I've got the Depuy Rotating Platform knee. I'm about 11.5 wks post op and haven't experienced any problems..It was my desire before surgery to get back in to martial arts. I've taught some classes but haven't actively jumped into it. After having the surgery, I believe I will rethink my goals. I enjoy other activities that don't put quit the strain on the knee. I think that the development of the new knees is like buying a computer.. You can wait for the best one but as soon as you buy it, an new and better one is on the market. We can toss the computer but have to live with these knees for awhile...I hope a long long time.