MRI analysis of coracohumeral interval width and its relation to rotator cuff tear

Chronic Adaptation of the Coracohumeral Space and Subscapularis Tendon in Professional Baseball Pitchers

BACKGROUND

Pitchers frequently experience anterior shoulder pain, possibly associated with coracohumeral impingement; however, whether the coracohumeral distance (CHD) and/or subscapularis tendon adapt chronically (bilateral difference) due to pitching, and whether clinical measures are associated with CHD and subscapularis tendon organization have not been evaluated in professional pitchers.

HYPOTHESIS

The authors hypothesized that dominant arm CHD would be smaller than the nondominant arm, dominant subscapularis tendon would have increased spatial frequency (ie, be more disorganized), and humeral retroversion (HR) would predict CHD and subscapularis tendon organization.

LEVEL OF EVIDENCE

Level 4.

METHODS

Healthy professional baseball pitchers were recruited during their preseason physical examination. Bilateral diagnostic ultrasound measured CHD, HR, and posterior capsule thickness (PCT), and quantified subscapularis tendon organization. External rotation, neutral, and crossbody CHD was measured.

RESULTS

Overall, 52 healthy professional baseball pitchers participated. The dominant arm of pitchers demonstrated a significantly narrower CHD in all 3 positions (P < 0.01), increased scapular protraction (163 vs 156 mm; P < 0.01), and increased spatial frequency of the subscapularis tendon (1.8 vs 1.6 peaks/mm; P < 0.01). HR was associated with CHD in 30° of external rotation (R2 = 0.12; P < 0.01), neutral rotation (R2 = 0.11; P < 0.01), and the crossbody position (R2 = 0.28; P < 0.01). PCT was associated with CHD in 30° of external rotation (R2 = 0.16; P = 0.05). HR and CHD in 30° of external rotation was associated most strongly with subscapularis tendon organization (R2 = 0.11; P = 0.03).

CONCLUSION

The dominant shoulder of professional pitchers presents with a smaller CHD, more scapular protraction, and more subscapularis tendon disorganization than the nondominant shoulder.

CLINICAL RELEVANCE

Professional pitchers demonstrate chronic CHD and subscapularis tendon adaptations, which may increase their risk for anterior shoulder pain and subscapularis tendon injury.

In Vivo Anatomical Research by 3D CT Reconstruction Determines Minimum Acromiohumeral, Coracohumeral, and Glenohumeral Distances in the Human Shoulder: Evaluation of Age and Sex Association in a Sample of the Chinese Population

Accurate measurement of the minimum distance between bony structures of the humeral head and the acromion or coracoid helps advance a better understanding of the shoulder anatomical features. Our goal was to precisely determine the minimum acromiohumeral distance (AHD), coracohumeral distance (CHD), and glenohumeral distance (GHD) in a sample of the Chinese population as an in vivo anatomical analysis. We retrospectively included 146 patients who underwent supine computed tomography (CT) examination of the shoulder joint. The minimum AHD, CHD, and GHD values were quantitatively measured using three-dimensional (3D) CT reconstruction techniques. The correlation between minimum AHD, CHD, and GHD value and age with different sexes was evaluated using Pearson Correlation Coefficient. The mean value of minimum AHD in males was greater than that in females (male 7.62 ± 0.98 mm versus female 7.27 ± 0.86 mm, p = 0.046). The CHD among different sexes differed significantly (male 10.75 ± 2.40 mm versus female 8.76 ± 1.38 mm, p < 0.001). However, we found no statistical differences in GHD with different sexes (male 2.00 ± 0.31 mm versus female 1.96 ± 0.36 mm, p > 0.05). In terms of age correlation, a negative curve correlation existed between age and AHD among the different sexes (male R2 = 0.124, p = 0.030, female R2 = 0.112, p = 0.005). A negative linear correlation was found in CHD among the different sexes (male R2 = 0.164, p < 0.001, female R2 = 0.122, p = 0.005). There were no differences between age and minimum GHD in both sexes. The 3D CT reconstruction model can accurately measure the minimum AHD, CHD, and GHD value in vivo and is worthy of further investigation for standard clinical anatomical assessment. Aging may correlate with AHD and CHD narrowing for both sexes.

Subscapularis Tendon Slip Number and Coracoid Overlap Are More Related Parameters for Subcoracoid Impingement in Subscapularis Tears: A Magnetic Resonance Imaging Comparison Study

PURPOSE

To investigate the effects of the subscapularis tendon slip number (STSN) and coracoid morphology by magnetic resonance imaging in patients with and without subscapularis tears.

METHODS

Patients who underwent shoulder arthroscopy between February 2004 and June 2015 were re-evaluated. Those with a subscapularis tear (study group) and those with other pathologies (control group) were compared with each other. Magnetic resonance imaging scans and surgery videos of the patients were reassessed. Transverse and sagittal coracohumeral distance (CHD), coracoid overlap (CO), coraco-coracoid base angle (CBA), coracoglenoid distance (CGD), and STSN were measured.

RESULTS

The study and control groups comprised 141 and 78 patients, respectively. The mean age was 57.01 ± 10.95 (similar in both the groups). The mean transverse CHD and sagittal CHD were not different between the groups and also between female and male patients. For the study and control groups, the mean CBA and CGD values were also similar. The mean CO was 24.01 ± 4.9 and 21.29 ± 4.58 for the study and control groups, respectively (P < .001). With the receiver operating characteristic curve of the CO, the sensitivity was 62% and the specificity was 64% at the cutoff value of 22.85 mm. The STSN was in the range between 1 and 6; the STSN was 3 or less in 61.5% of the study group and in 38.5% of the control group (P = .005).

CONCLUSIONS

The CO was the most valuable parameter predicting any potential subcoracoid impingement, and the STSN was inversely correlated with subscapularis tears. However, in predicting a potential subcoracoid impingement, the CHD measurements were not significant, as well the CGD and CBA.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.