Knee replacement surgery has an excellent safety record. The vast majority of patients — including those who undergo the procedure at COJRI in Chandigarh — experience a smooth recovery and go on to live active, comfortable lives. But like any surgery, knee replacement carries a small risk of infection. And when infection does occur around a joint implant, it is one of the most serious complications possible.
Knowing the signs, understanding what causes them, and acting quickly can make an enormous difference to outcomes. This guide is for patients in Chandigarh, Mohali, and Panchkula who want to understand periprosthetic joint infection (PJI) — what it is, how to recognise it, and how it is treated.
What Is Periprosthetic Joint Infection (PJI)?
Periprosthetic joint infection is an infection that occurs in or around a joint implant — in this case, a knee replacement. Bacteria can reach the implant in two main ways:
- During surgery (acute infection): Bacteria enter the surgical site at the time of the operation and begin causing problems within days to weeks. This type is less common thanks to stringent sterile protocols in modern operating theatres like those at COJRI.
- Through the bloodstream (late infection): Bacteria from elsewhere in the body — a dental procedure, a urinary tract infection, a skin infection — travel through the blood and lodge in the implant, where they can form a biofilm (a protective coating) that makes them very difficult to treat with antibiotics alone.
The implant surface provides bacteria with a place to attach and persist that the body’s immune system struggles to reach effectively. This is what makes PJI so challenging — and why prompt, specialist treatment is essential.
Warning Signs of Infection After Knee Replacement
Early Signs (Within Days to Weeks of Surgery)
- Wound that is not healing normally, or is discharging fluid
- Increasing redness, warmth, and swelling around the knee beyond what is expected
- Fever (temperature above 38°C)
- Pain that is increasing rather than improving
Late Signs (Months to Years After Surgery)
- New onset of knee pain after a period of comfortable function
- Persistent swelling and warmth in the knee
- Drainage from an old scar
- A loosening sensation in the knee without obvious mechanical cause
- Generally feeling unwell or feverish alongside knee symptoms
If you experience any of these symptoms — especially if they develop suddenly after a dental procedure, surgery elsewhere, or another infection — contact COJRI immediately. Do not wait for your next scheduled appointment.
How Is Infection After Knee Replacement Diagnosed?
Diagnosis of PJI requires a combination of clinical assessment, blood tests, and joint fluid analysis. Key investigations include:
- Blood tests: CRP (C-reactive protein) and ESR (erythrocyte sedimentation rate) are inflammatory markers that rise significantly with infection
- Joint aspiration: A sample of fluid is drawn from around the knee using a needle — this is the most reliable diagnostic test, with laboratory analysis identifying whether bacteria are present and which type
- Imaging: X-rays can show changes in implant position or bone; bone scans and MRI may be used in complex cases
At COJRI, we investigate suspected PJI thoroughly and systematically to ensure the correct treatment path is chosen.
Treatment of Infection After Knee Replacement
Treatment depends on when the infection is detected, which bacteria are involved, and how well the implant itself is fixed in place.
Debridement and Implant Retention (DAIR)
If the infection is caught early (typically within a few weeks of surgery or within a few weeks of a new infection episode), it may be possible to wash out the infected tissue, exchange the plastic spacer, and retain the existing metal implants — followed by a course of targeted antibiotics. This is called DAIR (debridement, antibiotics, and implant retention) and can be effective if performed promptly in appropriate cases.
Two-Stage Revision
For established infections, a two-stage revision is the gold standard. In the first stage, all infected tissue and the knee implant are removed and replaced with a temporary antibiotic spacer that delivers medication directly to the site. After 6–12 weeks of intravenous and oral antibiotics — and confirmation that the infection has been cleared — a second surgery implants a new knee replacement.
This approach is more involved but has the highest success rate for eradicating established PJI. COJRI specialises in complex revision cases including those arising from infection, serving patients from Chandigarh, Mohali, and Panchkula.
Suppressive Antibiotics
In patients who are not medically fit for further surgery, long-term antibiotic suppression may be used to keep the infection at bay — though this is rarely a permanent solution.
Preventing Infection After Knee Replacement
Prevention is far preferable to treatment. The risk of infection can be reduced through several measures:
- Antibiotic prophylaxis: Antibiotics are given before, during, and after surgery to minimise bacterial exposure
- Dental hygiene: Inform your dentist that you have a knee implant — they should prescribe prophylactic antibiotics before any dental procedure that could release bacteria into the bloodstream
- Wound care: Keep the surgical wound clean and dry, and report any concerns immediately
- Treat infections elsewhere promptly: Urinary tract infections, skin infections, and other bacterial infections should be treated promptly to prevent bloodstream spread to the implant
- Manage underlying conditions: Diabetes, obesity, and poor nutrition all increase infection risk — managing these actively before and after surgery reduces your risk profile significantly
Frequently Asked Questions About Knee Replacement Infection
How common is infection after knee replacement?
Periprosthetic joint infection occurs in approximately 1–2% of primary knee replacement surgeries. At high-volume specialist centres like COJRI, infection rates are typically at or below the lower end of this range due to stringent theatre protocols and careful patient selection.
Can infection after knee replacement be cured?
Yes — but the key is early detection and appropriate treatment. Early infections caught within weeks of surgery can often be treated with DAIR and targeted antibiotics. Established infections typically require staged revision surgery, which has excellent long-term success rates in specialist hands.
How long does treatment for knee replacement infection take?
Treatment is not quick. A two-stage revision involves two surgical procedures separated by 6–12 weeks of antibiotics, followed by recovery from the second surgery — typically 6–12 months in total. This is one reason early identification and action is so important.
Should I be worried about infection before going for knee replacement?
Infection is a risk that your surgeon should discuss with you before surgery — but it should not be a reason to avoid surgery if you need it. The consequences of living with severe, disabling knee arthritis are also significant. With a specialist surgical team, good surgical protocols, and your own active management of risk factors, the risk of infection is very low.
Concerned About Your Knee After Replacement? Contact COJRI Today
If you are experiencing symptoms that concern you after knee replacement surgery — whether it was performed at COJRI or elsewhere — please do not delay seeking specialist assessment. Early intervention makes all the difference.
Our team at COJRI provides specialist assessment and treatment for periprosthetic joint infections, serving patients from Chandigarh, Mohali, and Panchkula. We also manage revision knee replacement and complex cases arising from implant failure of all kinds.
Book an urgent consultation with COJRI today if you have concerns about your knee replacement.