A major potential risk is the risk of infection. Again, in this hospital, the risk of infection is in the order of 1/2% or less. 1/2% would be 1 case in 200 and, in our hospital, the risk is actually 1 case in 400. You will be receiving an antibiotic on the morning of surgery and this will be continued for 24-36 hours after surgery.

There are other preventive measures that will also be undertaken to reduce the possibility of infection. In spite of these, a very small percentage of patients will develop an infection and that generally can be treated by antibiotics and cured.

This would require longer hospitalization, treatment with antibiotics for a longer period of time, perhaps opening and draining of the knee and, in some instances, perhaps even removal of the artificial components themselves in order to cure the infection after which another knee replacement could be implanted.

There is also some risk of an infection elsewhere in your body after the surgery settling in the knee and therefore we strongly recommend that patients who have total joint replacement take antibiotics whenever they have infections in another area and particularly if they are going to have extensive dental work. Antibiotics do not need to be taken for routine cleaning or simple fillings. We will provide you with a card indicating what needs to be done if you can give this to your doctor or to your dentist should that be necessary.

Another risk of total knee replacement is that the motion of the knee may be more limited than before the surgery. To a certain extent, how well your prosthesis moves after it’s put in will depend upon how much your knee moved before the operation. People with very stiff knees before the operation may not get as much motion as patients without stiff knees.

In addition, some people whose knees moved easily before the operation may actually lose some motion after the operation. However, the important thing to understand is that it is motion without pain that is important. If there is a lot of motion before the operation but it is painful and after the operation there is some limitation of motion but it is pain-free, this is an improvement.

We would like the knee to move to about 105°. This makes it easy for the patient to get up and down stairs and go up and down out of a chair quite easily. This will be one of the things that you will be required to do in the post-operative period.

Physical therapy, both in the immediate post-operative period and after you go home, is very important. It’s important to recognize that this is not something that is just going to come your way without any participation on your part. You will have to extend some effort to get the best possible result. We will be asking you to move your knee in the post-operative period. We will be asking you to work on strengthening your muscles.

If, in about 10 days, you are not getting your knee to 90°, a right angle, we may recommend a manipulation. A manipulation means that you would be put to sleep and your knee would be passively, physically bent for you. This could break down some adhesions (scar tissue) that might have formed around your knee after the surgery.

One of the things that could occur is the loosening of the prosthesis. This loosening would not happen suddenly, but it would be a gradual process and it would be characterized by discomfort.

In most instances, if a prosthesis becomes loose, it can be corrected but that usually means further surgery. Now what is the nature of this risk? That depends on several circumstances. We think in general, it’s probably a cumulative risk of about 1% per year, so that if you have your prosthesis for 20 years, the possibility of loosening over that 20 years could be as high as 1 in 5.

If you have your prosthesis for 10 years, it could be 10%. However, improvements in the instruments, prostheses, and the surgical techniques used today may result in a reduction in the risk of loosening.