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. In the right knee it is a smaller operation than a full replacement, and the knee usually feels more natural afterwards.
By appointment only, at Kharar (Mohali) or Solan. Your confirmation says which.
When to consider it
The deciding question is where the arthritis is, more than how bad the pain is. 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. X-rays and examination show which compartment is worn; symptoms alone cannot. Any knee pain is assessed the same way.
It is usually suitable when:
- The pain is mainly on one side of the knee
- 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 the wear-and-tear kind; rheumatoid and other inflammatory types do not suit it
Roughly one in four knees that need replacing meet those conditions. If yours does not, a full knee replacement is the better operation, and you are not settling for less. In a younger patient whose leg has bowed inwards, realigning the shin bone is another way to put a replacement off.
How it compares with a full replacement
Less bone is removed, the incision is smaller and the ligaments are kept. The knee usually feels more like your own, and recovery is generally quicker. Bending often comes back further, and many people manage stairs sooner than they would after a full replacement.
The trade-off is how long it lasts. 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. The conversion is a well-established operation. It is still a second operation, and it belongs in the decision from the start.
What the operation involves
It usually takes about an hour. As with a full replacement, spinal anaesthesia is the common choice in India: you are numb from the waist down and sedated, but not 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 in a full replacement. The aim is to restore the alignment the knee had before it wore. Overcorrecting it only moves the load onto the side you were trying to protect.
Recovery, week by week
These are typical ranges. Age, general health and how regularly you do the exercises all shift them.
- Day 1. You stand and take your first steps with support, usually 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 does not look 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 as after a full replacement.
It is also not a way to put off deciding about a full replacement. If the wear has already spread across the knee, a partial replacement leaves you with pain from the parts it did not treat.
Risks
The ones that matter most are infection, clots in the leg or lung, ongoing pain, stiffness, loosening or wear of the components, and arthritis progressing in the remaining compartments. The risk that sets this operation apart from a full replacement is needing conversion to a total knee replacement in later years.
Which of these weigh more in your case depends on your health, weight, diabetes control and whether you smoke. You will be told 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, an examination of the ligaments and where the pain is. 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, no. It is more likely to need converting to a total replacement in later years, mainly because arthritis can progress in the parts of the knee that were left. In exchange, less bone is removed, your ligaments are kept and the knee usually feels more natural.
Can it be converted to a full knee replacement later?
Yes. It is a routine operation, not 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, so it should be part of the first decision.
Is recovery really faster?
Usually, yes. The hospital stay is often shorter, walking comes back sooner and bending often returns further. The difference is a matter of weeks, and you still need the physiotherapy.
Can both knees be done together?
Yes. Each side is a smaller operation than a full replacement, so doing both in one sitting is more often reasonable here. It still depends on your general health and on having help at home, so whether it suits you is decided case by case.
Not sure this is your problem?
These pages start from the symptom. They cover what else can cause it and what is usually tried first.
Not sure whether you need this?
Ask it at a consultation, and bring your imaging and any plan you have already been given. Second opinions on surgery advised elsewhere are routine. He sees patients by appointment only, in Kharar, Mohali, and on set days each month in Solan.