Correlation of Acromial Morphology With Risk and Direction of Shoulder Instability: An MRI Study.

BACKGROUND: The influence of bony morphology on the development of posterior shoulder instability is not well known. PURPOSE: To determine if acromial morphology, as measured on magnetic resonance imaging (MRI), is associated with posterior or anterior shoulder instability. DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: MRI measurements of posterior acromial coverage (PAC), posterior acromial height (PAH), posterior acromial tilt (PAT), and anterior acromial coverage (AAC) were completed for 3 separate matched groups who underwent surgical intervention: posterior instability, anterior instability, and a comparison group of patients who underwent arthroscopic surgery for snapping scapula. Inclusion criteria were patients with recurrent instability <40 years of age without multidirectional instability, glenoid bone loss >13.5%, or glenoid retroversion >10%. RESULTS: Overall, 37 patients were included in each group. PAC was significantly less in the posterior instability group than in the anterior instability and comparison groups (68.3° vs 88.7° vs 81.7°; P < .001). PAH was significantly greater in the posterior group than in the anterior instability group (11.0 mm vs -0.1 mm; P < .001) and comparison group (0.7 mm; P < .001). There was no difference between the posterior and anterior groups in terms of PAT or AAC (P = .45 and P = .05, respectively). PAT was significantly smaller in the posterior instability group than the comparison group (55.2° vs 62.2°; P = .026). The anterior and comparison groups were not significantly different in PAH or PAT (P = .874 and P = .067, respectively) but were significantly different in AAC (P = .026). CONCLUSION: A higher and flatter posterior acromion, as measured on preoperative MRI, appears to be associated with patients who require arthroscopic capsulolabral repair due to posterior shoulder instability. This information may help clinicians to both diagnose and predict the need for operative intervention for patients with posterior labral tears.

Anteroposterior and Lateral Coverage of the Acromion: Prediction of the Rotator Cuff Tear and Tear Size.

Background: The aim of this study was to assess whether the anteroposterior coverage of the acromion reflecting acromial morphology affects the rotator cuff tear (RCT) and tear size, in addition to the lateral coverage. Methods: Medical records of 356 patients with RCTs, concentric osteoarthritis, and calcific tendinitis identified using three-dimensional computed tomography between January 2016 and December 2017 were retrospectively analyzed. The patients were divided into group A (those with RCTs) and group B (those with concentric osteoarthritis or calcific tendinitis). Subsequently, group A was subdivided into three categories according to the size of RCTs: small-to-medium, large, and massive. The lateral coverage was measured through the lateral acromial angle (LAA) and critical shoulder angle (CSA), whereas the anteroposterior coverage was measured via the acromial tilt (AT), acromiohumeral interval (AHI) in the sagittal view, and anteroposterior coverage index (APCI) as a new radiologic parameter. Results: Between groups A and B, CSA (34.5° ± 3.4° and 30.8° ± 3.4°, respectively), APCI (0.83 ± 0.10 and 0.75 ± 0.08, respectively), and AHI (6.3 ± 2.0 mm and 7.8 ± 1.8 mm, respectively) were significantly different (all p < 0.001), whereas LAA and AT did not show a significant difference between the groups (p = 0.089 and p = 0.665, respectively). The independent predictive radiologic parameters of the RCT were the CSA, APCI, and AHI (p < 0.001, p < 0.001, and p = 0.043, respectively); among these, the APCI showed the highest regression coefficient (odds ratio = 2.82). The parameters associated with the size of RCTs were CSA (p = 0.022) and AHI, of which AHI, in particular, had the most significant effect on both small-to-medium and large tears (all p < 0.001). Conclusions: Large CSA, high APCI, and low AHI were predictors of RCTs, with the APCI showing the strongest correlation. In addition to the large CSA, low AHI also correlated with the size of RCTs and affected the entire size groups. We suggest that both the lateral coverage and anteroposterior coverage of the acromion should be considered essential factors for predicting the presence of RCTs and tear size.

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.

A prospective observational case control study investigating the coronal plane scapular morphological differences in full-thickness posterosuperior cuff tears and primary glenohumeral osteoarthritis.

INTRODUCTION: The critical shoulder angle (CSA) is a surrogate marker of the coronal plane morphology of the scapula. CSA differences between scapulae could be due to differences in glenoid inclination (GI) or the location of the most lateral part of the acromion relative to the inferior glenoid, or both. An understanding of the hierarchy of the scapular morphological changes associated with glenohumeral osteoarthritis (GHOA) and rotator cuff (RC) tears would allow accurate biomechanical modeling. METHODS: A prospective observational case control study was undertaken in which the GI, "nonglenoid"-CSA, acromial vertical offset index, acromial horizontal offset index, acromial horizontal-vertical offset index, and coronal plane angulation of the acromion (CPAA-m) were measured on high-quality radiographs to compare coronal plane scapular anatomy in: (1) patients with asymptomatic atraumatic full-thickness RC tears, (2) patients with symptomatic primary GHOA, and (3) a control group with no RC tear or GHOA treated for glenohumeral instability or symptomatic labral pathology. Intraobserver reliability of the measurements was performed. RESULTS: In the GHOA group, the GI was lower (less superiorly inclined) than the RC tear group (difference between the means: -4.8°, 95% confidence interval [CI] [-8.8°, -0.9°], P = .014) and the control group (difference between the means: -7.9°, 95% CI [-11.8°, -3.9°], P = .000); there was no difference in the acromial measurements. In the RC tear group, the nonglenoid-CSA was higher (difference between the means: 7.7°, 95% CI [3.0°, 12.3°], P = .001), the acromial vertical offset index was lower (difference between the means: -0.13, 95% CI [-0.24, -0.01], P = .026), and the acromial horizontal-vertical offset index was higher (difference between the means: 0.15, 95% CI [0.01, 0.28], P = .030) than the control group; there was no difference in the acromial horizontal offset index or the GI. The CPAA-m was lower (greater coronal plane downslope of the acromion) in both GHOA (difference between the means: -9.6°, 95% CI [-18.6°, -0.5°], P = .036) and RC tears (difference between the means: -9.9°, 95% CI [-19.0°, -0.9°], P = .029) compared with the control group. The intraclass correlation coefficients for intraobserver reliability demonstrated excellent reliability for the measurements (all >0.900). DISCUSSION: Scapulae associated with GHOA have lower GI, but no spatial differences in the location of the lateral acromion compared with a normal population. Scapulae associated with RC tears have a lower vertical offset of the lateral acromion, but no difference in horizontal offset or GI compared with a normal population. The downslope of the acromion in the coronal plane is greater (lower CPAA-m) in both RC tears and GHOA than the normal population.

Reliability of Bigliani's Classification using Magnetic Resonance Imaging for Determination of Acromial Morphology.

Introduction: Bigliani classification is used for determination of acromial morphology, but poor inter-observer reliability has been reported on conventional radiographs. This study aims to assess inter- and intra-observer reliability using magnetic resonance imaging (MRI). Materials and methods: Forty consecutive patients diagnosed with subacromial impingement syndrome were included to study. All subjects underwent standard shoulder MRI scan and acromial shape was evaluated by nine observers of different level of expertise (three attending surgeons, three senior orthopaedic residents and three radiologists). A second set of evaluation was performed in order to assess intra-observer reproducibility. Kappa (κ) coefficient analyses both for interobserver reliability and intra-observer reproducibility were then performed. Results: Overall inter-observer agreement among nine observers was fair (κ=0.323). κ values for all 4 individual types ranged from 0.234 to 0.720 with highest agreement for type 4 and lowest agreement for type 3. Second evaluation did not result with an increase of inter-observer agreement (κ=0.338, fair). The κ coefficients for intra-observer reproducibility of nine observers ranged from 0.496 to 0.867. Overall intra-observer reproducibility was substantial. Comparison of inter- and intra-observer reliability among three groups showed no significant difference (p=0.92 and 0.22, respectively). Conclusion: Results showed that MRI did not show superior reliability compared to conventional radiographs. Moreover, inter- and intra-observer agreement did not differ between observers of different level of expertise. Findings of present study suggest that despite a sophisticated imaging modality like MRI, Bigliani's classification apparently lacks accuracy and additional criteria, or different assessment methods are required to assess acromial morphology for clinical guidance.

Reliability of Bigliani’s Classification using Magnetic Resonance Imaging for Determination of Acromial Morphology

@#Introduction: Bigliani classification is used for determination of acromial morphology, but poor interobserver reliability has been reported on conventional radiographs. This study aims to assess inter- and intraobserver reliability using magnetic resonance imaging (MRI). Materials and methods: Forty consecutive patients diagnosed with subacromial impingement syndrome were included to study. All subjects underwent standard shoulder MRI scan and acromial shape was evaluated by nine observers of different level of expertise (three attending surgeons, three senior orthopaedic residents and three radiologists). A second set of evaluation was performed in order to assess intra-observer reproducibility. Kappa (κ) coefficient analyses both for interobserver reliability and intra-observer reproducibility were then performed. Results: Overall inter-observer agreement among nine observers was fair (κ=0.323). κ values for all 4 individual types ranged from 0.234 to 0.720 with highest agreement for type 4 and lowest agreement for type 3. Second evaluation did not result with an increase of inter-observer agreement (κ=0.338, fair). The κ coefficients for intra-observer reproducibility of nine observers ranged from 0.496 to 0.867. Overall intra-observer reproducibility was substantial. Comparison of inter- and intra-observer reliability among three groups showed no significant difference (p=0.92 and 0.22, respectively). Conclusion: Results showed that MRI did not show superior reliability compared to conventional radiographs. Moreover, inter- and intra-observer agreement did not differ between observers of different level of expertise. Findings of present study suggest that despite a sophisticated imaging modality like MRI, Bigliani’s classification apparently lacks accuracy and additional criteria, or different assessment methods are required to assess acromial morphology for clinical guidance.

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

OBJECTIVE: To analyze the relationship between the acromial morphology and the related rotator cuff injury using a three-dimensional (3D) measurement technology. METHODS: For the present study, 226 patients (113 men and 113 women) who underwent shoulder Coarthroscopy from June 2015 to December 2019 at the Department of Orthopedics at our hospital were selected retrospectively. A total of 113 shoulder joints of age-matched healthy people were selected as the control group. A 3D model coordinate system of the shoulder was established based on CT scan images. Patients were grouped according to the condition of the rotator cuff injury during surgery. The patients whose rotator cuff tear site corresponded to the 3D osseous proliferative structure of the acromion were classified into the impingement injury group (II group). The other patients were classified into the non-impingement injury group (NII group). The acromiohumeral interval (AHI), the acromial anterior protrusion (AAP), the acromial inferior protrusion (AIP), the acromioclavicular angle (AC angle), the distance from the most medial edge of the acromial anterolateral protrusion (AALP) to the most lateral point of acromion (MLPA) (a), the distance from the most posteromedial edge of the AALP to the MLPA (b), the anteroposterior diameters of the AALP (c), and the proportion of anteroposterior diameters of AALP to the anteroposterior diameters of acromion, (c/c + d) × 100(%), were measured using the 3D shoulder model. RESULTS: The results of the intraobserver (<5%) and interobserver variability (>87%) analysis found the parameters to have high intraobserver and interobserver concordance. There were no significant differences in age among the control group, the NII group, and the II group (P = 0.8416). There were significant differences in AAP among the three groups (P = 0.0374). The results were the same for men and women, respectively. The AAP in the control group and the NII group did not show a difference, while the AAP in the II group was increased by 26.9% (P = 0.015) and 25% (P = 0.023), respectively, compared with the NII group and the control group. AHI, AIP, and AC angles did not show significant differences among the three groups (P > 0.05). The (a) and (b) of the II group were significantly larger than those of the NII group; P-values were 0.0119 and 0.0003, respectively. The (a) and (b) in patients with rotator cuff injuries were larger than in the normal population (P < 0.05). The above results were the same for men and women. This suggested that the larger width of the AALP might cause the related rotator cuff injury. The (c/c + d) in the II group was significantly larger than those in the control and the NII groups, with P-values of 0.0005 and 0.0021, respectively. The risk of rotator cuff injury due to subacromial impingement was increased when the maximum width of the medial-lateral edge of the AALP exceeded 16.8 mm (17.4 mm in men, 15.1 mm in women), the maximum width of the posterior edge of the AALP exceeded 12.9 mm (13.8 mm in men,12.7 mm in women), or the anteroposterior diameters of the AALP exceeded the anteroposterior diameters of the acromion by 33.5%. CONCLUSION: We could predict the occurrence and development of the related rotator cuff injury in symptomatic patients with specific 3D changes in their acromion and intervene in the acromion of such patients as early as possible to prevent possible rotator cuff injuries in the future.

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.

Examining changes in acromial morphology in relation to spurs at the anterior edge of acromion.

BACKGROUND: Although acromial morphology is classified as flat, curved, and hooked, whether the morphology is primary or acquired is debated. There have been no investigations on the effect of acromial spurs on acromial morphology. This study therefore aimed to evaluate acromial morphology in relation to spur formation at the anterior edge of the acromion. MATERIALS AND METHODS: Acromial morphology was investigated in 40 scapulae taken from 20 cadavers (10 male and 10 female), with a median age of 82 years (range 62-97 years). Ink prints of the anteroposterior aspect of the acromion were used to evaluate acromial slope angle and curvature height in relation to spur incidence, length, and shape at the anterior edge of the acromion. RESULTS: Differences were observed in acromial morphology and acromial curvature in relation to acromial spurs (incidence, size, and shape). A hooked acromion was observed as a primary structure in 25% of specimens, which increased to 43% when acromial spurs were involved. No differences were observed in relation to sex or side, while a significant correlation was observed between acromial curvature and the age of the specimens. CONCLUSION: Acromial spurs increase acromial curvature and therefore change acromion morphology. Nevertheless, it is concluded that a hooked acromion occurs as a primary formed structure. LEVEL OF EVIDENCE: Basic science study, anatomy, cadaver dissection.

Arthroscopic lateral acromion resection (ALAR) optimizes rotator cuff tear relevant scapula parameters.

BACKGROUND: The acromion index (AI), critical shoulder angle (CSA) and lateral acromion angle (LAA) are predictive for degenerative rotatory cuff tears. Their unfavorable values are associated with a suboptimal deltoid force vector. The aim of this study was to evaluate whether an optimization of the radiological parameters could be achieved through a specific arthroscopic lateral acromion resection (ALAR). MATERIALS AND METHODS: The procedure was performed in eight fresh frozen cadaver shoulders. True a.p. and axial radiographs were taken before and after the intervention for radiological evaluation. The anterior and posterior acromion edges were marked with a spinal needle. Then 1 cm of the lateral acromion was resected with a 5.0 acromionizer (Arthrex Inc., Naples, FL, USA) beginning from the anterior aspect. The resection was completed over the total width of 1 cm from anterior to posterior. Finally the deltoid insertion was dissected via an open approach to ensure its integrity. The fluoroscopy images were evaluated regarding the pre- and postinterventional parameters AI, CSA and LAA. RESULTS: After the intervention, the mean AI could be significantly reduced from 0.62 ± 0.11 to 0.40 ± 0.15 (p = 0.012). Also the mean CSA was significantly reduced from 35.0° ± 7.65° to 25.12° ± 8.29° (p = 0.018). The LAA could not be significantly changed (76.5° ± 14.02° vs. 82.13 ± 8.93; p = 0.107). There was no injury to the deltoid insertion. CONCLUSION: The radiographic parameters AI und CSA can be optimized significantly by ALAR without macroscopic discontinuity of the deltoid insertion. LEVEL OF EVIDENCE: Level IV, case series without comparison group.

Differences in acromial morphology of shoulders in patients with degenerative and traumatic supraspinatus tendon tears.

PURPOSE: Distinct characteristics of acromial morphology seem to be one factor for the development of degenerative supraspinatus tendon tears. Thus, it is questionable whether patients with traumatic tendon tears also present these parameters. The hypothesis of the present study was that the acromial morphology of patients with degenerative supraspinatus tendon tears differs from patients with traumatic tears. METHODS: One hundred and thirty-six patients that were treated by arthroscopic rotator cuff repair from 2010 to 2013 were included in this study. Seventy-two patients had degenerative (group 1), and 64 had traumatic (group 2) supraspinatus tendon tears. On preoperative radiographs the Bigliani type, acromial slope, acromiohumeral (AH) distance, lateral acromial angle (LAA), acromion index (AI), and critical shoulder angle (CSA) were measured. Medians of these parameters as well as of age of both groups were compared using the t test. RESULTS: The percentaged distribution of the Bigliani type differed (group 1 vs. 2: type 1: 18/38, type 2: 56/55, type 3: 26/8). All parameters showed significant differences between degenerative and traumatic tears. Slope: 21.2° (SD 7.6°) versus 19.2° (SD 7.9°, p = 0.026), AH distance: 8.4 mm (SD 2.3 mm) versus 9.9 mm (SD 1.9 mm, p = 0.0006), LAA: 77.0° (SD 4.0°) versus 82.5° (SD 4.7°, p < 0.0001), AI: 0.77 (SD 0.07) versus 0.73 (0.06, p = 0.0239), and CSA: 36.8° (SD 3.6°) versus 35.3° (SD 2.9°, p = 0.007). An LAA <70° or an AH distance of <5 mm only occurred in degenerative tears. Patients with degenerative tears were significantly older (60 vs. 54 years). CONCLUSIONS: The hypothesis that the acromial morphology of patients with degenerative supraspinatus tendon tears differs from patients with traumatic tears was confirmed. Shoulders with degenerative tears show a narrower subacromial space and a larger lateral extension as well as a steeper angulation of the acromion than with traumatic tears. Thus, the results of this study support the theory of external impingement as a cause for degenerative rotator cuff tears. LEVEL OF EVIDENCE: IV.

Correlación entre la anatomía acromial y roturas del manguito rotador: estudio caso-control / Relationship between acromial anatomy and rotator cuff tears: a case control-study

Determinar si existe correlación entre la anatomía acromial documentada por radiología y la presencia de roturas del manguito rotador (MR) evaluadas en forma artroscópica. Hipótesis: Existe correlación positiva entre la morfología acromial y las roturas del MR. Métodos: Serie retrospectiva caso-control de 279 casos consecutivos tratados mediante cirugía artroscópica. Se analizaron 2 cohortes; un grupo con roturas completas del MR (N = 155) y un grupo control, tratados por inestabilidad glenohumeral (N = 124) a los que se documentó indemnidad del MR durante la artroscopia. Se documentó la anatomía acromial preoperatoria mediante radiografías de hombro anteroposterior verdadera y axial subacromial y se midieron la pendiente acromial según Bigliani (B), la inclinación acromial según Kitay (K) y el índice acromial según Nyffeler (AI). Resultados: Las diferencias entre los valores promedios de B y K entre grupos no fueron significativas (p = 0,6 y p = 0,3). No existió correlación entre B y AI (r = 0,054; p = 0,377). Evidenciamos una correlación positiva en ambos grupos entre la inclinación acromial (r = 0,2; p = 0,008) y la pendiente acromial (r = 0,1; p = 0,03). Encontramos diferencias significativas en el IA entre grupos, que fue mayor para los casos (p = 0,01). Conclusión: En los resultados de las mediciones radiológicas de la anatomía acromial en nuestra población, documentamos una correlación significativa entre extensión del AI y roturas del MR confirmadas durante artroscopia...

To study the anatomical relationship between acromial morphology documented on X- rays and rotator cuff (RC) tears evaluated using arthroscopy. Hypothesis: There is a positive correlation as regards acromial morphology and RC tears. Methods:A retrospective, case control series of 279 consecutives cases, who underwent arthroscopic surgery were included in this study; cases were separated into 2 cohorts; one group with complete RC tears (N=155) and a control group treated for glenohumeral instability (N=124) with indemnity of the RC confirmed during arthroscopy. Pre-operative acromial anatomy was documented with X- rays – true anteroposterior and sub-acromial outlet views – measuring the acromial slope according to Bigliani (B), acromial tilt according to Kitay (K), and acromial index according to Nyffeler (AI). Results: The differences in the mean values of B and K between groups were not significant (P=.6 and P=.3). There was no correlation between B and AI (r= 0.05; P=.3). A positive correlation was observed between the acromial tilt (r= 0.2; P=.008) and acromial slope (r= 0.1; P=.03). A significant difference was found regarding AI, with greater values in the case group (P=.01). Conclusion:In this study, the acromial slope according to Bigliani, and acromial tilt according to Kitay, does not correlate with RC tears. A positive correlation of the AI with RC tears was observed...

Relationship of individual scapular anatomy and degenerative rotator cuff tears.

BACKGROUND: The etiology of rotator cuff disease is age related, as documented by prevalence data. Despite conflicting results, growing evidence suggests that distinct scapular morphologies may accelerate the underlying degenerative process. The purpose of the present study was to evaluate the predictive power of 5 commonly used radiologic parameters of scapular morphology to discriminate between patients with intact rotator cuff tendons and those with torn rotator cuff tendons. METHODS: A pre hoc power analysis was performed to determine the sample size. Two independent readers measured the acromion index, lateral acromion angle, and critical shoulder angle on standardized anteroposterior radiographs. In addition, the acromial morphology according to Bigliani and the acromial slope were determined on true outlet views. Measurements were performed in 51 consecutive patients with documented degenerative rotator cuff tears and in an age- and sex-matched control group of 51 patients with intact rotator cuff tendons. Receiver operating characteristic analyses were performed to determine cutoff values and to assess the sensitivity and specificity of each parameter. RESULTS: Patients with degenerative rotator cuff tears demonstrated significantly higher acromion indices, smaller lateral acromion angles, and larger critical shoulder angles than patients with intact rotator cuffs. However, no difference was found between the acromial morphology according to Bigliani and the acromial slope. With an area under the receiver operating characteristic curve of 0.855 and an odds ratio of 10.8, the critical shoulder angle represented the strongest predictor for the presence of a rotator cuff tear. CONCLUSION: The acromion index, lateral acromion angle, and critical shoulder angle accurately predict the presence of degenerative rotator cuff tears.

Acromial morphometric analysis using imaging software / Análisis morfométrico del acromion usando software de imágenes

The aim of this study was to accurately measure acromial morphology in order to describe the anatomical patterns of its subtypes and to conduct a survey of the literature regarding the relationships between morphological subtypes and their related diseases. We photographed scapulae from the Institute of Anatomy, University Severino Sombra, and analyzed the images using Image-J Software®. The average acromial angle was 139.23° ± 2.781, with no significant difference between the right and left sides. There was a positive correlation between the acromial angle and the angle of the spine of the scapula. The correlation mentioned above plays an important role in disorders of the shoulder-particularly impingement syndrome-which reinforces the importance of acromial morphology studies.

El objetivo de este estudio fue medir con precisión la morfología acromial para describir los patrones anatómicos de sus subtipos y llevar a cabo un estudio de la literatura sobre las relaciones entre los subtipos morfológicos y las enfermedades relacionadas. Tomamos fotografías de la escápula del Instituto de Anatomía de la Universidad Sombra Severino, y se analizaron las imágenes con el Software Image-J®. El ángulo acromial medio fue de 139,23 ± 2,781°, no habiendo diferencias significativas entre los lados derecho e izquierdo. De observó una correlación positiva entre el ángulo acromial y el ángulo de la columna vertebral de la escápula. La correlación mencionada anteriormente, juega un papel importante en los trastornos de la inflamación del hombro, especialmente el síndrome, lo cual refuerza la importancia de los estudios de la morfología acromial.