Do knee implants have nickle parts?

Yes. Almost all knee replacements are made of a cobalt chrome alloy, which contains nickel. Nickel is important in making the metal hard enough to walk on. Unfortunately many patients are allergic to nickel. There is one knee replacement made of titanium that has been hardened by creating a ceramic layer called oxinium that does not contain nickel. Ask your surgeon if you are concerned!
Nickel. Most do have a small amount. Smith & nephew oxinium knee does not, & can be safely used for nickel allergy patients.