I am trying to make sure that I code this correctly. My doctor treated a patient that had a previous hemi several years ago by doing a total knee. He removed the hemi components and replaced with total knee components. He turned in 27447 for the total knee but I am thinking that I need to code this with the 27487: revision of total knee with a 52 modifier for the reduced services since the patient had the hemi in the past and not a total knee. Any thoughts?