What do you advise if i had a knee replacement and now my knee dosent ben t?

See Ortho doc: you may need exercises to range your knee, however if there is something wrong with your replacement the orthopedic doc may need to further evaluate you.

Re-evaluation: stiffness after knee replacement can be helped with PT and exercises, if it is within the first few weeks to months. If the stiffness is beyond that, then surgical options would need to be explored to determine if soft tissue releases and scar removal or whether component revision is necessary depending on the severity of the stiffness.