In patients with persistent shoulder instability, up to 90% of cases report glenoid bone loss. Consequently, clinical and radiological assessments are crucial. While 20% bone loss has traditionally been considered critical, a new “cut-off value” of greater than 13.5% glenoid bone loss has been shown to significantly decrease outcomes after soft-tissue procedures alone. Until recently, CT-based assessments were the gold standard, but comparisons between 3D-MRI and 3D-CT scans revealed no significant differences in bone defect sizes. However, 2D imaging showed notable distinctions between the modalities. With the increasing availability of 3D-MRI, both bone defects and soft-tissue pathologies can be examined in a single imaging procedure with reduced radiation. Arthroscopic evaluation is considered insufficient and is not recommended due to an overestimation of glenoid bone loss.