"My knee was great just a week ago." Infection as a cause of failure of total knee replacement

This is the third in a series of posts discussing causes of failure of total knee replacement.

          Knee replacement surgeries are usually performed to help people with end-stage degenerative changes of their knees get rid of pain and return to a more active lifestyle. Knee replacement surgeries are generally successful and represent one of the most successful procedures in orthopedic surgery and medicine in general. However, knee replacements can fail. Knee replacements can fail from a myriad of reasons. The third cause of total knee replacement failure to be discussed in this series is infection. 

          Knee replacements can get infected. Infection can happen shortly after surgery or can happen several weeks, months, or even years after the knee replacement surgery. Infections can be as a result of contamination during surgery, or can be as a result of bacteria in the blood that seed the knee replacement and cause infection.  

          An infected knee replacement can cause pain. Infections can also lead to implant loosening or other complaints from a previously well performing knee replacement. Pain from an infected knee can limit the ability to walk, bend the knee, or participate in activities. The knee can be swollen, warm, red, or painful to touch. Some patients with subclinical infections can have recurrent knee swelling without severe pain. 

           The suspicion for a knee infection is heightened when patients with well performing knee replacements suddenly develop severe pain. X-rays would typically be obtained to examine the knee replacement implants and their fixation. Physical examination, symptoms, and x-rays alone are not diagnostic of an infection, but they can heighten its suspicion. Blood work would often be done. A knee aspiration would be performed when the suspicion is high enough for an infection. The fluid aspirated from the knee would be sent for analysis and can confirm a knee infection.  

         Managing a painful, infected knee with pain medications alone is not an option. The treatment for an infected knee replacement is almost always surgical. It can be non-surgical in cases where surgery poses a significant risk to life. In those cases, the treating surgeon would consider the use of antibiotics for chronic suppression. Note that this would likely not eradicate the bacteria or infectious organism. The best surgical measures would depend on time from surgery, length of symptoms, health of patient, patient preference, surgeon preference, implant stability, and infectious organism among other factors.  The possible surgical measures would include washing out the knee, and exchanging the plastic; taking out all the knee replacement components, aggressively washing the knee, and replacing with new knee replacement components in the same setting; removing the components, implanting antibiotic spacers, and coming back in several weeks to months to remove the antibiotic spacer and implant new knee replacement components. Intravenous antibiotics are a necessary adjunct when treating knee replacement infections. The actual discussion of which surgical measure is best for an individual patient is beyond the scope of this post. 

          If you have a painful knee replacement with concern for an infection, call Hays Orthopedic Institute at 785 261 7599 to schedule an appointment with Dr. Akinbo.