Here’s a 65 year old male who presented with a chronic painful left ankle that he described as occasionally “giving out”.

Radiographs revealed an abnormally large fragment of bone (os trigonum) to the back of his ankle joint.
An MRI was performed as I was suspicious of a ruptured peroneal tendon. The MRI revealed no damage.

He was taken to surgery to remove the large fragment and cleaning out of any arthritis.  The associated joints (subtalar and talonavicular joint) are arthritic and may require fusion in the future, but this will definitely buy him some time!