Infection After Joint Replacement: Warning Signs, Tests and Treatment Options
Infection is uncommon after a hip or knee replacement, but it is the complication that most changes the plan. Knowing how it shows up, how it is tested for, and what treatment involves helps you act early.
Most people who have a hip or knee replaced never deal with an infection. When one does happen, though, it is one of the hardest problems in joint replacement to fix, and it is the one where acting early makes the biggest difference. This guide explains how infections around implants happen, what to watch for, how surgeons confirm them, and what the treatment options are.
It is written for patients and families, not as a substitute for care. If you have had a joint replaced and you are worried about any symptom below, contact your surgeon or seek care promptly.
How common is it?
The American Academy of Orthopaedic Surgeons says serious complications such as joint infection occur in fewer than 2% of patients after either a total knee replacement (AAOS OrthoInfo, 2026) or a total hip replacement (AAOS OrthoInfo, 2026). Both pages note that chronic illnesses can raise the risk. An infection can appear within days of surgery, weeks later, or years down the line.
Why implants are hard to keep clean
The AAOS page on infection after joint replacement (OrthoInfo, 2026) explains a few features that make these infections stubborn:
- The source is usually you. Most infections are thought to come from bacteria already living on the patient's skin, rather than from the operating room. The page cites a large study in which nearly 90% of infections came from these bacteria.
- Implants have no blood supply. Bacteria can stick to metal and plastic, and because there is no blood flow through the implant itself, the immune system struggles to find and clear them.
- Biofilm. Bacteria can build a protective layer on the implant and nearby tissue. Biofilm resists antibiotics and cannot be fully removed even with surgical cleaning.
- Dormant bacteria. Some bacteria can enter a resting state in which antibiotics do not reach them, then become active later.
That last point is part of why surgeons treat this as a long-term risk rather than something that ends when the wound heals.
Warning signs to report
The OrthoInfo infection page lists traditional signs that a replaced joint may be infected:
- Pain that does not change with activity
- Fatigue
- Redness and swelling at the incision
- Wound drainage, usually more than 10 days after surgery
- New pain or stiffness in a joint that had been working well
The knee and hip pages also list, for the recovery period, a fever above 100°F taken by mouth, chills, increasing redness, tenderness or swelling of the wound, drainage, and increasing pain both with activity and at rest. Interestingly, the dedicated infection page says fever is no longer considered a reliable sign of this kind of infection, even though it is common with other infections. The practical message is the same either way: do not wait for a fever before you call.
A useful habit: in the first weeks, look at the incision at the same time each day and take a photo in the same light. It makes a slow change in redness or drainage much easier to see, and it gives your surgeon something concrete if you need to call.
Do not start antibiotics on your own
OrthoInfo makes a point that surprises many patients: antibiotics taken before testing can mask an infection and make it harder to diagnose. If you think a replaced joint might be infected, the page suggests asking whether blood tests and joint fluid testing can be done before antibiotics are started. Leftover pills from an earlier prescription are not a safe shortcut.
How infection is diagnosed
Diagnosis usually moves in steps.
| Step | What it is | What it tells the surgeon |
|---|---|---|
| Blood tests | ESR and CRP, two general markers of inflammation | A screen only. They can be raised for many reasons, so a high result prompts further testing rather than confirming infection. |
| Joint fluid | Fluid drawn from the joint with a needle | Tested for markers such as alpha-defensin and CRP, and for bacteria. This is the more specific step. |
Identifying the organism matters because it shapes which antibiotics are used and whether some surgical options are possible.
Treatment options, from least to most involved
Treatment depends on how deep the infection is, how long it has been present, whether the implant is still firmly fixed, which organism is involved, and the patient's overall health. OrthoInfo describes these main approaches.
Antibiotics alone, for superficial infection
When infection is limited to the skin and soft tissue and caught early, intravenous or oral antibiotics can work well. For a deep infection around the implant, antibiotics alone are used only to suppress it; the infection returns once they stop, so surgery is part of treating a deep infection.
DAIR: debridement, antibiotics and implant retention
The surgeon opens the joint, cleans it thoroughly, and swaps the parts that can be changed, such as the plastic liner or the ball of a hip, while leaving the fixed components in place. A course of antibiotics follows. It suits early infections, firmly fixed implants and healthy patients. Because the risk of recurrence is higher, many patients need long-term or lifelong suppressive antibiotics afterward.
Two-stage revision
In the first operation the whole implant comes out, infected tissue is removed, and a spacer containing antibiotics is put in. Antibiotics continue, often for six weeks or more, usually with an infectious disease specialist involved and regular blood tests. Once the infection is judged cured, generally at least six weeks later, a second operation places a new implant, sometimes with longer stems to support bone that has been weakened. In some cases the spacer is left in place permanently.
One-stage revision
The infected implant is removed, the joint is cleaned, and a new implant goes in during the same operation, often fixed with antibiotic-loaded cement. OrthoInfo says it is usually reserved for patients with an identified organism that responds to available antibiotics, healthy soft tissue and stable general health. It means less bone loss and one fewer operation, but carries a risk of persistent infection, and it remains less common than the two-stage approach.
Prevention: what happens before, during and after surgery
Before surgery
- Nasal screening. Some programs test for staphylococcus in the nose several weeks ahead. Carriers may be given an antibacterial ointment.
- Chlorhexidine washing at home in the days before surgery.
- Skin checks. Report any cut, scratch, rash or insect bite on the leg or arm being operated on. An active skin problem can be a reason to postpone.
- No shaving of the surgical area at home.
- Dental work. The knee and hip guides recommend finishing major dental treatment, such as extractions, before surgery.
- Chronic conditions. Managing long-term illnesses well is part of lowering risk; your doctors will tell you what that means for you.
On the day
OrthoInfo describes antibiotics given within an hour before the incision and continued for 24 hours afterward, along with short operating times, limited traffic in and out of the operating room and strict sterile technique.
After you go home
Keep the wound dry until your team says otherwise, follow your wound care instructions, and keep your follow-up appointments. Because infection can surface years later, tell any doctor or dentist who treats you that you have a joint replacement.
Questions to ask your surgeon about infection
These belong in the conversation before you book, whether you are having surgery at home or abroad:
- Do you screen for nasal staphylococcus, and will I wash with chlorhexidine beforehand?
- Which antibiotics will I receive around surgery, and for how long?
- What would make you postpone my surgery on the day?
- Who do I call if the wound looks wrong after I leave, and how quickly will I be seen?
- If an infection were suspected, which tests would you do first, and would you want them before antibiotics?
- If I am travelling home after surgery, how would you coordinate with a surgeon near where I live?
A note for patients having surgery away from home
The CDC Yellow Book (2026) lists infections as the most common complications of medical tourism, and notes that some antibiotic-resistant organisms may be more common in certain destinations. It advises travellers not to delay care for a suspected complication, whether they are still abroad or back home, and to bring a full set of records in English. For a joint replacement, that record should include the operation note, the implant details and any culture results. If an infection does show up months later, the surgeon who treats it will want to know exactly what was implanted and how.
The bottom line
Infection after joint replacement is uncommon but serious, and it can appear long after the wound has healed. Know the warning signs, report them early, avoid self-treating with antibiotics, and choose a surgical team that can explain its prevention steps and its plan if something goes wrong. Your surgeon is the right person to judge your individual risk.
Common questions
Can a joint replacement get infected years after surgery?
Yes. AAOS notes that infection can appear days, weeks or years after surgery, and that bacteria can stay dormant and later become active. This is why you should tell any future doctor or dentist about your implant and report new pain in a joint that had been doing well.
Is redness around the incision always a sign of infection?
Not always. Some redness and swelling are part of normal healing in the early weeks. What matters is change: redness that spreads or deepens, new drainage, or pain that keeps rising instead of settling. When in doubt, send your surgeon a photo or call.
Why would my surgeon want to test the joint before giving antibiotics?
Antibiotics can suppress bacteria enough to hide them in test results without curing a deep infection. Testing first gives the team a better chance of confirming the infection and identifying the organism, which guides treatment.
What is a spacer in a two-stage revision?
It is a temporary implant made with antibiotic-loaded material that holds the space where the joint was while the infection is treated. It delivers antibiotics locally and keeps the soft tissues from contracting before the new implant is placed.
Does having one infected joint replacement affect my other joints?
AAOS says a previous infected joint replacement significantly raises the risk of a later infection, including in a different replaced joint. Make sure any surgeon planning another joint replacement knows the full history.
Related reading across the network
Colombia Orthopedics
Colombia-specific pricing, surgeon vetting, and city-by-city comparisons for joint replacement in Medellin and Bogota.
Visit colombiaorthopedics.co →Surgery Wait Times
Wait time research for Canadian and US patients facing delays for joint replacement and other elective procedures.
Visit surgerywaittimes.com →Want the infection plan in your quote?
Tell us the joint and your timeline. We send typical 2026 ranges from Medellin and Bogota and the questions to ask about infection prevention and follow-up.