MSRA-1268

A 42-year-old man is brought in by ambulance after falling off a 6-foot ladder and hitting his head. He has a deep laceration to the lateral left knee and is being kept overnight for observations. An x-ray of the left leg shows no fractures. He has a history of hypercholesterolemia.

During the night, he is using the maximum dose of prescribed PRN morphine due to pain in his left leg. The doctor is called to review the patient and on examination, there is reduced sensation on the medial aspect of the plantar left foot.

What is the most likely diagnosis?