Risk factors for displacement after closed reduction of greater tuberosity fracture associated with shoulder...

Greater tuberosity (GT) fractures associated with shoulder dislocation carry a high risk of secondary displacement, even when initial postreduction alignment appears acceptable. However, the specific factors predicting such displacement remain unclear. The aim of the study was to investigate risk factors associated with displacement of GT fragments following anterior shoulder dislocation.

This retrospective study included 52 patients (20 males, 32 females; mean age, 71.5 years) with anterior shoulder dislocation and concomitant GT fractures. Following closed reduction, patients with GT fragment displacement ≥5 mm on CT performed immediately after reduction were categorized as having primary displacement. Patients without initial displacement were followed up on weekly radiographs. Secondary displacement was defined as a fragment shift of ≥5 mm identified during follow-up. Radiographic variables included fragment displacement at dislocation (superior/inferior edge); fragment position; fracture type (avulsion/split/depression); fracture fragment extending across the superior facet (SF), middle facet, and inferior facet (IF) of the greater tuberosity, indicating broad rotator cuff insertion involvement (SF-IF involvement); comminution; bone defect; and critical shoulder angle (CSA). Univariate and multivariate analyses were performed to identify risk factors for both primary and secondary displacement.

Primary displacement was observed in 18 of 52 cases (34.6%). Among the 29 conservatively treated cases without primary displacement, 15 (51.7%) developed secondary displacement within 14 days. Cases with primary displacement showed significantly greater fragment displacement and superior positioning at the time of dislocation. In cases of secondary displacement, the CSA was significantly larger than in stable cases (34.1° ± 3.6° vs. 29.9° ± 5.0°). SF-IF involvement was identified as a significant independent risk factor in the multivariate analysis.

Secondary displacement was common after initially well-aligned reductions and was significantly associated with SF-IF involvement and greater CSA. These anatomical features may reflect increased biomechanical stress from the rotator cuff. Early postoperative monitoring is particularly important in such cases. Radiographic follow-up within the first 2 weeks is recommended to detect secondary displacement and to guide timely surgical decision-making.