I to had a tkr.Mine is a DePuy Rotating Platform Knee.It is made of Cobalt and Chromium.I started with a rash almost immediately after the surgery and still have it.I have been to 2 allergist and 2 dermatologist.No one has a solution to the problem.I did have the LTT test done and am allergic to the bone cement and metals.However my function is good but the constant itch is bad.My surgery was Jan. 2011.The only temporary relief is from taking the antibiotic Doxycycline Mono .Sarna cream also slows the itch.If you have found a cure for the rash I would be very grateful if you would share it with me.If you are contemplaing a replacement I strongly encurage the LTT test pre surgery.It should be the standard of care for all knee replacements.The lymphocyte Transformation Test is done by a Lab in Chicago.E-mail cure to blaulaw@zoomtown.com thanksView Thread