Examination of the factors associated with humeral head size as calculated by 3-dimensional computed tomography in patients with rotator cuff tears

Background

Despite the effectiveness of 3-dimensional computed tomography (3D-CT) for identifying bone and joint conditions, there are few clinical data on humeral head enlargement in patients with rotator cuff tears (RCTs), including cuff tear arthropathy (CTA). This study aimed to investigate the factors correlated with humeral head size measured through 3D-CT in patients with RCTs.

Methods

This cross-sectional study included 43 preoperative patients who were diagnosed via RCTs. The severity of RCTs was classified into 3 types: small-medium tears, large-massive tears, and CTA. The 3D-radius was calculated from the raw radius data using 3D-CT and adjusted by height as a corrected-radius. The reliability of the 3D-radius measurements was calculated as the intraclass correlation coefficient. Various statistical analyses, including correlation coefficients, group comparisons, and multiple regression analyses, were used to explore factors associated with humeral head size.

Results

The interobserver reliability of the 3D-radius was 0.903. The corrected-radius on the affected side exhibited correlations with age (r = 0.598, P < .001) and the acromion-humeral interval (r = −0.609, P < .001). Group comparison between tear sizes, the CTA group had larger corrected-radius than the other groups (P = .001), with no significant difference between the small-medium tear and large-massive tear groups (P = .932). Multiple regression analysis adjusted for covariates revealed that the corrected-radius was correlated with age and the acromion-humeral interval (P < .05, R² = 0.474).

Conclusion

These findings provide valuable clinical insights into the factors associated with humeral head enlargement, particularly in patients with RCTs. The measurement method we used holds promise for informing the selection of artificial head sizes during the preoperative planning of total shoulder arthroplasty.