Dr. Friedrich Boettner performed a total left knee replacement on me at HSS in October 2007 with outstanding success. HSS and its staff are a model of efficiency and expertise. I was walking and back at work, using neither cane nor any other walking aids and without a limp two weeks after surgery. I was very diligent with post-surgery exercises and have had total range of motion and no pain in the knee ever since. I am very physically active and am not inhibited at all by the knee. I cannot recommend HSS, and Dr. Boettner, highly enough.