Most patients understand that severe knee arthritis is often treated with surgery, but do you understand what a ‘knee replacement’, better yet a ‘total knee replacement’ is?  Is it a ‘hinge’ we put in your leg, or a replacement of the bones inside your knee ?  This is not true!  It’s time to be educated and know what really happens.  You may be surprised !

When joint replacement started in the 1860s, the first knee was what most people think they are:  a hinge made of ivory.  An improved hinge was make in 1951 – the ‘Walldius Hinge Joint’ – and was made from acrylic.  The modern concept of a metal-on-plastic  joint developed in the 1960s by John Charnley.  This led the way to improved designs into the knee we use today.

Knee joint surfacing

Today’s modern ‘knee replacement’ does not replace the knee at all! In fact, it is a resurfacing procedure.   Like a tire with tread on it, your knee has cartilage (like the tread) that wears down. The surgery is truly a ‘re-tread’ of the knee.

Knees are like tires
Your knee pain: Resurface or replace ?

The old worn out surfaces are prepared and new artificial surfaces are put back. This is not a new concept and has roots in the ideas of John Charnley from the 1960’s.

The idea of a ‘total knee’ comes from the concept that ALL surfaces are corrected.   There are three important areas in the knee.   The first is between the kneecap and the thigh bone (femur).  The other two are between the thigh and leg bones.   There is a medial (inside) and lateral (outside) bearing surface.  With this procedure, we correct all of them.

A ‘partial knee’ is a new bearing surface for only ONE of these areas.  I can tell you in the office if your arthritis pattern involves only one, two or all three areas.  A simple X-ray, and sometimes a special ‘stress view’ can give me this information


Bone Cuts for a total knee

With this resurfacing, you keep all your own ligaments, tendons, muscles and tissues except for the anterior cruciate ligament.  With a replacement, you will not need this ligament – and won’t miss it! –  as the new parts do the work it used to do.  Long rods are almost never used for this surgery.  If you have your knee replacement ‘re-done’, some of these concepts may change, and this is an entirely different topic to talk about.

Understanding what we do may change what you think !  Ask questions and make smart decisions about your future.