I had a total right knee replacement on 11/17/15 after 12wks of healing and therapy numbness from my knee down to my toes told tibial @ pop was nicked?

Varies. Numbness is typically a neurological complaint. After a knee replacement, numbness can be related to an aggravation of a nerve in the back, or it can be something more near the knee replacement itself; which is what you are implying when you say the nerve may have been "nicked". A nerve conduction test can usually tell the cause or at least location of the problem.