What are the complications?
One of the most common complications which can occur is loss of motion. Some patients have severely limited motion before the surgery, but they should at least get back the motion that they had prior to the surgery, and hopefully, gain more. It can be difficult to get the knee to bend back more than 90 degrees (a right angle) after this surgery. Early rehabilitation and physical therapy in the hospital and in the first month is very important. If you do not regain motion beyond 90 degrees, you will have some trouble with stairs, getting in and out of chairs, church seats, and getting on your clothes, socks, stockings, and so forth.
What about other complications? Infection is a major but relatively rare (approximately 1-2%) complication. This is pus in the knee as a result of having had the surgery. It can happen in the hospital or after discharge. It can come from germs acquired in the hospital at the time of surgery or the immediate post operative period, or they can come from your own body soon after surgery or months or years later. If this occurs, another surgery or surgeries will be necessary to at least clean out the knee. The components often have to be removed and sometimes cannot be put back in. Some organisms which are relatively sensitive to antibiotics can be successfully treated and an attempt can be made to replace the components about six weeks post-removal. This stands about an 80% chance of being successful. If unsuccessful, either because the components cannot be replaced or because the infection again recurs, the knee then has to be fused, or made stiff and not move, keeping it in a straight position. The only consolation is that the pain in your knee would be substantially diminished after it was made stiff. This is a very serious complication and if it occurs in the worst form, it could lead to loss of limb and, possible, life.
It is important that you take prophylactic antibiotics if you have dental work done or surgery on your stomach, intestine, or gall bladder, or any sort of “…oscopy”. You can become ill with a high fever, so be sure to tell your doctor that you have had a total knee replacement. Loosening or failure of the components is another complication. This occurs fairly rarely at this time, but it was more common ten to fifteen years ago. If that does happen, the knee usually hurts enough to require another surgery to replace the loose component.
Wear of the plastic portion of the components does occur, and the rate of wear depends on many factors such as age, activity level, weight, and so forth. A severely worn plastic component will most often require revision or replacement as is required when the components become loose.
Blood clots (thrombosis) or inflammation of the blood vessels (phlebitis) can occur in either leg of the deep veins of the thigh and pelvis and require treatment with a blood thinner. If the clot gets loose and goes to your lung, it can be life-threatening. Everything possible will be done to prevent this complication. The internal medicine physician or your family physician will give you a blood thinner, and you will have alternating compression devices on both legs to help prevent blood clots. For more information on DVT (Deep Vein Thrombosis - click here)
Blood loss occurs enough to sometimes require a transfusion, or blood replacement. There is, as you probably know, a small chance of getting HIV/AIDS and/or hepatitis from a blood transfusion. We ask our patients prior to surgery for them to donate their own blood and/or have their families donate blood for them, if they have the right type. My staff will discuss this with you. We use a machine to recover some blood lost during and after the surgery and can give that back to you, reducing the need for transfusion. Nerve and blood vessel damage can occur, but in my experience, is quite rare. Severely deformed knees are more likely to have this type complication.
Some patients complain about the amount of pain after surgery. This is a major operation, and you should expect a good bit of pain in the immediate post operative period. You will either have an epidural or a patient-controlled anesthesia machine, which means that you can, by pressing a button, give yourself pain medicine through an intravenous line when you want it. After a few days, usually one to three, you will be switched off the patient-controlled anesthesia machine or the epidural will be removed and you will take pills for pain. The tolerance of pain is a highly individual phenomenon. Some patients have a little pain and suffer a lot, and others have a lot of pain and suffer very little. Some patients have told me “You did not tell me it was going to hurt this much.” It will, but for most, pain is controlled satisfactorily by one of the above methods.