A 62-year-old woman with osteoporosis presents to the emergency department 2 hours after a fall on an outstretched hand. Clinical examination reveals a 'dinner fork' deformity of the right wrist with dorsal angulation. X-rays confirm a Colles fracture with dorsal displacement and angulation. The hand is warm, well-perfused, and sensations are intact. What is the most appropriate immediate next step in management?