Osteotomy or Knee Replacement: Which Is Right for Your Knee?

What is a knee osteotomy, and how is it different from a replacement?

A knee osteotomy is an operation that cuts the bone above or below the knee joint and sets it in a new position. This changes the angle of the leg. Your body weight then passes through the healthier side of the cartilage instead of the worn side. The joint itself stays in place.

A knee replacement works differently. The surgeon removes the damaged surfaces of bone and cartilage and replaces them with metal and plastic parts. It can be a total or partial knee replacement, depending on how many compartments of the knee are affected.

In short, an osteotomy keeps your own joint by changing the mechanics around it. A replacement removes the worn parts and puts manufactured parts in their place.

How do osteotomy and knee replacement compare?

Both operations aim to reduce pain and improve how the knee works. But they suit different situations. Here are the main differences side by side.

Am I too young for a knee replacement, or is osteotomy better?

Age is one factor, but not the only one. Surgeons weigh several things together before they recommend osteotomy or knee replacement.

There is no strict age limit for a knee replacement. But the younger you are when you have one, the more likely it is that the implant will need revision during your lifetime. That is why joint-preserving surgery, such as osteotomy or knock knee surgery, is often considered first in younger or very active patients.

Why does leg alignment matter when choosing between osteotomy and replacement?

Leg alignment is central to both operations. When your leg is not straight, weight passes unevenly through the knee. Over time, the overloaded side wears faster. The surgeon needs to see that wear pattern clearly before recommending one operation over the other.

Your body is a connected chain from your feet to your head. A misalignment at the hip or ankle can shift load through the knee in ways that are not obvious from looking at the knee alone. Pain in one place may be driven by a mechanical problem elsewhere in the chain.

Standard X-rays, CT and MRI taken lying down are done with the muscles relaxed and without the effect of gravity. So they can miss or understate the malalignment that is really there when you stand and walk. A standing, weight-bearing image shows how the leg takes load in real life.

How does standing imaging help plan an osteotomy or knee replacement?

Standing whole-body imaging captures the alignment of your whole leg, from hip to ankle, while you are upright and bearing weight. This gives the surgeon a true picture of how your body loads the knee in real life.

For an osteotomy, the surgeon needs to know exactly how many degrees to correct. Too little, and the symptoms come back. Too much, and the other side of the knee starts to wear. For a replacement, alignment data helps the surgeon position the implant parts so that the mechanical axis of the leg is properly restored.

EOS imaging, available at ScanAlign, standing EOS imaging in London, captures the full leg in a single standing exposure with about 90% less radiation than a standard X-ray, around ten times less. Because it images you from head to toe while you stand, it shows the true alignment that lying-down scans often miss.

Before you start treatment, or change the one you are on, it is worth getting a detailed diagnosis. Knowing whether the cause sits in the pelvis, the legs or the spine changes what will actually help.

Frequently asked questions