ORTHO- coding help

Hi everyone,
I have an operative report to code for severe bilateral leg fractures. On one leg surgeon did ORIF medial malleolus, tib shaft and distal wt bearing surface tib.. All of which are fine, what I am having a little trouble with is that he then indicates he did

"stem cell harvest from left proximal tibia and injection of stem cells into fracture site".

Can anyone guide me on coding this procedure? I am looking at CPT® 38206 but i'm not sure and of course I don't know if the fracture diagnoses codes would be appropriate for this procedure.
Any help would be greatly appreciated.
TIA
Margaret