A 27-year-old man is brought to the emergency department after a motorcycle collision. He sustained a closed right tibial shaft fracture, which was stabilized in a long-leg splint by emergency medical services. Six hours after presentation, he complains of progressively worsening, severe right leg pain. He describes the pain as feeling “tight and burning,” and states it is much worse than when he first arrived. He has required multiple doses of intravenous opioids with minimal relief. His medical history is unremarkable, and he takes no daily medications. He does not smoke or drink alcohol.

He appears distressed and is writhing in bed. He is afebrile. His blood pressure is 130/70 mmHg, his heart rate is 110 bpm, and his respiratory rate is 20/min.