Is lesser tuberosity morphology related to subscapularis tears and anterior shoulder instability?

Purpose Although the morphological relationship of the scapula and the humeral head has been claimed to be related to shoulder pathologies, few studies examined the relationship between subscapularis (Ssc) tears and lesser tuberosity (LT)—humeral head (HH) and between Ssc tears and HH—glenoid. This study aims to evaluate the relationship of LT with HH and glenoid in patients with Ssc tears and anterior shoulder instability (ASI). We hypothesized that the glenoid, HH, and their combined relationship with LT may impact Ssc tears and ASI. Material and methods The study included 34 patients with ASI, 28 patients with isolated Ssc tears, and 40 patients as the control group. The radius of HH (Hr), the distance between the center of HH and LT (LTr), and the glenoid radius (Gr) were measured in shoulder magnetic resonance (MR) images. The LTr to Hr (LTr/Hr) ratio was defined as the lesser tuberosity-humeral head index (LTHHI), whereas the LTr to Gr (LTr/Gr) ratio was defined as the lesser tuberosity-glenoid index (LTGI). The three groups were compared regarding LTHHI, LTGI, LTr, Hr, and Gr. Results There was a significant difference between each group concerning LTGI ( p