Nouveaux facteurs prédictifs de la rupture du subscapulaire : angle de coraco-petite tubérosité humérale, angle et hauteur de la tubérosité inférieure

Abstract Background The pathogenesis of degenerative subscapularis (SC) tear is not clear, several mechanisms are involved: intrinsic tendon degeneration or subcoracoid impingement. The aim of this study was to propose new radiographic markers, the coraco-lesser tuberosity angle (CLA), lesser tuberosity angle (LTA) and lesser tuberosity height (LTH). The hypothesis was that higher values of CLA, LTA, and LTH would be associated with a higher likelihood in detecting a SC tear. Method A total of 114 patients who classified as SC tears through arthroscopic evaluation were retrospectively enrolled in the study from 2016 to 2018. Fifty-seven patients with impingement syndrome were also enrolled as the control group for normal-population comparison. The CLA was measured on an anteroposterior shoulder x-ray image with the arm in neutral rotation, the LTA and LTH were measured on magnetic resonance imaging. Multivariable analyses were used to clarify the potential risks for SC tears. All measurements were calculated by two shoulder surgeons independently measured at 2 different times, 1 month apart. Results The intra- and inter-observer reliabilities for radiologic measurements and the interobserver reliability of SC tear classification were almost perfect. The mean CLA value of SC tear group (41.4 ± 4.2°) was significantly larger than that of the control group (38.7 ± 4.0°, p  Conclusion Our findings confirmed associations between new predictors (CLA and LTA) and SC tears. CLA and LTA values were greater in patients with SC tears than in controls, suggesting that they may be independent risk factors for SC tear onset. Level of evidence Level IV, retrospective study.