Knee
Partial Knee Replacement
A partial knee replacement, also called a unicompartmental replacement or UKR, resurfaces only the worn part of the knee and leaves the rest of it alone. The healthy cartilage and the ligaments that control the joint, including the cruciates, stay where they are. For the right knee it is a smaller operation than a full replacement, with a knee that usually feels closer to a natural one afterwards.
By appointment only, at Kharar (Mohali) or Solan. Your confirmation says which.
When it is worth considering
The deciding question is not how bad the pain is but where the arthritis actually sits. A partial replacement only works if the wear is confined to one compartment of the knee, most often the inner side, and the rest of the joint is still in reasonable condition. That is settled on X-rays and examination rather than on symptoms alone.
It tends to be suitable when:
- Pain is concentrated on one side of the knee rather than felt all through it
- X-rays show wear in one compartment with the others still holding up
- The cruciate ligaments are intact and the knee is stable
- The knee still bends well and any bowing straightens out on examination
- The arthritis is wear-and-tear rather than rheumatoid or another inflammatory type
Roughly one in four knees needing replacement meets those conditions. If yours does not, a full replacement is the better operation, and being told that is not a downgrade.
How it compares with a full replacement
Less bone is removed, the incision is smaller and the ligaments are kept, so the knee usually feels more like your own and recovery is generally quicker. Bending tends to come back further, and many people find stairs easier sooner than they would after a full replacement.
The trade is durability. Arthritis can still progress in the parts of the knee that were left, and a partial replacement is more likely than a full one to need converting to a total replacement later. That conversion is a well-established operation, but it is a second operation, and it belongs in the decision from the start rather than as a surprise years later.
What the operation involves
It usually takes around an hour. As with a full replacement, spinal anaesthesia is the common choice in India, so you are numb from the waist down and sedated rather than fully asleep.
Only the worn compartment is resurfaced, with a metal component on each bone surface and a plastic bearing between them. Positioning matters as much as it does in a full replacement: the aim is to restore the alignment the knee had before it wore, not to overcorrect it, because overcorrecting simply moves the load onto the side you were trying to protect.
Recovery, week by week
These are typical ranges and they move with age, general health and how consistently the exercises get done.
- Day 0 to 1. Standing and walking with support the same day or the next morning.
- Week 1 to 2. Hospital stay is often shorter than for a full replacement, commonly two to three days. Walking indoors with a frame or stick, working on straightening and bending. Stitches or clips out around day 12 to 14.
- Week 3 to 6. Most people are off the walker, managing stairs and back to desk work.
- Week 6 to 12. Walking unaided, driving again once an emergency stop is safe, back to normal daily activity.
- 3 to 12 months. Strength keeps building. Most people reach their settled result sooner than after a full replacement.
The physiotherapy still matters. A smaller operation is not the same as one that looks after itself.
What it will not do
It does not treat arthritis in the rest of the knee, and it does not stop arthritis developing there later. Running and jumping sports are still not advised, for the same reason they are not after a full replacement.
It is also not a way of avoiding a decision. If the wear is already spread across the knee, a partial replacement will leave you with pain from the parts that were not addressed.
Risks worth knowing about
Infection, clots in the leg or lung, ongoing pain, stiffness, loosening or wear of the components and progression of arthritis in the remaining compartments are the ones that matter most. The specific risk that separates this operation from a full replacement is that of needing conversion to a total knee replacement in the years afterwards.
Which of these weigh more in your case depends on your own health, weight, diabetes control and whether you smoke, and you will be told that plainly before anything is fixed.
Common questions
How do I know if I am suitable for a partial rather than a full replacement?
It is decided on X-rays, on examination of the ligaments and on where the pain actually is, not on preference. Standing X-rays and sometimes an MRI show whether the other compartments are still sound. If they are not, a full replacement is the operation that will work.
Does a partial knee replacement last as long as a full one?
On average it does not. It is more likely to need converting to a total replacement in the years afterwards, largely because arthritis can progress in the parts of the knee that were left. In exchange it removes less bone, keeps your ligaments and usually feels more natural.
Can it be converted to a full knee replacement later?
Yes, and that is a routine operation rather than a salvage one. Because less bone was removed the first time, there is normally enough left to work with. It is still a second procedure with its own recovery, which is why it belongs in the original decision.
Is recovery really faster?
Usually, yes. Hospital stay tends to be shorter, walking comes back sooner and bending often returns further. It is a difference of weeks rather than months, and it does not remove the need for physiotherapy.
Can both knees be done together?
Sometimes, and it is more often reasonable here than with full replacements because each side is a smaller operation. It still depends on general health and on having help at home, so it is decided case by case.
Not sure whether you need this?
That is the right question to bring to a consultation. Second opinions on surgery already advised elsewhere are a routine part of the practice. Bring your imaging and any plan you have been given.