Over five thousand consultations, before and after hip and knee replacement, produce the same questions in the same order. This page answers the twenty asked most often before surgery, with the numbers where numbers exist, and points to the chapter that covers each in depth. The companion page, What is normal after a hip or knee replacement, takes the questions that come afterwards.
One honest note first. The question patients ask least is the one that matters most: what can go wrong? It is number sixteen below, and it is raised at every consultation whether you ask or not.
1. How painful is it afterwards, and what will I take for the pain?
A knee replacement hurts more than a hip replacement in the first weeks, and it is better to know that in advance. Real, medication-needing pain usually lasts two to three weeks after a knee and less after a hip. In a study that followed knee patients closely, about one in five were pain-free at two weeks, about half at two months, and nearly nine in ten at six months.
Pain control starts in theatre. Most joint replacements are done under a spinal anaesthetic with local anaesthetic infiltrated around the joint, often with a general anaesthetic or sedation as well; the combination means you wake comfortable and can walk the same day. You go home on a combination: regular paracetamol, an anti-inflammatory where it is safe for you, and a short supply of a stronger opioid tablet for the first days and for the night. The opioid is weaned first. In studies that tracked it day by day, the average hip patient stopped the strong tablets in about eight days and the average knee patient in about seventeen, and taking them beyond a few weeks is something to raise rather than drift into. Expect constipation on them and take the laxative you are given.
Not everyone ends up pain-free. Across the best studies, about one in ten people after a hip replacement and about one in five after a knee replacement report some long-term pain, and most of those still describe the joint as much better than before. This is discussed before you consent, because it is the single most important thing to understand about a knee replacement.
2. How long will I be in hospital?
Most people go home after two or three nights, some after one, some after four. On a standard Australian pathway the average acute stay is about four days; on an enhanced-recovery pathway, which is how this practice works where the hospital supports it, it is about two. You go home when you are safe on your feet, can manage the stairs you have at home, and your pain is controlled on tablets, not on a set day. Some people go to a rehabilitation unit first, usually because home has many stairs or little support, and that is arranged before surgery, not on the day.
3. How long until I am up and walking, and doing stairs?
The day of surgery or the morning after, with a frame or crutches and a physiotherapist beside you. The implant is fixed and stable from the moment of surgery and is designed to take your full weight straight away; early walking is also the best protection against clots and chest complications. Stairs are taught before you leave hospital, “up with the good, down with the bad”. Most people are on a single stick by two to three weeks and walking without aids at about four to six weeks after a knee or posterior hip, and at two to four weeks after an anterior hip. In a trial that measured it, the average hip patient walked without any aid at about three to four weeks.
4. Will I be able to sleep, and sleep on my side?
Sleep is the thing people least expect to be disturbed, and it is disturbed, for everyone. Four in ten people sleep badly before surgery because of the arthritis, and the first month after surgery is no better. After that it improves: in a study using daily sleep diaries, sleep after a knee replacement was back to its pre-operative level by about two weeks, and after a hip replacement by about three months. By six months fewer people sleep badly than did before surgery.
Side sleeping: after a knee replacement, any position from the start, with a pillow between the knees for comfort and never a pillow under the knee. After an anterior-approach hip, either side from the start. After a posterior-approach hip, your back or the non-operated side with a firm pillow between the knees while the precautions apply, which in this practice is about six months.
5. Do I need it now, or can I wait? Am I too young, too old, is it bad enough?
Three separate questions.
Can I wait? Usually, and waiting itself does not spoil the result. A large English study of public patients found no effect of waiting time on the final hip or knee score. What does spoil the result is arriving deconditioned: two landmark studies found that people with the poorest function going in did not catch up to those who were fitter, and the difference was most marked for knees. In an Australian public-hospital study, more than half of those waiting lost measurable quality of life over a median wait of about nine months. So the sensible reading is: wait while you are still active and coping, and do not wait once you are not. The chapter How bad is my arthritis? sets out what “bad enough” means in practice: it is about what the joint stops you doing, not what the X-ray shows.
Too young? Covered in full on Am I too young for a joint replacement?. In short, the operation works as well in younger people; what changes is the chance of a second operation over a longer life. The Australian registry’s 20-year revision rate for a knee replacement is about 16% under age 55 and about 4% over 75; for a hip, about 10% under 55 and about 6% over 75.
Too old? Age on its own is not the barrier. Systematic reviews of people in their eighties having hip and knee replacement found surgical complication rates similar to younger patients, with longer hospital stays and more medical complications, and concluded that fitness and other conditions should decide, not the date of birth. That assessment is the anaesthetist’s job before surgery.
6. Will I need physio, how much, and what exercises?
Yes, but less than most people assume, and most of it is yours to do rather than something done to you. The trial evidence is consistent: a review of eleven trials found supervised rehabilitation gave no better pain or function than unsupervised exercise after knee replacement; an Australian randomised trial found a monitored home program matched inpatient rehabilitation; and reviews find no difference between clinic-based and home-based programs. Guidelines recommend a self-directed program taught before you leave hospital, with supervised physiotherapy for those who are not progressing or who have other limitations.
In this practice, you leave hospital with a written program, the physiotherapists see you in hospital and at review, and private patients are usually linked with a physiotherapist near home for the first six to twelve weeks. The exercises themselves, with photographs, dosages and the week they start, are in the rehabilitation guides. Before surgery, the stronger the muscles going in, the faster the recovery coming out; a pre-surgery program is worth doing.
7. How long does the replacement last? Will I need it redone?
Australia’s registry has tracked every joint replacement in the country since 1999. Its latest report puts the cumulative revision rate at 20 years at 7.9% for a total hip replacement and 8.0% for a total knee replacement done for osteoarthritis: about 92 in 100 have not needed further surgery two decades on. Looking further out, a pooled analysis of registries worldwide found about 58% of hip replacements and 82% of knee replacements lasting 25 years. These averages come mostly from people operated on in their late sixties and beyond. The younger you are, the longer the implant has to last and the more you ask of it; see question 5 and the too young page.
Materials matter. The registry shows the modern cross-linked plastic bearing in a hip has a 20-year revision rate of about 7%, against about 18% for the older plastic it replaced. Every implant used in this practice is a registry-proven design with a long track record.
8. Should I try a cortisone, gel or PRP injection first?
The honest summary of the guidelines, Australian and American, is this. A cortisone injection can settle a flare for weeks to a few months, on modest evidence, and is reasonable while you are deciding; repeated injections carry concerns about the cartilage. Hyaluronic acid gel is not recommended for routine use by either guideline. PRP has limited evidence either way. None of them slows or reverses arthritis. The detail, including the trials, is in Your options.
One rule matters for timing. A cortisone injection into the joint within three months of a replacement raises the risk of deep infection by about a third to a half, so once a date is set, no further injections into that joint.
9. What will it cost? What is the gap? Does my fund or Medicare cover it?
It depends entirely on where you are treated. In a public hospital there is no out-of-pocket cost, but there is a waiting list. Privately, Medicare pays 75% of the schedule fee for the operation and your fund pays at least the rest of it, your fund covers the hospital and the implant under a policy that includes joint replacement, and the surgeon’s, assistant’s and anaesthetist’s fees above the schedule fee are the gap, which depends on each doctor’s arrangement with your fund. You receive a written quotation before anything is booked, covering all of it in one place. The costs page explains “no gap” and “known gap” and the exact question to ask your fund.
10. Can I have it done publicly, and how long is the waiting list?
Yes. Dr Broadhead operates in the public system at Royal Prince Alfred Hospital in Sydney and Coffs Harbour Health Campus, and public patients are placed on the hospital’s waiting list after assessment. Joint replacement is a non-urgent category in the public system and the wait is measured in months, often around a year and sometimes more, varying by hospital and by how urgent your case is assessed to be. As RPA is a teaching hospital, the operation may be performed by a supervised training registrar. While you wait, the public Osteoarthritis Chronic Care Program helps you arrive fitter.
11. When can I go back to work?
Desk work from about four to six weeks after a knee, one to three after an anterior hip and two to four after a posterior hip, once you are comfortable sitting and have transport sorted. Physical work takes two to three months, with modified duties in between where they exist. Across the published studies the average return to any work is about eleven weeks after a hip and thirteen after a knee, slower for heavy work and for older workers, and nine in ten of those working before surgery are back within a year or two. Raise your job’s actual demands at the two-week review so a plan is in place early.
12. Can both be done at the same time? Which one first?
It can be done, but in this practice the usual advice is one at a time. For knees, a meta-analysis of 53 studies and more than half a million patients found doing both at once roughly doubled the short-term risk of death and raised the risk of clots and transfusion; staged surgery had slightly more wound infections. The best interval between the two is three to six months. The full argument, both ways, is on Should both knees be replaced at once?. For hips the evidence is more even, with no difference in death rates and a shorter total stay for doing both at once but far more transfusions, and the same caution applies.
Which first: the worse joint, unless there is a reason to prefer otherwise. When a hip and a knee on the same side both need replacing, the hip is usually done first, because hip pain often refers to the knee and a stiff hip makes knee rehabilitation hard. Many people find the second joint becomes less urgent once the first is comfortable.
13. What is it made of? Is it cemented? Metal, plastic, ceramic?
The structural parts are metal alloys, titanium or cobalt-chromium. The bearing surface is a highly cross-linked polyethylene, a dense plastic that the registry shows wears far better than the older plastic. The ball of a hip is ceramic or metal. The registry’s lowest 20-year revision rates for hips are with a ceramic or ceramicised-metal ball on cross-linked plastic.
Fixation: knees are usually cemented, and the registry shows cemented and hybrid knees have a lower revision rate than cementless at 20 years. Hips are more often fixed by bone growing onto a coated surface (about 63% of Australian hips), with a cemented stem or hybrid fixation giving lower revision rates in patients over 75 and chosen for older bone. The combination that suits you depends on your age, bone quality and anatomy, and the implant is named in your quotation. The operation covers this in more depth, including what robotic assistance does and does not do.
14. What caused this? Is it hereditary, or did I do it to myself?
Mostly neither. Osteoarthritis is not simple wear and tear and it is not your fault. Twin studies, which separate genes from environment, show that about half the susceptibility to needing a hip or knee replacement is inherited, and that hip arthritis is more genetic than knee arthritis, which depends more on body weight. The other large factors are previous injury (a torn ligament or meniscus roughly quadruples the risk of knee arthritis, and about four in ten people develop it within fifteen years of an ACL injury), body weight (obesity roughly quadruples the risk of knee arthritis), and the shape of the joint you were born with, particularly at the hip. Understanding arthritis covers the whole picture.
15. Do I need an MRI or more scans before you decide?
Usually not. A plain X-ray taken standing is the standard test for hip and knee arthritis and is often all that is needed; the Australian GP guideline recommends plain X-rays first and weight-bearing views for the knee. An MRI is for when something else is suspected, or when the X-ray and the symptoms do not match. Once surgery is planned, further X-rays or a scan of the joint may be taken to plan the implant, which is how “custom” planning is done, with or without a robot in theatre.
16. What are the risks? What can go wrong?
The question asked least, and the one raised at every consultation whether you ask or not. Serious complications are uncommon, but they are real:
- Deep infection around the implant: about one in a hundred. It can need further surgery, occasionally including removal of the implant. It is the complication that matters most, which is why teeth, skin and bladder infections are dealt with before surgery and why you will be asked about them.
- Blood clots: a symptomatic clot in about two to three in a hundred despite prevention (in the Australian CRISTAL trial, 1.8% on enoxaparin and 3.5% on aspirin). Clots in the lung are rarer and can be fatal, which is why the blood thinner, the stockings and the walking matter.
- Dislocation of a hip: about three to four in a hundred over two years in registry data, most in the early months, most treated without further surgery. Lower with larger bearings.
- Stiffness of a knee: about three to four in a hundred need a manipulation under anaesthetic to recover bend.
- Nerve injury: about seven in a thousand, usually temporary. Fracture of the bone around the implant: about seven in a thousand after a hip.
- Loosening and wear over the years: what the registry revision figures above measure.
- Death within 90 days: about three in a thousand, and in the largest study only two thirds of those were related to the surgery.
- Ongoing pain: see question 1.
Your own risk profile, age, weight, diabetes, smoking and other conditions, is part of the consent discussion. The surgeon’s job is to reduce every risk that can be reduced and to be honest about the ones that cannot.
17. Will I get back to golf, tennis, cycling, running or skiing?
Yes to most of it. Walking, cycling, swimming, golf, bowls, doubles tennis, gym work and hiking are activities most surgeons place no limit on. Skiing is realistic for experienced skiers; the risk is the fall, not the implant. Running and jumping sports are not recommended as regular exercise on a replaced joint, because of wear rather than any risk of sudden failure. Across the published studies, more than eight in ten people get back to sport, mostly low-impact, at an average of about four months after a hip and five after a knee; a hip is more forgiving of impact than a knee. The activity tables in the rehabilitation guides give the usual timing for each sport.
18. Do I stop my tablets, blood thinners, anti-inflammatories, supplements?
You will be given exact, written instructions for each medicine, and the rule is to follow them rather than guess. Blood thinners and aspirin (warfarin, apixaban, rivaroxaban, clopidogrel) are stopped or continued on the anaesthetist’s instruction, never on your own and never for longer than you are told. Anti-inflammatories are usually stopped in the week before surgery and can be restarted afterwards as part of pain control. Herbal and dietary supplements, including fish oil, turmeric, garlic and ginkgo, are stopped two weeks before, because few have proven benefit and some affect bleeding or the anaesthetic. The weekly injectable diabetes and weight-loss drugs (semaglutide, tirzepatide and similar) are held for a week before an anaesthetic, and daily ones on the day, because they slow stomach emptying. Rheumatoid arthritis and other immune-suppressing drugs follow a published guideline on which to continue and which to pause, applied by your rheumatologist and surgeon together. Bring every medicine, or an accurate list, to the pre-admission visit.
19. Will my leg be longer or shorter? Will I limp? (hip)
About half of people feel that the new hip is longer in the first weeks. Mostly this is not a true difference: muscles that were tight for years are suddenly at their proper length, the pelvis has been tilted to protect the arthritic hip and has to re-level, and the brain has to recalibrate. In one series, three quarters of those who noticed it said it had resolved by one year, and nearly all of the rest were still satisfied with the hip. The aim at surgery, with templating beforehand and measurement during, is a difference under a centimetre, at which point about one in fourteen still perceives it at a year. A small true difference is corrected with a heel raise; a larger one is rare and is discussed with you.
A limp is expected early. The outer-hip (abductor) muscles are weak for years before surgery and recover slowly afterwards, continuing to improve for up to two years. The exercises in the hip guides are what abolish it.
20. What happens if I do nothing, or leave it?
Nothing dangerous, but usually not nothing. Arthritis does not progress at a steady rate, many people plateau for years, and if you are coping, doing nothing beyond exercise and simple measures is a reasonable choice that is revisited rather than final. The costs of leaving a joint that is no longer coping are quieter than people expect: painful hip or knee arthritis raises the risk of recurrent falls by about half, more than half of those waiting for surgery in an Australian study lost measurable quality of life over the wait, and the fitness lost while waiting makes the eventual operation harder and the recovery slower. The joint will not become un-replaceable, but you will arrive at surgery less well than you could have.
Just below the cut
- When can I drive? Braking studies put reaction time back to its pre-operative level at about two weeks after a right hip and four weeks after a right knee; in practice most people are driving at four to six weeks after a knee or posterior hip and two to four after an anterior hip, sooner for a left-sided joint in an automatic, and only when off strong painkillers and able to emergency-stop without hesitation.
- Will I need crutches? A frame or crutches for the first one to three weeks, a stick after that, and nothing by about four to six weeks after a knee or posterior hip, sooner after an anterior hip.
- Spinal or general? Most are done under a spinal with local anaesthetic infiltration, often with sedation or a general as well. An international consensus recommends the spinal for hips and prefers it for knees, with lower rates of clots, chest complications and infection. The anaesthetist decides with you.
- Robotic or partial? Robotic assistance was used in 42% of Australian knee replacements in 2024; the registry shows no difference in revision rate from conventional instruments, and the planning matters more than the tool. A partial (unicompartmental) knee replacement suits the minority whose arthritis is confined to one compartment with intact ligaments; it recovers faster and feels more natural, but its revision rate is roughly twice that of a total knee, and under age 55 the registry’s 10-year revision rate is about 17%. Both are explained on The operation.
- Can I fly? Short flights are not the problem; hours of sitting are. The usual advice is to avoid long-haul flights for six weeks and to plan any earlier travel with the rooms.
- Do I need to lose weight first? A higher body weight raises the infection risk, and the fitter you are, the better. But the evidence that losing weight in the months before surgery improves the result is weak: a review of 21 studies found no reduction in complications from pre-operative weight loss. Weight is one factor in the risk discussion rather than an automatic bar, and a reason to be as active as the joint allows.
- Can I kneel? (knee) Kneeling does not damage the implant and there is no clinical reason not to. It is the thing people find hardest: about a third kneel comfortably at one year and about half by three, and with structured practice most regain it.