Association of a large lateral extension of the acromion with rotator cuff tears

Impact of critical shoulder angle in shoulder pathology: a current concepts review

Background

This review aims to describe the origin and development of critical shoulder angle (CSA) and its correlation with different shoulder pathologies. Current literature is inconclusive in characterizing the role of CSA in predicting pathology and surgical outcomes.

Methods

A literature search of both historical and more contemporary research articles on CSA was conducted to compare data points on the impact of CSA on shoulder pathology and postoperative clinical outcomes. This compilation of studies ranges from retrospective reviews to case series as well as cadaveric imaging studies.

Results

The CSA is a reliable radiographic measure in predicting shoulder pathology in correctly oriented radiographs. Surgically modifying the CSA with arthroscopic lateral acromioplasty and results has largely shown improved recovery of strength postoperatively as with no increase in postsurgical complication rates. However, it remains unclear whether surgical alteration of CSA has a role in preventing clinical failure after arthroscopic procedures such as acromioplasty and rotator cuff repair as well as following shoulder arthroplasty.

Discussion

Stronger conclusions regarding the prognostic utility of CSA are limited by the fact that most studies evaluating CSA are smaller retrospective cohorts. Moving forward, randomized controlled trials being conducted may offer greater insight as to how CSA can improve patient-reported outcomes postoperatively.

Anatomic factors associated with degeneration and fraying of the coracoacromial ligament

BACKGROUND

The coracoacromial ligament (CAL) is frequently observed to be damaged during arthroscopy and it is unclear how demographic, anatomic, and radiographic factors are related to CAL degeneration in full-thickness rotator cuff tears.

METHODS

A prospective study was conducted of patients at a single institution undergoing shoulder arthroscopy for first-time, full-thickness rotator cuff tears. We evaluated preoperative anteroposterior radiographs to obtain critical shoulder angle, glenoid inclination, acromial index, acromiohumeral distance, lateral acromial angle, and acromial morphology. We documented CAL quality, rotator cuff tear size and pattern during arthroscopy. Multiple logistic regression was used to identify predictive factors for encountering severe CAL fraying during arthroscopy.

RESULTS

Shoulders had mild CAL degeneration in 58.1% of cases, whereas severe CAL degeneration was present in 41.9% of shoulders. Patients with severe CAL attrition were significantly older (62.0 years vs. 58.0 years, P=0.042). Shoulders with severe CAL attrition had large rotator cuff tears in 54.1% of cases (P<0.001), and tears involving the infraspinatus (63.2% vs. 29.6%, P=0.003). The severe degeneration group was more likely to have a larger critical shoulder angle measurement on preoperative radiographs than those in the mild attrition group (36.1°±3.6° [range, 30°-45°] vs. 34.1°±3.8° [range, 26°-45°], P=0.037).

CONCLUSIONS

While the clinical impact of CAL degeneration remains uncertain, increased severity of CAL degeneration is associated with older age, larger rotator cuff tear size, presence of infraspinatus tearing, and increased preoperative critical shoulder angle. Level of evidence: III.

Evaluation of the prognostic value of the anatomical characteristics of the bony structures in the shoulder in bursal-sided partial-thickness rotator cuff tears

Background

In recent studies, individual scapular anatomy has been found to be related to degenerative full-thickness rotator cuff tears. However, research on the relationship between the anatomical characteristics of shoulder radiographs and bursal-sided partial-thickness rotator cuff tears (PTRCTs) is limited, and the risk factors for this pathology still need to be determined.

Methods

The bursal-sided PTRCTs group included 102 patients without a history of shoulder trauma who underwent arthroscopy between January 2021 and October 2022. A total of 102 demographically matched outpatients with intact rotator cuffs were selected as the control group. Radiographs were used to measure the lateral acromial angle (LAA), critical shoulder angle (CSA), greater tuberosity angle (GTA), β-angle, acromion index (AI), acromiohumeral distance (AHD), acromial tilt (AT), acromial slope (AS), acromial type, and acromial spur by two independent observers. Multivariate analyses of these data were used to identify potential risk factors for bursal-sided PTRCTs. Receiver operating characteristic (ROC) analysis was performed to assess the sensitivity and specificity of CSA, GTA, and AI for this type of pathology.

Result

The β-angle, AHD, AS and acromion type showed no difference between bursal-sided PTRCTs and controls (p = 0.009, 0.200, 0.747 and 0.078, respectively). CSA, GTA and AI were significantly higher in bursal-sided PTRCTs (p < 0.001). LAA, β-angle and AT were significantly lower in bursal-sided PTRCTs. Multivariate logistic regression analysis demonstrated significant correlations between the acromial spur (p = 0.024), GTA (p = 0.004), CSA (p = 0.003) and AI (p = 0.048) and bursal-sided PTRCTs. The areas under the ROC curves for AI, CSA, and GTA were 0.655 (95% CI 0.580-0.729), 0.714 (95% CI 0.644-0.784), and 0.695 (95% CI 0.622-0.767), respectively.

Conclusion

Acromial spur, GTA, CSA, and AI were independent risk factors for bursal-sided PTRCTs. Furthermore, CSA was the most powerful predictor of bursal-sided PTRCTs compared to GTA and AI.

Aktuelle Aspekte der Behandlung der Rotatorenmanschette

Rotatorenmanschettenrupturen gehören zu den häufigsten muskuloskeletalen Erkrankungen und können mit ausgeprägten Schmerzen und Funktionseinschränkungen einhergehen. Für ihre Entstehung ist eine Vielzahl von Faktoren relevant, u. a. die individuelle Anatomie des Akromions. Mit Hilfe der heutigen technischen Möglichkeiten wurde nun festgestellt, dass zusätzlich zu seiner lateralen Ausdehnung auch die sagittale Ausdehnung des Akromions eine Rolle zu spielen scheint. Die bildgebende Darstellung der Rotatorenmanschette (RM) hat von den technischen Fortschritten der letzten Jahrzehnte ebenfalls profitiert. Magnetresonanztomographie (MRT) und MR-Arthrographie werden heute flächendeckend eingesetzt. Letztere bietet die höchste Sensitivität für die Entdeckung selbst kleiner Partialläsionen. Neue Sequenzen und Nachbearbeitungsmöglichkeiten können als hilfreiche tools für die operative Planung eingesetzt werden. Grundsätzlich richtet sich die Behandlung der RM neben der Symptomatik nach der Rupturgenese und -morphologie sowie der erwarteten Gewebequalität des Muskel-Sehnen-Kontinuums. Auch das Gesamtprofil, die Erwartungshaltung und die Rehabilitationsmöglichkeiten des Patienten sind wichtig. Die heutigen operativen Techniken werden durch spannende Entwicklungen der Industrie mitbestimmt, die in den letzten Jahren immer bessere Fadenankersysteme, aber auch Augmentationsmaterialien auf den Markt gebracht hat. Letztere zielen nicht nur auf die mechanische Verstärkung der Sehnenrekonstruktion, sondern auch auf die Optimierung der biologischen Eigenschaften des Konstrukts ab. Hinsichtlich Fixation konnte die biomechanische Forschung zeigen, dass zweireihige oder Suture-Bridge-Fixationen einreihigen oder transossären Fixationen überlegen sind. Diese Überlegenheit im Labor spiegelt sich noch nicht klar in den klinischen Ergebnissen wider, dennoch sind die meisten Chirurgen heute auf diese Technik übergegangen. Was die postoperative Nachbehandlung angeht, stellen jüngste randomisiert-kontrollierte Untersuchungen das Konzept der postoperativen Immobilisation in Abduktion in Frage. Hier scheint das letzte Wort noch nicht gesprochen zu sein.

Acromion Morphology of Patients with Rotator Cuff Disease in Standard AP Shoulder Radiograph in Hospital Sultanah Bahiyah and Hospital Kuala Lumpur

Introduction

Rotator cuff pathology is commonly attributed to acromion morphology that is demonstrable in standard AP shoulder radiographs by measuring the critical shoulder angle (CSA), the lateral acromial angle (LAA), and the acromial index (AI). However, these parameters vary among races and countries. Therefore, our study aimed to get the local data on acromion morphology in patients with rotator cuff disease.

Materials and methods

MRI shoulder reports between January 2012 and June 2018 were reviewed. The study group consisted of 47 patients with rotator cuff injury with a partial or complete tear, and a control group of 37 patients with tendinitis or osteoarthritis and intact rotator cuffs. The CSA, LAA, and AI of both groups were measured on the anteroposterior shoulder radiograph. The risk factors for both groups and the acromion morphology were recorded.

Results

The CSA for the rotator cuff tear and the control group was 39.08° and 38.28°, LAA was 72.57 ° and 73.51°, and AI was 0.79 and 0.75. The acromion morphology differed in terms of gender, and only LAA was different among the different ethnic groups. There was a negative correlation between age and CSA, age and AI, LAA and CSA, LAA and AI, but a positive correlation between AI and CSA.

Conclusion

The CSA for rotator cuff tear patients in our population was 39.08°, LAA was 72.57°, and AI was 0.79. The acromion morphology was significantly influenced by age and gender.

Deep learning model for measurement of shoulder critical angle and acromion index on shoulder radiographs

Background

Several bone morphological parameters, including the anterior acromion morphology, the lateral acromial angle, the coracohumeral interval, the glenoid inclination, the acromion index (AI), and the shoulder critical angle (CSA), have been proposed to impact the development of rotator cuff tears and glenohumeral osteoarthritis. This study aimed to develop a deep learning tool to automate the measurement of CSA and AI on anteroposterior shoulder radiographs.

Methods

We used MURA Dataset v1.1, which is a large publicly available musculoskeletal radiograph dataset from the Stanford University School of Medicine. All normal shoulder anteroposterior radiographs were extracted and annotated by an experienced orthopedic surgeon. The annotated images were divided into train (1004), validation (174), and test (93) sets. We use pytorch_segmentation_models for U-Net implementation and PyTorch framework for training the model. The test set was used for final evaluation of the model.

Results

The mean absolute error for CSA and AI between human-performed and machine-performed measurements on the test set with 93 images was 1.68° (95% CI 1.406°-1.979°) and 0.03 (95% CI 0.02 - 0.03), respectively.

Conclusions

A deep learning model can precisely and accurately measure CSA and AI in shoulder anteroposterior radiographs. A tool of this nature makes large-scale research projects feasible and holds promise as a clinical application if integrated with a radiology software program.

Critical shoulder angle and failure of conservative treatment in patients with atraumatic full thickness rotator cuff tears

Background

Atraumatic full thickness rotator cuff tears (AFTRCT) are common lesions whose incidence increases with age. Physical therapy is an effective conservative treatment in these patients with a reported success rate near 85% within 12 weeks of treatment. The critical shoulder angle (CSA) is a radiographic metric that relates the glenoid inclination with the lateral extension of the acromion in the coronal plane. A larger CSA has been associated with higher incidence of AFTRCT and a higher re-tear rate after surgical treatment. However, no study has yet described an association between a larger CSA and failure of conservatory treatment in ARCT. The main objective of this study is to determine whether there is an association between CSA and failure of physical therapy in patients with AFTRCT.

Methods

We reviewed the imaging and clinical records of 48 patients (53 shoulders), 60% female, with a mean age of 63.2 years (95% CI ± 10.4 years); treated for AFTRCT who also underwent a true anteroposterior radiograph of the shoulder within a year of diagnosis of the tear. We recorded demographic (age, sex, type of work), clinical (comorbidities), and imaging data (CSA, size and location of the tear). We divided the patients into two groups according to success or failure of conservative treatment (indication for surgery), so 21 shoulders (39.6%) required surgery and were classified as failure of conservative treatment.

Univariate and multivariate analysis was performed to detect predictors of failure of conservative treatment.

Results

The median CSA was 35.5º with no differences between those with failure (median 35.5º, range 29º to 48.2º) and success of conservative treatment (median 35.45º, range 30.2º to 40.3º), p = 0.978.

The multivariate analysis showed a younger age in patients with failure of conservative treatment (56.14 ± 9.2 vs 67.8 ± 8.4, p < 0.001) and that male gender was also associated with failure of conservative treatment (57% of men required surgery vs 28% of women, p = 0.035).

Conclusions

It is still unclear if CSA does predict failure of conservative treatment. A lower age and male gender both could predicted failure of conservative treatment in AFTRCT. Further research is needed to better address this subject.

Evaluation of anatomical variations with morphological measurements and their relationship with rotator cuff tear and acromion types

Introduction: There many more anatomical measurements such as the acromiohumeral distance and lateral acromion angle and acromial configuration was reported as might be associated with rotator cuff tear. In our study, we aimed to reveal the effect of acromion index, acromiohumeral distance, lateral acromion angle, critical shoulder angle values and the acromion type in the development of rotator cuff tear. Material and Method: In our retrospective study, 58 patients and 29 asymptomatic volunteers who underwent shoulder magnetic resonance imaging examinations were examined. acromion index, acromion humaral distance, lateral acromion angle and critical shoulder angle were measured and their relationship with rotator cuff tear and acromion types were evaluated. Results: Type III (hooked) of acromial shapes, higher acromion index and critical shoulder angle values, lower acromiohumeral distance and lateral acromion angle values are more frequently seen in rotator cuff tear patients, in our study. Conclusion: Thus, we revealed anatomical malformations that predispose to rotator cuff tear concerning the shoulder joint.

Could radio-morphological changes in humerus greater tuberosity be an early indicator of rotator cuff tendon injuries?

OBJECTIVES

To reveal the possible relationship between greater tuberosity volume with rotator cuff tendon injuries.

MATERIALS AND METHODS

In our study, the morphology of the greater tuberosity was evaluated retrospectively by using radiographs and MR images of 335 cases. While critical shoulder angle (CSA) was measured on radiographs, greater tuberosity (GT) area and volume were calculated, and also supraspinatus, infraspinatus, and teres minor tendons were evaluated, on MR images. The relationship of the measurements with the tendon injuries was analyzed statistically.

RESULTS

Among 188 female and 147 male patients, no statistically significant relationship was found between tendon injuries in terms of gender. The relationships between supra and infraspinatus tendon injuries and GT angle, area, and volume measurements were statistically significant. There was a statistically significant relationship between teres minor injury and GT angle, but no significant correlation with GT area and volume. Finally, there was no statistically significant correlation between all three tendon pathologies and CSA.

CONCLUSION

Area, and especially volume measurements, which are morphological features of the GT, may reflect tendon damage without significant degenerative changes in the bone structure. In examinations before tendon damage progresses, GT volume is a morphological feature that needs to be evaluated and may facilitate early recognition of tendinopathies and be an early marker of rotator cuff injuries.

Arthroscopic debridement for management of massive, irreparable rotator cuff tears: a systematic review of outcomes

Background

Surgical management of massive irreparable rotator cuff tears remains controversial. Arthroscopic debridement (AD) has shown promising results especially in the population older than 65 years; however, there is no consensus on the benefits of various AD procedures. The aim of this systematic review was to evaluate the functional midterm to long-term outcomes in patients treated with AD in combination with subacromial decompression, biceps tenotomy, tuberoplasty, or bursectomy, without repair of the rotator cuff tear.

Methods

A comprehensive search was performed in PubMed, Cumulative Index to Nursing and Allied Health Literature (CINAHL), and Cochrane databases for studies reporting clinical outcomes of AD of massive rotator cuff tears. Quality was determined using the Methodological Index for Nonrandomized Studies (MINORS) criteria by two independent reviewers. Pooled frequency-weighted means and standard deviations were calculated for patient-reported outcomes.

Results

Sixteen articles containing 643 patients and 662 shoulders met the eligibility criteria. The mean age at the time of surgery was 65.9 ± 4.4 years with a mean follow-up period of 46.5 ± 27.3 months. There was notable clinically significant improvement across all patient-reported outcome scores postoperatively: Constant 70.4 ± 8.9 (P value = .06), University of California, Los Angeles ultrasonography 26.7 ± 5.2 (P value = .001), American Shoulder and Elbow Surgeons score 71.7 ± 2.1 (P value = .12), Disabilities of the Arm, Shoulder, and Hand score 35.3, and visual analog score 1.7 ± 0.9. Forty-nine patients (7%) required reoperation, which most commonly was a reverse total shoulder arthroplasty for the development of rotator cuff arthropathy.

Conclusion

Arthroscopic debridement with a combination of subacromial decompression, tuberoplasty, subacromial bursectomy, and biceps tenotomy, for treatment of massive irreparable rotator cuff tears, produces good functional outcomes and improvement in pain at mid to long term follow up for the low-demand population greater than 65 years of age looking for pain relief over substantial increase in function.

Accuracy of Critical Shoulder Angle and Acromial Index for Predicting Supraspinatus Tendinopathy

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. The acromial index (AI) is the distance from the glenoid plane to the acromial lateral border and is divided by the distance from the glenoid plane to the lateral aspect of the humeral head. Although both are used for predicting shoulder diseases, research on their accuracy in predicting supraspinatus tendinopathy in patients with shoulder pain is limited. Data were retrospectively collected from 308 patients with supraspinatus tendinopathy between January 2018 and December 2019. Simultaneously, we gathered the data of 300 patients with shoulder pain without supraspinatus tendinopathy, confirmed through ultrasound examination. Baseline demographic data, CSA, and AI were compared using the independent Student’s t test and Mann–Whitney U test. Categorical variables were analyzed using the chi-square test. A receiver operating characteristic curve (ROC) analysis was performed to investigate the accuracy of CSA and AI for predicting supraspinatus tendinopathy, and the optimal cut-off point was determined using the Youden index. No statistical differences were observed for age, sex, body mass index, evaluated side (dominant), diabetes mellitus, and hyperlipidemia between the groups. The supraspinatus tendinopathy group showed higher CSAs (p < 0.001) than did the non-supraspinatus tendinopathy group. For predicting supraspinatus tendinopathy, the area under the curve (AUC) of ROC curve of the CSA was 76.8%, revealing acceptable discrimination. The AUC of AI was 46.9%, revealing no discrimination. Moreover, when patients with shoulder pain had a CSA > 38.11°, the specificity and sensitivity of CSA in predicting supraspinatus tendinopathy were 71.0% and 71.8%, respectively. CSA could be considered an objective assessment tool to predict supraspinatus tendinopathy in patients with shoulder pain. AI revealed no discrimination in predicting supraspinatus tendinopathy in patients with shoulder pain.

Does the critical shoulder angle decrease after acromioplasty? A systematic review and meta-analysis

BACKGROUND

Rotator cuff tears are one of the most common shoulder injuries in the older population. This study aimed to determine whether acromioplasty reliably decreases the critical shoulder angle (CSA) and describe any associated complications.

METHODS

A systematic literature review was performed according to PRISMA guidelines using PubMed, EMBASE, Web of Science, and Cochrane Library Database. Two reviewers independently screened the titles and abstracts using prespecified criteria. Studies where the acromioplasty was performed as a surgical procedure were included. Patient characteristics and degree of CSA reduction were collected from each individual study. All statistical analyses were performed using Review Manager (RevMan) 5.4.1 software. A random-effects model was used for meta-analysis.

RESULTS

A total of 9 studies involving 1236 patients were included in the meta-analysis. The age of patients ranged from 23 to 82 years. The follow-up period ranged from 12 to 30 months. Of the 9 studies, 8 (88.9%) were retrospective, 1 (11.1%) was prospective, 5 were comparative, and 4 were case series. The mean CSA was significantly reduced from 36.1° ± 4.6° to 33.7° ± 4.2 (p < 0.05). The meta-analysis showed an overall best estimate of the mean difference in pre- and postoperative CSA equal to 2.63° (95% confidence interval: 2.15, 3.11] (p < 0.00001).

CONCLUSIONS

Acromioplasty can significantly reduce CSA, notably in cases of high preoperative CSA. In addition, the effect of lateral acromioplasty on the CSA was more significant compared to anterolateral acromioplasty. Acromioplasty was not associated with complications during the short-term follow-up.

Association of the Posterior Acromion Extension with Glenoid Retroversion: A CT Study in Normal and Osteoarthritic Shoulders

Posterior eccentric glenoid wear is associated with higher complication rates after shoulder arthroplasty. The recently reported association between the acromion shape and glenoid retroversion in both normal and osteoarthritic shoulders remains controversial. The three-dimensional coordinates of the angulus acromialis (AA) and acromioclavicular joint were examined in the scapular coordinate system. Four acromion angles were defined from these two acromion landmarks: the acromion posterior angle (APA), acromion tilt angle (ATA), acromion length angle (ALA), and acromion axial tilt angle (AXA). Shoulder computed tomography scans of 112 normal scapulae and 125 patients with primary glenohumeral osteoarthritis were analyzed with simple and stepwise multiple linear regressions between all morphological acromion parameters and glenoid retroversion. In normal scapulae, the glenoid retroversion angle was most strongly correlated with the posterior extension of the AA (R² = 0.48, p < 0.0001), which can be conveniently characterized by the APA. Combining the APA with the ALA and ATA helped slightly improve the correlation (R² = 0.55, p < 0.0001), but adding the AXA did not. In osteoarthritic scapulae, a critical APA > 15 degrees was found to best identify glenoids with a critical retroversion angle > 8 degrees. The APA is more strongly associated with the glenoid retroversion angle in normal than primary osteoarthritic scapulae.

The Influence of Critical Shoulder Angle in Secondary Rotator Cuff Failure After Shoulder Replacement: An Age- and Sex-Matched Case-Control Study

Introduction

Decreased or increased critical shoulder angles (CSA) are associated with osteoarthritis or rotator cuff failure respectively. Secondary cuff failure after shoulder arthroplasty is disabling and often requires additional surgery. The aim of this study was to investigate if the initial CSA correlated with cuff failure in the context of shoulder arthroplasty.

Methods

Patients from a tertiary referral centre were reviewed from 2011-2017. Those who underwent revision from hemiarthroplasty (HA) or anatomic total shoulder arthroplasty (TSA) to a reverse shoulder arthroplasty (RSA) following rotator cuff failure were compared to an age and sex-matched control group. The CSA was calculated from initial pre-operative radiographs.

Results

In this study, 16 patients with symptomatic cuff failure after anatomic TSA or HA requiring revision to RSA were compared to a control group of 16 age- and sex-matched patients showing no signs of symptomatic cuff failure. The median CSA in the study group was significantly greater than that of the control group (31.5^o, IQR = 29.8 - 36.1^o vs. 29.5^o, IQR = 27.6 - 30.4^o; p= 0.026).

Conclusion

The difference in CSA between those who required revision for secondary cuff failure than those who didn’t suggest that pre-operative measurement of CSA may help guide surgical planning in shoulder arthroplasty.

Correlation of Multiple Acromion Morphological Parameters on Radiographs in a Geriatric Chinese Population and Its Clinical Significance

Introduction

Previous clinical studies have reported associations between the acromion index, lateral acromion angle, and critical shoulder angle and the occurrence of rotator cuff tears. The objective of this study was to analyze the correlations of these different anatomic parameters in geriatric Chinese Population.

Methods

Healthy geriatric Chinese participants (n = 66) and geriatric Chinese patients with rotator cuff tears (n = 70) identified between January 2019 and October 2020 were included in this study. Standardized true anteroposterior radiographs were used to measure the acromion index, lateral acromion angle, and critical shoulder angle in each study participant.

Results

The mean acromion index was significantly larger, the mean lateral acromion angle was significantly smaller, and the mean critical shoulder angle was significantly larger in geriatric patients with full-thickness rotator cuff tears compared with geriatric healthy participants.

Conclusion

There were a negative linear relationship between the acromion index and lateral acromion angle and a positive linear relationship between the acromion index and critical shoulder angle in geriatric patients with rotator cuff tear and geriatric healthy participants; we termed this phenomenon “Hypothesis of Acromion Index.” The acromion index, lateral acromion angle, and critical shoulder angle are independent predictors of rotator cuff tears in a geriatric Chinese population.

Treatment Options for Massive Irreparable Rotator Cuff Tears

PURPOSE OF REVIEW

Massive irreparable rotator cuff tears present a significant challenge to the orthopedic surgeon. No single treatment, particularly among joint-preserving options, has been shown to be superior. The purpose of this review is to discuss recent advances in the treatment of massive irreparable rotator cuff tears, including partial repair with and without graft augmentation, interposition grafts, superior capsule reconstruction, subacromial balloon spacers, tendon transfer, and reverse total shoulder arthroplasty. We will also offer guidance on surgical indications based on our clinical experience.

RECENT FINDINGS

Partial repair may offer reasonable clinical improvement for patients with lower preoperative function despite high re-tear rates. Additionally, several types of interposition grafts have shown promising short-term results and may outperform repair alone. Subacromial balloon spacers may lead to clinical improvement, especially in patients without glenohumeral osteoarthritis or pseudoparalysis, and recently received FDA approval for use in the USA. Superior capsule reconstruction is a technically demanding procedure that appears to produce excellent short-term results particularly when performed at high volume, but long-term studies in heterogeneous study groups are needed. Tendon transfers improve function by restoring force coupling in the shoulder, offering a promising option for younger patients. Reverse total shoulder arthroplasty (RTSA) is a reliable option for treatment of irreparable cuff tears in elderly patients with lower functional demands. Irreparable cuff tears remain a difficult condition to treat. Recommended treatment for younger patients without glenohumeral osteoarthritis is particularly controversial. For older patients with low-demand lifestyles and glenohumeral osteoarthritis, RTSA is an effective treatment option. For all discussed procedures, patient selection appears to play a critical role in clinical outcomes.

Sharpened lateral acromion morphology (SLAM sign) as an indicator of rotator cuff tear: a retrospective matched study

Background

Bigliani types of acromion and critical shoulder angle (CSA) have been implicated as indicators of rotator cuff disease. A sharpened inferolateral edge of acromion (termed as Sharpened Lateral Acromion Morphology or SLAM sign) is frequently observed in anteroposterior radiographs of the glenohumeral joint in patients with rotator cuff tears (RCT). We aimed to evaluate the association of the SLAM sign with RCT in comparison to high CSA (≥35°) and Bigliani type 3 (hooked) acromion.

Methods

A cohort of 100 consecutive patients undergoing non-arthroplasty surgery for RCT and 106 patients with primary frozen shoulder were matched manually in 1:1 ratio based on age and gender to yield study population with 50 patients in each group. The 2 groups were compared for the presence of the SLAM sign, high CSA, and type 3 acromion on the radiographs.

Results

All the 3 parameters were found more prevalent in the RCT group than the frozen shoulder group (SLAM, 46% vs. 0; high CSA, 60% vs. 40%; type 3 acromion, 18% vs. 4%) (P < .05). The SLAM sign showed stronger correlation with RCT than high CSA and type 3 acromion (Ps = 0.562 vs. 0.220 vs. 0.224 respectively).

Conclusion

The SLAM sign is a simple and easily identifiable radiological predictor of rotator cuff disease.

The association between acromial anatomy and articular-sided partial thickness of rotator cuff tears

Background

Acromial anatomy has been found to be correlated with degenerative full-thickness rotator cuff tears in current studies. However, research on the relationship between acromial anatomy and articular-sided partial thickness of rotator cuff tears (PTRCTs) is still lacking. The purpose of this study was to evaluate whether these imaging graphic parameters exhibit any association between acromial anatomy and degenerative articular-sided PTRCTs.

Methods

Between January 2016 and December 2018, a total of 91 patients without a history of trauma underwent arthroscopy as an articular-sided PTRCT group. In the control group, with age- and sex-matched patients, we selected 91 consecutive outpatient patients who underwent shoulder magnetic resonance imaging (MRI) because of shoulder pain and an MRI diagnosis of only synovial hyperplasia and effusion. MRI was used to measure the acromial type, acromiohumeral distance (AHD), lateral acromial angle (LAA), acromion index (AI), and critical shoulder angle (CSA) by 2 independent observers.

Results

The acromion type, AHD and LAA showed no difference between degenerative articular-sided PTRCTs and controls (P = 0.532, 0.277, and 0.108, respectively). AI and CSA were significantly higher in degenerative articular-sided PTRCTs (P = 0.002 and 0.003, respectively). A good correlation was found between AI and CSA to measurement(Pearson correlation coefficient = 0.631).

Conclusions

Our study revealed that higher AI and CSA were found in degenerative articular-sided PTRCTs. Acromial anatomy with a large acromial extension was associated with the occurrence of degenerative articular-sided PTRCTs.

Radiographic shoulder parameters and their relationship to outcomes following rotator cuff repair: a systematic review

BACKGROUND

Anatomic parameters, such as the critical shoulder angle and acromion index, have emerged as methods to quantify scapular anatomy and may contribute to rotator cuff pathology. The purpose of this paper is to investigate the published literature on influences of scapular morphology on the development of re-tears and patient-reported outcomes following rotator cuff repair.

METHODS

A systematic review of the Embase and PubMed databases was performed to identify published studies on the potential influence of scapular bony morphology and re-tear rates and patient-reported outcomes after rotator cuff repair. Studies were reviewed by two authors.

RESULTS

A total of 615 unique titles and 49 potentially relevant abstracts were reviewed, with eight published manuscripts identified for inclusion. Two of three papers reported no relationship between these acromion index and rotator cuff re-tear rate, while one paper found an increased re-tear rate. All three studies on critical shoulder angle found a significant association between critical shoulder angle and cuff re-tear rate. There was no clear relationship between any bony morphologic measurement and patient-reported outcomes after rotator cuff repair.

CONCLUSIONS

Rotator cuff re-tear rate appears to be significantly associated with the critical shoulder angle and glenoid inclination, while not clearly associated with acromial morphologic measurements.

Correlation between full-thickness degenerative supraspinatus tear and radiographic parameters including the acromiohumeral centre edge angle and the greater tuberosity angle

BACKGROUND

Many radiographic parameters associated with the extrinsic cause of supraspinatus tears have been proposed. The aim of this study was to assess the relationship between a full-thickness degenerative supraspinatus tear (FTDST) and the patient's radiographic parameters, including the acromiohumeral centre edge angle (ACEA) and the greater tuberosity angle (GTA).

METHODS

A retrospective study was conducted. We included 116 patients who underwent shoulder arthroscopic surgery at our institute. The case group included FTDST patients, whereas the control group also included patients without evidence of supraspinatus tears. In each patient, the ACEA and GTA values were measured and analyzed by two independent observers. Intra- and interobserver reliabilities were assessed. Multivariate regression analysis was performed.

RESULTS

The ACEA values were significantly increased in the FTDST group with a mean of 26.44° ± 9.83° compared with 16.81° ± 7.72° in the control group (P < 0.001). Multivariate regression analysis also showed that higher ACEA values were associated with an FTDST (odds ratio 1.16 per degree, P = 0.01). For GTA values, a statistically significant difference was found with a mean of 70.92° ± 6.64 compared with 67.84° ± 5.56 in the control group (P = 0.02). However, stepwise regression analysis did not indicate that GTA was a predictor of FTDST.

CONCLUSIONS

Our study demonstrated that the presence of increased ACEA values is an independent significant risk factor for the presence of FTDSTs. Consequently, GTA values may be less helpful in assessing the risk of FTDST, especially in this specific population.

Acromioplasty reduces critical shoulder angle in patients with rotator cuff tear

Critical shoulder angle (CSA) is the angle between the superior and inferior bone margins of the glenoid and the most lateral border of the acromion and is potentially affected during a rotator cuff tear (RCT). Acromioplasty is generally performed to rectify the anatomy of the acromion during RCT repair surgery. However, limited information is available regarding the changes in the CSA after anterolateral acromioplasty. We hypothesized that CSA can be decreased after anterolateral acromioplasty. Data were retrospectively collected from 712 patients with RCTs and underwent arthroscopic rotator cuff repair between January 2012 and December 2018, of which 337 patients were included in the study. The presurgical and postsurgical CSA were then determined and compared using a paired samples t test. Because previous study mentioned CSA more than 38 degrees were at risk of rotator cuff re-tear, patients were segregated into two groups: CSA < 38° and CSA ≥ 38°; these groups were compared using an independent-samples t test. These 337 participants (160 male and 177 female) presented a CSA of 38.4° ± 6.0° before anterolateral acromioplasty, which significantly decreased to 35.8° ± 5.9° after surgery (P < .05). Before surgery, 172 patients were present in the CSA ≥ 38° group and 57 were preset in the CSA < 38° group after surgery. The CSA decreased significantly in the CSA ≥ 38° group rather than in the CSA < 38° group (P < .05). In conclusion, the CSA can be effectively decreased through anterolateral acromioplasty, and this reduction in the CSA is more significant among individuals with CSA ≥ 38° than among those with CSA < 38°, indicating that acromioplasty is recommended along with RCT repair especially among individuals with a wide presurgical CSA.

Morphological Characteristics of Acromion and Acromioclavicular Joint in Patients with Shoulder Impingement Syndrome and Related Recommendations: A Three-Dimensional Analysis Based on Multiplanar Reconstruction of Computed Tomography Scans

To find out which structure is crucial for the formation of shoulder impingement syndrome with the purpose of directing surgical procedures of subacromial decompression and discussing whether it is necessary to manage acromioclavicular joint during operation and how to do it properly.

The biomechanics of the rotator cuff in health and disease - A narrative review

The rotator cuff has an important role in the stability and function of the glenohumeral joint. It is a complex anatomic structure commonly affected by injury such as tendinopathy and cuff tears. The rotator cuff helps to provide a stabilising effect to the shoulder joint by compressing the humeral head against the glenoid cavity via the concavity compression mechanism. To appreciate the function of the cuff it is imperative to understand the normal biomechanics of the cuff as well as the mechanisms involved in the pathogenesis of cuff disease. The shoulder joint offers a wide range of motion due to the variety of rotational moments the cuff muscles are able to provide. In order for the joint to remain stable, the cuff creates a force couple around the glenohumeral joint with coordinated activation of adjacent muscles, which work together to contain the otherwise intrinsically unstable glenohumeral joint and prevent proximal migration of the humerus. Once this muscular balance is lost, increased translations or subluxation of the humeral head may result, leading to changes in the magnitude and direction of the joint reaction forces at the glenohumeral joint. These mechanical changes may then result in a number of clinical presentations of shoulder dysfunction, disease and pain. This narrative review aims to highlight the importance of functional rotator cuff biomechanics whilst assessing the kinetics and kinematics of the shoulder joint, as well as exploring the various factors involved in cuff disease.

Influence of Radiographic Parameters on Reduction of the Critical Shoulder Angle With Arthroscopic Lateral Acromioplasty-A Mathematical Model

Objectives

To develop a mathematical model for the preoperative planning of arthroscopic lateral acromioplasty (ALA) and to evaluate the role of radiographic parameters with regards to the critical shoulder angle (CSA).

Methods

Anteroposterior (AP) radiographs of patients who underwent rotator cuff surgery were screened to identify true AP radiographs. Radiographs were assessed for (1) native CSA, (2) CSA after simulated resection of a spur if present, (3) amount of ALA necessary to achieve a CSA of 34°, (4) CSA after 5-mm ALA, (5) lateral acromion angle, (6) acromion index, and (7) sclerosis of the greater tuberosity.

Results

A total of 1191 radiographs were screened. Of the 124 patients included, the native CSA was large (≥35°) in 56 patients (45%). In 30 patients (24%), a subacromial spur was detected and resection reduced the CSA by a median of 2°. Spur resection alone reduced the CSA to ≤34° in 19 patients (15.3%). Mean amount of ALA to achieve a CSA of 34° was 3.9 ± 1.8 mm, and this value strongly correlated with the CSA before ALA (R = 0.88, P < .001). The linear regression model to determine the amount of ALA to achieve a CSA of 34° was as follows: R e q u i r e d A L A i n m m = - 39.120 + 1.165 ∗ C S A n a t i v e The multiple R² for this model was 0.777. Mean reduction of CSA by 5-mm ALA was 3.8 ± 0.8° and 75% of large CSAs were reduced to a CSA of 30-34°. The acromion index had no significant independent influence on the model (P = .427), whereas lateral acromion angle was an independently significant predictor of required ALA to achieve a CSA of 34° (P = .019). Sclerosis of the greater tuberosity was significantly associated with a CSA of 35° or greater (P = .003).

Conclusions

The amount of ALA needed to reduce a large CSA to 34° correlates with the CSA before ALA and can preoperatively be planned with the use of a simple equation.

Level of Evidence

Level III; cross-sectional design; epidemiology study.

The relationship between rotator cuff integrity and acromiohumeral distance following open and arthroscopic rotator cuff repair

Background: Acromiohumeral distance (AHD) has become both a diagnostic and prognostic parameter related to rotator cuff pathology which is always measured in a 2-dimensional plane. The purposes of this study were (1) to evaluate the regional AHD with MRI following open and arthroscopic rotator cuff repair and, (2) to investigate its association to the rotator cuff integrity following medium to large size rotator cuff repair with open and arthroscopic manner. Methods: A retrospective review of 112 patients who were treated for full-thickness medium to large size rotator cuff tears either by open repair (open group) or arthroscopic repair (arthroscopic group) was done. All patients included in the study are those with at least 12 and 18 months for the post-operative MRI and clinical follow-up. Propensity score matching was used to select controls matched for age, sex, body mass index, tear size, and affected site. There were 56 patients in each group with a mean age of 63.3 years (range, 50 to 77 years). The post-operative functional and radiologic outcomes for both groups were compared. AHD was measured at three regions of interest (ROI) with MRI and compared pre-and post-operatively. Results: AHD was significantly greater in the open group when measured at the anterior third of the lateral acromion border compare to the arthroscopic group (p = 0.005). The re-tear rate was affected by AHD at the anterior third of the lateral border of the acromion for the arthroscopic and open group (p = 0.021, p = 0.029). The AHD measured at the anterior and middle third of lateral acromion border were significantly greater in healed compared to the re-tear rotator cuff group (p = 0.019, p = 0.022). Conclusions: Open rotator cuff repair showed greater AHD at the anterior third of the lateral border of the acromion. Regional AHD measured at anterior third of the lateral border of acromion significantly associated with rotator cuff integrity following repair. Level of evidence: propensity-matched case-control (Level II)

Exploring the functional morphology of the Gorilla shoulder through musculoskeletal modelling

Musculoskeletal computer models allow us to quantitatively relate morphological features to biomechanical performance. In non‐human apes, certain morphological features have long been linked to greater arm abduction potential and increased arm‐raising performance, compared to humans. Here, we present the first musculoskeletal model of a western lowland gorilla shoulder to test some of these long‐standing proposals. Estimates of moment arms and moments of the glenohumeral abductors (deltoid, supraspinatus and infraspinatus muscles) over arm abduction were conducted for the gorilla model and a previously published human shoulder model. Contrary to previous assumptions, we found that overall glenohumeral abduction potential is similar between Gorilla and Homo. However, gorillas differ by maintaining high abduction moment capacity with the arm raised above horizontal. This difference is linked to a disparity in soft tissue properties, indicating that scapular morphological features like a cranially oriented scapular spine and glenoid do not enhance the abductor function of the gorilla glenohumeral muscles. A functional enhancement due to differences in skeletal morphology was only demonstrated in the gorilla supraspinatus muscle. Contrary to earlier ideas linking a more obliquely oriented scapular spine to greater supraspinatus leverage, our results suggest that increased lateral projection of the greater tubercle of the humerus accounts for the greater biomechanical performance in Gorilla. This study enhances our understanding of the evolution of gorilla locomotion, as well as providing greater insight into the general interaction between anatomy, function and locomotor biomechanics.

Neither critical shoulder angle nor acromion index were related with specific pathology 20 years later!

PURPOSE

The critical shoulder angle (CSA) and the acromion index (AI) are measurements of acromial shape reported as predictors of degenerative rotator cuff tears (RCT) and glenohumeral osteoarthritis (GH OA). Whether they are the cause or effect of shoulder pathologies is uncertain since pre-morbid radiographs most often are lacking. The main aim of this study was to investigate if CSA or AI were related to the development of RCT or GH OA after 20 years. A secondary aim was to investigate if the CSA and AI had changed over time.

METHODS

In the hospital archive, 273 preoperative plain shoulder radiographs were found of patients scheduled for elective surgery other than cuff repair and arthroplasty. Forty-five images fulfilled the strict criteria published by Suter and Henninger (2015) and were used to measure CSA and AI with two independent assessors. No patient had any sign of OA in the index radiographs or any information in the medical records indicating RCT. After a median of 20 (16-22) years, 30 of these patients were radiologically re-examined with bilateral true frontal views and ultrasound of the rotator cuff. There were 19 men (20 study shoulders) and 11 females (12 study shoulders).

RESULTS

Mean age at follow-up was 56 (32-78) years. There was no correlation between CSA (r = 0.02) (n.s) or AI (r = - 0.13) (n.s) in the primary radiographs and OA at follow-up. Nor was any correlation found between index CSA (r = 0.12) (n.s) or AI (r = - 0.13) (n.s) and RCT at follow-up. Mean difference in CSA was - 1.7 (- 10-3) degrees and mean AI difference was - 0.04 (- 0.13-0.09) between the first and the second radiographs, 20 years later. Bilaterally, mean CSA was 32 and AI 0.61 at follow-up.

CONCLUSION

In this study, no correlation between the CSA, AI and development of OA or RCT could be found. The mean CSA and AI decreased over a 20-year period but the difference was very small. No difference was found between the study shoulders and the contralaterals. These findings question previously reported etiological associations between scapular anatomy and the development of OA or RCT and thereby the use of these calculations as the basis of treatment.

LEVEL OF EVIDENCE

III.

[Rotator cuff tear : Indications and pathology-specific reconstructive procedures]

Rotator cuff (RC) tears comprise a broad spectrum of lesions ranging from partial to full thickness tears of a single tendon and massive cuff tears. Both glenohumeral trauma as well as degenerative processes can result in tearing of the RC. Treatment therefore requires a meticulous diagnosis as well as a differentiated approach by careful consideration of morphological and patient-specific factors. The pathogenesis, tear morphology, clinical symptoms and functional demands of the patient determine the therapeutic approach. Despite pathological and individual patient-related factors, early surgical repair is generally recommended for traumatic RC tears in young patients and in patients with high functional demands due to the high risk of tear progression. The results of RC repair are negatively correlated with the size of the lesion, the number of tendons involved, the degree of tendon retraction, muscular alteration and patient age. This article provides an overview of the various pathogenesis, indications and surgical repair of RC tears with respect to modern pathology-specific reconstructive procedures.

Effect of arthroscopic acromioplasty on reducing critical shoulder angle: a protocol for a prospective randomized clinical trial

Background

The critical shoulder angle (CSA), which helps to predict patients who are at risk of rotator cuff tears (RCTs) with large degree and who are susceptible to osteoarthritis with low angle, has been identified as one of the most vital acromial parameters; anterolateral and lateral acromioplasties have been proven to be valid ways to reduce CSA. However, no study has compared the effect of different acromioplasties on the reduction of the large CSA (≥33°) clinically. Additionally, either anterolateral or lateral acromioplasty could not precisely correct large CSAs to a favorable range (30–33°) in each patient. Thus, we will propose a novel precise acromioplasty technique for the purpose of reducing CSA accurately and effectively, and compare the effectiveness of different acromioplasties on the reduction of the CSA.

Methods

A total of 60 RCT patients who have indications for arthroscopic rotator cuff repair and with pre-operative CSA ≥33° will be recruited in outpatient center of Sun Yat-sen Memorial Hospital. Eligible participants will be randomly allocated to Group A (anterolateral acromioplasty), Group B (lateral acromioplasty) or Group C (precise acromioplasty) via a random, computer-generated number system. Three surgical plans will be made for each participant respectively by one professional surgeon according to the results of randomization allocation. The post-operative CSA will be measured 2 days post-operation. Follow-up will be maintained at 3, 6, and 12 months after surgery including the visual analog scale score, the University of California at Los Angeles score, the Constant Shoulder Score and the American Shoulder and Elbow Surgeon Shoulder Assessment Form. Finally, all outcomes will be assessed by two researchers who are blinded to the recruitment and allocation.

Discussion

This is the first clinical trial to evaluate the impact of different acromioplasties on the reduction of the CSA. Additionally, this study will provide a new precise acromioplasty technique, which is a novel precision and individualized treatment to prevent degenerative RCTs by reducing the CSA.

Trial registration

ChiCTR2000032343. Registered on April 26th, 2020.

Long-term follow-up of patients with a high critical shoulder angle and acromion index: is there an increased retear risk after arthroscopic supraspinatus tendon repair?

BACKGROUND

The effect of the acromion index (AI) and critical shoulder angle (CSA) on the short-term healing rate after arthroscopic repair of the supraspinatus tendons is already known. Long-term effects have not been published yet.

PURPOSE

Long-term evaluation of the effect of the AI and CSA on the postoperative healing rate and clinical results after arthroscopic repair of the supraspinatus tendon.

METHODS

Patients with a symptomatic, single-tendon, full-thickness supraspinatus tear in whom nonoperative management had failed were treated with an arthroscopic repair. Preoperative radiographs were used to measure CSA and AI. Eight years postoperatively, magnetic resonance imaging (MRI) studies were performed and evaluated on repair integrity. Patient-reported outcome measurements were collected pre- and postoperatively.

RESULTS

Thirty-one patients were evaluated 8 years postoperatively. The mean age at the time of surgery was 61 ± 9 years. MRI evaluation showed that 20 patients (65%) had an intact repair and 11 (35%) had a full-thickness retear. No significant differences were found between the intact and retear groups regarding age (P = .605), initial tear size (P = .485), retraction grade (P = .439), and all PROMs. The mean CSA for the intact group (33° ± 1°) was significantly lower than the CSA in the retear group (38° ± 1°; P = .004). Eighteen patients (58%) had a CSA ≥35°, and 9 (50%) among them had a retear and 9 (50%) had an intact repair.The mean AI for the intact group (0.72 ± 0.11) was significantly lower than the AI in the retear group (0.81 ± 0.08 ; P = .021). Seventeen patients (55%) had an AI ≥0.75, and 9 (53%) among them had a retear and 8 had an intact repair. If the AI was ≥0.75, the odds ratio of having a retear was 6.19 (P = .045). No progressive worsening of PROMs and clinical results could be demonstrated related to a higher CSA or AI during the entire follow-up.

CONCLUSION

At long-term follow-up, a higher CSA has the tendency to have an increased rate of retear after arthroscopic supraspinatus tendon repair, but this was not significant. A higher AI significantly increased the retear risk. A higher CSA and AI did not impair the clinical results over time. An AI ≥0.75 was associated with a 6-fold increase in risk of retear after arthroscopic supraspinatus tendon repair.

Prediction of Rotator Cuff Injury Associated with Acromial Morphology: A Three-Dimensional Measurement Study

Objective

To analyze the relationship between the acromial morphology and the related rotator cuff injury using a three‐dimensional (3D) measurement technology.

Methods

For the present study, 226 patients (113 men and 113 women) who underwent shoulder Coarthroscopy from June 2015 to December 2019 at the Department of Orthopedics at our hospital were selected retrospectively. A total of 113 shoulder joints of age‐matched healthy people were selected as the control group. A 3D model coordinate system of the shoulder was established based on CT scan images. Patients were grouped according to the condition of the rotator cuff injury during surgery. The patients whose rotator cuff tear site corresponded to the 3D osseous proliferative structure of the acromion were classified into the impingement injury group (II group). The other patients were classified into the non‐impingement injury group (NII group). The acromiohumeral interval (AHI), the acromial anterior protrusion (AAP), the acromial inferior protrusion (AIP), the acromioclavicular angle (AC angle), the distance from the most medial edge of the acromial anterolateral protrusion (AALP) to the most lateral point of acromion (MLPA) (a), the distance from the most posteromedial edge of the AALP to the MLPA (b), the anteroposterior diameters of the AALP (c), and the proportion of anteroposterior diameters of AALP to the anteroposterior diameters of acromion, (c/c + d) × 100(%), were measured using the 3D shoulder model.

Results

The results of the intraobserver (<5%) and interobserver variability (>87%) analysis found the parameters to have high intraobserver and interobserver concordance. There were no significant differences in age among the control group, the NII group, and the II group (P = 0.8416). There were significant differences in AAP among the three groups (P = 0.0374). The results were the same for men and women, respectively. The AAP in the control group and the NII group did not show a difference, while the AAP in the II group was increased by 26.9% (P = 0.015) and 25% (P = 0.023), respectively, compared with the NII group and the control group. AHI, AIP, and AC angles did not show significant differences among the three groups (P > 0.05). The (a) and (b) of the II group were significantly larger than those of the NII group; P‐values were 0.0119 and 0.0003, respectively. The (a) and (b) in patients with rotator cuff injuries were larger than in the normal population (P < 0.05). The above results were the same for men and women. This suggested that the larger width of the AALP might cause the related rotator cuff injury. The (c/c + d) in the II group was significantly larger than those in the control and the NII groups, with P‐values of 0.0005 and 0.0021, respectively. The risk of rotator cuff injury due to subacromial impingement was increased when the maximum width of the medial–lateral edge of the AALP exceeded 16.8 mm (17.4 mm in men, 15.1 mm in women), the maximum width of the posterior edge of the AALP exceeded 12.9 mm (13.8 mm in men,12.7 mm in women), or the anteroposterior diameters of the AALP exceeded the anteroposterior diameters of the acromion by 33.5%.

Conclusion

We could predict the occurrence and development of the related rotator cuff injury in symptomatic patients with specific 3D changes in their acromion and intervene in the acromion of such patients as early as possible to prevent possible rotator cuff injuries in the future.

The Critical Shoulder Angle as a Diagnostic Measure for Osteoarthritis and Rotator Cuff Pathology

The purpose of this study was to correlate critical shoulder angle (CSA), a measurement that takes into account both glenoid tilt and the acromial index (AI), with shoulder pathologies as presented in an earlier study by Moor et al. (2013). Based on Moor et al.’s predicted normal CSA range of 30-35°, we hypothesized that a greater-than-normal CSA would be correlated to or associated with rotator cuff pathology, while a smaller-than-normal CSA would be associated with osteoarthritis (OA). Following Moore et al., we utilized Grashey radiographic imaging because it provides the clearest view of the entire glenoid fossa and acromion. We analyzed 323 anterior-posterior (AP) radiographs to identify and measure the CSA, classifying each patient into one of five groups [none reported (n=94), mild OA (n=156), moderate OA (n=36), severe OA (n=37), and rotator cuff pathology (n=40)]. Our results were statistically significant, supporting the association of smaller CSAs with OA and larger CSAs with rotator cuff pathology. CSA measurements could provide a new means for identifying shoulder pathology and thereby reduce the need for costly and timely imaging techniques. CSA values could also provide useful information to utilize preventatively with interventions such as physical therapy to alter the CSA and reduce the prevalence of OA and shoulder arthroplasties. This study builds on the findings of Moore et al. in creating a correlation between CSA and shoulder pathology.

The Effect of Acromioplasty on the Critical Shoulder Angle and Acromial Index

Purpose

To evaluate the effect of acromioplasty using a cutting block technique on bony coverage as measured by the critical shoulder angle (CSA) and acromial index (AI).

Methods

This study is a retrospective radiographic review using data from a previous prospective randomized clinical trial that offered enrollment to patients aged 18 years or older with a full-thickness tear of the superior rotator cuff between October 2007 and January 2011. Each patient was allocated to repair with either acromioplasty using a cutting block technique or non-acromioplasty treatment arms in a blinded fashion. Medical and demographic information was recorded for each patient. Between January 2017 and December 2017, patients were contacted for repeat follow-up clinical evaluation and radiographs. Measurements of acromial index and critical shoulder angle were performed on pre- and postoperative radiographs by a single reviewer.

Results

Seventy-one (75%) patients were available for follow up. The 2 groups were similar in terms of baseline demographics and acromial type. When compared with preoperative measures, acromioplasty did not result in significant reductions in mean CSA (34.5° vs 35.5°; P = .293) or AI (0.68 vs 0.66; P = .283). Furthermore, postoperative CSA (34.5° vs 36.2°, P = .052) and AI (0.66 vs 0.67, P = .535) demonstrated no statistically significant differences between patients with and without acromioplasty, respectively.

Conclusions

There was no statistically significant change in either the CSA or AI following acromioplasty, nor was there a significant postoperative difference in CSA or AI between the group that underwent acromioplasty and the group that did not.

Clinical Relevance

Some studies suggest a greater postoperative CSA may result in greater risk of retear after arthroscopic rotator cuff repair. The CSA and AI may not be modifiable with acromioplasty.

Thinking outside the glenohumeral box: Hierarchical shape variation of the periarticular anatomy of the scapula using statistical shape modeling

Variation in the shape of the glenoid and periarticular anatomy of the scapula has been associated with shoulder pathology. The goal of this study was to identify the modes of shape variation of periarticular scapular anatomy in relation to the glenoid in nonpathologic shoulders. Computed tomography scans of 31 cadaveric scapulae, verified to be free of pathology, were three-dimensionally reconstructed. Statistical shape modeling and principal component analysis identified the modes of shape variation across the population. Corresponding linear and angular measurements quantified the morphometric variance identified by the modes. Linear measures were normalized to the radius of the inferior glenoid to account for differences in the scaling of the bones. Five modes captured 89.7% of total shape variation of the glenoid and periarticular anatomy. Apart from size differences (mode 1: 33.0%), acromial anatomy accounted for the largest variation (mode 2: 32.0%). Further modes described variation in glenoid inclination (mode 3: 11.8%), coracoid orientation and size (mode 4: 9.0%), and variation in coracoacromial (CA) morphology (mode 5: 3.1%). The average scapula had a mean acromial tilt of 49 ± 7°, scapular spine angle of 61 ± 6°, the glenoid inclination of 84 ± 4°, coracoid deviation angle of 26 ± 4°, coracoid length of 3.7 ± 0.3 glenoid radii, and a CA base length of 5.6 ± 0.5 radii. In this study, the identified shape modes explain almost all of the variance in scapular anatomy. The acromion exhibited the highest variance of all periarticular anatomic structures of the scapula in relation to the glenoid, which may play a role in many shoulder pathologies.

The effect of critical shoulder angle on functional compensation in the setting of cuff tear arthropathy

Introduction

Critical shoulder angle (CSA) has been shown to influence rates of rotator cuff tears and glenohumeral arthritis with a larger CSA associated with rotator cuff tears and a smaller CSA associated with glenohumeral arthritis. There has been no study to determine whether such radiographic measurement influences the function of patients with demonstrated cuff tear arthropathy (CTA). The purpose of this study was to examine whether smaller CSAs were associated with greater range of motion (ROM) in patients diagnosed with CTA.

Materials and methods

Ninety-three patients with a diagnosis of CTA with adequate anteroposterior shoulder radiographs were included in the study. Patient demographics were recorded. The presence of a rotator cuff tear was confirmed via advanced imaging or when applicable via the operative report. Patients' ROM was evaluated through the physician's office note. Shoulder radiographs were used to measure CSA, glenoid inclination, acromial index (AI), and acromiohumeral interval. Patient ROM was measured and grouped into 2 different tiered cohorts: cohort 1 had 4 subgroups of forward elevation (FE) (ie, ≤45°, 45°-90°, 91°-135°, and 136°-180°) and cohort 2 had 2 subgroups of FE (ie, ≤90° and >90°). We then analyzed FE between these groups in the context of their radiographic measurements.

Results

The average patient age was 73.8 ± 8.0 years. There was no significant difference in acromiohumeral interval. AI was found to be significantly different between patients presenting with ≤90° in FE compared with those >90° (P = .02). Average CSA was significantly lower in patients with FE greater than 90° at 33.7° ± 3.9° compared with patients with FE less than 90° at 37.1° ± 6.3° (P = .002). There was also a significant difference with regard to CSAs, with those patients with FE ≤ 45° having a mean CSA of 38.2° ± 8.3° compared with those patients with FE ≥ 135° having a mean CSA of 33.3° ± 4.3° (P = .02).

Conclusion

Patients diagnosed with CTA can significantly vary in their shoulder function and ability to forward elevate. Lower CSA was found to be associated with higher FE in patients with CTA preoperatively. In addition, patients with a smaller AI were also found to have better overhead function. Analyzing CSA on plain radiographs may help manage functional expectations in patients with CTA.

The Lateral Deltoid Originates From the Entire Lateral Wall of the Acromion: MRI and Histologic Cadaveric Analysis Regarding Vertical Lateral Acromioplasty

Purpose

The aim of this study was to assess the nature of the middle deltoid muscle insertion onto the lateral acromion by macroscopic, MRI and histologic examination and to, therefore, assess the potential impact of a vertical lateral acromioplasty on the deltoid origin.

Methods

We assessed the acromial origin of the deltoid in 6 cadaver shoulders by macroscopic, MRI and histologic examination. The cadavers were scanned with T1 and proton density-weighted sequences. H&E- and Masson trichrome-stained histologic sections through the acromion were taken and visualized under polarized microscopy.

Results

The enthesis of the deltoid muscle consisted of dense birefringent bundles of collagen that blended with the bony endplate of the acromion at all points on its lateral wall. A prominent band of collagen was seen on both MRI and histologic slices, traversing the superior surface of the acromion. It was continuous with the deltoid origin and blended with the superficial fascia of the deltoid laterally.

Conclusions

The middle deltoid muscle occupies the entire lateral acromion.

Clinical Relevance

A high critical shoulder angle is associated with rotator cuff tears. A lateral acromioplasty resects the lateral acromion and aims to normalize the critical shoulder angle. However, a vertical lateral acromioplasty may release the middle deltoid origin from the lateral acromion. The superior band of collagen may anchor the middle deltoid to the superior acromion and prevent retraction.

Critical Shoulder Angle and Its Clinical Correlation in Shoulder Pain

Introduction The critical shoulder angle is defined as the angle formed between the plane of the glenoid and the line connecting the most lateral border of the acromion process, as seen on the true anteroposterior radiograph of the shoulder. The purpose of this study was to determine the association between the critical shoulder angle and shoulder pathologies like rotator cuff tears and glenohumeral osteoarthritis. It was also to assess the reproducibility and accuracy of critical shoulder angle values, which were measured with radiographs.  Objective The aim of the study was to find out the association between the critical shoulder angle and shoulder injuries in a rural population cohort. The secondary aims were to assess clinical and radiological correlations between the critical shoulder angle and the symptomology of shoulder pain. Materials and methods Our study analysis was a prospective design conducted at R L Jalappa Hospital & Research Centre, Karnataka, South India. After meeting the inclusion and exclusion criteria, 100 patients were recruited for the study. Forty-five patients had glenohumeral osteoarthritis and 55 patients had a diagnosis of rotator cuff tears. The majority of the patients were male (70%) in both the glenohumeral osteoarthritis and rotator cuff tear groups. The mean critical shoulder angles in the glenohumeral osteoarthritis and rotator cuff tear groups were 30.31 and 33.62, respectively. Conclusions Our data aid in demonstrating that glenohumeral osteoarthritis is associated with a significantly narrower critical shoulder angle and wider critical shoulder angles in rotator cuff disease. Further studies, however, should determine whether this association has a cause-and-effect relationship.

Three-dimensional scapular morphology is associated with rotator cuff tears and alters the abduction moment arm of the supraspinatus

BACKGROUND

Numerous studies have reported an association between rotator cuff injury and two-dimensional measures of scapular morphology. However, the mechanical underpinnings explaining how these shape features affect glenohumeral joint function and lead to injury are poorly understood. We hypothesized that three-dimensional features of scapular morphology differentiate asymptomatic shoulders from those with rotator cuff tears, and that these features would alter the mechanical advantage of the supraspinatus.

METHODS

Twenty-four individuals with supraspinatus tears and twenty-seven age-matched controls were recruited. A statistical shape analysis identified scapular features distinguishing symptomatic patients from asymptomatic controls. We examined the effect of injury-associated morphology on mechanics by developing a morphable model driven by six degree-of-freedom biplanar videoradiography data. We used the model to simulate abduction for a range of shapes and computed the supraspinatus moment arm.

FINDINGS

Rotator cuff injury was associated with a cranial orientation of the glenoid and scapular spine (P = .011, d = 0.75) and/or decreased subacromial space (P = .001, d = 0.94). The shape analysis also identified previously undocumented features associated with superior inclination and subacromial narrowing. In our computational model, warping the scapula from a cranial to a lateral orientation increased the supraspinatus moment arm at 20° of abduction and decreased the moment arm at 160° of abduction.

INTERPRETATIONS

Three-dimensional analysis of scapular morphology indicates a stronger relationship between morphology and cuff tears than two-dimensional measures. Insight into how morphological features affect rotator cuff mechanics may improve patient-specific strategies for prevention and treatment of cuff tears.

Clinical features and repair integrity after knotless - In situ suture bridge technique in high-grade bursal side rotator cuff tears

Introduction

The purpose of study is to describe outcome of the knotless-in-situ suture-bridge repair technique, combining concept of articular-preservation, medial-row knotless, and full-layer repair on the high-grade bursal-side rotator cuff tear (PBS-RCT).

Methods

The repair-technique, on 27 shoulders with PBS-RCT, were retrospectively evaluated. Range of Motion (RoM), visual analog scale (VAS), American Shoulder and Elbow Surgeon (ASES) score were evaluated. Minimal 6-months Post-operative MRI were evaluated for repair-integrity.

Result

RoM evaluation, VAS, and ASES Score were improved significantly (P < 0.01). Post-operative MRI showed intact repaired tendon in 25-patients (96.2%).

Conclusion

Arthroscopic knotless-in-situ suture-bridge repair technique in PBS- RCT showed good functional-outcome and repair-integrity at minimum 2-years after surgery.

Anatomical variations of the acromial and coracoid process: clinical relevance

PURPOSE

The acromial and coracoid process morphology is of clinical relevance due to associations with functional limitations and shoulder pathology. Our objective was to describe the anatomical characteristics of the acromial and coracoid process using computed tomography (CT).

METHODS

Descriptive, observational, transversal and retrospective study. A total of 155 CT of patients without shoulder pathology, of both genders, and indistinct age were evaluated and grouped by age: Group 1 < 25 years; group 2 25-40 years; group 3 > 40 years. The following parameters were evaluated: Acromial type (AcT), vertical coracoid distance (VCD), acromial tilt (AT), acromial projection (AP), critical shoulder angle (CSA), type of the subcoracoid outlet (TSO), and the area of the subcoracoid outlet (ASO).

RESULTS

Statistically significant differences were found between men and women for VCD (14.44 ± 4.79 vs. 11.76 ± 4.00 mm; p < 0.001) and AP (3.66 ± 4.71 vs. 1.62 ± 4.99 mm; p < 0.05) as well as between age groups 1 and 3 for AT (35.08 ± 11.53 vs. 28.41 ± 6.60; p < 0.05) and ASO (398.99 ± 153.91 vs. 255.56 ± 124.58 mm²; p < 0.001). An unexpected high ASO variation was identified with 11% of S-shaped acromion and 1.3% clock-shaped TSO.

CONCLUSION

The age group between 25-40 years had the most uniform distribution of data. There is a high morphological variability present in an asymptomatic population, which should be considered in the clinical assessment such as shoulder impingement syndrome.

Calcifying tendinitis and outlet impingement - Evaluation of the prevalence analyzing radiological and intraoperative criteria

Introduction

The question of our study was to evaluate the incidence of coexisting outlet impingement among patients with calcifying tendinitis and a failure of the conservative treatment using intraoperative in addition to radiological criteria.This question is of clinical relevance as there is still a discussion about whether an additional arthroscopic subacromial decompression (ASD) should be performed when arthroscopic removal of the calcific deposits is needed.

Materials and methods

From February 2017 to 02/2018, we prospectively enrolled 50 patients who needed shoulder arthroscopy for calcifying tendinitis. We evaluated the x-rays for outlet impingement, measuring the lateral acromial angle (LAA), acromion slope, acromion index (AI) and Bigliani-type of the acromion. During shoulder arthroscopy, we evaluated the acromial undersurface for a bony impingement using a standardized view. If impingement was present, we performed an additional ASD. Before surgery, three months later and at final follow-up 20 months after surgery, we determined the relative Constant Score (rCS).

Results

92.5% of the patients had an intraoperatively confirmed outlet impingement, whereas 82.5% of the patients had a radiological outlet impingement. The sensitivity of the radiographs was 83.8%, the specificity 33.3% when combining all parameters. The mean rCS improved significantly from 45% to 100% at final follow-up.

Conclusion

Our results show that coexisting outlet impingement is very common in patients with calcifying tendinitis and failure of the conservative treatment. As the radiological diagnosis is uncertain, an intraoperative assessment for impingement is rational and justifies an additional ASD.

Critical shoulder angle is intrinsically associated with the development of degenerative shoulder diseases: A systematic review

Aim of this study was to investigate the potential influence of Critical Shoulder Angle (CSA) as a predisposing factor for the development of degenerative full-thickness rotator cuff tears (DRCT) or primary glenohumeral osteoarthritis (PGOA). A systematic review of the Pubmed, Scopus, Mendeley, ScienceDirect and the Cochrane Central Register of Controlled Trials online databases was performed for literature regarding CSA and its association with DRCT and PGOA. In order to evaluate solely the relationship between CSA as a predisposing factor for the development of the aforementioned degenerative shoulder diseases (DSDs), we precluded any study in which traumatic cases were not clearly excluded. Our search strategy identified 289 studies in total, nine of which were eligible for inclusion based on our pre-established criteria. Quality assessment contacted using the Newcastle Ottawa Scale for case-control studies. There were a total of 998 patients with DRCT and 285 patients with PGOA. The control groups consisted of a total of 538 patients. The mean CSA ranged from 33.9° to 41.01° for the DRCT group, from 27.3° to 29.8° for the PGOA group and from 30.2° to 37.28° for the control group. All studies reported statistically significant differences between the DRCT and PGOA groups and the respective control groups. Our study results showed that there is moderate evidence in the literature supporting an intrinsic role of CSA in the development of DSDs. Level of evidence: IV. Systematic review of diagnostic studies, Level II-IV.

Critical shoulder angle: what do radiologists need to know?

The critical shoulder angle (CSA) constitutes a straightforward and highly reproducible tool. Degenerative rotator cuff tears (RCT) are associated with a significantly larger CSA. In this review, the most relevant features of the CSA are summarized: (1) the relationship between the CSA and RCT pathophysiology, (2) accurate measurement of the CSA according to various imaging modalities, (3) the contribution of the CSA in predicting the occurrence of RCT, and (4) RCT recurrence after surgical repair.

Association of acromial morphological parameters and rotator cuff tears, and evaluation of the influence of age and gender on the parameters and impact on cuff tears: A study on a Middle Eastern population

Objective

The aim of this study is to evaluate the presence of significant differences regarding the lateral acromial angle, critical shoulder angle, and the acromial index between patients with and without rotator cuff tears.

Method

The MRIs (Magnetic Resonnance Imaging) of 82 patients were studied. The rotator cuff tear group (RCT group) included 41 patients while the control group also included 41 patients without rotator cuff tears. Acromial parameters and demographical data were extracted for statistical analysis.

Results

No statistical significant difference was found in terms of the studied acromial parameters between patients with and without rotator cuff tears. No correlation was found between age and any of the studied parameters. LAA (Lateral Acromial Angle) was found to be significantly different between males and females of the studied sample. However, no difference was found between patients with and without rotator cuff tears when both genders were studied separately. Moreover, no statistical significant difference was found in terms of the studied acromial parameters between males and females when the RCT group and the control group were studied separately. When gender was the covariate in the one-way MANCOVA test, gender was not significantly dependent on the type of groups (RCT group vs control group).

Conclusion

The results obtained from this study suggested that the studied acromial parameters in patients with rotator cuff tears were not different from the parameters found in patients without rotator cuff tears. Moreover, gender was not found to influence the acromial parameters, with no subsequent effect on the development of rotator cuff tears. Further studies may be required for better understanding on the biomechanics, taking into consideration age, gender, and the given population.

Evaluation of the cross-sectional area of acromion process for shoulder impingement syndrome

Background

Anatomic changes in the acromion have been considered a main cause of shoulder impingement syndrome (SIS). To evaluate the relationship between SIS and the acromion process, we devised a new morphological parameter called the acromion process cross-sectional area (APA). We hypothesized that the APA could be an important morphologic diagnostic parameter in SIS.

Methods

We collected APA data from 95 patients with SIS and 126 control subjects who underwent shoulder magnetic resonance imaging (MRI). Then we measured the maximal cross-sectional area of the bone margin of the acromion process on MRI scans.

Results

The mean of APAs were 136.50 ± 21.75 mm² in the male control group and 202.91 ± 31.78 mm² in the male SIS group; SIS patients had significantly greater APAs (P < 0.001). The average of APAs were 105.38 ± 19.07 mm² in the female control group and 147.62 ± 22.90 mm² in the female SIS group, and the SIS patients had significantly greater APAs (P < 0.001). The optimal APA cut-off in the male group was 165.14 mm² with 90.2% sensitivity, 91.4% specificity, and an area under the curve (AUC) of 0.968. In the female group, the optimal cut-off was 122.50 mm² with 85.2% sensitivity, 84.9% specificity, and an AUC of 0.928.

Conclusions

The newly devised APA is a sensitive parameter for assessing SIS; greater APA is associated with a higher possibility of SIS. We think that this result will be helpful for the diagnosis of SIS.

The value of radiographic markers in the diagnostic work-up of rotator cuff tears, an arthroscopic correlated study

OBJECTIVE

To evaluate the value of radiographs during the diagnostic work-up of rotator cuff tears, using arthroscopy as reference standard.

MATERIALS AND METHODS

This retrospective study included 236 shoulders of 236 patients. All radiographs were evaluated for inferior cortical acromial sclerosis, lateral acromial spur, superior migration of the humeral head, greater tubercle cysts, and subacromial space calcifications. Predictive value of these radiographic signs in predicting rotator cuff tears was determined with arthroscopy as reference standard.

RESULTS

According to arthroscopy, 131 shoulders were diagnosed with rotator cuff tears. Seventy-two out of 131 shoulders (55%) had inferior cortical acromial sclerosis, 37 (28%) lateral acromial spur, 21 (16%) superior migration of the humeral head, 7 (5%) greater tubercle cysts and 15 subacromial space calcifications (11%). Inferior cortical acromial sclerosis (P = 0.001), lateral spur (P = 0.001), superior migration (P = 0.002), and cysts (P = 0.03) were significantly and independently associated with rotator cuff tears, whereas subacromial calcifications (p = 0.21) was not. Inferior cortical acromial sclerosis, superior migration, lateral acromial spur, and cysts combined have a positive predictive value of 78%.

CONCLUSIONS

The combination of inferior cortical acromial sclerosis, lateral acromial spur, superior migration of the humeral head, and greater tubercle cysts has a high positive predictive value for the presence of full-thickness rotator cuff tears. In patients with a high suspicion for having a rotator cuff tear based on radiographic findings, MRI can be performed directly without the delay and costs caused by an additional ultrasound exam.

Correlation of acromial morphology in association with rotator cuff tear: a retrospective study

Purpose

There have been many studies that have attempted to correlate radiographic acromial characteristics with rotator cuff tears, but the results have not been conclusive. Rotator cuff tears (RCT) are the common aetiology of shoulder pain. We assessed the association of rotator cuff tears with commonly used radiographic parameters of acromial morphology and their different radiographic characteristics.

Material and methods

From a retrospective study of 98 patients, we characterised acromial type and measured acromial thickness (AT), critical shoulder angle (CSA), lateral acromial angle (LAA), acromiohumeral distance (AHD), and acromion index (AI) on a 1.5T MRI, from 68 patients with partial or full-thickness supraspinatus tendon tears and 30 controls without tears.

Results

Out the 68 patients with rotator cuff tear, supraspinatus was the most commonly affected tendon, with 86% (59) cases showing abnormalities. The average age of the patients was 45.11 ± 21.45 years with male dominance (80%). Partial tears of rotator cuff were more common than complete tears. Forty-eight cases showed partial tears in supraspinatus as compared to 11 cases of complete tears. The acromial type did not show any correlation with any particular cuff lesion. The AT and AI of controls were significantly smaller than cuff-tear patients. The LAA of cuff-tear patients was significantly different from that of control patients. The impingement patients demonstrated a significantly greater acromial thickness, larger CSA, decreased AHD, and decreased LAA than their control counterparts.

Conclusions

A higher prevalence of rotator cuff tears and impingement associated with low lateral acromial angle, larger CSA and decreased AHD was observed. AT and AI have a direct correlation with rotator cuff tear.

Effect of different geometrical structure of scapula on functional recovery after shoulder arthroscopy operation

Background

There are no published studies of the influence of geometry of the scapula on the postoperative recovery of rotator cuff injuries. Our aim was to explore the relationship between the critical shoulder angle (CSA), acromion index (AI), glenoid inclination (GI), and postoperative repair outcomes in shoulder joints after arthroscopic supraspinatus tendon repair.

Methods

Sixty two patients suffering a supraspinatus tear were analyzed retrospectively following failure of conservative treatment and subsequent shoulder arthroscopy in our hospital. Standard anterior and posterior X-rays of the injured shoulder had been performed prior to surgery, with follow ups for at least 2 years (24–43 months). Magnetic resonance imaging (MRI) was performed 2 years after surgery to assess repair of the supraspinatus tendon. Patients were divided into either the intact or re-tear group, according to the MRI results. In addition, assessments using the Constant Shoulder Score (CSS), the American Shoulder and Elbow Surgeon (ASES) Shoulder Assessment Form, the University of California at Los Angeles (UCLA) score and visual analog scale (VAS) score were performed to establish shoulder function at the 2-year evaluation for each patient.

Results

The mean CSA of all patients was 35.79° ± 3.59°, mean AI was 0.72 ± 0.05, and mean GI was 15.87° ± 3.62°. The CSA, AI, and GI in the intact group were statistically significantly different than the re-tear group (p < 0.05). There was no correlation between the magnitude of the CSA, AI, or GI and any shoulder function score (p > 0.05).

Conclusions

The geometry of the scapula had no significant effect on the recovery of postoperative function of patients with rotator cuff injury, but the value of the CSA, AI, and GI affected the risk of rotator cuff re-tear.

The Effect of Critical Shoulder Angle on Clinical Scores and Retear Risk After Rotator Cuff Tendon Repair at Short-term Follow Up

The authors aimed to investigate whether standard acromioplasty can reduce critical shoulder angle (CSA) effectively and to investigate the effects of postoperative CSA on the clinical outcomes and retear rates. Patients are divided in to three groups: group 1 (24 patients): CSA under 35° before surgery, group 2 (25 patients): CSA over 35° before surgery and under 35° after surgery and group 3 (17 patients): CSA over 35° before and after surgery. Standard acromioplasty was performed if CSA is over 35 and no acromioplasty was performed if the CSA is already under 35. Preoperative and postoperative CSAs, UCLA, Constant-Murley clinical score and visual analog scale (VAS) pain score were measured. The size of the rotator cuff tear was classified by the Patte classification in preoperative MRI and the quality of the repair was evaluated as retear if discontinuity detected in the postoperative first year MRI. There were 31 female and 35 male patients with a mean age of 59.3 ± 4.5 years (range, 48–68) at the time of surgery. The mean CSA is reduced from 37.8° ± 1.4 to 34.9° ± 1.2 (p < 0.001) significantly for patients who underwent acromioplasty. In 25 (59.5%) of the 42 patients, the CSA was reduced to under 35°, whereas in the other 17 (40.5%) patients, it remained over 35°. The mean Constant and UCLA score was 46.4 ± 6.6; 18.5 ± 1.6 preoperatively and 82.4 ± 6.2; 31.1 ± 1.9 postoperatively respectively (p < 0,001). The mean VAS decreased from 4.94 ± 1.09 to 0.79 ± 0.71 (p < 0.001). No Clinical difference was seen between patients in which CSA could be reduced under 35° or not in terms of Constant-Murley score, UCLA and VAS score. Retear was observed in 2 (8.3%) patients in group 1, in 4 (16%) patients in group 2 and in 3 patients (17.6%) in group 3. There was not any significant difference between the patients who had retear or not in terms of neither the CSA values nor the change of CSA after the surgery. Standard acromioplasty, which consists of an anterolateral acromial resection, can reduce CSA by approximately 3°. This is not always sufficient to decrease the CSAs to the favorable range of 30°–35°. In addition, its effect on clinical outcomes does not seem to be noteworthy.