If knee pain is still stopping you from walking, climbing stairs or sleeping after months of physiotherapy, tablets and injections, knee replacement may be the next step. It is one of the most common and successful operations in orthopaedics. But "knee replacement" is not one single operation. There are several types of knee replacement surgery, and the right one depends on which part of your knee is worn out, your age, your activity level and your general health.

This guide explains each type in plain language, with what the research actually shows, so you can have a better conversation with your surgeon.

What is a knee replacement?

In a knee replacement (doctors call it knee arthroplasty), the surgeon removes the worn cartilage and a thin layer of bone from the ends of the thighbone and shinbone. These surfaces are then capped with smooth metal parts, with a medical-grade plastic spacer in between so the joint glides again. Think of it as resurfacing a damaged road rather than rebuilding the whole road.

Your knee has three areas, or "compartments", that can wear out:

Inner side (medial compartment): the most common place for arthritis to start, especially in bow-legged knees.
Outer side (lateral compartment): less commonly affected.
Front of the knee (patellofemoral compartment): where the kneecap glides over the thighbone.

How many of these areas are damaged is the main thing that decides which operation you need.

How common is it in India?

Knee replacement numbers in India are rising fast. One review in the Indian Journal of Orthopaedics cited estimates of around 2 lakh knee replacements a year by 2020 [1]. The Indian Joint Registry now holds about 3.8 lakh hip and knee records from more than 1,000 surgeons, and nearly all knee replacements recorded are for osteoarthritis [2, 3].

Types of knee replacement surgery

There are two main operations (total and partial). The other options below are ways of doing them: one knee or both, a first operation or a redo, and different tools, incisions and implant designs.

Type	What is replaced	Best suited to	Typical hospital stay
Total knee replacement	All three compartments	Arthritis in more than one area	3 to 5 days
Partial knee replacement	One compartment	Arthritis in one area, healthy ligaments	1 to 3 days
Bilateral replacement	Both knees, same day or weeks apart	Severe arthritis in both knees	Depends on approach
Revision replacement	A worn or failed implant	A previous replacement that has failed	Longer
Robotic-assisted	Total or partial, planned by computer	Most patients; surgeon and centre dependent	Same as manual
Minimally invasive	Total or partial, through a smaller cut	Healthy weight, mild deformity	Often shorter
High-flex implant	Total, with a design for deeper bending	Patients who want to sit on the floor	Same as standard
Gender- or patient-specific	Total, with a custom-shaped or custom-planned implant	Unusual anatomy, surgeon preference	Same as standard

1. Total knee replacement (TKR)

This is the most common operation. All three areas of the knee are resurfaced, and sometimes the back of the kneecap too.

Who it helps: People with advanced osteoarthritis in more than one area, rheumatoid arthritis, or pain and stiffness that no longer respond to other treatment.

What the evidence shows: Knee replacements last longer than many people think. A large Lancet study pooled registry data on almost 3 lakh total knee replacements. About 93% were still working at 15 years, 90% at 20 years and 82% at 25 years [4]. So for most people, the new knee is likely to last the rest of their life.

2. Partial knee replacement (unicompartmental)

Only the worn-out area is replaced. The healthy bone, cartilage and ligaments in the rest of the knee are kept. The inner (medial) side is the one most often replaced; the outer side or the kneecap groove can also be done.

Who it helps: People whose arthritis is limited to one area and whose ligaments, especially the ACL, are intact. Proper X-rays, sometimes an MRI, and an examination are needed to check this.

What the evidence shows: The TOPKAT trial randomly assigned 528 patients with inner-knee arthritis to partial or total replacement. At five years both worked well, with small benefits for partial replacement. More partial-knee patients said they would have the operation again, and reoperation rates were similar [5].

The trade-off: Over 25 years, partial knees are redone more often. Registry data show about 70% of partial knees still working at 25 years, compared with 82% of total knees [4]. Results depend heavily on the surgeon's experience with this operation.

3. Bilateral knee replacement (both knees)

If both knees are badly damaged, they can be replaced in one of two ways:

Same day (simultaneous): both knees under one anaesthetic.
Staged: one knee first, the second weeks or months later.

What the evidence shows: Same-day surgery means one hospital stay and fewer reoperations. But it carries a higher risk of blood transfusion, complications affecting the brain and nerves, and death in the early weeks [6, 7]. The extra risk is small but real, and higher in older patients and those with heart or lung disease.

In practice: Same-day surgery is best kept for younger, fit patients. Many Indian patients prefer the staged approach, because one healthy leg can support them while the other recovers.

4. Revision knee replacement

A revision replaces an implant that has worn out, loosened, become infected or become unstable. The surgeon removes the old parts, rebuilds any lost bone, and fits new, often more stabilising, parts.

What to expect: Revision is a bigger, longer operation than a first replacement, and recovery is slower. It is best done by a surgeon who regularly performs complex knee surgery. As more Indians have had knee replacements over the past 20 years, the need for revisions is growing.

5. Robotic-assisted knee replacement

The surgeon still does the operation. A robotic arm and computer help plan the bone cuts from a 3D model of your knee, and guide them to within a millimetre or a degree.

What the evidence shows: The largest trial so far, RACER-Knee, was published in The Lancet in August 2026 [8]. It randomised 339 patients in the UK. Robotic surgery placed the implants more precisely and was just as safe. But at one year, patients' pain, function and satisfaction were the same as with conventional surgery. Longer follow-up is planned to see if precision brings benefits years later, for example in how long the knee lasts.

What this means for you: Robotic surgery is a precise, safe option. It is not yet proven to give a better-feeling knee. A skilled surgeon's results with conventional instruments are also excellent.

6. Minimally invasive knee replacement

The same implant is placed through a shorter cut (often about 8 to 14 cm, compared with 20 cm or more), using techniques that spare the thigh muscle. One example is the subvastus approach, which goes under the quadriceps muscle rather than through it.

What the evidence shows: A review of 38 studies with about 3,300 operations found shorter hospital stays, less blood loss and earlier leg-raising with minimally invasive surgery. Pain, kneecap pain and revision rates were similar [9]. The technique is harder to learn and is not suitable for everyone.

Who it suits: People of healthy weight, without severe deformity, and with good bone quality.

7. High-flex knee replacement

Standard implants usually allow the knee to bend to about 110 to 120 degrees. High-flex implants are designed to allow deeper bending. This matters in India, where many people sit cross-legged, squat, pray on the floor or use Indian-style toilets.

What the evidence shows: A review of 17 randomised trials with nearly 1,800 patients found no clear difference in how far the knee bent, or in function, between high-flex and standard implants [10]. How much you can bend after surgery depends mostly on how much you could bend before surgery, the surgical technique and how hard you work at physiotherapy.

What this means for you: Tell your surgeon early if floor sitting matters to you. The implant design is one piece of a bigger plan.

8. Gender-specific and patient-specific implants

Women's knees are on average narrower. Gender-specific implants are shaped to fit them better. Patient-specific implants or cutting guides are planned from your own CT or MRI scan.

What the evidence shows: Gender-specific implants fit with less overhang, but trials have not shown better pain, movement or function than standard implants [11]. Modern standard implants come in many sizes, so most knees can be fitted well.

How your surgeon chooses the right operation

The choice is made with you, not for you. UK national guidance (NICE) says people with arthritis on the inner side of the knee only should be offered a genuine choice of partial or total replacement, after talking through the benefits and risks of each [12]. At Sports Orthopedics Institute, we look at five things:

Your story: how long you have had pain, what it stops you doing, and what you have already tried.
Examination: how far your knee bends and straightens, its alignment (bow-legged or knock-kneed), and whether the ligaments are stable.
Imaging: standing X-rays to see which areas are worn, and an MRI when needed to check the ligaments and the other compartments.
You as a person: age, weight, job, activity goals, and whether you need to sit on the floor or squat.
General health: a check by a physician to make sure your heart, lungs, sugar and blood pressure are ready for surgery.

Conditions that commonly lead to knee replacement

Osteoarthritis: by far the most common reason. Nearly all knee replacements recorded in the Indian Joint Registry are for osteoarthritis [3].
Rheumatoid arthritis and other inflammatory arthritis, which damage the whole joint.
Arthritis after an injury: a fracture, ligament tear or meniscus injury years earlier. This can affect younger people.
Avascular necrosis: loss of blood supply causing part of the bone to collapse.
Failed earlier treatment: when keyhole surgery, a bone realignment operation (osteotomy) or a partial replacement no longer helps.

When should you see an orthopaedic surgeon?

Knee pain is common with age, but it is not something you simply have to live with. Guidance generally suggests considering surgery when pain is not controlled after about three months of good non-surgical care [16]. Book an assessment if:

Knee pain has lasted more than three months despite rest, exercise and medicines
You struggle to climb stairs, walk to the market or get up from a chair
Your knee is often swollen, or is becoming bow-legged or knock-kneed
Pain wakes you at night
You are losing independence or giving up things you enjoy

An early visit does not mean early surgery. Weight loss, strengthening exercises, physiotherapy and medicines help many people for years.

Recovery: what to expect, week by week

Most people are walking with a frame or stick within a day or two, and physiotherapy starts on day one. Partial knee replacement usually recovers faster. These are typical timelines; yours will depend on your age, health and how consistently you do your exercises.

Milestone	Total knee replacement	Partial knee replacement
Hospital stay	3 to 5 days	1 to 3 days
Walking with support	Within 24 to 48 hours	Within 24 hours
Physiotherapy starts	Day 1	Day 1
Back to daily activities	6 to 8 weeks	4 to 6 weeks
Full recovery	3 to 6 months (can improve up to a year)	2 to 4 months
Still working at 25 years	About 82%	About 70%

The 25-year figures are from pooled national registry data [4].

How well does it work?

Knee replacement reliably relieves arthritis pain for most people. In large studies, about 4 out of 5 people are satisfied with their new knee one year later [13]. The strongest predictor of being unhappy was expectations that were not met [13]. That is why we spend time before surgery explaining what a replaced knee can and cannot do. A new knee will not let you do more than you could before the arthritis began [14].

Risks and how we reduce them

Knee replacement is a safe operation, but no surgery is risk-free. Serious complications such as joint infection happen in fewer than 2 in 100 people, and heart attack or stroke are rarer still [14].

Risk	How often	How we lower it
Blood clots in the leg (DVT)	The most common complication [14]	Early walking, blood thinners, calf exercises, compression
Infection of the joint	About 1 in 100 [15]	Sugar control before surgery, antibiotics, sterile theatre
Stiffness	Varies	Physiotherapy from day one; keep up exercises at home
Implant wear or loosening	Low each year; rises over decades [4]	Healthy weight; avoid running and jumping
Nerve or blood vessel injury	Rare	Careful surgical technique
Metal allergy	Rare	Allergy testing when there is a history

Call your surgeon straight away if you notice fever, increasing redness or discharge from the wound, calf pain or swelling, or sudden breathlessness.

Preparing for surgery: 6 things that make a real difference

Control your blood sugar. If you have diabetes, aim to bring your HbA1c down before surgery. Poorly controlled sugar raises the risk of infection.
Lose a little weight if you can. Even a few kilos less reduces strain on the new knee and helps recovery.
Stop smoking at least four weeks before surgery. Smoking slows wound and bone healing.
Start "prehab". Strengthening the thigh muscles before surgery, as advised by your physiotherapist, helps you get moving faster afterwards. NICE recommends giving every patient advice on this [12].
Get your home ready. Fit a raised toilet seat or commode chair, non-slip mats and a grab rail in the bathroom. Clear loose rugs and clutter from walkways. Arrange a bed on the ground floor if possible.
Line up help. Plan for a family member or caregiver to stay with you for the first two to four weeks.

Frequently asked questions

1. What is the difference between total and partial knee replacement? A total knee replacement resurfaces all three areas of the knee. A partial replaces only the one worn area and keeps your own ligaments. Partial knees often recover faster and feel more natural, but are redone a little more often over 25 years [4, 5].

2. How long does a knee replacement last? Longer than most people expect. Registry data show about 9 in 10 total knees still working at 20 years and about 8 in 10 at 25 years [4]. Younger, very active patients are more likely to need a revision one day.

3. Is knee replacement surgery painful? There is pain for the first few days, which is controlled with nerve blocks and medicines. Pain eases steadily over weeks. Most people are back to routine activities in 6 to 8 weeks and fully recovered in 3 to 6 months.

4. What is the right age for knee replacement? There is no fixed age. In India it is most often done between 55 and 75. The decision depends on how much your knee limits your life, not your birthday. Because modern knees last so long, being "too young" is less of a worry than it used to be [4].

5. Can I sit cross-legged or use an Indian toilet after knee replacement? Some people can, many cannot do so comfortably. Studies have not shown that high-flex implants reliably give more bending than standard ones [10]. Your bend before surgery and hard work in physiotherapy matter most. Tell your surgeon early if floor sitting is important to you.

6. Is robotic knee replacement better? It is more precise and just as safe. But the largest trial so far found patients' pain and function at one year were the same as with conventional surgery [8]. Whether precision helps knees last longer is still being studied.

7. Should I have both knees done together? It means one operation and one recovery. But same-day surgery has a higher risk of serious complications and death in the early weeks than doing the knees separately [6, 7]. It is best for younger, fit patients.

8. Is knee replacement covered by insurance in India? Coverage varies, so check with your insurer and get pre-authorisation before you fix a date.

9. How do I choose a knee replacement surgeon in Bengaluru? Look for a surgeon who does knee replacements regularly, offers both partial and total options, explains the risks clearly, and has a structured physiotherapy programme. Ask how many of your type of operation they do each year.

10. What can I do after a knee replacement? Walking, swimming, cycling, travel, yoga with modifications and most daily activities. Running, jumping and heavy lifting are best avoided to protect the implant.

Talk to us about your knee

If knee pain is limiting your life, a consultation at Sports Orthopedics Institute, HSR Layout, can help you understand all your options, including the non-surgical ones. Our team is led by Dr. Naveen Kumar L.V., an orthopaedic surgeon with UK fellowship training and over 27 years of experience in joint replacement. We see patients from across Bengaluru, including Koramangala, Marathahalli, Whitefield, Electronic City and Jayanagar.

This article is for general information and does not replace a consultation with your doctor.

References

India Joining the World of Hip and Knee Registries: Present Status — A Leap Forward. Indian Journal of Orthopaedics, 2020.
Indian Joint Registry at the 19th National Congress of ISHKS, Pune 2026. NEC Software Solutions, 2026.
Indian Joint Registry: knee replacements reported, 2006–2019. Summary of Indian Joint Registry data.
Evans JT et al. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. The Lancet, 2019;393:655–63. Plain-language summary: NIHR Evidence.
Beard DJ et al. Total versus partial knee replacement in patients with medial compartment knee osteoarthritis: the TOPKAT RCT. Health Technology Assessment, 2020;24(20).
Hussain N et al. Simultaneous versus staged bilateral total knee arthroplasty: a meta-analysis. HSS Journal, 2013.
Simultaneous bilateral total knee arthroplasty lowers reoperation and cost at the expense of higher complications and mortality: a meta-analysis. Knee Surgery & Related Research, 2025.
Parsons H, Metcalfe A et al. Robotic-arm-assisted versus conventional total knee replacement (RACER-Knee). The Lancet, August 2026. Summary: University of Warwick press release.
Migliorini F et al. Better outcomes after minimally invasive surgeries compared to the standard invasive medial parapatellar approach for total knee arthroplasty: a meta-analysis. Knee Surgery, Sports Traumatology, Arthroscopy, 2021.
Jiang Y et al. No superiority of high-flexion vs standard total knee arthroplasty: an update meta-analysis of randomized controlled trials. Journal of Arthroplasty, 2015.
Sappey-Marinier E et al. No clinical benefit from gender-specific total knee replacement implants: a systematic review. SICOT-J, 2020.
National Institute for Health and Care Excellence. Joint replacement (primary): hip, knee and shoulder (NG157). 2020.
Bourne RB et al. Patient satisfaction after total knee arthroplasty: who is satisfied and who is not? Clinical Orthopaedics and Related Research, 2010.
American Academy of Orthopaedic Surgeons. Total Knee Replacement — OrthoInfo.
American Academy of Orthopaedic Surgeons. Joint Replacement Infection — OrthoInfo.
British Orthopaedic Association and Royal College of Surgeons. Commissioning guide: painful osteoarthritis of the knee, 2017, as summarised by NIHR Evidence.

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