Subtalar instability is a complex sequela of lateral ankle sprain, often associated with concomitant CFL and ATFL injuries. The intrinsic subtalar ligaments, particularly the cervical ligament, also contribute to joint stability and are frequently underrecognized due to small size and partial ruptures. Diagnosis requires integration of clinical findings, MRI, and intraoperative assessment. Surgical management should restore anatomy and biomechanics, with a low threshold for addressing CFL pathology. Treatment options include repair, augmented repair, or reconstruction, increasingly performed endoscopically. In advanced cases, intrinsic subtalar ligament reconstruction may be required to achieve durable stabilization.