Procedure Overview
What Is a Prosthetic Joint Infection (PJI)?
A prosthetic joint infection (PJI) is an infection that occurs in or around an artificial hip or knee joint after joint replacement surgery (arthroplasty).
It occurs when bacteria attach to the surface of the artificial joint, forming a protective layer and making the infection harder to treat than an infection in normal tissue.
While PJI is uncommon, it is a serious complication that requires prompt specialist care.
When Can a PJI Occur?
PJI may occur at different times after surgery:
- Early infection: within 3 months of surgery
- Delayed infection: between 3 and 12 months
- Late infection: more than 1 year after surgery, sometimes caused by bacteria spreading through the bloodstream from another infection
What Are the Symptoms?
- Symptoms may develop gradually or suddenly and can include:
- Persistent or worsening pain in the hip or knee
- Swelling, warmth, or redness around the joint
- Leakage or discharge from the surgical wound
- Stiffness or reduced ability to move the joint
- Fever or chills
- Feeling generally unwell or tired
- ⚠️ Important: Some patients do not have a fever. Ongoing pain or swelling should always be assessed.
How Is PJI Diagnosed?
- Diagnosing PJI usually involves several tests, including:
Blood tests to look for inflammation or infection
Imaging (X-rays, ultrasound, CT, or MRI)
Joint aspiration where fluid is taken from the hip or knee using a needle
Microbiology tests to identify the bacteria causing the infection
Diagnosis is often complex and requires specialist expertise.
How Is PJI Treated?
Treatment depends on:
- How long the infection has been present
- The type of bacteria involved
- The condition of the implant
- Your overall health
Depending on the above, treatment may include:
- Long courses of antibiotics
Surgery that will: - Clean the joint while keeping the implant in place
- Replace part or all of the hip or knee components
- In some cases, the implant will be removed temporarily before a new one is inserted
- Treatment plans are individualised and often take several months.
Recovery and Follow-Up
Recovery from PJI can take time. It is important to:
- Take antibiotics as prescribed
- Attend all follow-up appointments
- Follow physiotherapy and rehabilitation advice
- Discuss any concerns with your healthcare team
Specialist Centres and Surgeons
PJI after hip or knee replacement is a complex condition that is best treated in specialist centres by experienced teams.
Specialist centres offer:
- Surgeons with expertise in complex hip and knee revision surgery
- Infection specialists who focus on bone and joint infections
- Access to specialised laboratories and imaging
- Multidisciplinary team care, including surgeons, infectious disease specialists, microbiologists, physiotherapists, and specialist nurses
- Evidence shows that care in specialist centres improves:
- Accuracy of diagnosis
- Infection control
- Surgical outcomes
- Long-term joint function
- The Ottawa Hospital is a specialized center for the treatment of PJI.
Dr Grammatopoulos is an arthroplasty surgeon with expertise for the treatment of PJI.
He provides care across the province and inter-provincially.
He regularly publishes on the topic, presents nationally and internationally, and contributes to meetings on the topic (International PJI consensus meeting).
He fosters collaborations across different disciplines and has led national initiatives (webinar and COA topic in focus).
The Ottawa Hospital has a dedicated PJI research program, leading initiatives around Canada. For more information you can refer to: https://impact-program.webflow.io/
Can PJI Be Prevented?
Not all infections can be prevented, but risk can be reduced by:
- Careful surgical technique and infection prevention measures in the operating room
- Giving antibiotics at the time of surgery
- Taking proper care of the wound after discharge
- Managing medical conditions such as diabetes
- Prompt treatment of infections elsewhere (e.g. skin, dental, urinary)
- Informing healthcare providers that you have a hip or knee replacement
When Should I Seek Medical Advice?
Early assessment and treatment can help improve outcomes. Contact your healthcare provider urgently if you notice:
- Increasing pain, redness, or swelling around your hip or knee
- New or ongoing wound leakage
- Fever, chills, or feeling unwell
- Sudden difficulty walking or bearing weight
Key Messages
PJI after hip or knee replacement is uncommon but serious
Symptoms may be subtle—do not ignore ongoing pain or swelling
Diagnosis and treatment often require specialist expertise
Care in specialist centres improves outcomes