ARTHRITIS OF THE KNEE JOINT

The main long-term problem of joint replacements is loosening.

With time and stress, fixation of cement to bone can fail. It is hoped that in time cementless replacements will prove more able to withstand vigorous activities than the cemented replacements. They have not been in use long enough for anyone to be sure yet that this will be the case. Both cemented and cementless knees should therefore be treated with the same care. You should minimize activities which could cause loosening (see below). If the implant comes loose, movement between it and bone can cause pain and require re-operation.

If you have a cemented knee, your new knee should be pain-free after 3 months. However, from time to time, especially in the first year, you may have a twinge of pain. This you can ignore. If you have pain that doesn’t go away, or seems to increase from day to day, you should come in to see Dr. Huddleston for x-rays and evaluation. It could signify infection or loosening.

The longevity of your knee replacement can be increased by:

It is important that you not become overweight, since excess weight increases the stresses on the knee replacement, and can cause loosening.

The possibility of infection occurring around the replacement is another concern.

Therefore, if you develop an infection you should consult your family physician and have him treat it promptly. Viral infections, such as colds and most sore throats, are not a problem. Dental work can push bacteria into your bloodstream and cause an infection in your joint replacement. We recommend that you take antibiotics if you are to have dental work (other than simple cleaning of your teeth). You will be given a plastic card to keep in your wallet containing information about dosage.

If you are to have cystoscopy, bronchoscopy, or colonoscopy you should also be covered by an antibiotic. Doctors vary on their recommendations as to which antibiotics should be used and for how long.

The following is recommended:

Not Allergic to Penicillin: Cefalexin or amoxicillin: two grams by mouth one hour before the procedure.

Allergic to Penicillin: Clindamycin 600 mg. by mouth one hour before the procedure.

Dental procedures that pose increased risk and should be covered by antibiotics: extractions, periodontal procedures, dental implant placement, root canal work, and dental cleaning where bleeding is anticipated.

Patients with immunosupression, rheumatoid arthritis, lupus erythematosis, insulin-dependent diabetes, hemophilia, or who have had previous prosthetic joint infections, are especially at risk and should take these precautions for life. A recently published American Academy of Orthopedic Surgeons Advisory Statement suggests that all others are at risk for only two years after a joint replacement operation.