Problem & Significance

 

Total knee arthroplasty (TKA) is the replacement of damaged tissue and bone with a biocompatible metal and a polyethylene prosthesis to allow for free movement. When a primary surgery fails, a revision surgery must be performed to remove and replace the damaged implant. TKAs are one of the most commonly performed procedures in the United States, with over 600,000 primary TKAs and 60,000 revision TKAs performed annually. Knee surgery accounts for 7.3 billion dollars of the 43 billion dollar global orthopedic industry.

 

The leading cause of primary implant failure is periprosthetic infection (PPI), which is a bacterial infection at the site of the implant. Bacteria forms an adhered layer on the surface of the implant called a biofilm, which prevents successful intervention of antibiotics to eradicate the infection. In order to treat PPI with antibiotics, infection must be detected prior to biofilm formation.

 

Periprosthetic infection (PPI) is the primary cause of premature implant failure, accounting for about 25.2% of all revision surgeries. At around $50,000 dollars per revision surgery, PPI costs roughly 385 million dollars per year. Although PPI at the site of the implant can be treated with antibiotics if detected early enough, it is rare that patients present with symptoms until the infection has progressed to biofilm formation where it is too late to save the implant. Patients who present with symptoms such as pain and swelling at the site of the implant, are subjected to a number of tests and scans to confirm the diagnosis. However, because patients rarely present with symptoms until the infection has progressed, treatment with antibiotics is often no longer a viable treatment option and a revision surgery must be performed. Therefore, there is a large deficit in care that current diagnostic and treatment methods do not address.