Haven't had knee replacement however have had two knee surguries and my wife is about to get her other (from last year) knee operated on (maniscus) and both of ours so far have been very suscessful. That said, do ask you doc about it and tell them your cycling needs. They should be able to give you the skivvy on what kind of PT you might need to do. In my wife's and my cases, the only PT we needed or did was riding.