A 72-year-old woman presents to the emergency department following a fall at home while walking to the bathroom at night. She reports severe pain in the left hip and is unable to bear weight. On examination, the left lower limb is held in external rotation and appears shortened compared to the right. Plain radiographs confirm a displaced intracapsular fracture of the left femoral neck. Her past medical history includes hypertension and type 2 diabetes. What is the most appropriate initial management for this patient?