A new method for measurement of subcoracoid outlet and its relationship to rotator cuff pathology at MR arthrography

Relationship between Radiological Measurement of Subcoracoid Impingement and Subscapularis Tendon Lesions

Background

The value of radiological measurements of subcoracoid impingement such as the coracohumeral interval in predicting subscapularis tendon injuries is controversial. We aimed to assess the relationship between radiological measurements of subcoracoid impingement and subscapularis tendon lesions in young and middle-aged adults.

Methods

This study was designed as a retrospective cohort study. Patients between the ages of 18–55 years without a history of shoulder surgery or major trauma were included and patients with arthritis, instability, or retracted rotator cuff tears were excluded from the study. Magnetic resonance images were evaluated and patients were grouped into two according to the subscapularis tendon condition: normal or pathologic. Glenoid version, axial coracohumeral distance, coracoglenoid angle, coracoid index, sagittal coracoid-glenoid tubercule distance, and axial coracoacromial inclination-glenoid version difference were measured for all patients. Measurement findings were compared between the groups. Correlation analysis was performed for age and radiologic measurements. A p < 0.05 was considered statistically significant for all tests.

Results

A total of 298 patients, 107 women (35.1%) and 191 men (64.9%), with a mean age of 34.46 ± 10.10 years (range, 18–55 years) were examined in the study. Subscapularis tendon pathology was noted in 85 patients (28.5%). The diagnosed pathologies were tendinosis in 48 patients (56.5%), partial tears in 28 (32.9%), and full thickness tears in 9 (10.6%). A significant relationship was observed between increasing age and subscapularis tendon lesions (p = 0.001). There was no statistically significant relationship between subscapularis pathology and calculated measurements. Axial coracohumeral distance and coracoglenoid angle measurements showed a statistically significantly negative correlation with age. A positive correlation was found between axial coracohumeral distance and coracoglenoid angle measurements (p < 0.001) and also between glenoid version and coracoid index measurements (p = 0.004). Axial coracohumeral distance and coracoglenoid angle measurements showed a negative correlation with glenoid version and coracoid index measurements (p < 0.05).

Conclusions

In this study, the coracohumeral distance and coracoglenoid angle decreased and the incidence of subscapularis tendon lesions increased as the age progressed. However, no relationship was found between radiological measurements and subscapularis tendon lesions.

Less than 9.5-mm coracohumeral distance on axial magnetic resonance imaging scans predicts for subscapularis tear

Background

Diagnosis of subscapularis (SSC) tendon lesions on magnetic resonance imaging (MRI) can be challenging. A small coracohumeral distance (CHD) has been associated with SSC tears. This study was designed to define a specific threshold value for CHD to predict SSC tears on axial MRI scans.

Methods

This retrospective study included 172 shoulders of 168 patients who underwent arthroscopic surgery for rotator cuff tear or glenohumeral instability. Diagnostic arthroscopy confirmed an SSC tear in 62 cases (36.0%, test group a), rotator cuff tear tears other than SSC in 71 cases (41.3%, control group b) and glenohumeral instability without any rotator cuff tear in 39 cases (22.7%, zero-sample group c). All patients had a preoperative MRI of the shoulder (1.5T or 3T). Minimum CHD was measured on axial fat-suppressed proton density-, T2-, or T1-weigthed sequences. Receiver operating characteristics analysis was used to determine the threshold value for CHD, and sensitivity and specificity were calculated.

Results

CHD measurement had a good interobserver reliability (Intraclass correlation coefficient 0.799). Mean CHD was highly significantly (P < .001) less for test group a (mean 7.3 mm, standard deviation ± 2.2) compared with control group b (mean 11.1 mm, standard deviation ± 2.3) or zero-sample group c (mean 13.6 mm, standard deviation ± 2.9). A threshold value of CHD <9.5 mm had a sensitivity of 83.6% and a specificity of 83.9% to predict SSC tears.

Conclusion

A CHD <9.5 mm on MRI is predictive of SSC lesions and a valuable tool to diagnose SSC tears.

Anatomical variations of the acromial and coracoid process: clinical relevance

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Magnetic resonance imaging based coracoid morphology and its associations with subscapularis tears: a new index

BACKGROUND

We aimed to assess the validity of magnetic resonance imaging (MRI) in assessing the subcorocoid space and determine the validity of novel sagittal plane subcorocoid space measurements.

METHODS

We assessed 33 arthroscopically proven subscapularis tears with MRIs compared to 33 (instability) controls with normal subscapularis tendons. Three examiners analyzed MRIs for seven static indices of corocoid morphology, in axial and sagittal planes. We explored reviewer variation using intraclass correlation coefficients (ICC) and differences between the two groups was explored using t-tests.

RESULTS

Groups were similar in characteristics but different in age (cases = 53, controls = 23). ICC showed good (2/7) or excellent (5/7) reliability. Small differences(<1.6 mm) were identified between subscapularis tears and controls in coraco-humeral distance, in axial (p = 0.092) and sagittal planes (p = 0.045). There were statistically significant differences between groups when analyzing the angular projection of the coracoid from the glenoid, in both sagittal (p < 0.0001) and axial planes (p = 0.045).

CONCLUSIONS

Acute inferior angulation of the corocoid in the sagittal plane may be associated with subscapularis tears. Static indices are measured within the scapula and not affected by arm position. MRI reliably provided a platform to assess the coracoid. Based on this, we currently consider corocoplasty in patients with subscapularis tears and a sagittal coroco-glenoid angle <60^o to reduce potential impingement.