What a partial knee replacement is
A partial (unicompartmental) knee replacement caps the arthritic compartment of your knee, usually the inner side, and leaves your ligaments and the rest of the joint alone. Done for the right knee, it recovers faster than a total and feels more natural. Done for the wrong knee, it fails early. That is why the decision starts with standing X-rays and a robotic plan.
Partial vs. total knee replacement
- Partial: smaller incision, less bone removed, ACL kept, usually home the same day from our surgery center, and a quicker return to driving and golf. The catch is that arthritis can later spread to the untouched compartments.
- Total: the answer when more than one compartment is worn, and the right first choice for most knees that reach us late. The full knee replacement page.
- Conversion: if the remaining compartments wear out years later, a partial converts to a total. It is a known, planned-for path.
Why robotic planning matters here
A partial knee lasts only if the implant matches your anatomy and alignment within tight tolerances. Our Mako robotic system builds a 3D plan from a CT scan and holds your surgeon to it in the operating room.
Is your knee a candidate?
Three questions decide it: Is the pain on one side of the knee? Are your ligaments intact? Is your alignment reasonable? Standing X-rays answer most of this. About a third of the people who ask us are better served by something else, sometimes including waiting.
Common questions
What is the difference between a partial and total knee replacement?
A partial knee replacement resurfaces one worn compartment of the knee and keeps the healthy bone, cartilage and ligaments, including the ACL. A total knee replacement resurfaces the whole joint. For the right candidate, a partial means a smaller operation, a faster recovery and a knee that feels more natural.
Am I a candidate for partial knee replacement?
You may be if your arthritis is confined to one compartment, your ligaments are intact and your alignment is reasonable. Standing X-rays and an exam give the answer, and robotic planning maps your knee closely enough to confirm whether a partial will hold up for you.
How long does a partial knee replacement last?
Modern partial knee replacements commonly last 15 or more years. If arthritis later spreads to the other compartments, the partial can be converted to a total knee replacement. Individual results vary.
The surgeons who do this here
Read each profile for training, areas of care and office locations.
Paul C. Chin, MD, PhD, FAAOS, FAANA
Brian Flowers, MD, FAAOS
Rohan Gheewala, MDMedically reviewed by Keith W.V. Johnson, MD, FAAOS · Updated October 21, 2026