPSA lesion; and 75% with the MSTS, an ALPSA lesion, and a history of overhead or contact sports participation., Conclusion: The MSTS is a variation of the anterior shoulder joint capsule. It is a sign of capsular insufficiency or thinning, which may be a risk factor for recurrence after anterior stabilization. Considering the low success rates of anterior capsulolabral repair in patients participating in overhead or contact sports, especially when an ALPSA lesion is present, encountering the MSTS during surgery in this at-risk group may be an indicator for the surgeon to choose the surgical procedure more carefully., Competing Interests: The authors declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.