Infection after Knee Replacement

Not all knee implant complications occur as a result of defective devices. One of the most serious complications of knee replacement surgery is infection. Fortunately, the chance of having an infected knee prosthesis is relatively low. In 2010, the rate of infection for knee replacements was less than 1 percent. People who undergo revision surgery — a second surgery to replace an implant — have a higher risk of developing infection.

Typically, when a microorganism enters a part of the body, the body’s defenses can travel to the site through the blood supply and any medicines can also circulate through the blood to kill bacteria. Because the knee implant does not have its own blood supply, it is easier for microorganisms to attach to the device and infect surrounding tissues. The surfaces of the implant components are ideal for organisms to adhere to and multiply. Once they multiply, they create a film that acts like a biological shield and protects them from antibiotics. Although rare, the risk of infection continues for as long as the prosthesis remains in the body.

Prosthetic joint infections are classified into three types based on the amount of time that has elapsed from the surgery to the onset of infection:
Early infections occur within 3 months of surgery and are usually caused by microorganisms that enter the body during the operation. People with these infections may suffer from a leaking wound, fever, swelling and effusion around the implant.  
Delayed infections can occur from 3 months to 12 months after the surgery and are also caused by organisms entering the body during the surgery. The symptoms of these infections are usually the same as those seen in early infections.  
Late infections occur more than a year after surgery. These infections are usually haematogenus, meaning they are acquired from another location in the body. Bacteria from other infections such as a dental infection, pneumonia, skin infection or urinary tract infection can travel in the blood and adhere to the prosthesis. To prevent these types of infections, doctors recommend that patients with prostheses take antibiotics before any surgical procedure. In late infections, joint pain and effusion are common symptoms. Sometimes, the joint is also inflamed, and sepsis may set in.  

Doctors test for infections using blood tests, radiology tests, blood cultures and joint aspirations (removing fluid from a joint). The type of bacteria that is present in the infection is tested by culturing the tissue sample in a lab.


If you or a loved one has had problems after knee replacement, Contact us today for a free legal case consultation and evaluation. Joel A. Nash, Esq. (216) 691-3000