Knee Replacement FAQs

A knee replacement, also called a knee arthroplasty, resurfaces a worn joint rather than removing it entirely. The surgeon takes away the damaged cartilage and a thin layer of bone from the ends of the thigh bone and shin bone, then caps those surfaces with metal components and fits a smooth plastic spacer between them. The result is a joint that bends and takes weight without bone grinding on bone.

You are taken to theatre and given an anaesthetic, usually a spinal block with sedation. The surgeon makes a single incision down the front of the knee and moves the kneecap aside to reach the joint.

The worn ends of the thigh bone and shin bone are trimmed to precise shapes so the implant sits flush against healthy bone. The components are fitted, often with surgical cement. The surgeon checks the knee bends and straightens correctly, then closes the wound and applies a dressing.

An artificial knee has three parts: a curved metal cap over the end of the thigh bone, a flat metal tray on the top of the shin bone, and a durable plastic insert that sits between them and acts as the new cartilage. Some patients also have a plastic button fitted behind the kneecap. From the outside, only the scar is visible.

Yes. It involves cutting bone, a general or spinal anaesthetic, a hospital stay and a recovery measured in months rather than weeks. It is a routine operation in the sense that it is performed constantly and outcomes are well documented, but that is not the same as minor. Treating it as major surgery is the right mindset, because preparation and rehabilitation genuinely change the result.

A total knee replacement resurfaces the whole joint. A partial replacement resurfaces only the damaged compartment and leaves your healthy bone and ligaments alone, which suits a smaller group of patients.

We cover eligibility, recovery and longevity for both in our full comparison: Total vs partial knee replacement.

Robotic-assisted surgery uses a 3D model of your knee to guide the surgeon's cuts and implant positioning with tighter tolerances. The surgeon still performs the operation. The robotic arm improves precision.

For how it compares on outcomes and cost, read robotic vs conventional knee replacement.

For most people with advanced arthritis, yes. The large majority report significantly less pain and better mobility, and satisfaction rates for the procedure are consistently high.

The honest counterpoint is that roughly one in five patients is not fully satisfied. Some are left with stiffness, kneeling difficulty or an ongoing awareness that the knee is artificial. A replaced knee is a very good knee. It is not the knee you had at thirty, and expecting that is the most common source of disappointment.

Surgeons generally look for three things together. First, pain that limits daily life: disturbed sleep, difficulty with stairs, a shrinking walking distance. Second, X-ray evidence of advanced joint damage. Third, a fair trial of non-surgical treatment that has stopped working.

The trigger is usually function rather than a scan. If you are planning your week around your knee, declining invitations, or relying on pain relief to get through the day, that is the point at which most surgeons will discuss replacement seriously.

Arthritic knee pain is usually felt deep inside the joint rather than on the surface, most often on the inner side, which is where wear typically starts. Many people also feel it at the front, around or behind the kneecap, particularly on stairs or standing up from a chair.

Pain that is sharp, pinpoint and on the outer edge is more often a ligament or tendon problem, which needs a different assessment.

An X-ray shows how much joint space is left and whether bone is contacting bone, so it confirms the extent of arthritis. It cannot tell you whether to have surgery.

Plenty of people have severe changes on film and manage comfortably, while others have moderate changes and are in constant pain. The X-ray supports the decision. Your symptoms drive it.

Several things genuinely help, and they are worth trying properly before surgery.

Strengthening the quadriceps and glutes reduces load through the joint and has good evidence behind it. Losing weight makes a measurable difference, because each kilogram removes several kilograms of force through the knee when walking. Switching high-impact exercise for cycling or swimming keeps you active without the pounding. Anti-inflammatories, and for some people corticosteroid injections, can buy useful time.

None of this reverses arthritis, but it can delay surgery by years.

Most knee replacements are performed on people in their late sixties. Joint registries in Australia, the UK and the United States all cluster around 67 to 70. The range is wide, and patients in their fifties and eighties are both common. Age alone rarely decides it. Your overall health and how much the knee limits you matter more.

Probably not, but the timing question is real. Surgeons are cautious with younger patients because a more active life wears an implant faster and a revision later is a bigger operation than the first.

The trade-off is spending years in avoidable pain. Implant longevity is the crux of this decision, so read how long a knee replacement lasts.

The operation itself usually takes one to two hours. Add anaesthetic preparation beforehand and time in recovery afterwards, and you should expect to be away from the ward for around three to four hours in total.

Bilateral and complex revision cases take longer. For a fuller breakdown, see our complete guide to knee and hip replacement.

Most knee replacements today are done under a spinal anaesthetic, which numbs you from the waist down while sedation keeps you comfortably drowsy. You will not feel or remember the operation.

A general anaesthetic is used when a spinal is unsuitable. Either way, the surgical team usually adds a nerve block or local anaesthetic around the joint, which takes the edge off the first day considerably.

Three to five days is typical, though many hospitals now discharge fit patients in one to two days on a rapid recovery pathway.

Our Bangkok pathway works differently. The inpatient stay is similar, but you then stay locally under supervision until you are cleared to fly, so physiotherapy and wound checks happen before you travel rather than after. Your coordinator confirms the exact schedule before you book.

Expect a straight vertical scar down the front of the knee, usually 15 to 20 centimetres long. It is closed with dissolving sutures, staples or clips and covered with a waterproof dressing.

Early on the area looks bruised, swollen and pink. The scar fades over 12 to 18 months to a thin pale line, and numbness along one side of it is normal.

Usually within a few days, once your team confirms the dressing is waterproof. Keep the shower brief, let water run over the dressing rather than scrubbing it, and pat the area dry afterwards.

Avoid baths, spas and swimming pools until the wound is fully healed and your surgeon gives the go-ahead.

Around 10 to 14 days after surgery. Dissolving sutures need nothing done at all.

This timing matters for medical travel. We schedule removal and a final wound check in Bangkok before you fly, so you are not arriving home with an open wound and no local follow-up arranged.

Yes, particularly in the first two weeks. This is one of the more uncomfortable orthopaedic recoveries, and anyone telling you otherwise is not being straight with you.

Pain is managed with a nerve block during surgery, then regular medication that steps down over the following weeks. Most people find the worst is days two to five, easing noticeably by weeks three to four.

The important distinction is that this is healing pain, not the arthritic pain you had before. It improves. The old pain did not.

Bone has been cut, soft tissue stretched and the joint capsule opened, so the swelling and inflammation that follow are substantial. Pain also comes from the physiotherapy itself, because the knee has to be pushed to bend.

For managing it week by week, see our complete guide to knee and hip replacement.

Clicking is normal and very common. You now have metal and plastic surfaces moving against each other, and they make sounds that a natural joint does not. Many patients notice it most when straightening the leg or standing up.

On its own it is not a problem. Raise it with your surgeon if a clunk comes with pain, giving way or new swelling.

Yes. Small skin nerves are unavoidably cut during the incision, which usually leaves a numb patch on the outer side of the scar. Most people notice it when kneeling or when something brushes the area.

It often shrinks over the first one to two years, though a permanent patch of reduced sensation is common and does not affect how the knee works.

New pain in a knee that had settled well is worth investigating rather than tolerating. The possible causes include implant loosening, wear of the plastic insert, infection, or a problem elsewhere such as the hip or lower back referring pain to the knee.

See your surgeon for an X-ray and blood tests. Our guide to implant lifespan explains what wear looks like over time.

Most people walk unaided by six weeks, return to normal daily activities by three months, and reach their final result somewhere between nine and eighteen months as swelling settles and strength returns.

Recovery is gradual rather than linear. For the full timeline, see our complete guide to knee and hip replacement.

The same day, or the morning after at the latest. Standing and taking a few supported steps within 24 hours is standard practice and speeds up recovery considerably.

You will use a frame for the first few days, then crutches or a stick for two to six weeks. Most people walk short distances unaided by around six weeks.

Walking without a limp takes longer, typically three months or more, because that depends on quadriceps strength rather than the joint itself.

A reasonable benchmark is 20 to 30 minutes of continuous walking, or roughly one to two kilometres, spread across several shorter walks rather than one long effort.

Progress varies widely and this is a guide, not a target to force. What matters more is that distance is trending upward week on week and that swelling settles overnight rather than building up. If it does not, ease back and tell your physiotherapist.

Function returns well before the knee feels like your own. Most people are managing daily life comfortably by three months, but the sensation of the joint being different can persist for a year or more.

Many patients always retain some awareness of the implant, particularly when kneeling or in cold weather. That is a normal outcome rather than a complication, and it usually stops registering as you get on with things.

Fatigue after major surgery is real and widely underestimated. Your body is rebuilding bone and soft tissue, which is metabolically demanding. Disturbed sleep, reduced fitness during recovery and the effort of walking differently all add to it. Mild post-surgical anaemia is also common.

It usually lifts by around three months. If it does not, ask your doctor to check your iron levels.

Formal physiotherapy usually runs for about three months. The exercises themselves should continue well past that point.

Quadriceps strength is the single biggest predictor of how well a replaced knee functions, and it is also the thing that fades fastest if you stop. Aim to keep a reduced maintenance routine going for at least a year, then fold strength work into your normal exercise habits permanently.

The usual target is full straightening, meaning zero degrees, with bend of at least 110 to 120 degrees.

For context: walking on level ground needs roughly 65 degrees, climbing stairs needs about 90, and rising from a low chair needs closer to 105. Anything past 120 is a bonus rather than a requirement.

Getting the knee fully straight matters more than most people expect, because a knee that will not extend causes a limp.

Skip running, jumping, deep squats below 90 degrees, and pivoting sports such as tennis, squash and skiing in the early months. Avoid twisting through a planted foot at any stage.

Cycling, swimming, walking and resistance work are all encouraged. For the wider list of setbacks to sidestep, read top mistakes to avoid after knee replacement.

Typically four to six weeks for a right knee, and often sooner for a left knee in an automatic. You must be off opioid pain medication and able to perform an emergency stop without hesitation.

Most countries set no fixed legal period, so clearance comes from your surgeon and your insurer. See our complete recovery guide.

It depends almost entirely on what you do.

Desk work is realistic at around four to six weeks, and sooner if you can work from home part-time with your leg elevated. Jobs involving standing all day, driving or light manual work usually need eight to twelve weeks.

Heavy manual work, ladder work and roles requiring repeated kneeling often need three to six months, and some people change duties permanently. Discuss this with your surgeon before you commit to a return date.

Push the seat all the way back and recline it slightly. Reverse up to the seat, sit down first with your operated leg extended out of the car, then swing both legs in together while keeping the knee relatively straight.

Reverse the sequence getting out. A plastic bag on the seat helps you pivot, and the front passenger seat is far easier than the back.

The rule is good leg up, bad leg down. Going up, lead with your unoperated leg, then bring the operated leg and any crutch to the same step. Coming down, lead with the crutch and your operated leg, then follow with the good leg.

Use the handrail every time. Take one step at a time until your physiotherapist says otherwise.

A frame for the first two to five days, then crutches for around two to four weeks, then a single stick held in the opposite hand for another week or two.

Most people are walking unaided indoors by six weeks. Do not rush this. Dropping support too early tends to produce a limp that takes months of physiotherapy to unlearn.

Sleep on your back for the first few weeks. It keeps the leg straight, which protects your extension, and it is the easiest position to get in and out of while you are still sore.

Do not put a pillow directly under the knee, however tempting it is. Propping the knee bent overnight is one of the most common causes of a permanent flexion deformity, meaning a knee that will not fully straighten. If you want elevation, place the pillow under the calf and ankle so the knee stays flat.

Side sleeping becomes comfortable at around four to six weeks. Lie on your unoperated side with a pillow between your knees to stop the operated leg dropping and twisting.

Take pain medication before bed rather than waiting to be woken, and ice the knee beforehand.

Several things stack up. Inflammation peaks overnight when you are still, so the knee often throbs more in bed than during the day. Pain relief taken in the evening wears off in the small hours. You cannot move into your usual positions, and reduced daytime activity leaves you less physically tired.

It typically improves markedly from around six weeks.

Slide to the edge of the bed. Use your hands or a towel looped under the ankle to lower the operated leg towards the floor while pushing up onto your elbow, then your hand.

Let the good leg take the load as you stand, with your frame or crutches already in position.

Fifteen to twenty minutes at a time, up to four or five times a day in the first fortnight, and always with a cloth between the ice and your skin.

The most useful times are after physiotherapy, after walking and before bed. Longer sessions do not help and risk skin damage, particularly over the numb patch beside the scar where you may not feel the cold properly.

Lie flat rather than sitting in a chair, and raise the whole leg above heart level with pillows under the calf and ankle, never under the knee itself. Thirty minutes, three or four times a day, works well in the first few weeks.

Swelling that has not settled by morning is a signal to elevate more. Our guide to swelling after knee replacement covers the warning signs.

Most surgeons advise against it. Running sends repeated impact loads through the plastic insert and accelerates wear, which shortens the life of the implant. A small number of patients do return to light jogging, but it is the exception rather than the norm.

Cycling, swimming, walking, golf and doubles tennis are the usual recommendations instead. See our complete guide for activity guidance by sport.

You can, and it will not damage the implant, but many people find it uncomfortable or oddly numb and simply stop doing it. Roughly half of all patients report ongoing difficulty kneeling, so it is worth expecting.

A cushioned pad helps, and it often becomes easier after the first year. More on activity expectations in our complete guide.

Chipping and putting from around six to eight weeks. A full round with a full swing at roughly three to four months, once strength and balance have returned.

Use a buggy rather than walking the course at first. Our complete guide covers return-to-sport timing in more detail.

Possibly. Knee implants contain enough metal to trigger older archway detectors, though many airports now use millimetre-wave body scanners that do not react to them.

If it does alarm, you will simply be directed for a secondary scan or a pat-down. Arrive with a little extra time, mention the implant to the screening officer, and it takes moments.

Yes. You receive a card recording the implant brand, model and serial number. Carry it when travelling and keep a photo on your phone.

Every patient we coordinate also goes home with full surgical records and imaging, so any doctor anywhere can see exactly what was fitted.

Not while you are taking opioid pain medication, because the combination increases sedation and the risk of falls at exactly the point you can least afford one.

Alcohol also interacts with the blood thinners prescribed after surgery. Once you are off both, moderate drinking is fine. Check with your surgeon first, and be aware that alcohol worsens sleep quality while you are already sleeping badly.

Many patients report more aching in cold or damp conditions, and the effect is common enough that surgeons take it seriously. The evidence linking symptoms to barometric pressure is mixed rather than conclusive.

Whatever the mechanism, it is harmless. Keeping the knee warm and staying active usually settles it.

Yes. Modern knee implants use non-magnetic alloys such as cobalt-chrome and titanium, and are safe in an MRI scanner.

The one limitation is image quality. The implant creates distortion on scans of the knee itself, so radiographers use specific settings to reduce it. Always tell the radiography team about the implant and bring your implant card.

It depends entirely on your pathway. Public patients pay nothing but join a waiting list. Privately insured patients face gap fees that vary considerably by surgeon and hospital. Self-funded patients pay the full amount.

We break down all three pathways, including the costs people routinely forget to budget for, in how much a knee replacement costs in Australia.

In Australia, yes. Treated as a public patient in a public hospital, Medicare covers the surgery, the stay and rehabilitation at no cost to you, but you join the elective waiting list and you do not choose your surgeon.

If you go private, Medicare pays only a portion of the surgeon's fee. The rest falls to your health fund and to you.

In Australia, joint replacement sits in the highest hospital cover tiers, so a basic policy usually will not cover it. Expect a 12-month waiting period for a pre-existing condition, which matters if you take out cover specifically for this.

Even with the right policy, out-of-pocket gap fees are common. Ask your surgeon for written informed financial consent before agreeing to a date.

Knee replacement is one of the longest waits in most public health systems. Australian AIHW reporting puts the median at several months, with a significant share waiting beyond a year. UK patients on NHS lists often face comparable or longer delays.

That is before the wait to see a specialist. If waiting is the obstacle, see our knee replacement in Thailand page.

It can be, provided you choose carefully. Bangkok's leading private hospitals hold international accreditation, operate high-volume orthopaedic units and use the same implant brands fitted in Australia, the UK and the United States.

What separates a good outcome from a bad one is rarely the surgery itself. It is the surrounding decisions: verified hospital credentials, a surgeon with genuine arthroplasty volume, a realistic length of stay, and an aftercare plan for when you get home.

Our knee replacement in Thailand page sets out how we vet each of these.

Plan for around three weeks in total. That covers pre-operative assessment, the hospital stay, the early physiotherapy that matters most, wound review, suture removal and a final fitness-to-fly clearance before you travel.

Some patients choose to stay longer and recover locally. The full week-by-week schedule is set out on our knee replacement in Thailand page.

This is the fair question to ask, and it should be answered before you book rather than after.

You travel home with complete surgical records, implant details and imaging, so any doctor, physiotherapist or surgeon at home can pick up your care immediately. We stay contactable throughout your recovery and coordinate directly with your treating team if something needs review.

Details on our treatment page.

Usually around two weeks, once clot risk has dropped and your wound has been reviewed. Long-haul flights need compression stockings, an aisle seat and regular movement.

Full guidance, including class of travel and clot prevention, is in how long after knee replacement can you fly.