Dear Dr. Roach: I am thinking of having a total knee replacement done, as recommended by my doctor. I have bone on bone in my knee. What is your opinion? I know a friend of a friend who had one done three months ago and has had nothing but trouble. He has had two manipulations because he cannot bend past 95 degrees. Even though he goes to physical therapy, they have had no results. Does this happen often with knee replacement? How about stiffness? How long before a patient is as good as new? Would you recommend the surgery, and what percentage of patients have the issues he is having? Anon.
Answer: Knee replacement (also called total knee arthroplasty) is one of the most effective surgeries performed, in terms of improving quality of life. Studies have shown that about 80 percent of people are satisfied with the outcome of their knee replacement. The reasons that the remainder are dissatisfied generally have to do with complications of surgery, including infection, nerve injury, instability and stiffness (the inability to properly flex the knee), which is the issue for your friend of a friend. Only about 5 percent of people have stiffness, according to a 2006 paper, and these mostly improved with manipulation, although some needed a second operation.
It is important to recognize the limitations of the surgery. You are never going to be as good as new that is, as good as before the arthritis in the knee developed. But most people are much better than where they started within three to six weeks of the surgery. Physical therapy after surgery is critical for success (but, as your friend shows, not a guarantee of success).
My own patients experiences have been largely favorable. I have seen some bad complications, but most people are very satisfied, and the most common regret I hear is that they had not done the procedure earlier. Eighty to 90 percent of knee replacements are expected to last 15-20 years.