How Long Does a Knee or Hip Replacement Actually Last?

The short answer, based on national joint registry data from countries that have tracked hundreds of thousands of implants: roughly nine out of ten total knee replacements and total hip replacements are still in place and functioning at fifteen years, and a meaningful proportion — broadly in the region of seven or eight in ten — are still working beyond twenty years. Those are good numbers, and they are the honest headline.

The caveat matters as much as the number. Those figures are averages drawn largely from patients who had surgery in their late sixties and seventies, who were not especially heavy, and who did not run, jump or do heavy physical work afterwards. If you are 50, if you weigh significantly more than ideal, or if you intend to stay very physically active, your personal survivorship is lower than the registry average — sometimes considerably lower. A 50-year-old having a knee replacement should plan on the realistic possibility of needing a revision at some point in their life. That is not a reason to avoid surgery. It is a reason to plan properly.

What the registries actually tell us

Large national registries in the United Kingdom, Sweden, Australia and elsewhere have followed joint replacements for decades. The pattern they show is consistent: most implants fail either very early (within the first two years, usually from infection, instability or a technical problem) or very late (after fifteen to twenty years, usually from wear and loosening). The middle years are relatively quiet.

This shape is worth understanding because it changes how you interpret “my replacement will last fifteen years”. It does not mean it will fail at fifteen years. It means that if it gets through the first two years cleanly, you are most likely looking at a long, uneventful period and then a gradual decline in the implant's bearing surface far down the line.

Modern implants and modern bearing materials — highly cross-linked polyethylene in particular — have measurably reduced wear compared with what was used in the 1990s. Registry data lags reality by definition: the twenty-year figures we quote today describe implants put in twenty years ago. It is reasonable to expect current implants to do at least as well, but that is an expectation, not proven data. Anyone who tells you a specific implant is guaranteed to last thirty years is going beyond the evidence. If you want to understand the hardware choices themselves, I have written about types of total knee replacement and about hip resurfacing compared with total hip replacement.

Why your number is probably not the registry number

Three factors move survivorship most:

Age at surgery. This is the strongest single predictor, and it is not because young bone is worse. It is because a younger patient walks more steps per year, loads the joint harder, and simply lives longer with the implant in place. A hip replaced at 45 has to survive forty years of use; one replaced at 75 has to survive fifteen. Registry analyses consistently show substantially higher revision rates in patients under 55.

Body weight. Every step transmits several times body weight through a knee. Higher body weight increases polyethylene wear, increases loosening risk, and increases the risk of wound complications and infection around the time of surgery. The relationship between weight and joint outcome is one of the few things in orthopaedics that is both well established and directly under the patient's control — I have discussed it in more detail in how obesity affects joint health.

Activity type. Not activity level — activity type. Walking a great deal is fine. Repeated impact is not.

What actually makes a replacement fail

Polyethylene wear and osteolysis

The bearing surface of the implant is a plastic (polyethylene) insert. Over years of use, microscopic particles wear off it. The body's immune cells try to clear these particles and, in doing so, release signals that dissolve bone around the implant. This is osteolysis. It is silent for a long time, which is exactly why long-term follow-up X-rays matter even when the joint feels fine.

Aseptic loosening

The bond between implant and bone fails without infection being present. Often this follows osteolysis. It typically presents as pain on starting to walk (start-up pain) and pain with weight-bearing that was not there before.

Infection

Periprosthetic joint infection is the complication we fear most, because treating it usually means further surgery and sometimes removing the implant in stages. It can occur early, from the surgery itself, or late, from bacteria travelling through the bloodstream from a dental abscess, a skin infection, a urinary infection or a diabetic foot ulcer. Diabetes, obesity and smoking all raise the risk.

Instability and dislocation

More relevant to hips than knees. A hip can dislocate if the components are malpositioned, if the soft tissues around the joint are weak, or with certain extreme movements, particularly in the first few months. In knees, instability presents as a sense of the knee giving way.

Periprosthetic fracture

A break in the bone around the implant, usually after a fall. This becomes more common with age and osteoporosis, which is one reason bone health matters after joint replacement and not just before it — the point I make in vitamin D and calcium deficiency in India.

What helps and what shortens implant life

Helps the implant last	Shortens implant life
Keeping body weight in a healthy range	Significant excess body weight, especially if it increases after surgery
Walking, swimming, cycling, cross-trainer, gentle gym work	Running, jumping, competitive contact sport, squash, singles tennis
Maintaining quadriceps and hip abductor strength lifelong	Letting muscle waste after the first year
Well-controlled diabetes (HbA1c in target range)	Poorly controlled diabetes
Prompt treatment of dental, skin and urinary infections	Ignoring a dental abscess or an infected foot wound
Not smoking	Smoking, which impairs wound and bone healing
Attending review X-rays even when pain-free	Never returning after the first year
Reporting new pain, swelling or a change in walking early	Waiting a year to report a joint that has started hurting again
Fall prevention: home lighting, footwear, treating osteoporosis	Repeated falls

Why revision surgery is harder than the first operation

A first (primary) replacement is done on undisturbed anatomy with good bone stock. A revision is not. By the time an implant needs replacing, some bone has usually been lost around it. The old components must be removed without destroying more bone. Scar tissue distorts the tissue planes. Ligaments may be deficient, so more constrained implants are often needed, and more constrained implants transmit more stress to the bone-implant interface, which is itself a longevity problem.

Practically, revision surgery takes longer, involves more blood loss, has a higher infection and complication rate, and the functional result is generally not as good as a well-performing primary. Recovery is slower. Costs are higher. And a revised implant does not last as long as a primary implant did. None of this makes revision a disaster — it is done routinely and most patients do well — but it is why we do not treat the first replacement as disposable. I have written in more detail about revision knee replacement.

So am I too young? The honest framing

The instinct to delay is a reasonable one, and I support it up to a point. The framing I use is: delay as long as is reasonable, but not so long that you lose muscle, mobility and independence.

Delaying is sensible when the pain is intermittent, sleep is intact, you can still walk what you need to walk, and non-surgical management has not been fully exhausted. Plenty can still be done at that stage — weight reduction, a serious strengthening programme, activity modification, and where appropriate injections. The full range is set out under arthritis treatment.

Delaying stops being sensible when you are no longer walking, when the quadriceps has visibly wasted, when the knee has developed a fixed deformity, when you have stopped leaving the house, or when the pain is waking you every night. Patients who come to surgery in that state have poorer outcomes: the muscle they lost has to be rebuilt from a worse starting point, contractures are harder to correct, and the achievable range of movement is lower. Waiting five extra years to protect an implant, and losing your walking capacity in the process, is a bad trade.

If you are weighing this up, the practical details of both operations — what is done, what recovery looks like, and what it costs in Bengaluru — are on the knee replacement and hip replacement service pages, with itemised costs at knee replacement cost in Bangalore and hip replacement cost in Bangalore.

Living with a replaced joint

Two rules cover most of it. First, use the joint — a replaced knee or hip that is walked on and kept strong does better than one that is protected. Second, do not shock it. Impact and twisting under load are what wear a bearing surface.

Practically: walking, brisk walking, stationary or road cycling, swimming, doubles badminton at a social level, gym work with controlled weights, yoga within comfortable range. Avoid running as exercise, jumping, competitive contact sport and repeated deep squatting under load. Sitting cross-legged and floor squatting are common questions in Indian households; many patients regain enough flexion to manage them, but I would not build your daily routine around repeatedly getting up from the floor.

Keep up dental hygiene and treat infections anywhere in the body promptly. Attend the review schedule, which typically means a check at six weeks, six months, one year, and then every few years with an X-ray. That last part is the one most people quietly drop, and it is the one that catches silent osteolysis while it is still easy to deal with.

When to see a doctor

See your surgeon promptly if you have a replaced joint and develop any of the following:

• Fever, a hot swollen joint, or wound discharge at any time after surgery — this needs same-day assessment, as infection around an implant is time-critical.
• New pain in a joint that had settled, particularly pain on taking the first few steps after sitting.
• A sensation of the joint giving way, clunking, or a hip that feels like it slips.
• Sudden severe pain, inability to bear weight, or an obviously shortened or rotated leg after a fall — treat this as an emergency.
• Progressive swelling, or a change in the way you walk that you cannot explain.
• A dental abscess, boil, urinary infection or infected foot wound — get it treated properly rather than partially, and mention that you have a joint replacement.

A replacement that is behaving well needs monitoring, not worry. A replacement that has started to hurt again needs assessment early, because almost every failure mode is easier to manage before bone has been lost.