Relationship between Critical Shoulder Angle and Rotator Cuff Tears in Patients with Non-Traumatic Shoulder Pain

Background: The critical shoulder angle (CSA) is the angle between the superior and inferior bony margins of the glenoid and the most lateral border of the acromion. Although studies have reported that the CSA is associated with rotator cuff tears (RCTs), few studies have examined the accuracy of the CSA for predicting RCTs in patients with shoulder pain. Purpose: To investigate the accuracy of the CSA for predicting RCTs among patients with nontraumatic shoulder pain. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Data were retrospectively collected from 301 patients who had RCTs and underwent arthroscopic rotator cuff repair between January 2014 and December 2018 (RCT group). During that same period, we also included 300 patients with shoulder pain but without RCTs, confirmed through ultrasound (non-RCT group). Baseline demographic data, the CSA, and the acromion index (AI) were compared using an independent t test. Categorical variables were analyzed using the chi-square test. Receiver operating characteristic (ROC) curve analysis was performed to investigate the accuracy of the CSA and AI for predicting RCTs, and the optimal cutoff point was determined using the Youden index. Multiple stepwise and binary logistic regressions were used to determine the predictors of RCTs. Results: A total of 301 patients (123 males, 178 females) and 300 patients (116 males, 184 females) were included in the RCT and non-RCT groups, respectively. The RCT group had a higher CSA ( P < .001) than the non-RCT group. The area under the ROC curve (AUC) was 70.5% ( P < .001) for the CSA, but there was no significance for the AI, with an AUC of 47.7% for predicting RCTs in patients. Stepwise logistic regression revealed the CSA as an independent predictor of RCTs, with an adjusted odds ratio of 1.295 (95% CI, 1.019-1.571; P = .006). For patients with a CSA greater than 37.52°, binary logistic regression revealed an adjusted odds ratio of 3.92 (95% CI, 2.79-5.51; P < .001) for the presence of an RCT. Conclusion: The CSA was an objective assessment tool to identify patients with shoulder pain who may have RCTs. Our study indicated that the CSA predicted RCTs more accurately than did the AI for patients with shoulder pain.

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Relationship between Critical Shoulder Angle and Rotator Cuff Tears in Patient with Non-Traumatic Shoulder Pain

EAS Journal of Radiology and Imaging Technology ◽

10.36349/easjrit.2020.v02i06.007 ◽

2020 ◽

Vol 2 (6) ◽

pp. 134-138

Author(s):

Dr. Deepak KS ◽

Dr. Bharat MP

Keyword(s):

Rotator Cuff ◽

Shoulder Pain ◽

Rotator Cuff Tears ◽

Critical Shoulder Angle ◽

Shoulder Angle

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Critical shoulder angle is associated with full-thickness rotator cuff tears in patients with glenohumeral osteoarthritis

Journal of Shoulder and Elbow Surgery ◽

10.1016/j.jse.2017.05.020 ◽

2017 ◽

Vol 26 (12) ◽

pp. e376-e381 ◽

Cited By ~ 22

Author(s):

Matthew T. Mantell ◽

Ryan Nelson ◽

Jeremiah T. Lowe ◽

Donald P. Endrizzi ◽

Andrew Jawa

Keyword(s):

Rotator Cuff ◽

Rotator Cuff Tears ◽

Full Thickness ◽

Critical Shoulder Angle ◽

Glenohumeral Osteoarthritis ◽

Shoulder Angle

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Relationship Between Deltoid and Rotator Cuff Muscles During Dynamic Shoulder Abduction: A Biomechanical Study of Rotator Cuff Tear Progression

The American Journal of Sports Medicine ◽

10.1177/0363546518768276 ◽

2018 ◽

Vol 46 (8) ◽

pp. 1919-1926 ◽

Cited By ~ 13

Author(s):

Felix Dyrna ◽

Neil S. Kumar ◽

Elifho Obopilwe ◽

Bastian Scheiderer ◽

Brendan Comer ◽

...

Keyword(s):

Rotator Cuff ◽

Dynamic Testing ◽

Correlation Coefficients ◽

Biomechanical Study ◽

Rotator Cuff Tears ◽

Shoulder Abduction ◽

Mean Values ◽

Critical Shoulder Angle ◽

Anterior Deltoid ◽

Shoulder Angle

Background: Previous biomechanical studies regarding deltoid function during glenohumeral abduction have primarily used static testing protocols. Hypotheses: (1) Deltoid forces required for scapular plane abduction increase as simulated rotator cuff tears become larger, and (2) maximal abduction decreases despite increased deltoid forces. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen cadaveric shoulders with a mean age of 67 years (range, 64-74 years) were used. The supraspinatus and anterior, middle, and posterior deltoid tendons were attached to individual shoulder simulator actuators. Deltoid forces and maximum abduction were recorded for the following tear patterns: intact, isolated subscapularis (SSC), isolated supraspinatus (SSP), anterosuperior (SSP + SSC), posterosuperior (infraspinatus [ISP] + SSP), and massive (SSC + SSP + ISP). Optical triads tracked 3-dimensional motion during dynamic testing. Fluoroscopy and computed tomography were used to measure critical shoulder angle, acromial index, and superior humeral head migration with massive tears. Mean values for maximum glenohumeral abduction and deltoid forces were determined. Linear mixed-effects regression examined changes in motion and forces over time. Pearson product-moment correlation coefficients ( r) among deltoid forces, critical shoulder angles, and acromial indices were calculated. Results: Shoulders with an intact cuff required 193.8 N (95% CI, 125.5 to 262.1) total deltoid force to achieve 79.8° (95% CI, 66.4° to 93.2°) of maximum glenohumeral abduction. Compared with native shoulders, abduction decreased after simulated SSP (–27.2%; 95% CI, –43.3% to –11.1%, P = .04), anterosuperior (–51.5%; 95% CI, –70.2% to –32.8%, P < .01), and massive (–48.4%; 95% CI, –65.2% to –31.5%, P < .01) cuff tears. Increased total deltoid forces were required for simulated anterosuperior (+108.1%; 95% CI, 68.7% to 147.5%, P < .01) and massive (+57.2%; 95% CI, 19.6% to 94.7%, P = .05) cuff tears. Anterior deltoid forces were significantly greater in anterosuperior ( P < .01) and massive ( P = .03) tears. Middle deltoid forces were greater with anterosuperior tears ( P = .03). Posterior deltoid forces were greater with anterosuperior ( P = .02) and posterosuperior ( P = .04) tears. Anterior deltoid force was negatively correlated ( r = −0.89, P = .01) with critical shoulder angle (34.3°; 95% CI, 32.0° to 36.6°). Deltoid forces had no statistical correlation with acromial index (0.55; 95% CI, 0.48 to 0.61). Superior migration was 8.3 mm (95% CI, 5.5 to 11.1 mm) during testing of massive rotator cuff tears. Conclusion: Shoulders with rotator cuff tears require considerable compensatory deltoid function to prevent abduction motion loss. Anterosuperior tears resulted in the largest motion loss despite the greatest increase in deltoid force. Clinical Relevance: Rotator cuff tears place more strain on the deltoid to prevent abduction motion loss. Fatigue or injury to the deltoid may result in a precipitous decline in abduction, regardless of tear size.

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Risk Factors, Pathobiomechanics and Physical Examination of Rotator Cuff Tears

The Open Orthopaedics Journal ◽

10.2174/1874325001610010277 ◽

2016 ◽

Vol 10 (1) ◽

pp. 277-285 ◽

Cited By ~ 6

Author(s):

Samuel G. Moulton ◽

Joshua A. Greenspoon ◽

Peter J. Millett ◽

Maximilian Petri

Keyword(s):

Risk Factors ◽

Rotator Cuff ◽

Physical Examination ◽

Diagnostic Accuracy ◽

Literature Search ◽

Glenohumeral Joint ◽

Rotator Cuff Tears ◽

Critical Shoulder Angle ◽

Common Risk Factors ◽

Shoulder Angle

Background: It is important to appreciate the risk factors for the development of rotator cuff tears and specific physical examination maneuvers. Methods: A selective literature search was performed. Results: Numerous well-designed studies have demonstrated that common risk factors include age, occupation, and anatomic considerations such as the critical shoulder angle. Recently, research has also reported a genetic component as well. The rotator cuff axially compresses the humeral head in the glenohumeral joint and provides rotational motion and abduction. Forces are grouped into coronal and axial force couples. Rotator cuff tears are thought to occur when the force couples become imbalanced. Conclusion: Physical examination is essential to determining whether a patient has an anterosuperior or posterosuperior tear. Diagnostic accuracy increases when combining a series of examination maneuvers.

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Critical shoulder angle is an effective radiographic parameter that is associated with rotator cuff tears and osteoarthritis: a systematic review

Journal of ISAKOS Joint Disorders & Orthopaedic Sports Medicine ◽

10.1136/jisakos-2018-000255 ◽

2019 ◽

Vol 4 (2) ◽

pp. 113-120

Author(s):

Gabriel Kuper ◽

Ajaykumar Shanmugaraj ◽

Nolan S Horner ◽

Seper Ekhtiari ◽

Nicole Simunovic ◽

...

Keyword(s):

Systematic Review ◽

Rotator Cuff ◽

Predictive Value ◽

Rotator Cuff Tears ◽

Radiographic Parameter ◽

Rater Reliability ◽

Critical Shoulder Angle ◽

Patient Reported ◽

Shoulder Angle ◽

Shoulder Pathologies

ImportanceThe critical shoulder angle (CSA) is a relatively new radiographic parameter correlated with pathologies such as rotator cuff tears and osteoarthritis.ObjectiveThe purpose of this systematic review was to: (1) determine the degree of correlation between the CSA and shoulder pathologies, (2) determine the reliability of measuring CSA between (inter-rater reliability) and within (intrarater reliability) clinicians, (3) assess the accuracy of different imaging modalities used for measuring the CSA and (4) determine the association of CSA with patient outcomes after surgery.Evidence reviewThe electronic databases MEDLINE, EMBASE and PubMed were searched in March 2018 for relevant studies. The results are presented in a narrative summary.FindingsA total of 26 studies and 4563 patients satisfied the inclusion criteria. The majority of CSAs were measured using radiographs (98.2%) in neutral rotation (72.9%). Significant associations (p<0.05) were found between lower CSAs (<30°) and osteoarthritis, and higher CSAs (>35°) with primary rotator cuff tears and the risk of re-tear following a repair. The CSA has excellent intrarater (intraclass correlation coefficient (ICC) 0.903 to 0.996) and inter-rater reliability (ICC 0.869 to 0.980) when measured with radiographs. High variability in measurements was found when using MRI. The CSA, however, is not a clear, significant independent predictor (p>0.05) of outcomes after the surgical management of shoulder pathologies.Conclusions and relevanceThe CSA is an effective radiographic parameter that is associated with rotator cuff tears and osteoarthritis. Lower CSAs (<30°) are associated with osteoarthritis, whereas higher CSAs (>35°) are associated with primary rotator cuff tears and re-tear after arthroscopic repair. Currently, there is a limited predictive value of the CSA in patient-reported outcomes after rotator cuff repair. The CSA is measured with high intrarater and inter-rater reliability for both radiographs and CT scans. Measuring the CSA using radiographs with the arm in the neutral rotation is currently recommended. Future studies are required to further investigate how best use the CSA to guide patient management and its predictive value.Level of evidenceIV.

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The Critical Shoulder Angle is Predictive of Rotator Cuff Tears and Shoulder Osteoarthritis and is Better Assessed with Radiographs over MRI

Orthopaedic Journal of Sports Medicine ◽

10.1177/2325967114s00017 ◽

2014 ◽

Vol 2 (3_suppl) ◽

pp. 2325967114S0001

Author(s):

Ulrich Spiegl ◽

Marilee P. Horan ◽

W Sean Smith ◽

Charles P. Ho ◽

Peter J. Millett

Keyword(s):

Rotator Cuff ◽

Rotator Cuff Tears ◽

Shoulder Osteoarthritis ◽

Critical Shoulder Angle ◽

Shoulder Angle

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Lateral acromioplasty for correction of the critical shoulder angle

Obere Extremität ◽

10.1007/s11678-020-00578-w ◽

2020 ◽

Vol 15 (3) ◽

pp. 228-232

Author(s):

Mark Tauber ◽

Peter Habermeyer ◽

Nikolaus Zumbansen ◽

Frank Martetschläger

Keyword(s):

Rotator Cuff ◽

Rotator Cuff Repair ◽

Constant Score ◽

Logical Consequence ◽

Clinical Results ◽

Rotator Cuff Tears ◽

Critical Shoulder Angle ◽

Cuff Repair ◽

Shoulder Angle

Abstract The critical shoulder angle (CSA) was introduced as a radiological parameter associated with a higher incidence of rotator cuff tears. As a logical consequence, correcting the CSA together with rotator cuff repair should prevent re-tear and provide reliable and good clinical results. We present an all-arthroscopic technique resecting the lateral edge of the acromion (lateral acromioplasty) in order to reduce and correct the CSA after preoperative planning. Preliminary results from 20 patients with an average age of 62 years after rotator cuff repair are reported showing good clinical outcome with a Constant score of 88 points and no re-tear after an average follow-up of 16 months. The CSA was reduced from 39.7° to 32.1°. Previous concerns regarding weakening of the deltoid origin were not confirmed and there were no complications linked to lateral acromioplasty.

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