High Critical Shoulder Angle Research Articles

Comparative Analysis of Critical Shoulder Angle and Acromion Index in Patients with or without Rotator Cuff Tear

Background: Recent evidence suggests that a high value of radiographic acromial indices such as critical shoulder angle (CSA) and acromial index (AI) may be associated with a higher incidence of rotator cuff tears (RCTs). The objective of this observational study was to evaluate the relationship between RCTs, CSA, and AI. Materials and Methods: We divided 68 patients with shoulder pain into two groups: Group 1, RCT and Group 2, normal cuff. Patients were evaluated with standard true anteroposterior (AP) radiographs. CSA and AI were calculated on true AP X-ray. Twenty-four males and 10 females were selected for Group 1 whereas 23 males and 11 females for Group 2. Results: The mean age for Group 1 was 53.23 years and for Group 2 was 47.53 years. CSA findings (mean ± standard deviation [SD]) were 37.5 ± 4.37 for Group 1 and 32.23 ± 3.19 for Group 2. Mean ± SD for AI were 0.72 ± 0.07 and 0.66 ± 0.09 for Groups 1 and 2, respectively. CSA and AI revealed a statistically significant P < 0.0001 for both groups. Logistic regression confirmed CSA and AI to be strong predictors of an RCT. Conclusions: Higher CSA and AI are associated with degenerative RCT. Level of Study: Level III.

Effect of patient-specific scapular morphology on the glenohumeral joint force and shoulder muscle force equilibrium: a study of rotator cuff tear and osteoarthritis patients.

Introduction: Osteoarthritis (OA) and rotator cuff tear (RCT) pathologies have distinct scapular morphologies that impact disease progression. Previous studies examined the correlation between scapular morphology and glenohumeral joint biomechanics through critical shoulder angle (CSA) variations. In abduction, higher CSAs, common in RCT patients, increase vertical shear force and rotator cuff activation, while lower CSAs, common in OA patients, are associated with higher compressive force. However, the impact of the complete patient-specific scapular morphology remains unexplored due to challenges in establishing personalized models. Methods: CT data of 48 OA patients and 55 RCT patients were collected. An automated pipeline customized the AnyBody™ model with patient-specific scapular morphology and glenohumeral joint geometry. Biomechanical simulations calculated glenohumeral joint forces and instability ratios (shear-to-compressive forces). Moment arms and torques of rotator cuff and deltoid muscles were analyzed for each patient-specific geometry. Results and discussion: This study confirms the increased instability ratio on the glenohumeral joint in RCT patients during abduction (mean maximum is 32.80% higher than that in OA), while OA patients exhibit a higher vertical instability ratio in flexion (mean maximum is 24.53% higher than that in RCT) due to the increased inferior vertical shear force. This study further shows lower total joint force in OA patients than that in RCT patients (mean maximum total force for the RCT group is 11.86% greater than that for the OA group), attributed to mechanically advantageous muscle moment arms. The findings highlight the significant impact of the glenohumeral joint center positioning on muscle moment arms and the total force generated. We propose that the RCT pathomechanism is related to force magnitude, while the OA pathomechanism is associated with the shear-to-compressive loading ratio. Overall, this research contributes to the understanding of the impact of the complete 3D scapular morphology of the individual on shoulder biomechanics.

Investigating the multifactorial etiology of supraspinatus tendon tears.

The purpose of this study was to develop a multivariable model to determine the extent to which a combination of etiological factors is associated with supraspinatus tendon tears. Fifty-four asymptomatic individuals (55 ± 4 years) underwent testing of their dominant shoulder. Diagnostic ultrasound was used to assess for a supraspinatus tendon tear. The etiological factors investigated includeddemographics (age and sex), tendon impingement during shoulder motion (via biplane videoradiography), glenohumeral morphology (via computed tomography imaging), family history of a tear (via self-report), occupational shoulder exposure (via shoulder job exposure matrix), and athletic exposure (via self-report). Univariate relationships between etiological predictors and supraspinatus tears were assessed using logistic regression and odds ratios (ORs), while multivariable relationships were assessed using classification and regression tree analysis. Thirteen participants (24.1%) had evidence of a supraspinatus tear. Individuals with a tear had a higher critical shoulder angle (OR 1.2, p = 0.028) and acromial index (OR 1.2, p = 0.016) than individuals without a tear. The multivariable model suggested that a tear in this cohort can be explained with acceptable accuracy (AUROC = 0.731) by the interaction between acromial index and shoulder occupational exposure: a tear is more likely in individuals with a high acromial index (p < 0.001), and in individuals with a low acromial index and high occupational exposure (p < 0.001). The combination of an individual's glenohumeral morphology (acromial index) and occupational shoulder exposure may be important in the development of supraspinatus tears.

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

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. 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. 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. 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. 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.

Computer Image-Guided Precise Acromioplasty for Reducing the Critical Shoulder Angle

The shoulders with critical shoulder angle (CSA) of greater than 33-35° are associated with rotator cuff tears, whereas a CSA of less than 30° is likely to be osteoarthritic. However, anterior acromioplasty or lateral acromioplasty could not reduce high CSAs to the desired range (30-33°), with satisfactory accuracy and efficacy. Thus, we introduce a computer image-guided precise acromioplasty (CIG-PAP) technique, an individualized treatment based on three-dimensional planning. We believe that the introduction of this technique will provide an alternative approach to reduce a large CSA to the desired range (30-33°).

How much acromial bone should be removed to decrease the critical shoulder angle? A 3D CT acromioplasty planning study.

A high critical shoulder angle (CSA) is associated with rotator cuff tear (RCT) and retear rate after repair. CSA reduced to less than 33° by acromioplasty is correlated with better clinical results and healing. But up to 24% of patients retain a CSA above 35° after acromioplasty. The objective of the study was to evaluate the use of 3D when planning acromioplasty and measure acromial bone removal volume dimensions. Computed tomography (CT) scans from 45 patients with RCT and CSA ≥ 38° were retrospectively included. A 33° CSA cutting plane was positioned. Acromion was divided into 5mm slices and acromial bone resection measured on each slice. Intra- and inter-observer reproducibility measurements were rated strong or very strong. Patients' mean preoperative CSA was 40° (38°, 49° ± 2.3°). Measurements of acromial resection were: anteroposterior length: 32.7mm (20, 50 ± 7.4); inferior width: 7.6mm (4.2, 19 ± 2.9); superior width: 4.1mm (0, 16 ± 3.0); height: 6.1mm (1.7, 6.7 ± 1.6); and cutting angle: 74° (46, 91 ± 8.0). Maximum width of acromial resection was located 10.6mm (5, 17.5 ± 0.6) from the acromion's anterior edge and decreased gradually moving posteriorly. Preoperative CSA was linearly correlated with width (P < 0.0001, R = 84%) and length (P = 0.0001, R = 28%) of acromioplasty; the higher the CSA, the greater the width and length. 3D CT reconstructions are valid for planning a CSA decreasing acromioplasty. To reduce CSA to 33°, acromioplasty must be performed anterolaterally and resection is at least 2cm long anteroposteriorly. For higher CSAs, acromioplasty may require lateral resection over 1cm in width and up to 5cm in length. To decrease the CSA efficiently, acromioplasty must be adapted to patient anatomy and 3D planning could be considered. IV.

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

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

COMPARISON OF SCAPULAR MORPHOLOGY IN DEGENERATIVE AND TRAUMATIC ROTATOR CUFF TEARS

Background: Degenerative cuff tears have impingement pathophysiology due to altered scapular morphology as measured by increased critical shoulder angle (CSA), decreased lateral acromial angle (LAA) and increased acromion index (AI). But scapular morphology in traumatic tears has neither been studied nor compared with degenerative tears. Aim: To compare scapular morphology with CSA, LAA, AI between traumatic and degenerative tears and determine their reliability. Methods: This observational study includes 100 patients (50 with traumatic and degenerative tears). We analyzed MRI and standardized AP shoulder radiograph of these patients. Parameters, such as CSA, LAA, AI, were measured on AP radiographs by two separate observers in a blinded manner. The 1st observer repeated measurements after four weeks. We compared age, gender, degree of cuff tear, and CSA values, LAA, and AI between the two groups. Results: On comparison using chi-square test, degenerative group had significantly higher age, higher CSA (mean 37.55, SD 0.88 versus traumatic group mean 36.6, SD 0.95, [Formula: see text]-[Formula: see text], highly significant), higher AI (mean 0.73, SD 0.02 versus traumatic mean 0.69, SD 0.04 [Formula: see text]-[Formula: see text], highly significant), and lower LAA (77.14, SD 2.03 versus traumatic mean 78.36, SD 2.73, [Formula: see text]-value 0.013, significant). Interobserver and intraobserver reliability of parameters using the intraclass correlation coefficient (ICC) revealed excellent (CSA, LAA) and good (AI) agreement. ROC curve analysis calculated sensitivity (0.7) and specificity (0.66) to diagnose degenerative tear for CSA above 37.05[Formula: see text]. Conclusion: Scapular morphology in traumatic tears differs from degenerative. CSA, LAA, AI can be reliably measured on standardized shoulder AP radiographs.

702 The Role of Scapular Morphology in Traumatic Rotator Cuff Tears and Greater Tuberosity Fractures: A Retrospective Study

Abstract Aim Traumatic Rotator Cuff Tears(RCT) and Greater Tuberosity fractures(GT) are associated with high morbidity and reduced quality of life. Diagnostic and treatment pathways for both RCT and GT fractures are different. In this study we look at whether scapular morphology features can aid in our understanding of these traumatic injuries and influence patient pathways. Method A retrospective study was conducted at 2 hospitals. All patients between the period of 2010 and 2020 with Traumatic GT fractures or RCT were identified. Patients were case matched by age and laterality of injury. Primary outcome measurement was the Critical Shoulder Angle(CSA) and timing to further imaging. Statistical analysis was conducted using STATA™. Results Eighty patients met the inclusion criteria(40 traumatic RCT and 40 GT). Mean age was 61.8 years with 58(72.5%) left sided injuries. The difference between RCT and GT was 3.96 degrees(95% CI 2.5 to 5.41, p &amp;lt; 0.05). An CSA of 33.73 gave a sensitivity of 0.68 and a specificity of 0.8 to differentiate between RCT and GT fractures. The Area under the Curve(AUC) was 0.8 indicating high reliability. The overall difference in presentation to further scan between the 2 groups was 78. 3 days( P &amp;lt; 0.05, 95% CI 48.7 – 108). Conclusions Patients with a traumatic RCT and GT fractures have different scapular morphology and radiographic features which predisposes them to have these injuries. Patients presenting with a traumatic RCT are more likely to have a higher CSA and have a greater delay to further scan.

Risk Factors for Supraspinatus Tears: A Meta-analysis of Observational Studies.

Background:The pathogenesis of rotator cuff tears remains unclear, and there is a lack of high-quality evidence-based research on the risk factors for supraspinatus tears.Purpose:To explore 10 potential risk factors for supraspinatus muscle tears.Study Design:Systematic review; Level of evidence, 3.Methods:This review was conducted according to the MOOSE (Meta-analysis Of Observational Studies in Epidemiology) guidelines. PubMed, Embase, and Web of Science were searched for cohort, case-control and cross-sectional studies published before January 2021 on supraspinatus tears. The following potential risk factors were analyzed: age, body mass index, male sex, female sex, arm dominance, diabetes mellitus, smoking, hypertension, thyroid disease, and the critical shoulder angle (CSA). Risk ratios (RRs) or weighted mean differences (WMDs) of related risk were calculated. The Egger test was used to evaluate publication bias.Results:A total of 9 articles from 8 countries were included; among the 3240 patients, 687 were included in the supraspinatus tear group, and 2553 were included in the nonsupraspinatus tear group. The meta-analysis showed that older age (WMD, 3.36 [95% confidence interval (CI), 0.53-6.20]; P = .02), male sex (RR, 0.87 [95% CI, 0.78-0.97]; P = .01), smoking (RR, 2.21 [95% CI, 1.56-3.14]; P < .00001), diabetes (RR, 1.67 [95% CI, 1.03-2.70]; P = .04), hypertension (RR, 1.51 [95% CI, 1.16-1.97]; P = .002), and the CSA (WMD, 2.25 [95% CI, 1.39-3.12]; P < .00001) were risk factors for supraspinatus tears.Conclusion:Older age, male sex, smoking, diabetes, hypertension, and a higher CSA were found to be risk factors for supraspinatus tears in this meta-analysis review. Identifying risk factors for supraspinatus tears early can help clinicians identify these high-risk patients and choose appropriate treatments.

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

BackgroundBigliani types of acromion and critical shoulder angle (CSA) have been implicated as indicators of rotator cuff disease. A sharpened inferolateral edge of acromion (termed as Sharpened Lateral Acromion Morphology or SLAM sign) is frequently observed in anteroposterior radiographs of the glenohumeral joint in patients with rotator cuff tears (RCT). We aimed to evaluate the association of the SLAM sign with RCT in comparison to high CSA (≥35°) and Bigliani type 3 (hooked) acromion.MethodsA cohort of 100 consecutive patients undergoing non-arthroplasty surgery for RCT and 106 patients with primary frozen shoulder were matched manually in 1:1 ratio based on age and gender to yield study population with 50 patients in each group. The 2 groups were compared for the presence of the SLAM sign, high CSA, and type 3 acromion on the radiographs.ResultsAll the 3 parameters were found more prevalent in the RCT group than the frozen shoulder group (SLAM, 46% vs. 0; high CSA, 60% vs. 40%; type 3 acromion, 18% vs. 4%) (P < .05). The SLAM sign showed stronger correlation with RCT than high CSA and type 3 acromion (Ps = 0.562 vs. 0.220 vs. 0.224 respectively).ConclusionThe SLAM sign is a simple and easily identifiable radiological predictor of rotator cuff disease.

Higher Critical Shoulder Angle has an Increased Risk of Re-Tear After Arthroscopic Rotator Cuff Repair At Long Term Follow-Up

The purpose of this study was to examine the effect of critical shoulder angle (CSA), acromion index (AI), and glenoid inclination (GI) on functional outcomes and tendon integrity at a minimum follow-up of 10 years.

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

PurposeThe 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.MethodsWe 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.ResultsThe 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.ConclusionsThe middle deltoid muscle occupies the entire lateral acromion.Clinical RelevanceA 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.

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

BackgroundThe effect of the acromion index (AI) and critical shoulder angle (CSA) on the short-term healing rate after arthroscopic repair of the supraspinatus tendons is already known. Long-term effects have not been published yet.PurposeLong-term evaluation of the effect of the AI and CSA on the postoperative healing rate and clinical results after arthroscopic repair of the supraspinatus tendon.MethodsPatients with a symptomatic, single-tendon, full-thickness supraspinatus tear in whom nonoperative management had failed were treated with an arthroscopic repair. Preoperative radiographs were used to measure CSA and AI. Eight years postoperatively, magnetic resonance imaging (MRI) studies were performed and evaluated on repair integrity. Patient-reported outcome measurements were collected pre- and postoperatively.ResultsThirty-one patients were evaluated 8 years postoperatively. The mean age at the time of surgery was 61 ± 9 years. MRI evaluation showed that 20 patients (65%) had an intact repair and 11 (35%) had a full-thickness retear. No significant differences were found between the intact and retear groups regarding age (P = .605), initial tear size (P = .485), retraction grade (P = .439), and all PROMs. The mean CSA for the intact group (33° ± 1°) was significantly lower than the CSA in the retear group (38° ± 1°; P = .004). Eighteen patients (58%) had a CSA ≥35°, and 9 (50%) among them had a retear and 9 (50%) had an intact repair.The mean AI for the intact group (0.72 ± 0.11) was significantly lower than the AI in the retear group (0.81 ± 0.08 ; P = .021). Seventeen patients (55%) had an AI ≥0.75, and 9 (53%) among them had a retear and 8 had an intact repair. If the AI was ≥0.75, the odds ratio of having a retear was 6.19 (P = .045). No progressive worsening of PROMs and clinical results could be demonstrated related to a higher CSA or AI during the entire follow-up.ConclusionAt long-term follow-up, a higher CSA has the tendency to have an increased rate of retear after arthroscopic supraspinatus tendon repair, but this was not significant. A higher AI significantly increased the retear risk. A higher CSA and AI did not impair the clinical results over time. An AI ≥0.75 was associated with a 6-fold increase in risk of retear after arthroscopic supraspinatus tendon repair.

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.

The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears

The natural course of and risk factors for tear progression in full-thickness rotator cuff tears (FTRCTs) have not been clarified yet. The study's purpose was to retrospectively evaluate tear progression in FTRCTs by using magnetic resonance imaging (MRI) and to identify risk factors that are relevant to such tear progression. Between June 2010 and September 2019, a total of 345 patients with FTRCTs who had been diagnosed via MRI were treated conservatively. Of these, 48 patients who underwent post-treatment follow-up MRI were retrospectively enrolled. Tear progression was defined as significant when the tear size increased by >5 mm. The mean MRI follow-up duration was 22 ± 14 months (range, 12-65 months). Among the 48 patients (mean age, 69 years; range, 53-81), 26 (54%) and 20 (41%) showed medial-lateral (M-L) and anterior-posterior (A-P) tear progression on MRI follow-up. Multivariate analysis revealed that MRI follow-up duration (P = .011), diabetes mellitus (P = .017), and infraspinatus muscle atrophy (P = .011) were independent risk factors for tear progression in the A-P plane. A high critical shoulder angle (P = .011) and supraspinatus (P = .024) and infraspinatus (P = .020) muscle atrophy were risk factors associated with M-L tear progression. Among the assessed patients, a considerable number of FTRCTs increased in size during the follow-up period. Severe infraspinatus muscle atrophy was the independent risk factor for exacerbation of A-P and M-L tear progression.

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

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). 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. 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). 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 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

To scope the scientific literature and analyze the influence of bony risk factors for degenerative full-thickness primary rotator cuff tear. 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. 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). 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 IV, systematic review of level II to IV studies.

Rotator cuff tear incidence association with critical shoulder angle and subacromial osteophytes

The concomitant presence of a heel-type osteophyte may affect the critical shoulder angle (CSA) correlation with rotator cuff tears (RCT). We retrospectively reviewed patients with and without a full-thickness RCT who underwent magnetic resonance imaging (MRI) and radiographic imaging of the shoulder. The patients were divided into 3 groups according to the CSA as high CSA group, >38°; middle CSA group, 33°-38°; and low CSA group, <33°. We confirmed the presence of heel-type osteophytes, quadrangular osteophytes protruding inferiorly from the undersurface of the anterolateral acromion like the heel of a shoe, and excluded other types of osteophytes. Among the patients, 84.6% in the high CSA group, 60.3% in the middle CSA group, and 68.3% in the low CSA group had a RCT (P = .041). In patients without an osteophyte, 76.9% in the high CSA group, 38.5% in the middle CSA group, and 52.6% in the low CSA group had a RCT (P = .024). In patients with an osteophyte, 92.3% in the high CSA group, 80.3% in the middle CSA group, and 92.2% in the low CSA group had a RCT (P = .106). RCT was affected more by osteophytes than CSA when CSA and osteophytes were evaluated together as a related factor for RCT. This perhaps suggests no correlation of CSA alone with RCT. Therefore, the presence of an osteophyte must be considered when evaluating the relation of CSA to RCT.

High performance of critical shoulder angle for diagnosing rotator cuff tears on radiographs.

Previous studies have reported that a high critical shoulder angle (CSA) is associated with rotator cuff tears (RCTs). However, the available evidence concerning the strength of the association of these parameters with the pathogenesis of RCTs is conflicting. The aim in the present meta-analysis was to assess the diagnostic performance of CSA for detecting RCTs. The PubMed and EMBASE databases were searched for diagnostic accuracy studies of CSA for detecting RCT. Quality of the included studies was assessed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool. We calculated the pooled diagnostic accuracy of CSA, including diagnostic odd ratios (DORs) with 95% confidence intervals (CIs). Bivariate random-effect modeling with forest plots and hierarchical summary receiver operating characteristic curves was performed to evaluate the pooled sensitivity and specificity of CSA. For heterogeneity exploration, we performed meta-regression analyses. Eight studies including 902 patients (460 patients with RCT and 442 control patients) were included. According to DOR, CSA was an informative feature for RCT (DOR 8; 95% CI 4-16). The overall diagnostic performance of CSA for RCT was good (sensitivity 71% [95% CI 61-80%]; specificity, 77% [95% CI 65-86%]). Meta-regression analyses revealed that the sensitivity of CSA could be higher for differentiating full-thickness RCTs and normal patients. Furthermore, the specificity of CSA could be higher using a cut-off value of 35°. CSA on plain radiographs has good diagnostic performance for RCTs. A cut-off value of 35° is recommended for more accurate diagnosis of full-thickness RCTs. Measuring CSA on plain radiographs may provide clinicians with a readily available and reliable method for detecting RCT in daily practice. Diagnostic studies, Level III.