Overview
A revision total knee replacement is an operation in which part or all of a previously implanted knee replacement is removed and replaced. The reasons to revise a knee replacement are specific. The joint is painful, loose, infected, or unstable, or the plastic spacer has worn out. Not every ache in a replaced knee is a revision candidate. The workup is careful, and honest triage happens on the phone.
If you have a knee replacement, from here or from elsewhere, and are experiencing new pain, instability, swelling, or stiffness that is not settling, call our office before booking a clinic visit. Our team can usually tell on the phone whether the case fits our practice or whether you would be better served at a revision-specialty center. We would rather save you the trip than see you for something we would have to refer out.
Who is a Candidate
Most painful replaced knees are not revision candidates at first pass. The workup exists to separate problems with the parts from soft-tissue, nerve, or referred causes. Revision is considered when:
Plastic spacer wear
X-ray, exam, and sometimes a fluid sample suggest the plastic spacer has worn through or failed, with catching and other mechanical symptoms. When the metal parts are still solid and well-positioned, we can often swap the spacer alone and keep them. That is called an isolated spacer exchange.
Aseptic loosening
One or both parts have lost their bond to bone. Imaging shows growing clear lines around the implant (a sign of loosening), parts that have sunk or shifted, or a change in alignment compared to early X-rays.
Instability
The knee buckles, gives way, or feels loose, and bracing or therapy does not settle it. The workup sorts out whether the cause is a stretched ligament, an imbalance between the parts, or a part that is out of position.
Infection
Infection around a knee replacement is its own category. A surface wound problem is different from deep infection around the parts. Deep infection, especially with a long-standing draining opening in the skin, usually needs revision in stages at a dedicated revision-specialty center, not a single-stage revision here.
Periprosthetic fracture
A fracture of the femur or tibia around the implant. Treatment depends on the fracture pattern, whether the parts are still solid, and bone quality. Some are fixed with a plate or rod, and some need revision of the implant.
How the Decision Is Made
The decision begins on the phone. Our scheduling team will ask when the replacement was done, where, what the new symptoms are, and whether there has been fever, drainage, or a recent procedure elsewhere. That conversation sorts cases into three rough buckets:
Straightforward workup in our clinic
New knee pain with no signs of body-wide illness, no drainage, and no recent invasive procedure that could have seeded the joint. You are seen in clinic, imaged, and, if revision is the right call, the surgery is planned here. Spacer exchanges, single-part revisions, and many full revisions fall in this bucket.
Evaluated here, planned for referral
Some cases belong at a dedicated revision-specialty center. These include large amounts of missing bone that need complex rebuilding, suspected deep infection that needs staged surgery, and multi-part revisions that need a big step up in built-in implant stability. We work up the case, make the diagnosis, and help you land in the right hands.
Referred directly
An acute infection with a draining opening in the skin, a patient who is medically unstable, or a fracture pattern that needs specialty equipment we do not stock. The phone triage catches these and routes them right away.
A typical in-clinic workup starts with X-rays of the knee. If infection is possible, we add blood tests that measure inflammation (ESR and CRP). Often we also draw fluid from the knee (an aspiration) and send it for cell counts and culture. We obtain prior surgery and implant records when available. Knowing the exact make and model of your implant tells us whether we can swap the plastic spacer alone without removing the metal parts.
What Revision Involves
Revision covers a wide range. At one end is a short operation that swaps only the plastic spacer. At the other is a major rebuild that removes and replaces both metal parts, fills in bone loss, and restores soft-tissue balance. The common threads are listed below. What is actually done in any given case depends on what we find at surgery.
Exposure and implant assessment
The prior incision is usually reused. The knee is opened, the plastic spacer is removed, and each metal part is tested for stability. A part that is solid and well-positioned may stay. A loose part comes out.
Component removal
If a part must be removed, it is done with instruments designed to protect the bone. The goal is to take out the implant without taking extra bone, because every bit of bone matters for the revision implant that goes back in.
Assessment of bone stock
After removal, the femur and tibia surfaces are checked for areas of missing bone. Small defects are filled with bone cement or small metal wedges. Larger defects may need a bigger rebuild. Cases that need large bone graft or complex rebuilding of very large defects are generally better served at a revision-specialty center.
Stems, wedges, and built-in stability
Revision parts often add stems, which are extensions that reach down into the shaft of the femur or tibia to take load off the weaker bone near the joint. Metal wedges fill in small areas of missing bone. When the supporting ligaments are weak or missing, the parts are coupled together more tightly for added built-in stability. How much of that extra stability is needed depends on the ligaments found at surgery.
Soft-tissue balance and alignment
As with a first-time knee replacement, balancing the soft tissue and lining up the leg determine how the knee feels and wears. In a revision the soft tissue is scarred and the landmarks are less forgiving, which is why revision cases take longer than first-time replacements even when the hardware question looks simple.
Closure
The joint is irrigated, a drain is placed selectively, and the tissues are closed in layers. Intraoperative cultures are often sent even when infection was not the indication, because occult infection occasionally declares itself on the back end.
Recovery
Recovery after a revision total knee replacement moves in phases. It is generally slower than after a first-time replacement, because the soft tissue has already been operated on once and there is less bone to work with.
Early recovery
How much weight you can put on the leg depends on what was done. A simple spacer exchange allows full weight right away, while a case with a bone rebuild or a fracture repair is protected. A walker, then a cane, is used until your walk is steady. Physical therapy starts early, focused on motion and rebuilding the thigh muscle.
Return to activity
Progress is gradual and guided by exam findings at each follow-up: swelling, range of motion, thigh strength, and your walk. It is not a fixed calendar. Driving, desk work, physical work, and recreation each have their own criteria and are cleared one at a time.
Long-term surveillance
Revision knees are followed long-term, with periodic exams and X-rays to watch for spacer wear, parts that shift, and any change in alignment. Call early for new pain, drainage, or fever.
What Revision Treats
What to Expect from Our Practice
The posture in New Braunfels is call-first screening, honest scope of practice, and continuity of care. If your case is one our surgeons handle here, you will be seen in clinic, worked up, and, if revision is appropriate, operated on by our surgeons. If your case is better served at a dedicated revision-specialty center, our team will say so on the phone and help you find the right place. We would rather save you the trip than see you for something we would have to refer out.
Every operation carries risk. This procedure is offered because the condition, when left untreated, can cause a failed or failing knee replacement, from loosening, wear, instability, or infection, that grows more painful and harder to fix the longer it is left. The decision to proceed weighs the risks of surgery against the limitations the condition places on daily function. Surgery does not remove risk; it addresses a problem that is otherwise progressive. Whether it is appropriate is determined for each patient in consultation with the surgeon.
The risks we discuss with patients before revision arthroplasty include:
- bleeding and infection (including rare deep periprosthetic infection)
- anesthesia risk
- blood clot in the leg or lung, reduced with blood thinners, walking, and compression stockings after surgery
- stiffness that sometimes needs a procedure to loosen the knee under anesthesia
- pain that continues when the revision does not fully fix the source
- fracture of the bone around the implant
- injury to the tendon that straightens the knee
- problems with wound healing in a knee that has been operated on before
- rare injury to the nerves or blood vessels behind the knee
- another revision over time if the bone or soft tissue fails
Frequently Asked
questions we hear in clinicMy knee replacement hurts. Does that mean I need a revision?
Not necessarily. Most painful replaced knees are not revision candidates at first pass, and not every ache in a replaced knee calls for one. The workup exists to separate problems with the parts from soft-tissue, nerve, or referred causes.
What should I do first?
Call our office before booking a clinic visit. Our team will ask when the replacement was done, where, the nature of the new symptoms, and whether there has been fever, drainage, or a recent procedure elsewhere. They can usually tell on the phone whether the case fits our practice or whether a revision-specialty center would serve you better.
What does the workup include?
A typical in-clinic workup starts with X-rays of the knee. If infection is possible, we add blood tests that measure inflammation (ESR and CRP), and often draw fluid from the knee for cell counts and culture. We also obtain prior surgery and implant records when available.
Will every part be replaced?
Not always. Each metal part is tested at surgery, and a part that is solid and well-positioned may stay. When the metal parts are solid, we can often swap the worn plastic spacer alone, which is called an isolated spacer exchange.
Why does a revision take longer than a first-time replacement?
In a revision the soft tissue is scarred and the landmarks are less forgiving, which is why revision cases take longer than first-time replacements even when the hardware question looks simple. Balancing the soft tissue and lining up the leg still determine how the knee feels and wears.
What is recovery like?
It is generally slower than after a first-time replacement. How much weight you can put on the leg depends on what was done: a simple spacer exchange allows full weight right away, while other cases are protected. Physical therapy starts early, and progress is guided by exam findings at each follow-up rather than a fixed calendar.
Further Reading
External patient-education references and related OSI pages for additional background:
