Partial vs Total Knee Replacement: Who Suits Each
Key takeaways
- A total knee replacement resurfaces all three compartments; a partial (unicompartmental) resurfaces only the one damaged compartment, keeping healthy bone and ligaments.
- Partial suits wear confined to one compartment, usually the inner side, with intact ligaments; total suits widespread arthritis.
- Partial often recovers faster and can feel more natural, but carries a slightly higher chance of later revision if arthritis spreads.
- Both take about 1 to 2 hours, with a 1 to 3 day hospital stay, and both typically last 15 to 20+ years.
- Around 90 to 95% of implants are still in place at 10 years; total replacement is the more common and more predictable across a wide range of patients.
By Margaret Doyle | Medically reviewed by Mr Paul Henderson, FRCS (Tr&Orth)
Updated June 8, 2026 · 4 min read
The difference is how much of the joint is resurfaced: a total knee replacement resurfaces all three compartments of the knee, while a partial (unicompartmental) replacement resurfaces only the one damaged compartment, keeping the healthy bone and ligaments. A partial is a smaller operation that suits wear confined to one side, usually the inner (medial) compartment; a total suits widespread arthritis and is more predictable across a wide range of patients1. Neither is simply better; the right choice depends on your pattern of wear.
When my surgeon first mentioned a partial as a possibility, I was hopeful, because it sounded gentler. In the end my arthritis was too widespread and I had a total. That conversation is exactly what this guide, reviewed by a consultant orthopaedic surgeon, is meant to prepare you for. For the operation itself, see knee replacement surgery, and for all three types, types of knee replacement.
The core difference
A total knee replacement resurfaces all three compartments of the knee; a partial resurfaces only the one damaged compartment. In a total, the surgeon caps the worn surfaces of the thigh bone and shin bone across the whole joint and places a plastic spacer between them. In a partial, only the single worn compartment is resurfaced, and the healthy cartilage, bone, and crucially the ligaments are left alone1. Both take about 1 to 2 hours and involve a hospital stay of 1 to 3 days2.
| Partial (unicompartmental) | Total | |
|---|---|---|
| Resurfaces | One damaged compartment | All three compartments |
| Keeps | Healthy bone and ligaments | Less of the natural knee |
| Best for | Wear confined to one side | Widespread arthritis |
| Recovery | Often faster, can feel more natural | Predictable, slightly slower |
| Later revision | Slightly higher chance | Lower chance |
Who suits a partial knee replacement?
A partial knee replacement suits people whose arthritis is confined to one compartment, usually the inner (medial) side, with healthy ligaments and reasonable leg alignment. The cruciate ligaments need to be intact, because the partial relies on them to keep the knee stable. It is not suitable for people with widespread arthritis across the knee, inflammatory arthritis such as rheumatoid arthritis, or significant deformity. The appeal is real: it keeps more of your own knee, and many people find it feels more natural than a total.
Who suits a total knee replacement?
A total knee replacement suits people whose arthritis affects more than one compartment, which is the majority. It is the more common and more predictable operation, and it works across a wide range of patients, including those with inflammatory arthritis, poor alignment, or damaged ligaments3. The trade-off is that more of the natural knee is removed, and the recovery, while predictable, can feel slower and stiffer in the early months. In my case, my surgeon was clear that a total was the dependable choice for the state my knee was in.
Recovery compared
A partial replacement often recovers faster and can feel more natural, because less of the knee is disturbed. That said, the headline recovery milestones are similar for both: walking aids for 2 to 6 weeks, driving usually around 6 weeks, a return to most normal activities within about 3 months, and full recovery taking 6 to 12 months, sometimes longer. Physiotherapy and the bending exercises matter enormously whichever you have. It is normal for either knee to feel stiff and swollen for months.
Longevity and the risk of revision
Both types typically last 15 to 20+ years, with around 90 to 95% of implants still in place at 10 years4. The key difference is revision risk: a partial replacement carries a slightly higher chance of needing a later revision, because arthritis can spread to the compartments that were left alone, or the partial implant can wear or loosen. If that happens, a partial can be converted to a total in a revision knee replacement. Younger and more active patients should weigh this carefully.
How to decide with your surgeon
The decision rests on how much of your knee is worn, your alignment, the state of your ligaments, your age, and your bone quality, assessed by your surgeon from an examination and your X-rays. Bring your questions: ask why one type is being recommended over the other for your knee specifically, and what the plan would be if a partial later needed converting. If you are not yet sure you need surgery at all, start with signs you need a knee replacement and alternatives to knee replacement. Age is one factor among several; we look at it in the best age for a knee replacement.
References
- Unicompartmental Knee Replacement (OrthoInfo), American Academy of Orthopaedic Surgeons. ↩
- Knee replacement, NHS. ↩
- Total Knee Replacement (OrthoInfo), American Academy of Orthopaedic Surgeons. ↩
- How long does a knee replacement last?, National Joint Registry. ↩
Common questions
What is the difference between a partial and a total knee replacement?
A total knee replacement resurfaces all three compartments of the knee with metal and plastic components. A partial (unicompartmental) replacement resurfaces only the one damaged compartment, usually the inner side, keeping the healthy bone and ligaments. A partial is a smaller operation that keeps more of your natural knee, but only works when one compartment is worn.
Who is suitable for a partial knee replacement?
A partial knee replacement suits people whose arthritis is confined to one compartment, usually the inner (medial) side, with healthy ligaments and reasonable alignment. People with widespread arthritis across the knee, inflammatory arthritis, or significant deformity usually need a total replacement instead.
Is recovery faster after a partial knee replacement?
Often, yes. Because less of the knee is disturbed, a partial replacement frequently recovers faster and can feel more natural than a total. That said, both involve walking aids for 2 to 6 weeks, returning to most activities within about 3 months, and full recovery taking 6 to 12 months.
Which lasts longer, a partial or a total knee replacement?
Both typically last 15 to 20+ years, with around 90 to 95% of implants still in place at 10 years. A partial replacement carries a slightly higher chance of needing a later revision, because arthritis can spread to the compartments that were left alone.
Can a partial knee replacement be converted to a total?
Yes. If arthritis later spreads to the rest of the knee, or the partial implant wears or loosens, it can be converted to a total knee replacement in a revision operation. This is one reason surgeons weigh the choice carefully, particularly in younger patients.
Is a partial knee replacement better than a total?
Neither is simply better; they suit different patterns of wear. A partial keeps more of your natural knee and often recovers faster, but only works when one compartment is worn. A total is more predictable across a wide range of patients and handles widespread arthritis. The right choice depends on your knee, not on a ranking.
Written by Margaret Doyle. Medically reviewed by Mr Paul Henderson, FRCS (Tr&Orth).
Our guides are written from personal experience and reviewed by a qualified clinician for accuracy. Read our editorial policy.