Ortho Dx: Foot pain that is worse in the morning

A 64-year-old man presents with right foot pain that he has had for several months. He denies having a prior injury or known precipitating event. The pain is worse in the morning and when going downstairs. On examination, he has pain to palpation over the distal 2nd metatarsal. Anteroposterior X-ray of the foot shows mild flattening ...