Most people who get a "new hip" or "new knee" go on with their lives feeling healthier and happier, with a fresh and pain-free spring in their steps. However, the procedure doesn't go smoothly for everyone. Sometimes a sudden, intense pain can occur in a replacement joint, either shortly after the procedure or in the years to come. The slightest movement can feel agonizing. The skin can look red and warm. The likely culprit? An infection in the joint.
Surgeons perform about a million hip and knee replacement operations in the U.S. every year. Unfortunately, a small number of people who have the procedure — about 1 in 100 — develop an infection sometime later. Infection is more likely to happen in replacement knees than hips, and most typically occur within two years of having the replacement done.
Behind the infection
The cause of joint infections can be bacteria — such as the staphylococcus bacterium often carried on the skin, tuberculosis or the bacterium that causes the sexually transmitted infection gonorrhea — viruses, fungi and other germs. These organisms can reach the joint in two ways:
- If an infection is located elsewhere in your body — such as pneumonia in your lungs or a urinary tract infection — it can be transported through your blood and settle in a joint.
- Through direct injury such as a cut or puncture over the front of the knee.