Reviewed by Dr Vishal Pai
A revision knee replacement is an operation to replace some or all of the parts of a knee replacement that has failed, worn out or become infected. This page covers why revision may be needed, how it is planned and done, recovery, results and risks.
At a Glance
- A revision knee replacement replaces some or all of the parts of an existing knee replacement.
- Common reasons include infection, loosening, instability and wear of the plastic insert.
- Finding the cause comes first. Not every painful knee replacement needs more surgery.
- The operation is more complex than a first knee replacement, recovery usually takes longer and the risks are higher.
- Many people have less pain and better function afterwards, especially when a clear cause is found and treated.
What is a revision knee replacement?
A revision knee replacement replaces an artificial knee joint (prosthesis) that has failed or worn out. It aims to relieve pain and improve how your knee works. Revision is much less common than a first (primary) knee replacement. It is needed when the first operation has not given the result hoped for, or when a complication has developed.
Sometimes only the plastic insert needs to be replaced. If the metal components have loosened and bone has been lost, they may need to be removed and the joint rebuilt with revision components. Longer stems extend into the thigh bone (femur) or shin bone (tibia) for support, and extra implants or bone graft can fill areas of missing bone.
In the Australian joint registry, the most common reasons for revising a total knee replacement are infection, loosening and instability, followed by problems with the kneecap and pain. [1] A partial knee replacement is most often revised because arthritis has progressed in another part of the knee, and it is usually converted to a total knee replacement. [1]
Who might need a revision knee replacement?
New pain, swelling, stiffness or a feeling that your knee gives way after a knee replacement deserves an assessment. These symptoms do not automatically mean you need a revision. When no clear cause is found, treatment without surgery, such as physiotherapy, strength training and pain management, is usually tried first. Revision for unexplained pain or stiffness alone tends to give poorer results than revision for a clear problem with the implant. [2] No studies have yet compared revision surgery with non-surgical treatment for a failed knee replacement. [3]
A revision may be considered for:
- Infection
- Loosening of the implant
- Instability
- A fracture around the implant
- Wear of the plastic insert
- An implant that is poorly aligned or positioned
- Stiffness
People who had their first knee replacement at a young age are more likely to need a revision later, because the implant may not last their lifetime. Read more about how long a knee replacement lasts.
What is involved in revision knee replacement surgery?
Revision knee replacement surgery usually involves five steps:
1. Finding the cause
A thorough assessment is needed to find out why the knee replacement has failed. This usually involves blood tests, X-rays and scans such as CT or CT SPECT, and sometimes a sample of fluid from the knee (synovial fluid analysis) to look for infection.
2. Planning the operation
The type of revision depends on the cause. Sometimes only the worn plastic liner needs to be replaced. Other times the whole knee replacement is removed and replaced with specialised revision components.
3. Removing the old parts
The loose or worn components are removed while keeping as much bone as possible.
4. Rebuilding the knee
The revision components are fixed in place. Stems, cones or bone graft may be used where bone has been lost, and more constrained implants, which give the knee extra stability, may be used if the ligaments are weak.
5. Testing
The knee is moved through its range to check its fit and stability before the wound is closed.
What happens if the knee replacement is infected?
For a long-standing infection, a two-stage revision is the most common approach. In the first stage, the infected implant and surrounding tissue are removed, the joint is thoroughly cleaned and a temporary antibiotic-loaded cement spacer is placed. You then have antibiotics, usually for 6 to 8 weeks, guided by the bacteria grown from samples taken at surgery. Once tests show the infection has cleared, the second stage removes the spacer and puts in a new knee replacement.
In some people, a one-stage revision, where the old implant is removed and the new one is put in during the same operation, may be an option. Whether one or two stages is better depends on your circumstances and on the bacteria grown from the tissue samples (biopsies). More aggressive (virulent) bacteria usually need a two-stage revision.
How long does it take to recover from a revision knee replacement?
Recovery after a revision is usually longer than after a first knee replacement, because the operation is more complex. How long it takes depends on the reason for the revision and what was done. As a rough guide:
- First few daysYou will usually stay in hospital for several days.
- 2 weeksYour wound is checked. After this visit, you can usually shower without dressings.
- 6 weeksThis is the earliest you can return to driving.
- 8 weeksBy this stage, Dr Vishal Pai expects your knee to straighten fully and to bend beyond 90 degrees. You may still need a crutch.
- 4 monthsMost of your movement has usually returned, although some swelling remains.
- 12 to 18 monthsYou reach your final result.
After a two-stage revision, this timeline starts again from the second operation.
What results can you expect?
Many people have less pain and better function after a revision, especially when it is done for a clear reason such as loosening or wear. People revised for stiffness or unexplained pain have the poorest results. [2] On average, results are not as good as after a first knee replacement that has not needed revision. [4]
After a two-stage revision for infection, most infections are cured, but the infection comes back in some people, up to about 1 in 6. [5] [6] These figures are averages from many hospitals, not one surgeon’s results.
What are the risks and complications?
Every operation carries risks, and the risks of a revision are higher than those of a first knee replacement. Dr Vishal Pai goes through them with you before you decide. The main risks of a revision knee replacement are:
- Infection, which is more common than after a first knee replacement. About 5 in 100 people (1 in 20) develop an infection after a revision, and the risk is higher when the revision is done for infection. [7] [8]
- Blood clots in the leg, in about 2 in 100 people within 3 months of a revision for reasons other than infection, and more often after a revision for infection or fracture. [9]
- Bleeding into the knee, which occasionally needs a return to theatre to wash it out.
- Stiffness, which occasionally needs a manipulation under anaesthetic if the knee is not bending or straightening by 6 to 8 weeks.
- Ongoing pain, even when the new implant is well positioned.
- A fracture of the bone during surgery, which is more likely if the bone is weak (osteoporosis) and may need screws, a plate or a longer stem.
Rarely, the nerve or blood vessels behind the knee are injured, or a serious medical problem such as a heart attack, stroke or a clot in the lungs occurs. The new implant can also loosen or become unstable, and some people need further surgery. You will receive a written information sheet with the full list of risks.
Where does Dr Vishal Pai consult and operate?
Dr Vishal Pai consults at Sandringham Orthopaedic Specialists, Suite 1, 60 Bay Road, Sandringham. He performs revision knee replacements at Calvary Holmesglen Private Hospital, 490 South Road, Moorabbin, in Melbourne’s south-east. Patients come from across Bayside, Glen Eira and the Mornington Peninsula, and some travel from regional Victoria.
References
Show all 10 referencesHide references
- Lewis P et al. 2025. Hip, Knee and Shoulder Arthroplasty: 2025 Annual Report. Australian Orthopaedic Association National Joint Replacement Registry.
- Sabah SA et al. 2023. Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis. The Journal of Bone and Joint Surgery.
- Sabah SA et al. 2023. Patient-relevant outcomes following elective, aseptic revision knee arthroplasty: a systematic review. Systematic Reviews.
- Khow YZ et al. 2021. Aseptic revision total knee arthroplasty outcomes were equivalent to patients’ own pre-failure state but inferior to patients without revision. Knee Surgery, Sports Traumatology, Arthroscopy.
- Kunutsor S et al. 2015. Re-infection outcomes following one- and two-stage surgical revision of infected knee prosthesis: a systematic review and meta-analysis. PLoS ONE.
- Goud AL et al. 2021. Reinfection rates after one- and two-stage revision surgery for hip and knee arthroplasty: a systematic review and meta-analysis. Archives of Orthopaedic and Trauma Surgery.
- Mortazavi SMJ et al. 2010. Revision total knee arthroplasty infection: incidence and predictors. Clinical Orthopaedics and Related Research.
- Rasouli MR et al. 2014. Risk factors for surgical site infection following total joint arthroplasty. The Journal of Bone and Joint Surgery.
- Bass A et al. 2021. Periprosthetic joint infection is associated with an increased risk of venous thromboembolism following revision total knee replacement. The Journal of Bone and Joint Surgery.
- Kunutsor S et al. 2018. Debridement, antibiotics and implant retention for periprosthetic joint infections: a systematic review and meta-analysis of treatment outcomes. The Journal of Infection.
Frequently asked questions
Why do knee replacements fail?
Most knee replacements for osteoarthritis work well for many years. When one does fail, the main reasons are:
- Infection. Infection can start at the time of the operation or develop later, for example from poor wound healing or an infection elsewhere in the body. It may cause pain, swelling, redness and fever, and can erode the bone around the implant and loosen it. The most common bacteria are skin bacteria such as Staphylococcus aureus (including the antibiotic-resistant strain MRSA) and Staphylococcus epidermidis.
- Loosening or wear. Over time, the implant may wear or loosen from the bone. Tiny particles worn from the plastic insert can trigger a reaction that removes bone around the implant (osteolysis).
- Instability. The knee can feel unstable or give way if the ligaments are weak or the implant is not well aligned.
- Stiffness. Scar tissue, the position of the implant or other factors can limit how far the knee bends or straightens.
- A fracture around the implant. A fall or other injury, or weakened bone, can cause a break in the bone around the knee replacement.
- Poor positioning or alignment. Components that are not well positioned can cause pain, instability and early wear.
Treating an infected knee replacement often involves a team, including an infectious diseases physician and sometimes a plastic surgeon.
What is a two-stage revision knee replacement?
A two-stage revision is the most common approach for a long-standing infected knee replacement.
Stage 1: removing the infected implant. The infected knee replacement is removed along with any infected or damaged tissue. The joint is thoroughly cleaned (debrided) and washed out with an antiseptic solution. A temporary antibiotic-loaded cement spacer is placed in the knee to hold its alignment and spacing between the two operations. The spacer also releases antibiotics directly into the knee. After the first stage, you are usually given intravenous (IV) or oral antibiotics for 6 to 8 weeks. The choice of antibiotic is guided by the bacteria grown from samples taken at surgery.
Stage 2: putting in the new knee replacement. Before the second stage, blood tests, scans or a sample of fluid from the knee are used to check that the infection has cleared. The spacer is then removed and a new knee replacement is put in.
What if a knee replacement becomes infected soon after surgery?
An infection found early, soon after surgery or soon after symptoms start, may be treated without removing the whole implant. The knee is washed out, the plastic liner is replaced with a new sterile one and you have a course of antibiotics. Across many studies, this controls the infection in about 6 in 10 people, and results are better when it is done early. [10] If it does not control the infection, a two-stage revision may be needed.
What are the signs a knee replacement may need revision?
Increasing pain when walking, or a feeling that your knee gives way, should prompt an assessment. Persistent swelling or stiffness can also occur. These symptoms do not automatically mean you need a revision. An examination and X-rays help find the cause before any treatment is considered.
Seek medical advice promptly if your knee becomes hot, red or more swollen, or you develop a temperature above 38°C or chills.
Can a knee replacement be revised more than once?
Next step
Talk through your options
If your knee replacement is painful, stiff or unstable, Dr Vishal Pai can examine your knee, review your scans and explain all your options, including treatment without surgery.