Compared
Partial vs total knee replacement
A partial knee replacement resurfaces only the damaged compartment of the knee, keeping your own ligaments and healthy cartilage. A total knee replacement resurfaces all of the joint surfaces. Partial replacement usually means a quicker recovery and a more natural-feeling knee, but only a minority of people with arthritis are suitable, and registry data show a higher rate of later revision than total replacement.
Last checked: 2026-10-03
Key facts
At a glance.
-
Who qualifies
Arthritis confined to one compartment, intact cruciate ligaments, good range of movement and no significant deformity. Many people with knee arthritis have wider disease and are not suitable.
-
Recovery
Partial replacement typically involves a smaller incision, less bone removal and a faster return to walking. Both need structured physiotherapy.
-
Durability
National Joint Registry reports show partial knee replacements are revised more often than total replacements over time, although the revision operation is often straightforward.
-
Feel
Because ligaments and unaffected cartilage are kept, many partial knees feel closer to a natural knee, with better bending.
-
Surgeon volume
Outcomes of partial replacement depend heavily on case selection and on surgeons who do the operation regularly.
The core difference
The knee has three compartments: the inner (medial) side, the outer (lateral) side and the joint between the kneecap and the thigh bone. Osteoarthritis often wears one more than the others. In a partial knee replacement, only the worn compartment is replaced with metal and plastic. In a total knee replacement, the surfaces of the whole joint are replaced.
The attraction of partial replacement is preserving what still works: both cruciate ligaments, the healthy compartments, and more bone. The trade-off is that arthritis can progress in the untouched parts, and the operation has narrower criteria.
Who is suited to a partial replacement
Surgeons look for pain localised to one compartment, X-rays showing wear mainly there, a stable knee with working ligaments, only a mild fixed bend or bow-leg deformity, and generally good movement. Inflammatory arthritis, significant damage to the cartilage elsewhere in the knee, or a weak anterior cruciate ligament usually push the decision toward a total replacement.
Body weight, activity level and age are discussed, but they are no longer treated as rigid cut-offs. A surgeon with experience in partial knees will assess the individual knee rather than rely on one factor.
Comparison
| Criterion | Partial knee replacement | Total knee replacement |
|---|---|---|
| Part of the joint replaced | One compartment | All joint surfaces |
| Eligible patients | A minority with single-compartment arthritis and intact ligaments | The majority of people with advanced knee arthritis |
| Incision and bone removal | Smaller, less bone removed | Larger, more bone removed |
| Early recovery | Often quicker | Typically a longer rehabilitation |
| Revision rate in registry data | Higher over time | Lower over time |
| If it fails | Often converted to a total replacement | Revision to more complex implants |
| Knee feel and bending | Often closer to natural | Variable; some people notice the knee feels artificial |
What clinicians usually decide and why
NICE osteoarthritis guidance (NG226) advises that people be referred for joint replacement assessment when symptoms substantially affect quality of life and non-surgical treatment has not helped. The type of replacement is then a surgical decision, informed by imaging and examination.
Where both options are viable, many surgeons discuss the trade-off honestly: a quicker recovery with a higher chance of needing another operation later, versus a more extensive operation with greater long-term durability. The National Joint Registry provides outcome data by implant type that surgeons and patients can review.
How to decide
-
Pain is clearly localised to the inner or outer side and X-rays confirm single-compartment wear: ask whether a partial replacement is possible.
-
Wear throughout the knee, a lax ligament, inflammatory arthritis or fixed deformity: a total replacement is more likely to suit you.
-
You place a high value on a quick recovery and natural feel and accept a higher chance of a second operation: a partial replacement may fit.
-
You want the lowest chance of further surgery: a total replacement has the longer track record.
-
Your surgeon rarely performs partial replacements: consider asking about their experience, since outcomes rely on volume.
Common misconceptions
A partial knee replacement is not a "lesser" operation to try first and then upgrade as a matter of course; it is the right choice for some knees and the wrong one for others. And it is not true that a total replacement always lasts longer in every individual, only that registry averages favour it.
It is also a misconception that a partial replacement means a shorter physiotherapy commitment. Strengthening and movement exercises remain essential.
Questions to ask the surgeon
-
Is my arthritis confined to one compartment, and what do my scans show about the rest of the knee?
-
How many partial knee replacements do you perform each year?
-
What are the registry revision rates for the implant you propose?
-
What happens if I later need a revision?
Frequently asked
Questions people ask.
Quick, plain-English answers to the questions we hear most.
-
Is partial knee replacement better than total?
Not universally. It suits selected patients and offers faster recovery, while total replacement is suitable for more people and has a lower revision rate in registries.
-
How long does recovery take?
It varies, but partial replacement usually allows earlier return to walking and daily activity. Complete recovery takes months and relies on physiotherapy.
-
Can a partial knee be converted to a total knee?
Yes, revision to a total knee is the usual route if the partial implant fails or arthritis progresses.
-
Does being overweight rule out a partial knee?
Not automatically. Surgeons assess the whole picture, though higher weight increases stress on any implant.
-
Which gives less pain?
Both aim to relieve arthritis pain. Satisfaction is high with both when the selection is right.
-
Does a partial replacement keep my ACL?
Yes, preserved cruciate ligaments are a key requirement for most partial replacements.
-
Are partial replacements available on the NHS?
Yes, depending on the hospital and the surgeon's practice. Ask at your orthopaedic appointment.
-
What if I want to avoid surgery?
NICE recommends exercise, weight management if relevant, and pain relief first. Surgery is considered when these are not enough.
Where this comes from
Sources and checking.
This guide is for information, not medical advice.
Your GP or consultant knows your history and can tell you which parts apply to you. If your symptoms are severe, rapidly worsening, or come with red-flag features, seek urgent medical care. Figures and availability change, so treat them as a guide and confirm with the provider.
Published 2026-10-03, next review 2027-10-03.
-
NHS website (nhs.uk) patient information pages on the operations discussed, consulted October 2026
-
National Joint Registry (njrcentre.org.uk) public information on joint replacement outcomes and implant types, consulted October 2026
-
NICE guideline NG226: Osteoarthritis in over 16s, diagnosis and management (nice.org.uk/guidance/ng226), consulted October 2026