Revision Knee Replacement

Introduction

A knee replacement is one of the most successful operations in modern medicine. For most people, the new joint relieves pain and restores movement for many years. But artificial joints do not last forever, and in a minority of cases, problems develop — sometimes within a few years, sometimes only after a decade or two. When this happens, a second operation called a revision knee replacement may be needed.

If you have been told that your first knee replacement is failing, or if you have been living with pain, stiffness, swelling, or a feeling that your knee is unstable, you are likely reading this because revision surgery has been raised as a possibility. This guide explains what revision knee replacement is, why it is performed, how it differs from the first operation, what recovery involves, and what to expect in the longer term.

Revision surgery is more demanding than the first knee replacement — for the surgical team and for you. Understanding the reasons for revision, the choices involved, and the realistic timeline of recovery can help you have a more informed conversation with your orthopaedic surgeon.

What Is Revision Knee Replacement?

Revision knee replacement, also called revision total knee arthroplasty (arthroplasty means surgical replacement of a joint), is an operation to remove all or part of a previously implanted artificial knee and replace it with new components.

In a primary (first) knee replacement, the damaged surfaces of the thigh bone (femur), shin bone (tibia), and sometimes the kneecap (patella) are removed and replaced with metal and plastic components. These components are held in place by a combination of cement, press-fit fixation, and the surrounding soft tissues. Over time, the bond between implant and bone can weaken, the plastic spacer can wear down, the surrounding bone can lose strength, or the joint can become infected. Any of these can lead to a knee that hurts, feels unstable, or no longer works as it should.

During revision surgery, the surgeon carefully removes the old components, addresses any bone loss, infection, or soft-tissue problems, and implants new prosthetic parts. The new components are often different from the originals — they may have longer stems that anchor deeper into the bone, metal pieces called augments that fill in areas of missing bone, and more constrained designs that compensate for damaged ligaments.

A revision is technically more complex than a primary knee replacement because:

• The bone available to anchor the new implant is often reduced
• Scar tissue from the previous surgery makes the operation longer and more delicate
• Ligaments and soft tissues around the knee may be weakened or stretched
• Specialised implants and longer operating times are often required
• If infection is the reason for revision, treatment usually involves two separate operations

Revision knee replacement is almost always performed in adults, most often in people who had their primary knee replacement many years earlier. It is not a paediatric procedure.

Why Is Revision Knee Replacement Performed?

Aseptic Loosening

“Aseptic” means non-infected. Over time, the bond between the implant and the bone can weaken, even without infection. Microscopic plastic particles released as the implant wears can trigger a slow inflammatory response in the surrounding bone, gradually loosening the implant. This is one of the most common reasons for late revision.

Periprosthetic Joint Infection

An infection in or around the artificial joint is called a periprosthetic joint infection (PJI). It can develop soon after the original operation or, less commonly, years later if bacteria spread through the bloodstream from another source. Infection is one of the most serious causes of implant failure and usually requires a different surgical strategy than non-infected revision.

Polyethylene Wear

The plastic spacer between the metal components — made from a material called polyethylene — gradually wears down with use. Modern designs wear more slowly than older ones, but in active patients or after many years, the spacer can thin enough to affect alignment and stability.

Instability

If the ligaments around the knee become stretched or imbalanced, the joint can feel like it is going to give way. Instability can develop gradually or follow an injury. It is a common reason for revision even when the implant itself is not damaged.

Stiffness

Some knees develop significant scar tissue that limits bending or straightening. When non-surgical treatments such as physiotherapy and manipulation under anaesthesia do not improve range of motion enough, revision may be considered.

Periprosthetic Fracture

A fall or other injury can fracture the bone around the implant. Depending on the location and severity, this may require revision surgery to fix the fracture and replace the implant.

Component Malalignment or Mechanical Failure

In rare cases, a metal component can fracture, dislodge, or have been positioned in a way that leads to early wear. Imaging usually identifies these problems clearly.

Persistent Unexplained Pain

A knee replacement that has hurt continuously since the original surgery, without a clear cause on imaging, is a difficult situation. Surgeons typically pursue a thorough work-up before considering revision in this scenario, because revision for unexplained pain has less predictable outcomes than revision for a clearly identified mechanical or infectious problem.

Who Is a Candidate for Revision?

Whether revision knee replacement is appropriate is a clinical decision made by your orthopaedic surgeon based on careful evaluation. In general, candidates are people who:

• Have ongoing knee pain, instability, stiffness, or functional decline after a primary knee replacement
• Have imaging or laboratory findings that explain the problem — for example, signs of loosening, wear, infection, or fracture
• Are medically fit enough to undergo a longer and more complex operation
• Have realistic expectations about the recovery and the likely results

Several factors are weighed before recommending revision:

• Cause of failure. A clear, identifiable problem usually predicts a better revision outcome than vague, unexplained pain.
• Bone stock. The amount and quality of bone available to anchor the new implant.
• Soft-tissue condition. The strength of the ligaments, tendons, and skin envelope around the knee.
• General health. Heart, lung, kidney function, diabetes control, and nutritional status all affect surgical risk and healing.
• Infection status. If infection is present, it must be addressed before or as part of the revision strategy.

Some patients are not good candidates for revision — for example, those with very poor general health, uncontrolled infection that cannot be cleared, or such severe bone loss that reconstruction is not feasible. In these situations, surgeons may discuss alternatives such as long-term bracing or, rarely, more salvage-type procedures.

Alternatives and Non-Surgical Options

Before recommending revision surgery, surgeons typically explore whether the problem can be managed without another operation. Whether non-surgical management is reasonable depends entirely on the cause of the symptoms.

Physiotherapy and Activity Modification

For knees that are stiff or weak but not loose or infected, a structured physiotherapy programme can sometimes improve symptoms enough that revision is not needed. Activity modification — changing the types of movements or sports that aggravate the knee — can also help.

Pain Medications and Anti-inflammatory Drugs

Short courses of pain relief and anti-inflammatory medication can manage flare-ups, although they do not address the underlying cause of failure.

Bracing

For people with mild instability or for those who are not surgical candidates, a brace may improve walking comfort and stability.

Injections

Joint injections are used cautiously in artificial knees because of the small but real risk of introducing infection. Surgeons usually reserve them for selected cases and after carefully ruling out infection.

Antibiotic Treatment Alone

In rare situations, an early infection identified within a few weeks of the primary surgery may be treated with a smaller operation that washes out the joint and exchanges the plastic spacer, combined with long-term antibiotics. This is not appropriate for chronic infection, which usually requires full revision.

However, when imaging, blood tests, or joint fluid analysis confirm true implant failure, non-surgical treatments generally provide only temporary relief. Continuing to delay surgery in such cases can sometimes make eventual revision more difficult by allowing further bone loss.

Diagnosis and Pre-Operative Evaluation

Planning a revision knee replacement requires more detailed evaluation than a primary replacement, because the surgeon needs to understand exactly what has gone wrong.

Clinical Examination

The orthopaedic team will assess your walking pattern, the range of motion in the knee, signs of swelling or warmth, stability of the ligaments, and the condition of the skin and previous scar.

Imaging

• X-rays are the first imaging test and can show implant position, signs of loosening, wear, fractures, and alignment problems.
• CT scans give detailed three-dimensional information about bone loss and implant rotation, which is important for planning specialised implants.
• MRI can be used in selected cases, often with special techniques that reduce interference from the metal implant.
• Nuclear bone scans are sometimes used when loosening or infection is suspected but not clear on other imaging.

Blood Tests

Two blood markers of inflammation — ESR (erythrocyte sedimentation rate) and CRP (C-reactive protein) — are routinely checked when infection is suspected. They are not specific to joint infection but help guide further testing.

Joint Aspiration

A sample of fluid from the knee is drawn with a needle and tested for cell counts and bacteria. The Musculoskeletal Infection Society (MSIS) has published widely used criteria that combine clinical, laboratory, and microbiology findings to diagnose periprosthetic joint infection accurately.

General Pre-Operative Assessment

Before revision surgery, the team will also check your overall health: heart and lung function, blood pressure, diabetes control, nutritional status, kidney function, and any medications that might need to be adjusted (such as blood thinners). Dental and skin checks are common, because untreated dental infections or skin sores can be a source of bacteria.

Types of Revision Approaches

Revision knee replacement is not a single operation — the approach depends on what has failed and why.

Partial Revision

In some cases, only one component needs to be exchanged. For example, if the plastic spacer has worn down but the metal components are still well-fixed and correctly positioned, the surgeon may exchange only the spacer (a polyethylene exchange). Partial revisions are less common because surgeons usually find more than one component is affected once the joint is opened, but they remain an option in carefully selected cases.

Total Revision

Most revision knee replacements involve removing and replacing all components — the femoral component, the tibial component, and the plastic spacer, with the kneecap component exchanged or resurfaced as needed. New implants are often more specialised, with longer stems, augments, and a higher degree of constraint to compensate for missing bone or loose ligaments.

Two-Stage Revision for Infection

When the cause of failure is infection, current guidance from major orthopaedic societies generally favours a two-stage approach for chronic cases. This involves:

1. First operation: All implants are removed, the joint is thoroughly cleaned, and a temporary spacer made of antibiotic-loaded cement is placed in the knee. You are then treated with intravenous antibiotics, typically for several weeks.
2. A waiting period during which the infection is monitored with blood tests and clinical follow-up to confirm it has cleared.
3. Second operation: The temporary spacer is removed and a new permanent implant is placed.

In some early or selected infections, a single-stage exchange (removing the implant and placing a new one in the same operation) may be considered. Whether this is appropriate is a specialist decision based on the type of bacteria, the duration of infection, and the patient’s general health.

Revision for Periprosthetic Fracture

When a fracture has occurred around the implant, the revision may involve fixing the fracture with plates or rods alongside replacing the implant. The exact strategy depends on the location of the fracture and whether the existing implant was stable.

Robotic-Assisted and Computer-Navigated Revision

Some surgical centres now use robotic systems or computer navigation to help with implant positioning during revision surgery. These technologies are intended to improve the precision of bone cuts and alignment. Their role in revision (as opposed to primary) surgery is still evolving, and whether they are used depends on the specific case and the centre’s equipment.

Preparing for Revision Knee Replacement

Preparation for revision surgery is similar to preparation for primary knee replacement but usually more thorough.

Medical Optimisation

Doctors typically aim to optimise general health before surgery. This may include:

• Improving diabetes control (blood sugar targets before surgery are important for healing and infection risk)
• Treating anaemia (low red blood cell count)
• Reviewing and adjusting medications, particularly blood thinners
• Encouraging smoking cessation, which has a strong effect on wound healing
• Addressing nutritional deficiencies
• Treating any dental infections or skin problems

Pre-habilitation

Some surgeons recommend a period of physiotherapy before surgery, focused on strengthening the muscles around the knee and improving overall fitness. Going into surgery stronger generally helps with recovery.

Planning for After the Operation

Recovery from revision surgery is longer than from primary knee replacement, so it helps to plan ahead. This includes arranging help at home, preparing the living space (removing trip hazards, organising frequently used items at waist height), and arranging time off work.

Day Before and Day of Surgery

You will usually be asked not to eat or drink for several hours before surgery, to shower with a special antiseptic wash, and to follow specific instructions about medications. Antibiotics are typically given just before the operation starts.

What Happens During Revision Knee Replacement

The operation usually takes longer than a primary knee replacement — often two to four hours, sometimes longer for complex cases. Most revisions are performed under spinal or general anaesthesia. Your anaesthetist will discuss which is most appropriate.

The general sequence is:

1. Opening the knee. The surgeon usually uses the same scar as the previous operation, extending it as needed. Scar tissue is carefully released to expose the joint.
2. Removing the old implant. Each component is removed carefully, with attention to preserving as much bone as possible. Specialised instruments are used to separate the implant from the bone or cement.
3. Cleaning the joint. All cement, scar tissue, and any infected tissue is removed. If infection is involved, samples are sent for laboratory analysis.
4. Assessing bone loss. The surgeon examines the bone surfaces. If there are defects, they may be filled with bone graft (from a bone bank) or metal augments.
5. Trial fitting. Trial components are placed to check sizing, alignment, and stability before the final implants go in.
6. Placing the new implant. Definitive components are fixed, usually with bone cement, sometimes with longer stems that anchor deeper into the femur and tibia. More constrained designs may be used if the ligaments are weak.
7. Closing the wound. The soft tissues are repaired in layers, drains may be placed, and the skin is closed.

Recovery and Rehabilitation

Recovery from revision knee replacement is generally slower than from a primary replacement. This is partly because of the longer and more complex operation, partly because of the changed bone and soft tissue, and partly because of the rehabilitation needed to regain strength.

Hospital Stay

The hospital stay after revision surgery is typically longer than after primary replacement — often four to seven days, sometimes more in two-stage infection cases or when there are medical issues to manage. During this time the team focuses on pain control, prevention of blood clots, monitoring for infection, and early mobilisation.

Early Recovery (First Six Weeks)

Most patients begin standing and taking steps within a day or two after surgery, usually with a walker or crutches. Weight-bearing instructions vary depending on what was done during the operation — in some revisions, particularly those involving bone graft or fracture fixation, full weight on the leg may be limited for several weeks.

Physiotherapy starts in hospital and continues after discharge. Early goals include:

• Controlling pain and swelling
• Restoring basic range of motion
• Walking safely with an aid
• Doing simple strengthening exercises
• Preventing blood clots through movement and prescribed medication

Intermediate Recovery (Six Weeks to Three Months)

During this phase, physiotherapy intensifies. Most patients gradually progress from walker to cane to walking unaided, although the timeline varies. Activities such as climbing stairs and getting in and out of cars become more comfortable. Strength and balance exercises become a larger part of the rehabilitation programme.

Longer-Term Recovery (Three Months to One Year)

Returning to Activities

Timelines vary widely depending on the type of revision and individual recovery, but typical guidance includes:

• Walking longer distances unaided — usually by six to twelve weeks
• Driving — usually six to eight weeks, once you can safely operate the controls and react in an emergency
• Returning to desk-based work — often by six to eight weeks
• More physically demanding work — usually three to six months
• Low-impact recreational activities such as walking, cycling, and swimming — generally encouraged once cleared by your surgeon

High-impact activities such as running, jumping sports, and contact sports are generally not advised after revision knee replacement, as they may shorten implant life.

Risks and Complications

Revision knee replacement carries higher risks than primary knee replacement. Major orthopaedic societies are clear that this is true even in expert hands. Knowing the risks does not mean they will happen to you, but it helps you make an informed decision and recognise problems early.

Infection

The risk of infection is higher than in primary surgery, both because of the longer operation and because of the altered tissue. Strict surgical technique, prophylactic antibiotics, and careful wound care reduce but do not eliminate this risk.

Blood Clots

Deep vein thrombosis (a clot in the leg veins) and pulmonary embolism (a clot that travels to the lungs) are recognised risks after major lower-limb surgery. Blood-thinning medication, compression stockings, and early movement after surgery reduce this risk.

Nerve or Blood Vessel Injury

The nerves and blood vessels around the knee are close to the surgical area, and the scar tissue from previous surgery can make them harder to identify. Injury is uncommon but possible.

Stiffness

Some patients develop persistent stiffness despite physiotherapy. In some cases, a procedure called manipulation under anaesthesia may help.

Persistent Pain

Not every revision fully relieves pain, particularly when revision is being performed for unexplained pain rather than a clear mechanical or infectious cause.

Implant Loosening or Wear

Just as the original implant could loosen or wear, so can the revision implant — sometimes sooner, given the altered bone and soft tissue.

Periprosthetic Fracture

Bone around the implant can fracture during or after surgery, particularly if the bone is weakened.

Wound Healing Problems

The skin and soft tissue around a previously operated knee may heal more slowly. Diabetes, smoking, poor nutrition, and steroid use all increase this risk.

Anaesthetic and Medical Complications

As with any major surgery, there are risks related to anaesthesia and general medical complications, particularly in older patients or those with other health conditions.

Life After Revision Knee Replacement

Most patients experience meaningful improvement after revision surgery. Studies and clinical experience suggest that pain relief, stability, and walking ability typically improve substantially, although outcomes are, on average, not quite as good as those after a successful primary knee replacement. Setting realistic expectations is important.

What to Expect in the First Year

Longer-Term Outlook

How long a revision implant lasts depends on many factors, including the reason for the original failure, the quality of the surrounding bone, the type of implant used, activity level, body weight, and general health. Modern revision implants can last many years in most patients, although the average survival is somewhat shorter than that of primary implants.

Caring for the New Joint

General principles for looking after a revision knee replacement include:

• Maintaining a healthy body weight to reduce stress on the joint
• Continuing strengthening and flexibility exercises as a long-term habit
• Choosing low-impact activities such as walking, swimming, and cycling
• Avoiding high-impact sports such as running and jumping
• Telling dentists and other doctors about the implant, as antibiotic prophylaxis may be recommended for certain procedures (this is an individual clinical decision)
• Attending follow-up appointments and imaging as advised, even if the knee feels well

Signs That Need Medical Attention

Patients are usually advised to contact their surgeon if they develop:

• New or worsening knee pain after a period of being comfortable
• Sudden swelling, warmth, or redness
• Fever or chills without an obvious cause
• A sense that the knee is giving way or locking
• Wound problems such as drainage or opening
• Calf pain or swelling, or sudden breathlessness (possible signs of blood clot)

Frequently Asked Questions

How is revision knee replacement different from the first knee replacement?

Revision surgery is more complex because the surgeon must remove the old implant, deal with scar tissue and any bone loss, and place new components. The operation is usually longer, the implants are often more specialised, and recovery takes longer.

Is revision knee replacement more painful than the first surgery?

Pain levels in the early days after surgery are broadly similar, although recovery often takes longer and the rehabilitation phase may feel more demanding.

How long does recovery take?

Most patients regain basic function within a few weeks but continue to improve over six to twelve months. Patients having two-stage revision for infection have a longer overall timeline because of the gap between the two operations.

How long will the revision implant last?

Modern revision implants can last many years, although on average they tend not to last quite as long as a successful primary replacement. Activity level, weight, bone quality, and general health all influence longevity.

Will I be able to walk normally again?

Most patients walk much better after a successful revision than before. Whether walking is fully “normal” depends on the reason for revision, the strength of the surrounding muscles and ligaments, and the rehabilitation effort. Many patients use a cane only occasionally or not at all in the long term.

Can revision surgery be done more than once?

A second revision is possible but more difficult than the first, because each operation removes some bone and stresses the soft tissues. Surgeons weigh the risks and likely benefits carefully in such situations.

What if my knee replacement was done in another country?

Revision surgery can usually be planned even when the original operation was done elsewhere, provided your surgeon has access to records of what was implanted (the “implant card” or operative report). If those records are not available, the surgeon can usually identify the implant from imaging, although planning may be more challenging.

Are there alternatives to revision if I am not fit for major surgery?

For patients who are not surgical candidates, bracing, pain management, physiotherapy, and activity modification may help. Whether these are appropriate is an individual clinical decision.

Conclusion

Revision knee replacement is a specialised operation designed to address the problems that can develop years after a primary knee replacement — loosening, infection, wear, instability, fracture, and others. It is more complex than the first operation, recovery takes longer, and outcomes, while generally good, are on average slightly less predictable than after a successful primary replacement.

For most patients, however, a well-planned revision substantially relieves pain, improves stability, and restores meaningful function. The keys are an accurate diagnosis of why the original replacement failed, careful surgical planning, and a committed rehabilitation effort. If you are facing the possibility of revision surgery, a detailed conversation with your orthopaedic surgeon about the cause of failure, the proposed surgical approach, and the realistic recovery timeline is the most important next step.