A patient presents with significant heel pain which has gotten worse in the last few days. The patient is a regular runner. He has already been treated with shockwave therapy and has insoles, but the pain is still getting worse. What would be your next step?

The correct answer is C. Refer the patient for an MRI. The patient has been treated with shockwave therapy and insoles on the assumption that he has plantar fasciitis. However, despite conservative treatment, the pain is getting worse which could indicate a calcaneus stress fracture. This differential diagnosis becomes even more relevant if we consider the fact that the patient is a regular runner.