Periprosthetic Joint Infection (PJI): What Happens When an Artificial Joint Gets Infected
Updated: 2 days ago
Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026
A periprosthetic joint infection (PJI) is an infection of the area in and around a joint implant, such as a hip, knee, shoulder, or elbow replacement. It is uncommon but serious, usually requires both antibiotics and surgery, and can appear soon after surgery or years later. Warning signs include drainage from the incision, worsening pain and swelling, fever, and skin color changes. Seek medical care right away if these appear after a joint replacement [1].
Quick Answer
Periprosthetic joint infection is an infection of the tissue in and around an artificial joint, developing soon after replacement surgery or months to years later. Warning signs include drainage from the incision, increasing pain, swelling, warmth and fever. Call your surgeon immediately if these appear [1]. Treatment typically combines antibiotics and surgery, depending on how long the infection has been present [2].
What the research says
One-stage and two-stage revision had similar re-infection rates for infected hip replacements. A systematic review and meta-analysis pooled 38 one-stage studies (2,536 participants) and 60 two-stage studies (3,288 participants). Re-infection within two years occurred in 8.2% (95% CI, 6.0 to 10.8) after one-stage revision and 7.9% (95% CI, 6.2 to 9.7) after two-stage revision. No clinical trials were found, so the evidence comes from cohort studies (Kunutsor et al., PLoS One, 2015) [3].
Implant-sparing cleaning (DAIR) worked less well for fungal infections. In a network meta-analysis of 691 fungal PJI cases (335 hips and 356 knees) from 17 articles, the odds of treatment success with DAIR were 68% lower than with one-stage revision (OR 0.32; 95% CI, 0.11 to 0.90) and 60% lower than with two-stage revision (OR 0.40; 95% CI, 0.24 to 0.69). Fungal PJI is extremely rare, and most other comparisons showed no significant differences (Rattanaprichavej et al., J Arthroplasty, 2026) [4].
Research summaries are based on article abstracts retrieved from PubMed.
What Is Periprosthetic Joint Infection?
A periprosthetic joint infection (PJI) happens when bacteria or other microorganisms infect the area in and around a joint implant. This can include infection around a hip, knee, shoulder, or elbow replacement. In medical terms, “peri” means around or surrounding [1].
This kind of infection can happen soon after joint replacement surgery. It can also happen months or even years later. Some infections are long-lasting, and these are called chronic. Others come on more suddenly, and these are called acute [1].
PJI is treatable but often needs a combination of antibiotics and surgery. It is an uncommon complication, but recognizing it early matters because it is a serious condition that needs treatment right away [1].
Key Fact | Detail |
What it is | Infection in and around a joint implant (hip, knee, shoulder, elbow) [1] |
Timing | Soon after surgery, or months to years later [1] |
Types | Acute (sudden onset) and chronic (long-lasting) [1] |
Treatment approach | Usually antibiotics plus surgery [1] |
Frequency | Uncommon complication of joint replacement [1] |
What are the symptoms of periprosthetic joint infection (PJI)?
Periprosthetic joint infection symptoms include worsening joint pain, swelling and warm or discolored skin, and serious infections can also cause fever, chills, confusion or trouble walking [1]. Common symptoms of PJI include:
Movement and Function Symptoms
Pain that keeps getting worse, rather than gradually improving after surgery, is one of the clearest signals. Swelling that builds up around the joint and skin that feels warm or changes color can point to infection in the area.
When the Infection Spreads
A serious infection can affect the whole body. Fever and chills may accompany the local joint symptoms [1]. In more severe cases, the infection can cause confusion and suddenly make it difficult to walk or bear weight [1].
When should you see a doctor about a periprosthetic joint infection?
Anyone with a joint replacement should call their surgeon or seek care right away for signs of a serious periprosthetic joint infection [1].
Emergency Sign | Why It Matters |
Fever plus joint pain, swelling and warmth [1] | Suggests active infection needing prompt treatment |
Confusion [1] | Can signal a more serious, spreading infection |
Sudden trouble walking or bearing weight [1] | The infected joint can suddenly stop working safely |
Spreading skin color change around the joint [1] | A color change that spreads or grows needs urgent attention |
Time matters with PJI. The earlier the infection is caught, the more treatment options remain available, including options that let the existing implant stay in place [2].
What causes periprosthetic joint infection?
Periprosthetic joint infection can start after surgery before the wound heals, spread from a nearby infection or travel through the bloodstream from elsewhere in the body [1].
After surgery. Microorganisms get into your body after your joint replacement surgery, before the surgical wound has completely healed [1].
From a nearby infection. An infection nearby in the body spreads to the joint [1].
Through the bloodstream. Bacteria are carried in the bloodstream to the joint from another infection somewhere else in your body [1].
Why Implants Are Hard to Defend Against Infection
The immune system typically fights off microorganisms such as bacteria or fungi when they enter your body. But the immune system can have a harder time when microorganisms stick to the metal and plastic parts of a joint implant. These parts do not get blood flow. That means your immune system cannot easily find and fight the bacteria [1].
Many microorganisms can form a coating called a biofilm. The biofilm helps them hide from the immune system and from antibiotics [1]. This is one reason PJI is so difficult to treat.
Often, it is hard to know exactly how the infection began [1].
What are the risk factors for periprosthetic joint infection?
Periprosthetic joint infection is more likely in some people than others after joint replacement surgery. These risk factors make it harder for the body to fight an infection [1]:
Risk Factor | How It Affects Risk |
Diabetes [1] | Makes it harder to fight infection |
Poor circulation [1] | Weakens the body’s defenses around the joint |
Obesity [1] | Adds risk of infection after replacement |
Smoking [1] | Impairs healing and immune response |
Cancer [1] | Can weaken the immune system |
Chemotherapy or corticosteroids [1] | Treatments that lower immune function |
How can you lower your risk of periprosthetic joint infection?
Periprosthetic joint infection is uncommon, but you and your healthcare team can take steps to help prevent it [1].
Before surgery, try to be as healthy as possible. This may include managing blood sugar if you have diabetes and stopping smoking. Your healthcare team may check for any active infections and treat them before surgery [1].
During and after surgery, your healthcare team uses strict sterile techniques and may give antibiotics before, during and after the operation to prevent infection [1].
After surgery, good wound care is important. Watch for warning signs such as increasing pain, fever, swelling, a change in skin color, or drainage from the incision. Treating infections elsewhere in your body quickly also helps protect the new joint. While PJI cannot always be prevented, these steps can lower the risk [1].
What complications can periprosthetic joint infection cause?
Left untreated or recognized late, PJI can destroy the tissues around the joint, loosen the implant, and threaten the whole body through spreading infection. In the most severe cases, the infection cannot be controlled and treatment escalates to permanent joint removal or amputation [2].
Acting quickly on warning signs is the single best way to avoid these outcomes. Early treatment can mean simpler surgery, a shorter antibiotic course, and a much better chance of keeping a working joint.
How is periprosthetic joint infection diagnosed?
To diagnose a periprosthetic joint infection, your healthcare team may use a combination of a physical exam, lab tests, imaging tests and joint fluid tests. Your care team may include experts from orthopedic surgery and infectious disease [2].
Lab Tests
Your healthcare team will typically order the following blood tests to look for signs of infection or inflammation [2]:
Joint Fluid Testing
The healthcare professional often takes a sample of joint fluid using a needle. This is called a joint aspiration. The fluid samples are sent to the lab to check for signs of infection and to perform cultures [2].
For cultures, the joint fluid is kept warm, like your body temperature, so any microorganisms in the fluid can grow. Over days or weeks, microbiologists and infectious disease experts watch to see what kind of microorganisms grow. Most periprosthetic joint infections are caused by bacteria rather than fungi. Knowing what causes your infection helps your care team choose the right antibiotics [2].
Imaging Tests
Imaging tests help your care team see if your implant is loose. They also may show if there is an infection in or around your joint [2].
Acute vs. Chronic Infection
Treatment options depend on the type of infection you have. As part of your diagnosis, your healthcare team figures out whether you have an acute or chronic infection [2].
Infection Type | Timing | How It Develops |
Acute PJI | Within about six weeks of surgery, or sudden onset in a well-working joint | Starts during surgery, while the cut heals, or from the bloodstream; symptoms come on quickly [2] |
Chronic PJI | More than three months after surgery | Cause sometimes unknown; symptoms progress slowly over months or years [2] |
How is periprosthetic joint infection treated?
If the infection is caught early, you don’t always have to have the joint removed. But you likely need surgery. If you have had the infection for several weeks or months, you typically must have the artificial joint removed [2].
How your infected joint is treated depends on how long you have had the infection [2]. It also depends on:
Treatment Factor | How It Influences the Plan |
Cause of infection [2] | Determines which antibiotics will work |
Condition of joint replacement [2] | Affects whether the implant can be kept |
Soft tissue and bone health [2] | Influences surgical options and healing |
Other medical conditions [2] | May limit surgical or antibiotic choices |
Most treatment plans involve both antibiotics and surgery. It is common to need more than one surgery. You may need antibiotics for several weeks or even months before and after any surgery [2].
Antibiotics
Antibiotic therapy is part of treatment before and after PJI surgeries. Therapy usually starts with IV antibiotics and then sometimes changes to oral antibiotics. How long antibiotic therapy lasts depends on the treatment approach. Sometimes you need antibiotics for weeks, months or even longer [2].
For people who can’t have major surgery or who have an ongoing infection risk, long-term oral antibiotics may be used to control, but not cure, the infection [2].
Surgery Options
Most PJIs are treated with surgery [2]. The six main approaches are summarized below.
Surgical Approach | What Happens | When It’s Used |
DAIR (debridement, antibiotics, implant retention) | Joint cleaned, infected tissue removed, implant kept in place; plastic liners may be replaced | Most often for acute infections [2] |
One-stage revision | Infected joint removed, area cleaned, new implant placed in the same surgery; antibiotic cement may be used | Only when bacteria is known before surgery and bone/tissue is healthy [2] |
Two-stage revision | Infected implant removed, antibiotic spacer placed, at least 6 weeks of antibiotics, then second surgery to place new joint; flap surgery may help wound healing | Most common for chronic and complex infections [2] |
Resection arthroplasty | Joint removed and not replaced; lessens pain but leg won’t work like a healthy joint | When infection can’t be controlled or you’re not a candidate for another replacement [2] |
Arthrodesis (joint fusion) | Bones permanently joined; infection treated, joint more stable, but motion is lost and limb may be shorter | When joint replacement isn’t a good option [2] |
Amputation | Surgical removal of a body part such as a toe, foot, arm or leg | For life-threatening infections or when bone and soft tissue aren’t healthy [2] |
The two-stage revision deserves extra attention because it is the most common approach for chronic and complex infections. In the first surgery, the surgeon removes the infected implant and cleans the joint area, then places an antibiotic spacer — a temporary part fixed to the bone with cement that contains antibiotic medicine to kill bacteria. The spacer keeps the joint in place until a new implant is put in [2].
If needed, the surgeon may perform flap surgery to help the wound heal. This uses healthy tissue such as skin, fat or muscle that has its own blood supply, moved to cover the wound and bring blood flow to the area. More blood flow helps the wound heal and lowers the chance of another infection [2].
You receive IV or oral antibiotics for six or more weeks between surgeries. Your care team then monitors you for a time when you are not on antibiotics, to make sure the infection is gone. The second surgery removes the spacer, cleans the joint again, and implants a new, clean total joint. You may need more antibiotics afterward [2].
Nonsurgical Management
In rare cases, you may not have surgery for PJI. This usually happens if you already had several surgeries for infection or joint replacement and are still able to move around with little pain. Your healthcare professional may give long-term oral antibiotics to take as long as the joint implant stays in place [2].
The antibiotics help keep the infection under control. They also stop bacteria from causing increased symptoms around the joint or causing infections in other areas of the body. This approach is not common — most prosthetic hip or knee joint infections are treated with surgery, and often more than one surgery is needed [2].
How can people cope with periprosthetic joint infection and find support?
Treatment for PJI is a long process. Over time, it can involve more than one surgery. You may start with one surgical treatment option but later may need another. It is important to know that treatment may take months or even years, with several appointments and possibly many surgeries [2].
Having support helps you prepare for treatment and recover afterward. Your caregiver can be a partner or spouse, a sibling, your adult child, or a close friend. You may have more than one caregiver over time. Being a caregiver takes time and energy, so make sure caregivers understand their commitment [2].
Your caregiver should come with you to appointments and take part in the education about your treatment. The caregiver should be there when you have surgery and plan to support you with recovery and physical therapy afterward [2].
Clinical Trials
Research teams run clinical trials testing new treatments, interventions and tests to prevent, detect, treat or manage periprosthetic joint infection [2]. Asking your care team about trials can open access to newer approaches.
How should you prepare for a periprosthetic joint infection appointment?
During PJI treatment, your healthcare team may include experts in orthopedic surgery, infectious disease, physical therapy, occupational therapy and more [2].
What You Can Do
As you prepare for your appointment, make a list of:
Prepare | Details to Gather |
Symptoms | Your symptoms and when they began |
Conditions | Medical conditions you have |
Medicines | All medicines, vitamins and supplements you take, including doses |
Questions | Questions to ask your healthcare team |
Take a family member or friend along, if possible, to help you remember everything you discuss with your care team.
What to Expect From Your Doctor
Your healthcare professional is likely to ask:
When did your symptoms start?
Have your symptoms been ongoing or on-and-off?
How bad are your symptoms?
Does anything seem to make you feel better?
What things seem to make your symptoms worse?
Conclusion
Periprosthetic joint infection is an uncommon but serious complication of joint replacement surgery [1]. Because the bacteria hide on metal and plastic implant surfaces — protected from immune defenses and antibiotics by biofilm — PJI almost always requires coordinated treatment that combines antibiotics with surgery.
The good news is that early recognition changes everything. Watching for drainage from the incision, worsening pain and swelling, warmth or skin color changes, and fever after a joint replacement, and calling your surgeon right away, keeps options like implant-sparing procedures on the table [1] [2]. If you or a loved one has had a joint replacement and notices any of these warning signs, do not wait. Contact your surgical team immediately.
Next step: If you’ve had joint replacement surgery and develop fever with joint pain, swelling, or drainage near the incision, call your surgeon or seek medical care right away [1].
Frequently Asked Questions
What is a periprosthetic joint infection?
A periprosthetic joint infection (PJI) happens when bacteria or other microorganisms infect the area in and around a joint implant, such as a hip, knee, shoulder or elbow replacement. In medical terms, “peri” means around or surrounding. It is treatable but often needs a combination of antibiotics and surgery [1].
Can a joint replacement get infected years after surgery?
Yes. A periprosthetic joint infection can happen soon after joint replacement surgery, or it can happen months or even years later. Some infections are long-lasting (chronic), while others come on more suddenly (acute) [1].
What are the warning signs of an infected joint replacement?
Common signs include drainage or fluid coming from the incision site, increasing pain, swelling that gets worse around the joint, a change in skin color or warmth around the joint, and fever with chills [1].
When should I call my surgeon after joint replacement surgery?
Call your surgeon or seek medical care right away if you notice fever plus joint pain, swelling and warmth; confusion; sudden trouble walking or bearing weight; or a skin color change around the joint that spreads or grows [1].
Why are joint implants hard for the immune system to defend?
Microorganisms stick to the metal and plastic parts of an implant, and these parts do not get blood flow, so the immune system cannot easily find and fight the bacteria. Many microorganisms also form a biofilm coating that helps them hide from the immune system and antibiotics [1].
What increases the risk of a periprosthetic joint infection?
Risk factors include diabetes, poor circulation, obesity, smoking, a weakened immune system from conditions such as cancer, and treatments that lower the immune system, such as chemotherapy or corticosteroids [1].
How is periprosthetic joint infection diagnosed?
Diagnosis combines a physical exam, blood tests (CBC, CRP, ESR), joint fluid aspiration with cultures kept at body temperature for days or weeks, and imaging such as X-rays, MRI or CT scans, and bone scans. Most PJIs are caused by bacteria rather than fungi [2].
What is the difference between acute and chronic PJI?
Acute PJI typically happens within about six weeks of surgery or suddenly in a well-working prosthetic joint, with symptoms coming on quickly. Chronic PJI typically develops more than three months after surgery, and symptoms may progress slowly over months or years [2].
Do I always need my implant removed?
No. If PJI is caught early, you don’t always have to have the joint removed, though you likely need surgery. If you’ve had the infection for several weeks or months, you typically must have the artificial joint removed [2].
What is a two-stage revision surgery?
A two-stage revision surgery is the most common approach for chronic and complex infections. The first surgery removes the infected implant and places a temporary antibiotic spacer, followed by six or more weeks of antibiotics. The second surgery removes the spacer and implants a new, clean joint [2].
Can periprosthetic joint infection be prevented?
Not always, but risk can be lowered by being as healthy as possible before surgery (managing blood sugar, stopping smoking), treating active infections before surgery, using strict sterile techniques and antibiotics during the operation, and practicing good wound care afterward [1].
Related Resources
External resources for deeper reading:
American Academy of Orthopaedic Surgeons. Infection After Joint Replacement. OrthoInfo. Accessed October 30, 2026. https://www.orthoinfo.org/diseases--conditions/joint-replacement-infection — Joint Replacement Infection (OrthoInfo)
American Academy of Orthopaedic Surgeons. Periprosthetic Joint Infections. AAOS. Published March 11, 2019. https://www.aaos.org/quality/quality-programs/diagnosis-and-prevention-of-periprosthetic-joint-infections/ — Diagnosis and Prevention of Periprosthetic Joint Infections
MedlinePlus. Hip Replacement. MedlinePlus. Last updated June 25, 2025. https://medlineplus.gov/hipreplacement.html — Hip Replacement
Centers for Disease Control and Prevention. Surgical Site Infection Basics. CDC. April 11, 2024. https://www.cdc.gov/surgical-site-infections/about/index.html — Surgical Site Infection Basics
References
Mayo Clinic Staff. Periprosthetic joint infection (PJI): Symptoms and causes. Mayo Clinic. March 17, 2026. https://www.mayoclinic.org/diseases-conditions/periprosthetic-joint-infection/symptoms-causes/syc-20597706
Mayo Clinic Staff. Periprosthetic joint infection (PJI): Diagnosis and treatment. Mayo Clinic. March 17, 2026. https://www.mayoclinic.org/diseases-conditions/periprosthetic-joint-infection/diagnosis-treatment/drc-20597707
Kunutsor SK, Whitehouse MR, Blom AW, et al. Re-Infection Outcomes following One- and Two-Stage Surgical Revision of Infected Hip Prosthesis: A Systematic Review and Meta-Analysis. PLoS One. 2015;10(9):e0139166. PMID: 26407003. DOI: 10.1371/journal.pone.0139166
Rattanaprichavej P, Laoruengthana A, Chinwatanawongwan B, et al. Comparative Effects of Treatment Strategies for Fungal Periprosthetic Joint Infection: A Systematic Review and Network Meta-Analysis. J Arthroplasty. 2026. PMID: 42767532. DOI: 10.1016/j.arth.2026.09.013
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have about a medical condition.
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