Patients typically stay in the hospital for 3 to 5 days after the knee replacement surgery, depending on the complexity of the procedure. You will be able to stand up with the help of crutches within 12 to 24 hours of the surgery, and you may continue to need crutches until around 6 weeks after the surgery. Painkillers will be prescribed to help you manage the pain, and it may take up to 3 months for the pain to completely subside. Full recovery may take at least a year.