Hard lumps above knees

[5564ham]

My six year old mare has developed a hard splint like lump just above knee on the inside of each front leg. She has been in steady work, nothing too strenuous. Has anyone got any ideas?

 

[Daisychain]

Are you sure its not just her conformation? lots of horses have lumps like this on inside of knee.

 

[ofcourseyoucan]

pictures?