The knee is a very important joint. It allows a person to walk, run, sit, and kneel. Thus, when a person contracts a knee infection, it is important to seek a doctor's help for proper treatment. Often an infection can be treated with antibiotics, but surgery may also be needed to get rid of the problem. It all depends on the type and severity of infection.
There are several conditions that can be classified as a knee infection, including knee bursitis, septic arthritis, osteomyelitis, and cellulitis. Infections typically are caused by bacteria, virus, or a fungus. Of all the infections, knee bursitis may be the most common. It is caused when an organism, usually a bacterium, invades the bursae, a sac of fluid that helps lubricate the joint. Bacterial infections also can cause arthritis, such as with septic arthritis—the bacteria may enter the body through a wound and make its way to the knee where it settles. Bone also sometimes gets infected, causing a condition called osteomyelitis. This infection can cause an abscess in the bone that can cut off nutrients and oxygen to the bone. Another infection called cellulitis can affect the knee when bacteria infect the skin above the knee.
Doctors normally treat bacterial infections with antibiotics. Viral infections, however, commonly clear up by themselves and require no medication. Antibiotics are not commonly used for viral infections because viruses do not usually respond to them.
An infection can also be the result of a complication of knee surgery. This type of infection is called a postoperative infection. In this case, bacteria can invade the knee and cause pain, fever, and swelling. Often, the surgeon will have to go in and remove or wash out the bacteria. After this, antibiotics are usually administered to eradicate the rest of the pathogen.
Surgical treatment methods may also be used when the knee infection is severe, such as in advanced cases of osteomyelitis. If the abscess of bacteria has created a hole in the bone, a doctor may have to go in to drain the infection. Another treatment option for draining an infection is a needle aspiration. During this procedure, a doctor typically uses a needle to suck out the infection. In either case, antibiotics will usually have to be taken for a period of time after the procedure to ensure the bacteria is eradicated.