Summary

Several radiological parameters have been proposed as predictors of subscapularis tears to improve diagnostic sensitivity and accuracy. Among them, the coracohumeral angle emerges as the only statistically significant parameter, demonstrating low heterogeneity and with a mean difference that could have clinical value in decision making.

Abstract

Background

Accurate diagnosis of subscapularis tears remains challenging due to the limitations of physical examinations and imaging techniques. Furthermore, degenerative tears of this tendon are a well-recognized source of shoulder pain and dysfunction but have historically been underestimated and underdiagnosed. Therefore, certain radiological parameters have been proposed as predictors of subscapularis tears to improve diagnostic sensitivity and accuracy. These parameters include coracohumeral distance (CHD), coracoglenoid angle (CGA), coracoid angle (CA), coracoid overlap (CO), and coracohumeral angle (CHA). However, well-accepted cutoff values are still lacking, and there is no consensus on its clinical usefulness.

Hypothesis

Patients with subscapularis tears would present clear differences in coracoid-related measurements compared to those without subscapularis tears.

Study Design:
Systematic review; Level of evidence, III.

Methods

The PubMed, Scopus, and Cochrane Library databases were queried in July 2024. Inclusion criteria focused on studies that reported MRI-based radiological measurements of the coracoid process in patients with subscapularis tears versus controls. The Newcastle-Ottawa Scale was used to assess the quality of the studies. The raw mean differences (MD) were used to evaluate the effect size, with 95% CIs.

Results

In total, 14 studies involving 1,692 patients with subscapularis tears and 1,648 controls were included. Significant findings include a smaller axial CHD in the subscapularis tear group compared to controls (MD, -1.67; 95% CI, -2.61 to -0.72; P = 0.002). The sagittal CHD was also reduced in the tear group (MD, -1.43; 95% CI, -1.89 to -0.98; P < 0.0001). The CGA was (MD, -1.15; 95% CI, -2.20 to -0.10; P = 0.032), and the CA was also reduced (MD, -18.63; 95% CI, -35.60 to -1.66; P = 0.042). The CO showed no significant difference between the tear and control groups (MD, 1.68; 95% CI, -1.27 to 4.62; P = 0.21). In contrast, the CHA was increased in the tear group (MD, 3.71; 95% CI, 2.32-5.11; P < 0.01).

Conclusions

Although several radiological parameters such as CA, CHA, CGA, and axial and sagittal CHD showed statistical differences between patients with subscapularis tears and controls, axial CHD and CA showed high heterogeneity. Furthermore, although CGA and sagittal CHD were statistically significant, the differences were minimal, questioning its clinical usefulness. Coracohumeral angle (CHA) was the only parameter with statistical significance and low heterogeneity, along with a mean difference that could be clinically significant. However, further research is needed to standardize these measurements and validate their clinical relevance.