Prosthetic Joint Infection

What is Prosthetic Joint Infection?

Prosthetic joint infection (PJI) is an infection of an artificial joint, such as a hip or knee replacement, that occurs during both post-surgical implantation and through the development of long-term complications. It affects around 1-2% of people who have had total joint replacement surgery and is one of the most common and serious medical complications for people who have undergone joint replacement surgery.

Signs and Symptoms of Prosthetic Joint Infection

Common signs and symptoms of a prosthetic joint infection may include:

  • Pain – this usually increases when pressure is put on the joint or when the joint is moved.
  • Joint redness or warmth to the touch.
  • Swelling of the joint.
  • Flu-like symptoms such as fever, nausea, and chills.
  • Drainage or abscesses around the joint.

Causes of Prosthetic Joint Infection

Prosthetic joint infections can be caused by a number of different bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Pseudomonas aeruginosa. It can occur in the early post-surgical period, or can develop up to several years after the procedure.

A prosthetic joint infection can also be caused by entering the joint replacement through the skin after the procedure, such as through a surgical wound that was not properly sealed or cleaned. This type of contamination is known as a hematogenous infection.

Other contributing factors include:

  • Obesity
  • Diabetes
  • Smoking
  • Excessive alcohol consumption
  • Poor nutrition
  • Immunosuppressive medications
  • Long-term antibiotic therapy

Diagnosis of Prosthetic Joint Infection

The diagnosis of prosthetic joint infection is complex and difficult because there are no definitive signs or tests to identify the infection. A diagnosis is usually made through a combination of physical examination, laboratory tests, and imaging studies. For example, an MRI or CT scan can help to identify swelling, soft tissue collections, or abscesses. A joint fluid analysis can also be performed to detect the presence of an infection.

A tissue sample of the area may also be obtained for further testing. This sample can be used to detect the presence of bacterial, fungal, or viral agents in order to identify the specific bacteria causing the infection. Cultures may also be taken from the area to determine the effectiveness of antibiotics or other treatments.

Treatment of Prosthetic Joint Infection

The primary treatment for prosthetic joint infection is antibiotic therapy. The type of antibiotics used and the length of the treatment course will depend on the type of bacteria causing the infection. In some cases, surgery may be required to remove the infected tissue or implant.

In cases where the infection is resistant to antibiotics, joint revision surgery or debridement may be necessary to remove and replace the infected portion of the implant. Additional treatments may include medications to reduce inflammation and improve joint function.