Is it wise to walk for 30 minutes a day/5 days a week, 6 months after a total knee replacement surgery?

Yes: I generally encourage exercise after joint replacement. It is important to maintain muscle tone, weight control and general health. I don't recommend activities which involve impacts such as running.

Ask your doc: In general, I do not see a problem with that type of program but it is really best for someone with knee replacements to discuss the appropriate exercise program with the orthopedist who did the surgery. Not every surgery is the same and there may be some precautions that are applicable to the individual.

Yes.: Exercise is important to maintaining many aspects of health. Walking is typically well tolerated by an artificial joint. Use common sense to guide your initial efforts. Start slowly and add duration/distance in small increments.