Review Question - QID 7422

A 39-year-old man reports a 2-year history of increasing right anterior ankle pain. He denies trauma, steroid use, or heavy drinking. He states that he has chronic pain that worsens when he walks on irregular surfaces. Treatment consisting of two prior ankle arthrotomies for the debridement of anterior loose bodies has not alleviated his symptoms. Selective local injections show his symptoms are limited to the talonavicular and subtalar joints. A lateral radiograph, CT scans, and MRI scans are shown in Figures 34a through 34e. What is the most likely diagnosis?