"Doc, My Knee Still Hurts"

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My patients have encouraged me for a long time to write something that would help other patients understand what to expect after a total knee replacement. They have asked for this information following their surgery with the knowledge of my teaching activities, including all of the information on the Online Orthopaedics Web Site, www.orthopodsurgeon.com.

A patient should understand before surgery that total knee replacement is a unique procedure, as unique as the knee is from other joints in the body. The knee is a very complicated joint with many parts and is much more complicated than the hip for example.

Total knee replacement is a wonderful procedure that can relieve most of the patient's pain and sometimes all of the pain. But everybody doesn't get relief of all of their pain.

Why Not?

At surgery you replace the knee joint surface. All of the supporting tissue structure that controls the knee is still there to hold it in place. These tissue structures are tremendously affected by the arthritis process in addition to the bone, but it is not something the patient thinks about if we don't educate them about it.

Not only is the bone worn out and rubbing together with spurs etc, but the ligaments, tendons and muscles are also very sick and affected by the arthritis process. The knee is often tight, swollen and won't straighten out completely.

Most of a person's "arthritis tissue" remains after surgery and to some extent is further affected by the surgery itself.

All of this supporting tissue structure has to get better, to the extent it is able to improve for the person's knee to be "back to normal". As you will see it is never possible to get the knee "back to normal".

All of this supporting tissue is packed with nerves (ouch) and blood vessels (swelling) which are what causes the pain and swelling after surgery and before for that matter. To think about it in another way you take this old jalopy that has a bad motor (motor being equivalent to the inside part of the knee) and a car body that is pretty beat up (supporting tissue structure) and you put a shiny new motor in (total knee replacement). Beat up car body and chassis (tissue structures not replaced) remain. Add a new motor (inside joint surface).

The patient expects to have a new car, but only has a new motor. Are you beginning to get the point?

Add to this the huge variability of degrees of knee arthritis disease, body shapes, their weight, personal reaction to pain and surgery, and age. The spectrum of arthritis of the knee as a disease and the variability in the patients that we treat is very great.

Any patient not doing as well as they had expected compares their course with someone they heard about last week who only took two pain pills and was using a cane in one week. We hear stories like this a lot.

Patients who are very honest in assessing their situation describe what they feel after surgery as a hurt or soreness different from their preoperative PAIN. Their discomfort is often worse after they over do activities.

Occasionally patients do have pain similar to what they had before surgery. The x-ray looks fine, but they have pain and try as we do we cannot find out why. I'm sure in most cases it is still coming from the surrounding tissues that were not able to improve enough for the pain to decrease to the usual soreness.

Many patients do get rid of all their pain and soreness eventually. That is always our goal and hope. But for many of the foregoing reasons, that isn't always possible.

We haven't even mentioned that you do all of this very big surgery and then expect to get the joint moving immediately doing leg exercises and walking on a very achy joint.

So if tune ups don't work anymore and your car needs a new motor, the new motor can really help how the car runs, but you don't have a new car.

This is just like your new knee joint surface, but all the rest is still your own knee's surrounding structures. To the extent that these tissues can get better with time and therapy, that is when the knee feels better. This is obviously different in different people.

Why does my knee click?

The natural knee has this very wonderful slippery shock absorbing surface that you hardly know is there. A joint replacement with its hard metal and plastic surfaces can never feel completely like a natural knee and at times when the knee is moved in a certain way this plastic and metal slightly click together and the patient feels this occur.

In your normal healthy knee you wouldn't even be aware of it.

Why does it feel so warm?

Surgical healing is dependent to a large degree on the in growth of new blood vessels in the surgical area. This increased blood supply is present for several months after total knee surgery and in most patients causes the knee to feel warmer than the other knee.