There is no surgical procedure that comes without risks. The article discusses periprosthetic joint infection after knee replacement surgery, its causes, symptoms, diagnosis, treatment options, and steps to prevent infection before and after surgery.

---

Possible risks after knee replacement surgery

Total knee replacement is one of the most commonly performed elective operations for knee osteoarthritis. Although total knee replacement is a frequently performed elective surgery for knee osteoarthritis, there are inherent risks associated with any surgical procedure. Among these patients undergoing knee replacement (about 1 in 100, or 1%) may develop an infection after the operation. Periprosthetic joint infection is a severe complication that can occur after total knee arthroplasty.

---

Aetiology

Infection of the total knee joint can happen either during the surgical procedure or at any time ranging from weeks to years after the surgery.

Entry of pathogens is by:

• Any breaks or cuts in the skin
• Significant dental procedures (ex: tooth extraction or root canal)
• Through wounds from other surgical procedures

High-risk individuals are those having comorbid conditions like:

• Immune deficiencies (such as HIV or lymphoma)
• Diabetes mellitus
• Peripheral vascular disease
• Immunosuppressive treatments (such as chemotherapy or corticosteroids)
• Obesity
• Dermatitis, Psoriasis

The reason behind infections around an artificial knee is that bacteria are capable of adhering to its surface. Immune response won’t be there on the metal surface. So bacteria may multiply and cause an infection. Your knee can be infected by bacteria that spread from any part of your body.

---

Signs and symptoms of infection in knee joint replacement  

1. A joint that was previously functioning well may exhibit heightened pain or stiffness.
2. Swelling
3. Warmth and redness around the wound.
4. The discharge of fluids such as blood, pus, or other substances from a wound.
5. Fevers, chills, and night sweats.
6. Fatigue

It is essential to consider the following key points:

1. It is typical to experience slight swelling in the knee or ankle and observe redness and warmth around the incision site for about 3 to 6 months following knee replacement surgery.
2. Experiencing some pain after the procedure is normal, but if it progressively worsens, it may indicate a potential infection.

---

How to diagnose knee infection

Many tests are there such as:

• Blood test - ESR, CRP, WBC count
• An imaging test, such as an X-ray, CT scan, MRI, or bone scan
• Joint aspiration, in which fluid is sent for laboratory analysis

---

Treating a knee infection after replacement surgery

Treating an infection after a total knee replacement is determined by the severity and type of infection, and can become more complex if it has persisted for an extended period.

Antibiotics

To treat superficial infections after total knee replacement, antibiotics can be given either orally or through an intravenous (IV) line.

Surgery

Treatment of deep infections after knee replacement surgery typically involves surgical intervention. There are two commonly used approaches: one-stage surgery or two-stage surgery with staging.

During the first stage of the surgical treatment for deep infection after knee replacement, the implant is removed and the infected area is thoroughly cleaned. A spacer, which is a cement block treated with antibiotics, is then placed in the area where the implant was, with the goal of eliminating bacteria in the joint and surrounding tissues.

Debridement

A surgical washout, also known as debridement, may be sufficient for treating deep infections that occur shortly after knee replacement surgery, without the need for implant removal. The surgeon removes infected tissue, cleans the implant, and provides IV antibiotics for 2 to 6 weeks. Typically, the plastic or polyethene component is exchanged.

Staged surgery

During the first stage of this treatment approach, the implant is removed, and the infected area is cleaned thoroughly. Then, a temporary antibiotic spacer is inserted, and the patient is not allowed to bear weight on the affected leg during this time. IV antibiotics are administered for 4 to 6 weeks to treat the infection.

---

How to prevent an infection

Your surgeon can take preventive measures during knee replacement surgery to lower the risk of infection. Additionally, there are measures you can take before and after the surgery to minimize the chances of bacteria entering your body.

Steps to take before surgery

Before knee replacement surgery, a consultation with a dentist is usually carried out to ensure there are no cavities or other issues in the mouth that could potentially lead to an infection in the knee or any other part of the body.

Before your knee surgery, the following steps can help prevent infections:

1. Antibiotics: Your healthcare team will usually give you antibiotics in the hour before surgery, and then at 24-hour intervals afterwards.
2. Testing for and reducing nasal bacteria: There is some evidence that testing for Staphylococcus bacteria in the nasal passages, and using intranasal antibacterial ointment before surgery, could reduce infections.
3. Washing with chlorhexidine: Some evidence says that washing with a cloth soaked in chlorhexidine in the days leading up to surgery could help prevent infection. Brands include Betasept and Hibiclens.
4. Avoid shaving: Opt not to shave your legs before surgery as this can increase the bacterial load.

Steps to take after surgery

After surgery, the following steps can help reduce the chances of infection:

1. Follow your surgeon’s guidance on how to take care of your incision.
2. Treat any cuts, wounds, burns, or scrapes as soon as they happen. Clean it with an antiseptic product and then cover it with a clean bandage.
3. Keep up with preventive dental health and don’t delay in seeing your dentist. Your dentist or orthopaedic surgeon may want you to take antibiotics about an hour before any dental procedures to reduce your chance of infection.

Disclaimer- The views and opinions expressed in this article are those of the author and do not necessarily reflect the official policy or position of M3 India.

About the author of this article: Dr. Nithin Sunku is a Consultant Orthopaedic Joint Replacement & Arthroscopy Surgeon, at Global Hospital Trauma Centre, Mount Abu, Rajasthan.