Knee replacement surgery, is also known as knee arthroplasty, a surgical procedure to replace the weight-bearing surfaces of the knee joint to relieve pain and disability. It is most commonly performed for osteoarthritis, and also for other knee diseases such as rheumatoid arthritis and psoriatic arthritis. Hospital Admission: Normally , you need to stay in hospital 1-2 days in advance before your surgery for the preparation. Your doctor and nurses will give you the full details regarding anesthesia type used like spinal, epidural or general anesthesia. Knee replacement surgery will take 1-2 hours. Hospital Stay: Hospital stay is 5-7 days.