Case 29 AnswerNot a lot of answers on this one. Too easy?You can see a large loose bony fragment in the lateral aspect of the medial femoral...

Case 29 Answer

Not a lot of answers on this one. Too easy?

You can see a large loose bony fragment in the lateral aspect of the medial femoral condyle. This is a classic location for a loose osteochondral body, better known as osteochondritis dissecans. 

This one certainly looks free-floating, but MRI is a modality of choice.

Reference: http://radiopaedia.org/articles/osteochondritis-dissecans-of-the-knee