Critical shoulder angle in an East Asian population: correlation to the incidence of rotator cuff tear and glenohumeral osteoarthritis

Association between acromion morphological parameters and rotator cuff tears in Somali population-a three-dimensional computed tomographic study

BACKGROUND

Previous research has established connections between the acromion index (AI), critical shoulder angle (CSA), acromiohumeral distance (AHD), and lateral acromion angle (LAA) with the incidence of rotator cuff tears (RCTs). Despite numerous international studies exploring the variability of shoulder joint morphology and parameters, research incorporating these parameters has yet to be conducted in Somalia. This study aims to analyze and describe the radiological parameters of acromion morphology in the Somali populations. Furthermore, to investigate the relationship of these parameters with rotator cuff tears within the Somali population.

METHODS

The data and physical examination of 188 patients who had a CT scan of the shoulder from 2018 to 2023 were retrospective analyses, including 107 patients (49 females, 58 males) with RCT and 81 patients (20 females, 61 males) with non-RCT. Using Three-dimensional computed tomography (3D-CT), parameters such as the AI, CSA, AHD, and LAA were compared between the RCT and non-RCT groups. Two independent assessors measured Each parameter from anterior views of the scapula. The inter- and intra-observer reliability was evaluated using the intraclass correlation coefficient (ICC). Additionally, the relationship between these parameters and the presence of rotator cuff tears was explored, and the predictive value of each parameter was assessed through receiver operating characteristic (ROC) analysis.

RESULTS

The results showed excellent intra- and inter-observer reliability, with all ICC values above 0.75. Among these, the CSA exhibited the greatest measurement stability, with an intra-observer ICC of 0.929 and an inter-observer ICC of 0.911. Significant positive correlations were identified between the AI, CSA, and the presence of RCTs, with CSA exhibiting the strongest correlation (r = 0.629; P < 0.001). Additionally, significant negative correlations were found between the presence of RCTs and both AHD (-0.247) and LAA (-0.338; P < 0.001 for both). The ROC analysis revealed that the CSA is the most effective parameter for identifying the presence of RCT (area under the ROC curve. 0.857).

CONCLUSION

The outcome of this study shows that AI, CSA, AHD, and LAA are independent factors associated with rotator cuff tears in the East African, particularly the Somali population. Specifically, larger AI, CSA, and smaller AHD and LAA are correlated with an increased likelihood of RCTs in this population. In patients with shoulder disease suspected of RCTs, using a 3D-CT scan to measure the CSA may be helpful, as it is the best predictor measurement.

CLINICAL TRIAL NUMBER

Not Applicable.

The Critical Shoulder Angle as a Highly Specific Predictor of a Full-Thickness Rotator Cuff Tear: A Case-Control Study

BACKGROUND

The critical shoulder angle (CSA) has become an important topic of study in patients with rotator cuff tears (RCTs). However, there are conflicting data on whether the CSA can differentiate between patients with normal shoulder pathology and full-thickness RCTs on shoulder radiographs.

PURPOSE/HYPOTHESIS

The purpose of this study was to define the relationship between full-thickness RCTs and the CSA. It was hypothesized that patients with full-thickness RCTs would have an increased CSA compared with matched controls.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

This retrospective case-control study identified patients with magnetic resonance imaging scans showing full-thickness RCTs between 2009 and 2019. A 1 to 1 propensity score match was performed to identify a control group with normal rotator cuffs while controlling for baseline participant characteristics-including age, sex, body mass index, and tobacco use. A total cohort of 532 was identified, with 266 cases and 266 controls. Two independent observers measured CSAs on true anteroposterior shoulder radiographs.

RESULTS

There was no difference in baseline participant characteristics between the RCT and the non-RCT groups (P > .05). The mean CSA for the entire cohort was 33.6°± 4.2°. The CSA did not significantly vary by sex (P = .088) or tobacco usage (P = .16). The mean CSA for the RCT case group, 36.2°± 3.3°, was significantly different from the mean CSA for the control group, 30.9°± 3.3° (P < .0001). The receiver operating characteristic curve analysis produced an area under the curve of 0.88 (P < .0001). At CSAs ≥35°, there was a 67.7% sensitivity and 89.4% specificity for having a full-thickness RCT. Last, each degree of increase in the CSA increased the risk of having an associated RCT by 1.7 times (OR, 1.7 [95% CI, 1.551-1.852]; P < .0001).

CONCLUSION

Patients with RCTs had significantly higher CSAs compared with matched controls. Increased CSA was an independent risk factor for RCTs, with an odds ratio of 1.7 per degree. The CSA is an accurate test (area under the curve, 0.88) with good sensitivity (67.7%) and specificity (89.4%) at values ≥35°. The CSA is a simple, reproducible measurement that can assist in clinical decision-making regarding full-thickness RCTs.

Elevated Body Mass Index Is Associated With Rotator Cuff Disease: A Systematic Review and Meta-analysis

Purpose

To analyze the literature regarding obesity, body mass index (BMI), and rotator cuff disease (RCD).

Methods

In this Systematic Review and Meta-analysis, we queried PubMed, Embase, Cochrane, Cumulative Index to Nursing & Allied Health, and Science Direct using key words (August 25, 2023). Analytic observational studies (cohort, case-control, and cross-sectional studies) with more than 30 participants per comparison group, evaluating the association between obesity and rotator cuff pathology, were eligible for inclusion. Meta-analysis was performed to quantitatively summarize associations between BMI and RCD to report odds ratios and corresponding 95% confidence intervals (CIs) for regression-based models and BMI mean differences between cases and controls. Risk Of Bias In Non-randomised Studies - of Interventions tool was used to evaluate risk of bias across all studies in the systematic review.

Results

After full-text review of 248 articles, 27 presented data on obesity and RCD, and 17 qualified for meta-analysis. Individuals with RCD were 1.21 times (95% CI 1.10-1.34) as likely to have overweight and 1.44 times (95% CI 1.32-1.59) as likely to have obesity compared with those without RCD. Each 5-unit increase in BMI was associated with 35% greater odds of having rotator cuff tear (95% CI 1.06-1.71). In-depth assessment for risk of bias shows quality of studies varies greatly and highlights outcome heterogeneity, lack of temporality, confounding and selection bias as major concerns for individual studies.

Conclusions

In this study, we found a positive association between elevated BMI and RCD.

Level of Evidence

Level III, systematic review and meta-analysis of Level II-III studies.

Anthropometric study of the scapula in a contemporary population from granada. Sex estimation and glenohumeral osteoarthritis prevalence

Anthropometric studies of the scapula have been rare in Spanish populations, nevertheless they are of current interest in forensic anthropology for estimation of sex. Although the estimation of sex is usually carried out on the pelvis and skull, other measurements related to the scapula can be helpful when the skeletal remains are incomplete. Glenohumeral osteoarthritis development is influenced, among others, by the morphology of the scapula, which is one of the less studied aspects. We carried out a descriptive study of anthropometric parameters in a series of 157 scapulae (82 individuals) on bone remains dated to the 20th century from a population of Granada (Southern Spain). Seventy seven (49%) were right-side and 80 (51%) left-side; 72 (45.9%) were from males and 85 (54.1%) from females, and the mean age at death was 70.76±11.7 years. The objective was to develop a discrimination function for sex estimation based on anthropometric parameters of the scapula other than those considered to date, and to analyze the prevalence of glenohumeral osteoarthritis in relation to selected anthropometric parameters. A logistic regression model based on parameters of the upper-external segment of the scapula was done. The obtained formula: 1/1+e^ (- (-57.911 + 0.350*B + 0283*C + 0.249*b + 0.166*a +-0.100*β) classifies male sex with 98.3% accuracy and female sex with 92.1%. Glenohumeral osteoarthritis was detected in 16.6% of individuals and was related to age (p<0.05), scapular length (p<0.05), glenoid width (p<0.05), glenopolar angle (p<0.05), and α angle (p<0.05) in bivariate analyses but showed no significant associations in multivariate analyses. This approach can be useful for anthropological-forensic identification when scapula remains are incomplete. Glenohumeral osteoarthritis is significantly associated with a smaller α angle.

The Critical Shoulder Angle: A Significant Radiological Measure in Rotator Cuff vs. Glenohumeral Osteoarthritis in Chilean Patients-A Descriptive Cross-Sectional Study

Background: Shoulder pain is one of the most important musculoskeletal conditions affecting the upper extremities. Glenohumeral osteoarthritis (GHOA) and rotator cuff injuries (RCIs) are notable for their high prevalence. The critical shoulder angle (CSA) is a significant radiological measure for determining the diagnosis and progression of patients with these conditions. Although there are reports in the international literature about this measure, in our country, guideline values considering these two pathologies are unknown. Objective: Our objective was to assess patients diagnosed with GHOA and RCI using an AP X-ray view and the CSA. Methods: To conduct this, we identified differences between sexes and age categories. Fifty-nine adult patients with GHOA and RCI were included. CSA grades varied depending on the age category and type of injury evaluated. Results: Significant differences between the age ranges of 40 and 54 (p = 0.05), 55-69 (p = 0.001), and 70-84 (p = 0.017) were observed. Conclusions: Patients with RCI tended to be younger and have a higher CSA compared to those with GHOA. It is important to have more normative values and to continue monitoring the critical shoulder angle in these patients.

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.

Critical Shoulder Angle in Patients With Cuff Tears

OBJECTIVE

The pathogenesis of rotator cuff tears (RCTs) is multifactorial. Critical shoulder angle (CSA), which represents the lateral extension of the acromion over the cuff, has been proposed as an extrinsic risk factor. The aim of the present systematic review and meta-analysis was to analyze the available literature regarding the correlation between RCT and CSA.

METHODS

A review was carried out in accordance with the "Preferred Reporting Items for Systematic reviews and Meta-Analyses" guidelines on July 17, 2023, using the following databases: PubMed, Ovid, and Cochrane Reviews. The following keywords were used: "critical shoulder angle," "rotator cuff tears," and "rotator cuff lesions." The methodological quality of the studies was assessed with the MINORS SCORE.

RESULTS

Twenty-eight studies were included. The average CSA among the 2110 patients with full-thickness RCT was 36.7 degrees, whereas the same value among the 2972 controls was 33.1 degrees. The average CSA in the 348 patients with partial-thickness RCT was 34.6 degrees, whereas it was 38.1 degrees in the 132 patients with massive RCT. The average MINORS score was 15.6.

CONCLUSIONS

CSA values were significantly higher in patients with RCT compared with the asymptomatic population. In addition, it appears that CSA values increase with the severity of rotator cuff involvement.

Does Morphology of the Shoulder Joint Play a Role in the Etiology of Rotator Cuff Tear?

BACKGROUND

The etiology of rotator cuff tears (RCTs) have been investigated for years and many underlying causes have been identified. Shoulder joint morphology is one of the extrinsic causes of RCTs.

AIM

Morphometric measurements on MRI sections determined which parameters are an important indicator of RCT in patients with shoulder pain. The aim of this study was to determine the risk factors in the etiology of RCTs by evaluating the shoulder joint morphology with the help of previously defined radiological parameters.

METHOD

Between January 2019-December 2020, 408 patients (40-70 years old) who underwent shoulder MRI and met the criteria were included in the study. There were 202 patients in the RCT group and 206 patients in the control group. Acromion type, acromial index (AI), critical shoulder angle (CSA), acromiohumeral distance (AHD), lateral acromial angle (LAA), acromial angulation (AA), acromion-greater tuberosity impingement index (ATI), and glenoid version angle (GVA) were measured from the MRI images of the patients.

RESULTS

AI (0.64 vs. 0.60, p = 0.003) CSA (35.3° vs. 32.4°, p = 0.004), ATI (0.91 vs. 0.83, P < 0.001), and AA (13.6° vs. 11.9°, p = 0.011) values were higher in the RCT group than in the control group and the difference was significant. AHD (8.1 mm vs. 9.9 mm, P < 0.001), LAA (77.2° vs. 80.9°, p = 0.004) and GVA (-3.9° vs. -2.5°, P < 0.001) values were lower in the RCT group than in the control group, and again the difference was significant. According to the receiver operating characteristic curve analysis, the cutoff values were 0.623 for AI and 0.860 for ATI.

CONCLUSION

Acromion type, AI, CSA, AHD, LAA, AA, ATI, and GVA are suitable radiological parameters to evaluate shoulder joint morphology. High AI, CSA, AA, ATI, GVA and low AHD and LAA are risk factors for RCT.

The role of bone morphology of the greater tuberosity and lateral acromion on subacromial space during scaption: a three-dimensional dynamic simulation analysis

BACKGROUND

The bone morphology of the greater tuberosity and lateral acromion plays a central role in subacromial impingement syndrome. The critical shoulder angle (CSA) and greater tuberosity angle (GTA) are two-dimensional measurement parameters that have been validated to evaluate it radiologically. These markers are, however, static and don't consider the dynamic effect of glenohumeral motion.

OBJECTIVES

This study aimed to better understand the biomechanics in subacromial impingement with a dynamic simulation based on a validated 3D biomechanical model coupling joint kinematics and 3D reconstructed computed tomography.

STUDY DESIGN & METHODS

Sixty-one patients were included in this study: a case group of 44 patients with degenerative rotator cuff tears involving only the supraspinatus, and a control group of 17 without a rotator cuff tear. Patients with previous surgeries, traumatic cuff tears, and cuff tear arthropathy were excluded. CSA, GTA, and impingement-free range of motion (IF-ROM) of the glenohumeral joint in scaption were calculated. Correlation tests were used to determine the relationship between ROM and CSA, GTA, and combined CSA and GTA values.

RESULTS

CSA and GTA were significantly higher in the rotator cuff tear group (p = 0.001 and < 0.001), while IF-ROM was significantly higher in the control group (p = 0.001). There was no overall correlation between CSA and GTA (R = 0.02, p = 0.8). Individual correlation between both angles with IF-ROM was negatively weak for CSA (R = -0.4, p < 0.001) and negatively moderate for GTA and IF-ROM (R = -0.5, p < 0.001). However, combining both angles resulted in a negatively high correlation with IF-ROM (R = -0.7, p < 0.001).

CONCLUSION

Subacromial space narrowing during scaption is highly correlated to the cumulative values of GTA and CSA. These findings suggest that the combined bony morphology of the lateral acromion and greater tuberosity plays an important role in subacromial impingement.

LEVEL OF EVIDENCE

III.

Discovering the Forgotten Trauma Behind Chronic Shoulder Pain: The Critical Role of a Thorough Medical Interview

We report a rare case of a patient experiencing pain and dysfunction attributable to bone fragments from a trauma sustained over two decades prior. A 43-year-old Japanese woman presented with persistent left shoulder pain. Initial radiographs revealed glenohumeral joint osteoarthritis, an unusual finding for her age. Her medical history included a previously overlooked traumatic dislocation of the left acromioclavicular joint over 20 years ago. Computed tomography scans later uncovered bone fragments below the coracoid process without signs of scapular or tuberosity fractures. The fragments were arthroscopically removed, resulting in significant pain relief. The patient's Shoulder Pain and Disability Index score improved from 60 to 9 at the six-month postoperative follow-up. This case underscores the importance of considering historical trauma in patients presenting with atypical shoulder pain and highlights the potential diagnostic value of revisiting a patient's medical history when unusual lesions are discovered.

The Critical Shoulder Angle Can be Accurately and Reliably Determined from Three-Dimensional Computed Tomography Images

OBJECTIVE

Anteroposterior (AP) radiographs do not necessarily offer the optimal approach to measuring the critical shoulder angle (CSA) due to the malposition of the scapula. Three-dimensional computed tomography (3D-CT) may offer some advantages, including the ability to rotate the scapula for position alignment and pre-operative planning for reducing CSA. This study aimed to investigate the accuracy and reliability of CSA measurement in 3D-CT and to determine whether there is an association between CSA and rotator cuff tears (RCTs).

METHODS

In this retrospective study we identified 200 patients who received shoulder arthroscopy from 2019 to 2021, including 142 patients (81 females, 61 males) with RCTs and 58 patients (14 females, 44 males) with non-RCTs. For each participant, CSA was measured from standard shoulder AP radiographs and anterior views of 3D-CT of the scapula by two independent assessors. Inter- and intra-observer agreements were assessed by the intraclass correlation coefficient (ICC). The relationship between the two measurement methodologies was determined by Spearman's correlation coefficient and Bland-Altman plots. Discriminative capacity was calculated by using receiver operating curve (ROC) analyses in the whole cohort and age sub-groups above and below 45 years.

RESULTS

We found perfect inter-observer (ICC >0.96) and intra-observer (ICC >0.97) reliabilities for CSA measurements obtained from the standard AP radiographs and the 3D-CT. There was a strong correlation between the two methods (r = 0.960, P < 0.001). The mean CSA was 31.7° ± 4.2° in the standard AP radiographs and 31.8° ± 4.4° in the 3D-CT (mean difference 0.02°, P = 0.940; bias 0.02°, limits of agreement -2.29° to +2.33°). ROC analysis of the whole cohort showed that the CSA measured in the standard AP radiographs (area under the ROC curve [AUC] = 0.812, P < 0.001) and the 3D-CT (AUC = 0.815, P < 0.001) predicted RCT with high confidence. ROC analysis of patients aged ≥45 years showed that the CSA measured from the standard AP radiographs (AUC = 0.869, P < 0.001) and the 3D-CT (AUC = 0.870, P < 0.001) were very good at predicting RCTs.

CONCLUSION

CSA measured from standard AP radiographs and 3D-CT showed high consistency, and the CSA could be accurately and reliably measured using 3D-CT. CSAs measured from standard AP radiographs and 3D-CT could predict RCTs, especially in patients aged ≥45 years.

Reliability and accuracy of the critical shoulder angle measured by anteroposterior radiographs: using digitally reconstructed radiograph from 3-dimensional computed tomography images

BACKGROUND

Accuracy of current standard radiographic measurement of the critical shoulder angle (CSA) is not well established. This study analyzed the reliability and accuracy of the CSA measurements obtained via anteroposterior (AP) radiographs, using a digitally reconstructed radiograph (true AP view) generated from a computed tomography image as the gold standard.

METHODS

The CSA was measured on the radiographs and true AP views of 88 consecutive patients who had undergone shoulder arthroscopy for rotator cuff tears. Intraobserver and interobserver reliabilities of the CSA, measured by 2 orthopedic surgeons, were evaluated, and the average deviation of the CSA between radiographs and true AP views was calculated. Moreover, we compared the deviation of CSA between standard AP films (types A1 and C1) and nonstandard AP films (other types) against the Suter-Henninger criteria.

RESULTS

Intraobserver and interobserver reliabilities were almost perfect on radiographs (0.96, 0.86) and true AP views (0.93, 0.85). The average deviation of CSA was 2.1° ± 1.6° for observer 1 and 2.2° ± 1.9° for observer 2. The percentage of cases with deviations of 2° or more when compared with the true AP view was 42% (37 of 88) for observer 1 and 53% (47 of 88) for observer 2. Only 22% (19 of 88) of films were standard AP films. The average deviation of CSA was not significantly different between standard and nonstandard AP films for observer 1 (standard 1.9° ± 1.3°; nonstandard 2.1° ± 1.7°; P = .76) and observer 2 (standard 1.6° ± 1.5°; nonstandard 2.4° ± 1.9°; P = .09).

CONCLUSION

The CSA measurements using radiography were highly congruent, but a large measurement deviation occurred between radiographs and true AP views. The clinical usefulness and role of CSA in diagnosis require careful consideration.

Anatomy features of the shoulder joint in asymptomatic chinese Han adults

BACKGROUND

To evaluate the shoulder anatomical characteristics in asymptomatic Chinese adults.

METHODS

The prospective study enrolled individuals without shoulder pain at Beijing Tiantan Hospital Affiliated to Capital Medical University between January 2019 and January 2020. Six radiographic parameters were measured and analyzed, including glenoid plane to the acromion (GA), glenoid plane to the lateral aspect of the humeral head (GH), acromion index (AI), lateral acromial angle (LAA), acromion-humeral interval (AHI), and critical shoulder angle (CSA).

RESULTS

103 participants (51 males and 52 females) were enrolled. The mean values of GA, GH, AI, CSA, LAA, and AHI were 32.88 ± 5.68 mm, 47.16 ± 4.82 mm, 0.70 ± 0.11, 37.45 ± 6.00°, 6.32 ± 3.99°, and 9.611.86 mm, respectively. Females had lower GA (30.78 ± 5.06 vs. 35.01 ± 5.51 mm, P < 0.001) and GH (44.28 ± 3.67 vs. 50.11 ± 4.02 mm, P < 0.001) than males and LAA was significantly smaller in the Bigliani flat type compared with the curved type and the hooked type (5.07 ± 2.31° vs 12.33 ± 5.46°vs 10.00 ± 3.37, P = 0.001).

CONCLUSIONS

Females had lower GA and GH than males in asymptomatic Chinese Han adults. Asymptomatic Chinese Han subjects with Bigliani flat type had lower LAA. CSA appears lager in Chinese Han individuals. Curve type of acromion performed lager LAA. The results may help establish an anatomical model of the shoulder joint and elucidate the anatomy features of the shoulder joint in asymptomatic Chinese Han adults.

A predictive model for the critical shoulder angle based on a three-dimensional analysis of scapular angular and linear morphometrics

BACKGROUND

The purpose of this study was to define the features of scapular morphology that are associated with changes in the critical shoulder angle (CSA) by developing the best predictive model for the CSA based on multiple potential explanatory variables, using a completely 3D assessment.

METHODS

3D meshes were created from CT DICOMs using InVesalius (Vers 3.1.1, RTI [Renato Archer Information Technology Centre], Brazil) and Meshmixer (3.4.35, Autodesk Inc., San Rafael, CA). The analysis included 17 potential angular, weighted linear and area measurements. The correlation of the explanatory variables with the CSA was investigated with the Pearson's correlation coefficient. Using multivariable linear regression, the approach for predictive model-building was leave-one-out cross-validation and best subset selection.

RESULTS

Fifty-three meshes were analysed. Glenoid inclination (GI) and coronal plane angulation of the acromion (CPAA) [Pearson's r: 0.535; -0.502] correlated best with CSA. The best model (adjusted R-squared value 0.67) for CSA prediction contained 10 explanatory variables including glenoid, scapular spine and acromial factors. CPAA and GI were the most important based on their distribution, estimate of coefficients and loss in predictive power if removed.

CONCLUSIONS

The relationship between scapular morphology and CSA is more complex than the concept of it being dictated solely by GI and acromial horizontal offset and includes glenoid, scapular spine and acromial factors of which CPAA and GI are most important. A further investigation in a closely defined cohort with rotator cuff tears is required before drawing any clinical conclusions about the role of surgical modification of scapular morphology.

LEVEL OF EVIDENCE

Level 4 retrospective observational cohort study with no comparison group.

Controversy on the Association of the Critical Shoulder Angle and the Development of Degenerative Rotator Cuff Tears: Is There a True Association? A Meta-analytical Approach

BACKGROUND

The role of the critical shoulder angle (CSA) as a risk factor for rotator cuff tear (RCT) remains controversial. Studies on the association between the CSA and RCT show considerable differences in design, and this could be responsible for the variation in study results.

PURPOSE

To (1) describe the reliability of CSA measurement and (2) evaluate the results of the studies reporting the association between the CSA and RCT using meta-analytical techniques to explore potential sources of variation of study results.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

MEDLINE, EMBASE, and CINAHL electronic databases were searched through June 30, 2019. Case-control and cross-sectional studies reporting the association of the CSA and RCT were selected. The weighted mean difference in the CSA was estimated using a random-effects model. Prediction interval was computed to better express uncertainties in the effect estimate. Metaregression and subgroup analyses were performed to explore potential sources of heterogeneity.

RESULTS

A total of 14 studies, including 1154 cases and 1271 controls, were identified. Of these studies, 79% (11/14) assessed the reliability of the CSA measurement, demonstrating an excellent intraobserver (range, 0.91-0.99) and interobserver (range, 0.87-0.99) reliability. Compared with controls, cases with RCT showed larger measurements of the CSA (3.3° [95% CI, 2.3°- 4.4°]). However, there was a high heterogeneity (I² = 93%), and the 95% prediction interval (-0.4° to 7.1°) included no difference in the CSA. Results of the metaregression analysis showed a significant association of several methodological aspects with the heterogeneity. The difference in the CSA tended to be larger when only full-thickness tears were included, when no specific defined criterion for assessing radiographic viewing perspective was used, in studies with smaller sample sizes, and in studies at higher risk of bias.

CONCLUSION

While the CSA can be reliably measured, the difference in the CSA between cases and controls varied from very large to modest or almost no difference. Several determinants of heterogeneity were determined. Owing to this heterogeneity, it is difficult to gain an insight into the strength and exact nature of the association between the CSA and RCT with the current evidence.

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.

Implication of bone morphology in degenerative rotator cuff lesions: A prospective comparative study between greater tuberosity angle and critical shoulder angle

BACKGROUND

Degenerative rotator cuff tear is a frequent and multifactorial pathology. The role of bone morphology of the greater tuberosity and lateral acromion has been validated, and can be measured with two plain radiographic markers on true anteroposterior views: the greater tuberosity angle (GTA) and the critical shoulder angle (CSA). However, the interdependence of both markers remains unknown, as well as their relationship with the level of professional and sports activities involving the shoulder. The aim of this prospective comparative study was to describe the correlation between the GTA and CSA in patients with degenerative rotator cuff tears.

HYPOTHESIS

GTA and CSA are independent factors from one another and from demographic factors, such as age, dominance, sports, or professional activities.

PATIENT AND METHODS

All patients presenting to a shoulder specialized clinic were assigned to two groups. The first consisted of patients with a symptomatic degenerative rotator cuff tear visible on MRI and the control group consisted of patients with any other shoulder complaints and no history or visible imaging of any rotator cuff lesion.

RESULTS

There were 51 shoulders in 49 patients in the rotator cuff tear group (RCT) and 53 shoulders in 50 patients in the control group. Patient demographics were similar in both groups. Mean GTA was 72.1°±3.7 (71.0-73.1) in the RCT group and 64.0°±3.3 (63.1-64.9) in the control group (p<0.001). Mean CSA was 36.7°±3.7 (35.7-37.8) in the RCT group, and 32.1°±3.7 (31.1-33.1) in the control group (p<0.001). A summation of GTA and CSA values over 103° increased the odds of having a rotator cuff tear by 97-fold (p<0.001). There was no correlation between GTA and CSA, nor between GTA or CSA and age, sex, tear size, or dominance. Patients with different levels of professional and sports activities did not have significantly different GTA or CSA values.

CONCLUSION

GTA and CSA are independent radiologic markers that can reliably predict the presence of a degenerative rotator cuff tear. A sum of both values over 103° increases the odds of having a rotator cuff tear by 97-fold. These markers are not correlated with patient demographic or environmental factors, suggesting that the variability of the native acromion and greater tuberosity morphology may be individual risk factors for rotator cuff tear.

LEVEL OF EVIDENCE

II; diagnostic study.

Does isolated arthroscopic anterior acromioplasty modify critical shoulder angle?

INTRODUCTION

Critical shoulder angle (CSA)>35° correlates significantly with primary rotator cuff tear and re-tear after repair. Acromial axial orientation varies between individuals. The present study aimed to assess the impact of strictly anterior acromioplasty on CSA.

HYPOTHESIS

CSA is reduced by arthroscopic anterior acromioplasty.

MATERIAL AND METHODS

A single-center retrospective study included patients receiving isolated arthroscopic acromioplasty between January 2016 and December 2017. Exclusion criteria comprised history of surgery and fracture or dislocation of the shoulder. Pre- and post-operative AP shoulder radiographs were taken. The angle subtended by a line between the inferior and superior edges of the glenoid and a line between the inferior edge of the glenoid and the most lateral point on the acromion was measured.

RESULTS

One hundred and two patients were included: mean age, 50.5±10.1 years (range, 23-82 years). Mean CSA was 34.7±4.4° (range, 26-48°) preoperatively and 31.7±3.7° (range, 23-40°) postoperatively (p<0.001). In the group with CSA >35°, the decrease was significant: 34.4±3.2° (range, 28-40°) versus 38.9±2.8° (range, 36-48°) (p<0.001), with 64% CSA <35° after isolated anterior acromioplasty.

DISCUSSION

CSA was decreased by arthroscopic acromioplasty. However, in 36% of cases with preoperative CSA >35°, CSA was not normalized.

CONCLUSION

Anterior arthroscopic acromioplasty significantly reduced CSA in the overall population, and especially in case of high CSA.

LEVEL OF EVIDENCE

IV; retrospective study.

The Relationship of Aging and Smoking With Rotator Cuff Disease: A Systematic Review and Meta-analysis

OBJECTIVE

Despite rotator cuff disease being one of the most common causes of shoulder pain, its pathogenesis and biology are poorly understood. In this study, we synthesized evidence from studies reporting associations for aging and smoking status in relation to rotator cuff disease.

DESIGN

A systematic review was performed using multiple databases (PubMed, Embase, Cochrane, CINAHL, and Science Direct). Articles that met our eligibility criteria and presented data on the association between aging and/or smoking status and rotator cuff disease were included. We performed meta-analyses and reported cumulative effects using odds ratios and corresponding 95% confidence intervals.

RESULTS

Of the 212 articles eligible for full-text review, seven studies reported on the relationship between aging and rotator cuff disease, and 10 studies reported on the relationship between smoking and rotator cuff disease. Aging was consistently associated with increased odds of having rotator cuff disease when assessed continuously (per 10-yr increase: odds ratio = 1.20, 95% confidence interval = 1.18-1.21) or categorically (ages <40 yrs vs: [a] 40-44 yrs [odds ratio = 2.71, 95% confidence interval = 1.78-4.13], [b] 45-49 yrs [odds ratio = 4.33, 95% confidence interval = 2.88-6.55], and [c] ≥50 yrs [odds ratio = 6.97, 95% confidence interval = 4.85-10.01]). Assessing studies that reported smoking status as current smokers versus nonsmokers, current smokers were more likely to have rotator cuff disease (odds ratio = 1.94, 95% confidence interval = 1.52-2.48). However, a statistically significant association was not found when never smokers were compared with former smokers (odds ratio = 1.08, 95% confidence interval = 0.97-1.20) and to current smokers (odds ratio = 0.97, 95% confidence interval = 0.87-1.07).

CONCLUSIONS

In this systematic review and meta-analysis, increasing age was a strong risk factor for rotator cuff disease. The finding that current smokers are more likely to have rotator cuff disease as compared with nonsmokers implies that cessation of smoking can potentially lead to mitigation of this risk factor.

Are critical shoulder angle and acromion index correlated to the size of a rotator cuff tear

PURPOSE

Scapular morphology is an extrinsic factor playing role in rotator cuff tear (RCT) etiology. The objective of this study was to evaluate the relationship between critical shoulder angle (CSA) and acromion index (AI) with partial-bursal side and full thickness RCT and the size of the RCT.

HYPOTHESIS

The hypothesis was that CSA and AI would be greater in partial bursal-side RCT and full-thickness RCT patients and would increase with the size of the RCT.

METHODS

This retrospective study assessed 218 patients who had standard shoulder radiographs and magnetic resonance imaging. Patients were divided into three groups: intact rotator cuff (68), partial bursal-side RCT (34) and full-thickness RCT (116). In the second part, full-thickness RCT patients were divided into four groups according to RCT size; small (<1cm), medium (1-3cm), large (3-5cm) and massive (>5cm). AI and CSA measurements were evaluated from radiographs.

RESULTS

The mean CSA was 32.8̊ in control group, 34.3̊ in partial group and 36.9̊ in full-thickness group. The mean AI was 0.66, 0.68 and 0.72 respectively. Significant difference was found in AI and CSA between full thickness RCT and intact RC group (p<0.01), and partial RCT and full thickness RCT group (p<0.05) in paired comparisons. In full thickness RCT size groups the mean CSA was 34.2̊, 36.4̊, 39.0̊ and 40.8̊ and mean AI was 0.70, 0.71, 0.73 and 0.79 respectively. Significant difference was found between small-large, small-massive, medium-massive groups for CSA in paired comparisons and between small-massive, medium-massive groups for AI.

CONCLUSION

CSA and AI were significantly greater in full-thickness RCT patients and the size of the RCT increased with CSA and AI. The greater CSA and AI could be predictors for larger RCT.

LEVEL OF EVIDENCE

III; Cross-Sectional Design; Prognosis Study.

High Critical Shoulder Angle Values Are Associated With Full-Thickness Posterosuperior Cuff Tears and Low Values With Primary Glenohumeral Osteoarthritis

PURPOSE

To compare critical shoulder angle (CSA) measurements using high-quality radiographs in the following groups: Group 1: symptomatic atraumatic full-thickness rotator cuff (RC) tears; Group 2: symptomatic primary glenohumeral osteoarthritis (GHOA); and Group 3: no RC tear or primary GHOA being treated for glenohumeral instability or symptomatic labral pathology (control group).

METHODS

A prospective observational case control study with 10 shoulders in each group was performed GHOA and full-thickness RC tears were diagnosed by radiographs and magnetic resonance imaging (MRI). For these three groups, the exclusion criteria were the following: Group 1) partial thickness RC tears, traumatic RC tears, isolated subscapularis tears, and advanced cuff tear arthropathy with erosion of the superior glenoid; Group 2) secondary causes of glenohumeral arthritis; coexistent full-thickness RC tear; and Group 3) glenoid bone lesions that may affect the CSA measurement. Only shoulders with adequate radiographic quality (Suter-Henninger type A and C) were eligible. A one-way ANOVA, followed by Tukey multiple pairwise-comparisons test, was performed to compare the groups. Interobserver and intraobserver reliability was assessed using Intraclass Correlation Coefficients (ICC).

RESULTS

Mean CSA values were 37.4° ± 4.7 (RC tear group), 28.9° ± 2.4 (GHOA group), and 32.8° ± 1.1 (control group). The CSA of the RC group was higher than the control group (P = .006) and the GHOA group (P = .000). The CSA of the GHOA group was lower than the control group (P = .027). Intraobserver and interobserver reliabilities for the CSA measurement were excellent (Observer 1 [ICC]: .986 [95% CI .970-.993]; Observer 2 [ICC]: .976[95% CI .951-.989]; and Observer 1v2: 0.968[95% CI .933-.985]).

CONCLUSIONS

There is a difference in the CSA between patients with symptomatic atraumatic full-thickness RC tears (4.6° higher than the control group), symptomatic GHOA (3.8° lower than the control group), and glenohumeral instability or labral pathology with no RC tear or GHOA.

LEVEL OF EVIDENCE

Level 2, prospective observational case control diagnostic study.

Editorial Commentary: Current Indications for Lateral Acromioplasty Include Patients With Elevated Critical Shoulder Angle Plus Subacromial Impingement With Rotator Cuff Pathology or Previous Rotator Cuff Repair

The critical shoulder angle (CSA) reflects the lateral extent of the acromion and the inclination of the glenoid. In 2013, CSA was first introduced and its association with rotator cuff (RC) tears and glenohumeral osteoarthritis (GHOA) was shown. It was speculated that with a high CSA, there was an increased superior force vector from the deltoid and that this superior force led to RC tears. Conversely, when the CSA was low, there was a greater compressive force from the deltoid and that this compressive force led to GHOA. CSA serves as a further development of 2 previously reported measurements (glenoid inclination and acromial index). A key potential therapeutic aspect of the CSA is the ability to modify it surgically, which theoretically could protect RC repairs or prevent progression. In our current clinical practice, we perform lateral acromioplasty (LA) in patients undergoing treatment of subacromial impingement with an "at-risk" rotator cuff (partial rotator cuff tear and severe tendinopathy on magnetic resonance imaging) with a CSA > 38° or all patients with a CSA >35° after an RC repair to protect the RC repair construct. The relationships of high and low CSA, the anatomic safe zone, and thus clinical applicability of LA are well established and performed in our daily surgical practice. However, we do not yet have widespread clear clinical evidence on potential benefits regarding the clinical outcome after LA. Finally, at this time, the downsides seem minimal, so we continue to use LA as an adjunct in patients with RC tears and RC tendons that are at risk.

Critical shoulder angle (CSA): age and gender distribution in the general population

Objective

Anatomical parameters and pathologies that can affect the critical shoulder angle (CSA) are subjects of discussion. To date, we do not know if the CSA value changes in the different decades of life in a population characterized by the same ethnicity, nor if there are differences related to gender or side. This study hypothesizes that age and gender may affect the CSA.

Methods

Patients older than 15 years old affected by a shoulder trauma and who were discharged with a diagnosis of shoulder contusion were enrolled. A true AP view of the shoulder was obtained as well as data regarding age and gender of all participants. The CSA was measured by three authors, and interoperator reliability was assessed. Eight subcategories, according to decades of life, were considered. Finally, the studied population was divided into three subcategories according to CSA values (< 30°; 30–35°; ≥ 35°).

Results

The initial sample comprised 3587 shoulder X-rays. The interobserver reproducibility was high, with an intraclass correlation coefficient of 0.865 (95% CI 0.793–0.915).

Two thousand eight hundred seventy-three radiograms were excluded. The studied group comprised 714 patients [431 females, 283 males; mean age (SD): 47.2 (20.9) years, range: 11–93 years]. The mean CSA was 33.6° (range: 24–50°; SD: 3.9°). The mean CSA values in females and males were 33.7°and 33.5°, respectively. The mean CSA values of the right and left shoulders were 33.3° and 33.9°, respectively (p > 0.05). Linear regression analysis showed a CSA increase by 0.04° every year. The mean CSA in subjects aged between 15 and 19 years was significantly lower than all the other groups, except for patients older than 80 years.

No significant differences were found between CSA subcategories, gender, or side.

Conclusions

In the general population, the mean CSA value was 33.6°. No significant differences were found regarding the mean CSA value according to gender or side. A significant positive linear correlation between CSA and age was detected. In each decade of life, the CSA value, which is genetically determined, shows a large variability.

Level of evidence: IV.

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.

What Factors Are Associated with Symptomatic Rotator Cuff Tears: A Meta-analysis

BACKGROUND

Rotator cuff tears are common. A previous systematic review reported on factors associated with rotator cuff tears; however, it included relatively few studies and few variables, and in addition, it had considerable heterogeneity. To identify the factors associated with symptomatic rotator cuff tears and to help guide clinicians to potentially modifiable factors, we felt a broader and more inclusive meta-analysis would be useful.

QUESTIONS/PURPOSES

In this systematic review and meta-analysis, we asked what (1) demographic, (2) disease, and (3) imaging factors are associated with symptomatic rotator cuff tears?

METHODS

PubMed, Embase, and Web of Science were searched, and the search period were from the inception of each database through February 2021. The keywords included "risk factor," "rotator cuff injury," "rotator cuff tears," and "rotator cuff tendinitis." All comparative studies on symptomatic rotator cuff tears were included. We considered that the diagnosis of rotator cuff tear could be made by any imaging tool (MRI or ultrasound). We considered either partial- or full-thickness tears to be a rotator cuff tear. No language restrictions were applied. Twenty-six articles from 14 countries involving 9809 individuals, consisting of 3164 patients and 6645 controls, were included. The Newcastle-Ottawa Scale and the Agency for Healthcare Research and Quality (AHRQ) scale were used to evaluate the risk of bias of the included studies, and the highest scores were 9 and 11, respectively. The Newcastle-Ottawa Scale was used for retrospective comparative studies, and the AHRQ was used to evaluate prospective comparative studies. The eight retrospective comparative studies we included were scored from 4 to 9. The quality score of the 18 prospective comparative studies ranged from 6 to 9. Publication bias was explored using the Egger test. Heterogeneity was estimated using the I2 value. If there was no heterogeneity (I2 ≤ 50%), a fixed-effects model was used to determine the overall effect size; if there was heterogeneity (I2 > 50%), a random-effects model was used to merge the effect values. A meta-analysis was performed with RevMan 5.3, and the risk ratio (RR) and weighted mean difference of related factors were calculated.

RESULTS

Our meta-analysis identified the following demographic factors associated with an increased risk of rotator cuff tears: older age (mean difference 3.1 [95% CI 1.4 to 4.8]; p < 0.001), greater BMI (mean difference 0.77 [95% CI 0.37 to 1.17]; p < 0.001), smoking (RR 1.32 [95% CI 1.17 to 1.49]; p < 0.001), dominant arm (RR 1.15 [95% CI 1.06 to 1.24]; p < 0.001), greater height (mean difference 0.9 [95% CI 0.4 to 1.4]; p < 0.001), and heavier weight (mean difference 2.24 [95% CI 0.82 to 3.66]; p = 0.002). Regarding disease factors, we found that traumatic events (RR 1.91 [95% CI 1.40 to 2.54]; p < 0.001) and hypertension (RR 1.50 [95% CI 1.32 to 1.70]; p < 0.001) were associated with symptomatic rotator cuff tears. Regarding imaging factors, we found that the following three factors were associated with symptomatic rotator cuff tears: greater acromion index (mean difference 0.11 [95% CI 0.06 to 0.16]; p < 0.001), greater critical shoulder angle (mean difference 1.9 [95% CI 1.5 to 2.3]; p < 0.001), and smaller glenoid version angle (mean difference -1.3 [95% CI -1.9 to -0.8]; p < 0.001). We found no association between the patient's sex or the presence or absence of thyroid disease and the likelihood of a rotator cuff tear being present.

CONCLUSION

This study identified several factors associated with symptomatic rotator cuff tears, including blood glucose, blood pressure, weight, and smoking. Clinicians may seek to modify these factors, possibly in patients with symptomatic rotator cuff tears, but also in symptomatic patients who have not yet been diagnosed with rotator cuff tears because there would be no harm or risk associated with modifying any of the factors we identified. Future research should further study whether addressing these factors can delay the progression and size of rotator cuff tears.Level of Evidence Level III, prognostic study.

Clinical outcomes and temporal changes in the range of motion following superior capsular reconstruction for irreparable rotator cuff tears: comparison based on the Hamada classification, presence or absence of shoulder pseudoparalysis, and status of the subscapularis tendon

BACKGROUND

Superior capsular reconstruction (SCR) has recently gained popularity as a surgical solution for patients with massive rotator cuff tears or shoulder pseudoparalysis (PPS). Good clinical outcomes have been reported after SCR; however, the factors that influence its clinical outcomes remain unclear. Therefore, in this study, we aimed to clarify the factors influencing postoperative outcomes after SCR using tensor fascia lata graft, for which we evaluated the Hamada grade, patients with or without PPS, and the status of the subscapularis tendon (SSC).

METHODS

In total, 54 consecutive patients with irreparable rotator cuff tears or PPS who underwent SCR between June 2014 and October 2018 were included. The enrolled patients were grouped and compared as follows: (1) Hamada grade 2 (11 patients) and Hamada grade 3 (43 patients) and (2) non-PPS (22 patients), moderate PPS (16 patients), and severe PPS (16 patients). For subanalysis, the 32 PPS patients were divided into 3 groups: intact SSC (11 patients), repairable SSC (16 patients), and irreparable SSC (5 patients). To assess shoulder function, the American Shoulder and Elbow Surgeons (ASES) score was evaluated before surgery and at 24 months postoperatively; shoulder range of motion was evaluated at 2, 3, 4, 5, 6, 8, 10, 12, and 24 months postoperatively.

RESULTS

No significant differences in postoperative ASES scores and shoulder range of motion were observed between the Hamada grade 2 and grade 3 groups or between the non-PPS, moderate PPS, and severe PPS groups. However, significant differences in postoperative shoulder elevation and ASES scores were observed between the intact SSC and irreparable SSC groups (P = .006) and between the repairable SSC and irreparable SSC groups (P = .003).

CONCLUSIONS

This study demonstrated that the status of the SSC, rather than the Hamada grade or the presence or absence of PPS, influences the clinical outcomes after SCR. Therefore, reparability or intactness of the SSC is an important factor in considering the surgical indication for SCR.

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.

Are any radiologic parameters independently associated with degenerative postero-superior rotator cuff tears?

BACKGROUND

Several radiologic parameters representing scapular morphology have been proposed as risk factors for degenerative posterosuperior rotator cuff tear (PSRCT). The causes of PSRCT are multifactorial; many reported risk factors are compound entities. However, no determination, made after adjustment with previously reported risk factors, of which radiologic parameters are independent risk factors for degenerative PSRCT, has been reported. Therefore, this study's purpose was to determine which radiologic parameters representing scapular morphology are independent risk factors for degenerative PSRCT in a general population after adjustment with previously suggested risk factors.

METHODS

This study involved 629 subjects (629 shoulders) drawn from a cohort of rural residents. PSRCT diagnoses were based on magnetic resonance imaging findings. Logistic regression analysis was used to determine the odds ratios and 95% confidence intervals for the following variables: sex, age, height, weight, waist circumference, dominant-side involvement, smoking, alcohol consumption, manual labor, diabetes, hypertension, metabolic syndrome, thyroid dysfunction, serum lipid profile, high-sensitivity C-reactive protein, and radiologic parameters. The evaluated radiologic parameters were the superior displacement of the humeral head (SDHH) and those representing the scapular morphology. The radiologic parameters representing the scapular morphology were lateral acromial angle, acromial slope, acromial tilt, acromial index, and critical shoulder angle (CSA). Univariate logistic regression analyses for all variables, as well as multivariable logistic regression analyses for variables with significant associations and clinical effect sizes in the univariate logistic regression analyses, were performed. In order to determine the cutoff value for significant radiologic parameters, each pair of candidate cutoff values was obtained as follows: 1 candidate, as the lowest significant ordinal value in a univariate analysis, and the other candidate, according to a receiver operating characteristic curve analysis. Then, the cutoff values were determined by selecting the value in each candidate pair that had the larger area under the receiver operating characteristic curve, using the DeLong test.

RESULTS

In the multivariable analyses, CSA was significantly associated with degenerative PSRCT after controlling for the following factors: age, waist circumference, dominant-side involvement, manual labor, diabetes, metabolic syndrome, hypo-high-density lipoproteinemia, and SDHH (P ≤ .033). CSA (odds ratio, 1.58 [95% confidence interval, 1.45-1.72]; P < .001) was the only significantly associated radiologic parameter among the studied radiologic parameters representing scapular morphology.

CONCLUSION

CSA (≥35°) is an independent associated factor for degenerative PSRCT after adjustment for the following suggested risk factors: age, waist circumference, dominant-side involvement, manual labor, diabetes, metabolic syndrome, hypo-high-density lipoproteinemia, and SDHH.

WITHDRAWN: Does anterior arthroscopic acromioplasty modify critical shoulder angle?

This article has been withdrawn because we accidentally published the same article twice due to an error by the Managing editor/Elsevier. The correct version of the article has been published later in Orthop Traumatol Surg Res, 108 (2022) 103040, https://doi.org/10.1016/j.otsr.2021.103040. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal

Acromial and glenoid morphology in glenohumeral osteoarthritis: a three-dimensional analysis

Background

The purpose of this study was to determine the association between glenohumeral osteoarthritis (GHOA) and three-dimensional acromial and glenoid morphology.

Methods

In this retrospective study, we compared computed tomographic studies of three groups of scapulae: normal healthy, mild GHOA (Samilson-Prieto grade 1), and severe GHOA (Samilson-Prieto grade 3). All scans were segmented to create three-dimensional reconstructions. From these models, critical shoulder angle and acromial offset were measured, as normalized to scapular height. The coronal plane inclination of the glenoid was measured using a glenoid sphere-fit method. Reliability was confirmed via intraclass correlation coefficients > 0.75.

Results

Eighty scapulae were included: 30 normal, 20 mild GHOA, and 30 severe GHOA. There were no differences in acromial offset between the normal group and either the mild-GHOA group or the severe-GHOA group. The severe-GHOA group had a smaller critical shoulder angle than either the normal (30 ± 5° vs. 34 ± 4°, P = .003) or mild-GHOA groups (34 ± 4°, P = .020), but the normal and mild-GHOA groups did not differ (P = .965). The severe-GHOA group had more inferiorly inclined glenoids than either the normal (7 ± 6° vs. 12 ± 5°, P = .002) or mild-GHOA groups (14 ± 5°, P ≤ .001), but the normal and mild-GHOA groups did not differ (P = .281).

Conclusion

Normal and severe-GHOA shoulders differ in critical shoulder angle and glenoid inclination but not acromial offset. The lack of a difference in critical shoulder angle or inferior inclination between mild-GHOA and normal groups calls into question whether inclination and critical shoulder angle differences predate severe GHOA.

The Ratio of the Transverse to Longitudinal Diameter of the Glenoid Projection Is of Good Predictive Value for Defining the Reliability of Critical Shoulder Angle in Nonstandard Anteroposterior Radiographs

PURPOSE

To investigate (1) whether measurement of the critical shoulder angle (CSA) is still reliable in some nonstandard anteroposterior radiographs; and (2) whether the ratio of the transverse to longitudinal diameter of the glenoid projection (RTL) could be used to determine the reliability of the CSA in nonstandard anteroposterior radiographs.

METHODS

The authors analyzed radiology records from 2017 to 2019 for patients with computed tomography (CT) scans of the shoulder. According to the Suter-Henninger classification system, each CT scan underwent 3-dimensional (3D) reconstructions to obtain 8 digitally reconstructed radiographs (DRRs), including 1 type A1 film and 7 type D1 films with different rotation angles. CSA and RTL were measured on all films, and 2 blinded reviewers evaluated DRRs. The relationship between RTL and CSA was determined by Pearson correlation test. The threshold value was determined by receiver operating characteristic (ROC) analyses using RTL as predictors and defined reliable CSA as criterion in the logistic regression. Intra- and inter-rater reliability were assessed by the intraclass correlation coefficient (ICC). Discriminative capacity was calculated with ROC analyses and area under the curve (AUC). An optimal measurement cutoff with resultant sensitivity and specificity was calculated.

RESULTS

A total of 86 patients were included, mean age 40.70 ± 18.25 years, 19 of whom had rotator cuff tears (RCTs) and 67 without RCTs. Spearman's correlation test revealed that the deviation of CSA was positively correlated with RTL, correlation coefficient 0.544 (P < .001) in all patients and 0.686 (P < .001) only in patients with RCTs. ROC analysis of all patients showed that the AUC of the RTL was 0.90, and the optimal cutoff point was 0.25 (sensitivity 88%, specificity 87%). ROC analysis only of patients with RCTs showed that the AUC of the RTL was 0.95, and the optimal cutoff point was 0.22 (sensitivity 95%, specificity 92%).

CONCLUSION

The ratio of the transverse to longitudinal diameter of the glenoid projection (RTL) is of good predictive value in defining the reliability of the CSA in malposition films. Based on the results, the CSA can be considered reliable if its RTL is <0.25.

LEVEL OF EVIDENCE

III, retrospective cohort study investigating a diagnostic test.

Research Trends on the Rotator Cuff Tendon: A Bibliometric Analysis of the Past 2 Decades

BACKGROUND

Clinical research on the rotator cuff tendon is increasing, and new approaches are being applied to rotator cuff disease. Considering the integration of research resources and research trends, it is necessary to conduct an analysis of recent research on the topic.

PURPOSE

To identity the research trends, influential journals, key researchers, and core countries of rotator cuff tendon research between 2000 and 2019.

STUDY DESIGN

Cross-sectional study.

METHODS

All the literature related to rotator cuff tendon research was retrieved from the Web of Science Core Collection on January 7, 2020. Qualitative and quantitative analyses were processed based on Web of Science and CiteSpace.

RESULTS

A total of 4131 studies, which included 3830 articles and 301 reviews, were obtained. There was an upward trend of studies on the topic, with small fluctuations in the past 2 decades. The United States had the most studies, and the number of studies from other countries increased over the study period. Most of the funding sources came from the United States. Articles in the Journal of Shoulder and Elbow Surgery had the most citations for rotator cuff research. Frontier topics, such as arthroscopic repair, mesenchymal stem cell, and "platelet-rich plasma, were identified. The number of citations in 2018 (r = 0.280; P = .005) and 2019 (r = 0.307; P = .002) had a weak positive correlation with publication date, indicating that the more recently published articles had a higher number of citations.

CONCLUSION

Valuable information on rotator cuff research based on bibliometric analysis was identified. Arthroscopic repair, mesenchymal stem cell, and platelet-rich plasma might be the research frontiers in this field, and researchers should focus on these topics in future studies.

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.

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.

Acromial morphology is not associated with rotator cuff tearing or repair healing

BACKGROUND

The purposes of this study were to determine whether acromial morphology (1) could be measured accurately on magnetic resonance images (MRIs) as compared to computed tomographs (CTs) as a gold standard, (2) could be measured reliably on MRIs, (3) differed between patients with rotator cuff tears (RCTs) and those without evidence of RCTs or glenohumeral osteoarthritis, and (4) differed between patients with rotator cuff repairs (RCRs) that healed and those that did not.

METHODS

This is a retrospective comparative study. We measured coronal, axial, and sagittal acromial tilt; acromial width, acromial anterior and posterior coverage, and glenoid version and inclination on MRI corrected into the plane of the glenoid. We determined accuracy by comparison with CT via intraclass correlation coefficients (ICCs). To determine reliability, these same measurements were made on MRI by 2 observers and ICCs calculated. We compared these measurements between patients with a full-thickness RCT and patients aged >50 years without evidence of an RCT or glenohumeral osteoarthritis. We then compared these measurements between those patients with healed RCRs and those with a retorn rotator cuff on MRI. In this portion, we only included patients with both a preoperative MRI and a postoperative MRI at least 1 year from RCR. Only those patients without tendon defects on postoperative MRIs were considered to be healed. In these patients, we also radiographically measured the critical shoulder angle.

RESULTS

In a validation cohort of 30 patients with MRI and CT, all ICCs were greater than 0.86. In these patients, the inter-rater ICCs of the MRI measurements were >0.53. In our RCT group of 110 patients, there was greater acromial width [mean difference (95% confidence interval) = 0.1 (0, 0.2) mm, P = .012] and significantly less sagittal acromial tilt [9° (5°-12°), P < .001] than in our comparison group of 107 patients. A total of 110 RCRs were included. Postoperative MRI scans were obtained at a mean follow-up of 24.2 ± 15.8 months, showing 84 patients (76%) had healed RCRs. Aside from acromial width, which was 0.2 mm different and thus did not have clinical significance, there was no association between healing and any of the measured morphologic characteristics. Patients with healed repairs had significantly smaller tears in terms of both width (P < .001) and retraction (P < .001).

CONCLUSION

Although the acromion is wider in RCTs, the difference of 0.1 mm likely has no clinical significance. The acromion is more steeply sloped from posteroinferior to anterosuperior in those with RCTs. These findings call into question subacromial impingement due to native acromial morphology as a cause of rotator cuff tearing. Acromial morphology, critical shoulder angle, and glenoid inclination were not associated with healing after RCR. This study does not support lateral acromioplasty.

Does anterior acromioplasty reduce critical shoulder angle?

INTRODUCTION

Critical shoulder angle (CSA) is the angle between glenoid inclination and the lateral edge of the acromion. CSA>35° has been shown to be a risk factor for primary and iterative rotator cuff tendon tear. The present study aimed to assess change in CSA after anterior acromioplasty. The study hypothesis was that CSA is significantly reduced.

METHOD

A single-center retrospective descriptive observational study included patients undergoing open or arthroscopic anterior acromioplasty, with strict AP pre- and post-operative radiographs. Patients with radiographs not meeting Moor's criteria were excluded.

RESULTS

One hundred and forty-eight patients were included: arthroscopy, 112; open surgery, 36. Mean age was 57.8 years (range, 29-80 years). Mean preoperative CSA was 36.1±4.25° (range, 25-48.4°) and postoperative CSA 33.5±3.9° (23.8-45.2°), for a significant reduction of -2.6±2.5° (p=0.001). Surgical technique did not affect change in CSA: open surgery, -2.3±1.9° (-6.3° to -1°); arthroscopy, -2.7±2.7° (-10.5° to -5°) (p=0.06). In pathologic CSA (>35°), the mean reduction was -3.2±2.6° (-10.5°to -5°). CSA normalized below the 35° threshold in 48% of patients.

DISCUSSION

Despite reduction in CSA, the 35° threshold for iterative tear is not always reached after anterior acromioplasty. Complementary strictly lateral resection is theoretically required. However, change in CSA is difficult to predict intraoperatively.

CONCLUSION

Anterior acromioplasty significantly reduced CSA, independently of technique and preoperative value.

LEVEL OF EVIDENCE

IV, retrospective descriptive study.

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.

Reduced acromiohumeral distance and increased critical shoulder angle: implications for primary care clinicians

Objectives: The literature indicates that reduced acromiohumeral distance (AHD) and increased critical shoulder angle (CSA) are associated with large and massive rotator cuff (RC) tears which may not be amenable to a successful repair. The purpose of this study was to examine the overall accuracy of these two radiographic features in diagnosing significant RC pathology. Methods: This was a diagnostic study of patients with shoulder pain. To examine the overall accuracy of the measurements, the area under the Receiver Operating Characteristic curves (AUC) were calculated. The validity indices (sensitivity, specificity and likelihood ratios) examined the predictive value of specific cutoff categories of AHD<6 mm and the CSA >35°. Results: Data of 200 consecutive patients; mean age: 59(11), 117 males were used for analysis. There was a weak inverse correlation (r = 0.46) between the AHD and CSA. The AUCs for presence and size of RC tear and different stages of fatty infiltration of supraspinatus and infraspinatus muscles varied from fair to excellent for AHD and poor to good for CSA. Specificity was high for the cutoff categories of both AHD and CSA (>90%). The positive LRs were large for AHD and small to moderate for CSA. Conclusion: The AHD and CSA were reliably measured in the true AP radiographic view. Both radiographic features (AHD<6mm and CSA>35°) were able to confirm the presence of a major RC pathology. However, the AHD<6 mm, an acquired radiologic abnormality secondary to failure of the RC muscles/tendons had better measurement properties. This information is of value to primary care physicians, sports medicine specialists and advanced practice physiotherapists in their clinical decision making.

Position of the acromioclavicular joint and relation to the critical shoulder angle in shoulders with rotator cuff tears

OBJECTIVE

To evaluate the position of the acromioclavicular joint (ACJ) and relation to the critical shoulder angle (CSA) in shoulders with rotator cuff tears (RCT).

METHODS

In a matched pair study including 75 shoulders with arthroscopically validated RCT and 75 controls (mean age 59.4 ± 7.9 years) the position of the ACJ in relation to the glenoid and the CSA were measured on true ap radiographs.

RESULTS

The CSA is larger (p = 0.0018) and the position of the ACJ is more lateral (p = 0.0016) in shoulders with RCT in comparison to matched controls.

CONCLUSION

The more lateral position of the ACJ in shoulders with a large CSA might be an additional component in the multifactorial pathogenesis of RCT.

Hypo-High-Density Lipoproteinemia Is Associated With Preoperative Tear Size and With Postoperative Retear in Large to Massive Rotator Cuff Tears

PURPOSE

To evaluate any association of specific subtypes of dyslipidemia with increments of preoperative tear size and with structural integrity after arthroscopic rotator cuff repair (ARCR).

METHODS

One surgeon's consecutive patients who underwent ARCR from January 2011 to June 2018 were reviewed. The inclusion criteria were minimum 1-year follow-up ultrasonography, blood tests, physical examination, and provision of informed consent. The exclusion criteria were incomplete laboratory tests, history of acute trauma, previous shoulder surgery, isolated subscapularis tendon tear, inappropriate radiographs, no 1-year follow-up ultrasonography, and medication with lipid-lowering drugs. Associated preoperative factors for the increments of tear size and for retear after ARCR were determined using logistic regression analysis. Statistical significance was set at P < .05.

RESULTS

Of the 502 ARCR patients from the study period, 195 patients (195 shoulders), with a mean age of 60.5 ± 7.5 years, met the inclusion and exclusion criteria. Age (odds ratio [OR], 1.2; 95% confidence interval [CI], 1.1-1.3), diabetes (OR, 3.6; 95% CI, 1.7-7.5), and hypo-high-density lipoproteinemia (hypo-HDLemia) (OR, 2.9; 95% CI, 1.5-5.6) were significantly associated with increments of preoperative tear size (P ≤ .01). Diabetes (OR, 3.0; 95% CI, 1.3-6.6), critical shoulder angle (OR, 2.0; 95% CI, 1.4-3.0), and tear size (OR, 2.1; 95% CI, 1.3-3.4) were significantly associated with retear after ARCR in overall study subjects (P = .01). Diabetes (OR, 3.8; 95% CI, 1.3-11.4), hypo-HDLemia (OR, 3.0; 95% CI, 1.1-8.8), and critical shoulder angle (OR, 1.5; 95% CI, 1.1-2.3) had significant associations with retear after ARCR in patients with a large to massive preoperative tear size (P ≤ .04).

CONCLUSIONS

Preoperative hypo-HDLemia (high-density lipoprotein level < 40 mg/dL in male patients and < 50 mg/dL in female patients) has a significant association with the increments of preoperative tear size and with retear after ARCR in large- to massive-sized rotator cuff tears.

LEVEL OF EVIDENCE

Level IV, case series.

Accuracy of the Critical Shoulder Angle for Predicting Rotator Cuff Tears in Patients With Nontraumatic 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.

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.

WITHDRAWN: Does anterior arthroscopic acromioplasty modify critical shoulder angle?

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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.

The Critical Shoulder Angle Shows a Reciprocal Change in Magnitude When Evaluating Symptomatic Full-Thickness Rotator Cuff Tears Versus Primary Glenohumeral Osteoarthritis as Compared With Control Subjects: A Systematic Review and Meta-analysis

PURPOSE

To determine whether a high critical shoulder angle (CSA) is associated with symptomatic full-thickness rotator cuff (RC) tears and/or whether a low CSA is associated with primary glenohumeral osteoarthritis (GHOA).

METHODS

A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. All observational studies that examined an association between CSA and full-thickness RC tears and/or primary GHOA were included. A primary meta-analysis was performed including all studies that met the inclusion criteria regardless of radiographic quality. A secondary meta-analysis was performed to explore the hypothesis that radiographic quality was a source of heterogeneity, which excluded those studies in which radiograph quality was not strictly defined and controlled.

RESULTS

For the primary meta-analysis, 11 studies met the inclusion criteria for RC tears and 5 for primary GHOA. The CSA was greater in the RC tear group than the control group (mean difference 4.03°, 95% confidence interval 2.95°-5.11, 95% prediction interval 0.0487°-8.01°; P < .001). The CSA was lower in the GHOA group than the control group (mean difference -3.98°, 95% confidence interval -5.66° to -2.31°, 95% prediction interval -10.2° to -2.19°; P < .001).A high level of heterogeneity was observed in the RC tear analysis (I² = 88.4), which decreased after the exclusion of 5 studies based on radiographic quality (I² = 75.3). A high level of heterogeneity also was observed in the primary GHOA analysis (I² = 87.3), which decreased after the exclusion of 2 studies based on the radiographic quality (I² = 48.2).

CONCLUSIONS

There is a reciprocal change in magnitude of the CSA when evaluating symptomatic full-thickness RC tears versus primary GHOA as compared with control subjects. Radiographic quality is a source of heterogeneity in studies that investigate a link between CSA and RC tears and primary GHOA.

LEVEL OF EVIDENCE

Level III, systematic review and meta-analysis of Level III studies.

Is Bony Morphology and Morphometry Associated With Degenerative Full-Thickness Rotator Cuff Tears? A Systematic Review and Meta-analysis

PURPOSE

To scope the scientific literature and analyze the influence of bony risk factors for degenerative full-thickness primary rotator cuff tear.

METHODS

A systematic review of databases PubMed, Scopus, EMBASE, and Cochrane Library was performed up to June 30, 2018. Meta-analysis was performed with mean difference (MD) or risk ratio for degenerative full-thickness rotator cuff injury, and when there were ≥3 studies for the considered potential risk factor. Methodologic quality was assessed using the Newcastle-Ottawa scale.

RESULTS

We analyzed 34 studies comprising 5,916 shoulders (3,369 shoulders with rotator cuff tear and 2,546 controls) and identified 19 potential risk factors for degenerative full-thickness rotator cuff tears. There was moderate evidence that a higher critical shoulder angle (MD = 4.41, 95% confidence interval [CI] 3.43 to 5.39), higher acromion index (MD = 0.06, 95% CI 0.04 to 0.09), and lower lateral acromion angles (MD = -7.11, 95% CI -8.32 to -5.90) were associated with degenerative full-thickness rotator cuff tears compared with controls. Moderate evidence showed that a type III acromion significantly increases the risk for full-thickness degenerative rotator cuff tear (risk ratio = 2.26, 95% CI 1.38 to 3.70).

CONCLUSION

There is moderate evidence that larger critical shoulder angle, higher acromion index, lower lateral acromion angles, and a type III acromion are significantly associated with degenerative full-thickness rotator cuff tears. Other potential risk factors identified showed insufficient evidence.

LEVEL OF EVIDENCE

Level IV, systematic review of level II to IV studies.

Critical shoulder angle and greater tuberosity angle according to the partial thickness rotator cuff tear patterns

BACKGROUND

Current studies suggest that radiographic markers such as the critical shoulder angle (CSA) and the greater tuberosity angle (GTA) are associated with rotator cuff tears (RCTs). However, because the analysis of CSAs and GTAs according to the partial thickness rotator cuff tear patterns is limited, the purpose of the present study was to evaluate the relationship of CSAs and GTAs with partial thickness rotator cuff tear (PTRCT) patterns.

METHOD

This retrospective study included 1,069 patients from 2013 to 2017. The subjects were divided into 4 groups: Group A, control group; Group B, articular-sided PTRCTs; Group C, bursal-sided PTRCTs; and Group D, full thickness rotator cuff tears (FTRCTs). RCTs were diagnosed with magnetic resonance imaging and the CSA and GTA were measured on simple radiographs. Multivariable analyses were used to clarify the potential risks for these pathologies.

RESULTS

The mean CSAs of articular-sided PTRCTs (34.2°±4.7°) and FTRCTs (34.7°±4.4°) were significantly larger than those of the control group (32.3°±4.3°) and the bursal-sided PTRCTs (31.5°±4.6°), (P<0.001). Multivariable analysis also showed that larger CSAs had a significantly increased risk of both articular-sided PTRCTs and FTRCTs, with odds ratios of 1.12 and 1.17 per degree, respectively. The mean GTAs of bursal-sided PTRCTs (73.2°±4.8°) and FTRCTs (72.3°±5.4°) were significantly larger than that of the control group (70.5°±5.1°) (P<0.001), although the mean GTA of articular-sided PTRCTs (71.5°±6.9°) did not show a significant difference when compared with the other groups. Multivariable analysis also showed that larger GTAs had a significantly increased risk of both bursal-sided PTRCTs and FTRCTs, with odds ratios of 1.13 and 1.07 per degree, respectively.

CONCLUSION

A large critical shoulder angle was associated more with articular-sided PTRCTs than bursal-sided PTRCTs. A large greater tuberosity angle was associated more with bursal-sided PTRCTs than with articular-sided PTRCTs. Both critical shoulder angle and greater tuberosity angle were positively associated with the occurrence of full thickness rotator cuff tears.

LEVEL OF EVIDENCE

IV, Retrospective study.

Anatomic shoulder parameters and their relationship to the presence of degenerative rotator cuff tears and glenohumeral osteoarthritis: a systematic review and meta-analysis

BACKGROUND

Scapular anatomy, as measured by the acromial index (AI), critical shoulder angle (CSA), lateral acromial angle (LAA), and glenoid inclination (GI), has emerged as a possible contributor to the development of degenerative shoulder conditions such as rotator cuff tears and glenohumeral osteoarthritis. The purpose of this study was to investigate the published literature on influences of scapular morphology on the development of degenerative shoulder conditions.

METHODS

A systematic review of the Embase and PubMed databases was performed to identify published studies on the potential influence of scapular bony morphology on the development of degenerative rotator cuff tears and glenohumeral osteoarthritis. The studies were reviewed by 2 authors. The findings were summarized for various anatomic parameters. A meta-analysis was completed for parameters reported in more than 5 related publications.

RESULTS

A total of 660 unique titles and 55 potentially relevant abstracts were reviewed with 30 published articles identified for inclusion. The AI, CSA, LAA, and GI were the most commonly reported bony measurements. Increased CSA and AI correlated with rotator cuff tears, whereas lower CSA appeared to be related to the presence of glenohumeral osteoarthritis. Decreased LAA correlated with degenerative rotator cuff tears. Five articles reported on the GI with mixed results on shoulder pathology.

DISCUSSION

Degenerative rotator cuff tears appear to be significantly associated with the AI, CSA, and LAA. There does not appear to be a significant relationship between the included shoulder parameters and the development of osteoarthritis.

The Relationship Between the Critical Shoulder Angle and the Incidence of Chronic, Full-Thickness Rotator Cuff Tears and Outcomes After Rotator Cuff Repair: A Systematic Review

PURPOSE

To summarize the available evidence and examine the relationship between the critical shoulder angle (CSA) and (1) the incidence of chronic full-thickness rotator cuff tears (RCTs) and (2) outcomes after rotator cuff repair (RCR).

METHODS

A comprehensive search of MEDLINE, Embase, and CINAHL was completed. Comparative studies were included and the influence of the CSA on either the incidence of chronic, full-thickness RCTs, or outcomes following RCR was evaluated. Demographic variables and outcomes were collected.

RESULTS

Seven comparative studies analyzed the influence of the CSA on the incidence of chronic, full-thickness RCTs (the control group constituted patients with a normal rotator cuff). High heterogeneity limited pooling of studies, but the majority concluded that a greater CSA significantly increased the likelihood of a chronic, full-thickness RCT. Conversely, 5 comparative studies analyzed the influence of CSA on outcomes following RCR, and although a greater CSA was associated with a greater re-tear rate, the majority reported that CSA did not significantly influence postoperative functional outcomes, including patient-reported outcome measures (PROMs), range of motion (ROM), and strength.

CONCLUSIONS

Based on the available evidence, there appears to be a relationship between a greater CSA and the presence of a chronic, full-thickness RCT. Furthermore, a greater CSA may be associated with a greater re-tear rate following RCR; however, CSA does not appear to influence functional outcomes following RCR. Despite these observations, the available evidence is of poor quality, and the clinical utility and role of the CSA in the diagnosis and surgical management of a chronic, full-thickness RCT remains in question.

LEVEL OF EVIDENCE

Level IV: Systematic review of Level II-IV studies.

The Effectiveness of Using the Critical Shoulder Angle and Acromion Index for Predicting Rotator Cuff Tears: Accurate Diagnosis Based on Standard and Nonstandard Anteroposterior Radiographs

PURPOSE

To explore whether the critical shoulder angle (CSA) and acromion index (AI) on nonstandard anteroposterior (AP) radiographs could be used as parameters for rotator cuff tear (RCT) diagnosis and to determine the optimized parameters.

METHODS

This study included 174 patients with RCTs or intact rotator cuffs in whom AP radiographs were obtained at our hospital. The radiographs were assessed by 2 independent radiologists and were grouped according to the Suter-Henninger criteria. The CSA and AI were measured on all films. We performed receiver operating characteristic curve analysis by calculating the area under the curve (AUC) to compare the sensitivity and accuracy of both parameters.

RESULTS

Of the 174 enrolled patients, only 47 (27%) met the requirements for standard AP films (types A1 and C1). On standard AP films, both the CSA and AI were significantly different between the RCT and control groups (P < .001 for CSA and P < .001 for AI), with AUCs of 0.86 and 0.80 for the CSA and AI, respectively. On nonstandard AP films (other radiograph types), the mean CSA value was not significantly different between the RCT and control groups (P = .536) whereas the AI showed a significant difference (P = .024). The AUCs were 0.57 for the CSA and 0.64 for the AI.

CONCLUSIONS

On standard AP films, both the CSA and AI could predict rotator cuff disorders, and the CSA had a higher diagnostic accuracy than the AI. In contrast, on nonstandard AP films, the diagnostic efficacy of the AI was better than that of the CSA. On the basis of this study, we suggest an evaluation of the AP films of patients before diagnosis to confirm whether the AP films meet the criteria for standard AP films.

LEVEL OF EVIDENCE

Level I, diagnostic study.