When a Hip or Knee Replacement Needs Replacing: Understanding Revision Surgery

The patients I see about revision surgery are usually frightened in a particular way. They had a hip or knee replaced years ago, it worked, they got their life back, and now something has changed. The pain has crept back, or the joint feels unreliable underneath them, and the thing they were promised would last has apparently stopped lasting.

The word revision does not help. It sounds like an admission that something went wrong. Occasionally it is. Far more often it is simply what happens when a mechanical device that has carried your entire body weight through fifteen or twenty years of walking reaches the end of its working life. I want to explain how I think about it, because understanding what revision surgery is takes a surprising amount of the fear out of it.

First, Some Perspective on How Long Replacements Last

Before anything else, I think patients deserve the reassuring context, because the internet rarely provides it.

Hip and knee replacement are among the most successful operations in modern medicine. National joint registry data in the UK consistently shows that roughly nine out of ten hip and knee replacements are still in place and working at fifteen years. A patient who has their hip replaced in their late sixties has a very good chance of never needing anything further done to it.

So revision is not the expected outcome. It is the exception. But with hundreds of thousands of joint replacements performed in this country, the exception still accounts for a meaningful number of patients, and those patients deserve the same quality of thinking that went into their first operation.

What Revision Surgery Actually Means

Revision surgery means replacing some or all of an existing joint replacement. That "some or all" matters more than most patients realise.

At the simpler end, revision can mean exchanging a single worn plastic bearing surface while leaving the metal components that are fixed into your bone completely undisturbed. This is a much smaller operation than a first-time replacement. At the more complex end, it can mean removing well-fixed implants, rebuilding lost bone, and inserting longer, more heavily engineered components that gain their stability further down the shaft of the bone.

Two patients can both be told they need a revision and be facing genuinely different operations. One of the first things I do in clinic is work out which end of that spectrum a patient is actually on, because it changes everything about what I advise and what I promise.

Why a Replacement Might Need Revising

There are a handful of reasons, and they behave quite differently from one another.

• Aseptic loosening. The commonest reason in the long term. The bond between the implant and the bone gradually fails without any infection being present, and the component starts to move very slightly under load. That movement is what produces pain.
• Wear of the bearing surface. The plastic liner that acts as the new cartilage wears down over years of use. The debris it releases can also provoke the body into thinning the surrounding bone, which is a process called osteolysis.
• Infection. Uncommon, affecting well under one in a hundred primary replacements, but the reason I take any hot, swollen, newly painful replacement seriously until proven otherwise. Infection changes the whole plan, so it has to be excluded properly rather than assumed away.
• Instability. In a knee this feels like the joint giving way or shifting. In a hip it can mean recurrent dislocation. It usually reflects the balance of the soft tissues or the position of the components rather than the implant wearing out.
• Stiffness. A joint that never achieved a useful range of movement, or that has lost it, despite committed physiotherapy.
• Malposition or malalignment. Components that sit slightly wrongly relative to the mechanical axis of the limb load unevenly, which causes pain and shortens the life of the implant.
• Fracture around the implant. A break in the bone next to a component, usually after a fall, which sometimes needs the implant revised rather than simply fixed.

The Symptoms That Should Prompt a Review

I would rather see a patient who turns out to be fine than miss one who is not, so I am deliberately generous with what I think is worth a look.

The single most important pattern is new pain in a replacement that had been comfortable. A joint that settled well, gave you several good years, and has now started aching is telling you something. Start-up pain as you rise from a chair, or a deep ache in the thigh or groin when you put weight through the leg, is a classic description of a loosening component.

Other things worth acting on include a sense that the joint is giving way or that you cannot trust it on stairs, a noticeable loss of movement that has developed over months, a change in the length of the leg or the way you walk, or new clicking and clunking that is accompanied by pain. Painless noise on its own is very often nothing.

Redness, heat, swelling, a wound that has never quite settled, or feeling generally unwell with a temperature all need looking at promptly, because they raise the question of infection.

None of these findings means your replacement has failed. Plenty of them turn out to be a muscle, a tendon, the other joint, or the back referring pain into the area. But they all justify a proper assessment rather than waiting to see.

How the Cause Gets Worked Out

I will not take a patient to theatre for a revision without knowing what I am revising and why. Operating on unexplained pain around a replacement is one of the reliable ways to leave a patient worse off.

Working it out usually involves tracking down the records of the original surgery so I know exactly which implant is in place, comparing X-rays taken at intervals rather than relying on a single film, and often adding a CT scan to assess how much bone stock is there to work with. Where infection is a possibility, blood tests such as CRP and ESR help, and taking a sample of fluid from the joint is frequently the step that settles the question.

That groundwork is unglamorous and it takes time. It is also the part that most determines whether the operation goes well.

What the Surgery Involves

A revision is a longer and more demanding procedure than a first-time replacement, and I am always straightforward with patients about that.

The hard part is often the removal. Implants that have been fixed into bone for two decades have to come out while preserving as much of that bone as possible, because what remains is what the new components have to hold onto. Where bone has been lost, it can be rebuilt using graft or filled with metal augments. The replacement components themselves are usually larger, with stems that reach further into the bone to find solid support.

Where infection is confirmed, the standard approach is often a two-stage revision. The infected implants come out, a temporary spacer loaded with antibiotic goes in, a course of antibiotic treatment follows, and the new joint is implanted once the infection has genuinely cleared. It is a longer road, and it is the approach that gives the best chance of getting rid of the problem for good rather than suppressing it.

Recovery Takes Longer, and That Is Expected

Most patients stay in hospital two to three nights. Walking with support generally starts within the first day or two, and independence from crutches or a frame typically comes over the first one to two weeks, though this depends heavily on whether bone graft was needed and what weight-bearing restrictions I have set.

The honest headline is that full recovery from a revision usually takes three to six months, which is somewhat longer than a primary replacement. Most patients are managing light daily activity by eight to twelve weeks and feel the real benefit somewhere in the four to six month range. Patients who do best are the ones who expect that timeline from the start rather than measuring themselves against how quickly their first replacement recovered.

Being Honest About the Results

Revision surgery in experienced hands works well, and the great majority of patients get substantial relief and a joint they can rely on again.

I do think patients should hear two qualifications. The first is that a revision generally does not perform quite as well as a well-functioning primary replacement, so the goal I set is reliable pain relief and a stable, usable joint rather than a return to a brand new knee or hip. The second is that every revision is technically harder than the one before it, which is why preserving bone at each operation matters so much, and why I am careful not to revise a joint until there is a clear reason to.

What I Tell My Patients in Clinic

If your replacement has started hurting after years of behaving itself, get it assessed. Do not talk yourself out of it, and do not assume that being told a replacement lasts twenty years means nothing can be checked before then.

If it turns out that nothing is wrong with the implant, that is a genuinely good outcome and worth the appointment. If something is wrong, finding it early tends to mean a smaller operation, better bone to work with, and a better result. The patients who struggle most are the ones who lived with a deteriorating joint for two years before mentioning it.

And if a revision is the right answer, it is a well-established operation with a good track record. It asks more of you than the first one did, and it is usually worth it.

If you have a hip or knee replacement that has become painful or unreliable and would like an unhurried assessment of what is going on, I would be glad to see you at either of my clinics.

Book a consultation →

• Spire Yale Hospital, Wrexham, 01978 268065
• Practice Plus Group Hospital, Birmingham, 03330 607558

You may also find it useful to read more about the revision hip and knee surgery pathway, or our prehabilitation guide, which matters even more before a revision than before a first replacement.

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This article is written for general information only and does not replace personalised medical advice. Whether a joint replacement needs revising depends on individual circumstances and should always be assessed by a qualified clinician following examination, imaging, and where appropriate laboratory tests.