A 72-year-old woman from Delhi presents with severe left hip pain and inability to bear weight after a fall from standing height while walking in her garden. On examination, the left lower limb is held in external rotation and slight flexion. Neurovascular examination is intact. Plain radiographs show a fracture of the femoral neck with the fracture line running horizontally across the narrowest part of the neck. The fracture is non-displaced and involves the intracapsular region. Which of the following is the most appropriate initial management?