Adhesion of the subacromial bursa may cause subacromial impingement in patients with rotator cuff tearsPressure measurements in 18 patients

Context: Shoulder muscle activation in patients with subacromial impingement is highly cited and variable in the literature. Differences between studies could be due to artifacts introduced by normalization practices in the presence of pain. Ultimately, this lack of knowledge pertaining to pathogenesis limits the clinical treatment and restoration of muscular function. Design: A total of 21 patients with stage 2 subacromial impingement and 21 matched controls were recruited for EMG testing of their affected shoulder during an arm elevation task. The patients were tested before and after receiving an injection to their subacromial bursa. Methods: The EMG from 7 shoulder muscles were measured before and after treatment during humeral motion in the scapular plane. Results: Our findings indicate an increase in anterior deltoid, middle deltoid, and upper trapezius activity following the injection; further, this trend extended to the controls. The control subjects had a greater activation of the latissimus dorsi at peak arm elevation when compared with the patient group postinjection. Conclusions: Our results indicate that a reduction in subacromial pain is associated with changes in shoulder muscle recruitment, primarily of the deltoid. This change in deltoid activity may lend evidence to rotator cuff function in patients without rotator cuff tears.

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The Role of Indian Hedgehog Signaling in Tendon Response to Subacromial Impingement: Evaluation Using a Mouse Model

The American Journal of Sports Medicine ◽

10.1177/03635465211062244 ◽

2021 ◽

pp. 036354652110622

Author(s):

Yulei Liu ◽

Xiang-Hua Deng ◽

Xueying Zhang ◽

Ting Cong ◽

Daoyun Chen ◽

...

Keyword(s):

Rotator Cuff ◽

Hedgehog Signaling ◽

Molecular Mechanisms ◽

Healing Process ◽

Biomechanical Testing ◽

Indian Hedgehog ◽

Control Group ◽

Subacromial Impingement ◽

Subacromial Space ◽

Gradual Improvement

Background: The underlying cellular and molecular mechanisms involved in the development of tendinopathy due to subacromial supraspinatus tendon (SST) impingement and the response to subsequent removal of impingement remain unknown. Purpose: To investigate the involvement of Indian hedgehog (IHH) signaling in the development of SST tendinopathy and the subsequent healing process after the relief of subacromial impingement in a novel mouse shoulder impingement model. Study Design: Controlled laboratory study. Methods: A total of 48 male wild-type C57BL/6 mice were used in this study. Supraspinatus tendinopathy was induced by inserting a microsurgical clip into the subacromial space bilaterally. Eleven mice were sacrificed at 4 weeks after surgery to establish impingement baseline; 24 mice underwent clip removal at 4 weeks after surgery and then were euthanized at 2 or 4 weeks after clip removal. Thirteen mice without surgical intervention were utilized as the control group. All SSTs were evaluated with biomechanical testing; quantitative histomorphometry after staining with hematoxylin and eosin, Alcian blue, and picrosirius red; and immunohistochemical staining (factor VIII, IHH, Patched1 [PTCH1], and glioma-associated oncogene homolog 1 [GLI1]). Results: The mean failure force and stiffness in the 4-week impingement group decreased significantly compared with the control group ( P < .001) and gradually increased at 2 and 4 weeks after clip removal. Histological analysis demonstrated increased cellularity and disorganized collagen fibers in the SST, with higher modified Bonar scores at 4 weeks, followed by gradual improvement after clip removal. The IHH-positive area and PTCH1- and GLI1-positive cell percentages significantly increased after 4 weeks of clip impingement (20.64% vs 2.06%, P < .001; 53.9% vs 28.03%, P = .016; and 30% vs 12.19%, P = .036, respectively) and continuously increased after clip removal. Conclusion: The authors’ findings suggest that the hedgehog signaling pathway and its downstream signaling mediator and target GLI1 may play a role in the development and healing process of rotator cuff tendinopathy due to extrinsic rotator cuff impingement. Clinical Relevance: This study suggests the potential for the hedgehog pathway, together with its downstream targets, as candidates for further study as potential therapeutic targets in the treatment of supraspinatus tendinopathy.

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MicroRNA-29a Mitigates Subacromial Bursa Fibrosis in Rotator Cuff Lesion with Shoulder Stiffness

International Journal of Molecular Sciences ◽

10.3390/ijms20225742 ◽

2019 ◽

Vol 20 (22) ◽

pp. 5742 ◽

Cited By ~ 1

Author(s):

Jih-Yang Ko ◽

Wei-Shiung Lian ◽

Tsai-Chen Tsai ◽

Yu-Shan Chen ◽

Chin-Kuei Hsieh ◽

...

Keyword(s):

Rotator Cuff ◽

Rotator Cuff Tear ◽

Shoulder Function ◽

Pathological Feature ◽

Subacromial Bursa ◽

Shoulder Disorder ◽

Shoulder Stiffness ◽

Cuff Tear ◽

Rotator Cuff Lesion

Rotator cuff lesion with shoulder stiffness is a major cause of shoulder pain and motionlessness. Subacromial bursa fibrosis is a prominent pathological feature of the shoulder disorder. MicroRNA-29a (miR-29a) regulates fibrosis in various tissues; however, the miR-29a action to subacromial bursa fibrosis remains elusive. Here, we reveal that subacromial synovium in patients with rotator cuff tear with shoulder stiffness showed severe fibrosis, hypertrophy, and hyperangiogenesis histopathology along with significant increases in fibrotic matrices collagen (COL) 1A1, 3A1, and 4A1 and inflammatory cytokines, whereas miR-29a expression was downregulated. Supraspinatus and infraspinatus tenotomy-injured shoulders in transgenic mice overexpressing miR-29a showed mild swelling, vascularization, fibrosis, and regular gait profiles as compared to severe rotator cuff damage in wild-type mice. Treatment with miR-29a precursor compromised COL3A1 production and hypervascularization in injured shoulders. In vitro, gain of miR-29a function attenuated COL3A1 expression through binding to the 3’-untranslated region (3′-UTR) of COL3A1 in inflamed tenocytes, whereas silencing miR-29a increased the matrix expression. Taken together, miR-29a loss is correlated with subacromial bursa inflammation and fibrosis in rotator cuff tear with shoulder stiffness. miR-29a repressed subacromial bursa fibrosis through directly targeting COL3A1 mRNA, improving rotator cuff integrity and shoulder function. Collective analysis offers a new insight into the molecular mechanism underlying rotator cuff tear with shoulder stiffness. This study also highlights the remedial potential of miR-29a precursor for alleviating the shoulder disorder.

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Correlation between Rotator Cuff Tears and Repeated Subacromial Steroid Injections: A Case-Controlled Study

Annals of The Royal College of Surgeons of England ◽

10.1308/003588409x428261 ◽

2009 ◽

Vol 91 (5) ◽

pp. 414-416 ◽

Cited By ~ 29

Author(s):

M Bhatia ◽

B Singh ◽

N Nicolaou ◽

KJ Ravikumar

Keyword(s):

Rotator Cuff ◽

Causative Factor ◽

Rotator Cuff Tears ◽

Controlled Study ◽

Distribution Analysis ◽

Subacromial Impingement ◽

Subacromial Space ◽

Retrospective Case ◽

Significant Difference ◽

Magnetic Resonance Imaging Mri

INTRODUCTION Concern exists regarding potential damage to the rotator cuff from repeated corticosteroid injections into the subacromial space. PATIENTS AND METHODS In this retrospective, case-controlled study, 230 consecutive patients presenting to three orthopaedic units with subacromial impingement and investigated as an end-point with magnetic resonance imaging (MRI) of the shoulder were divided into groups having received less than three or three or more subacromial injections of corticosteroids. RESULTS With no significant difference in age and sex distribution, analysis by MRI showed no significant difference between the two groups in the incidence of rotator cuff tear (P < 1.0). CONCLUSIONS This suggests that corticosteroid use in patients with subacromial impingement should not be considered a causative factor in rotator cuff tears.

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