Clicking Noises From a Knee Replacement

Knee clicking after knee replacement surgery is common. Some people describe it as a clicking or clunking sound when they walk.

In general, knee replacement clicking does not indicate a problem. However, if you are in pain, your knee is swollen or deformed, or the sound starts suddenly after the knee has healed, call your orthopedic surgeon for guidance.

This article discuss knee replacement clicking. It explains the different parts of a knee replacement that can cause clicking, and when you should see your healthcare provider.

What the Clicking Means

While any clicking following a knee replacement can be unsettling and even annoying, it is generally not a problem. It is not unusual for people to be able to hear or feel their knee replacement after they have surgery.

Usually, a little reassurance that nothing harmful is taking place is all that is needed in these situations. Your surgeon can examine your knee, and possibly obtain tests such as an X-ray, to ensure nothing is wrong with the implant.

Noises can come from a number of possible sources, including the metal and plastic implants, tendons, and scar tissue around the knee. Determining the source of the noise is something your surgeon can help you with.

However, take comfort in the fact that many patients describe clicks and other noises that come from their knee replacement.

When to See the Doctor

There are specific circumstances in which clicks and other noises should be investigated. As a rule, you should see your healthcare provider if the clicking noises are accompanied by:

• Joint deformity
• Pain
• Swelling

A new noise that develops out of the blue also warrants a call to your orthopedic surgeon. Generally speaking, you would expect noises to diminish over time, not increase.

Parts of a Prosthetic Knee

Most knee replacements are made of four separate parts. While there are some variations, the most common knee replacement device has two metal parts and two plastic parts.

Each part of the implant is held within the bone, either with cement or wedged tightly into place so that bone can grow into the implant. Different implants are designed to be held in place in different ways. Moreover, your surgeon may have a preference for a particular type or brand of implant to use.

Femoral Component

The femoral component is the metal cap that is fitted to the end of the thigh bone, the femur. It is a U-shaped cap that covers the end of the bone, wrapping around the front and the back.

There are different shapes to the femoral component that can be based on patient size, and how much stability is needed to reconstruct the normal knee function.

Tibial Component

The tibial component is also made of metal and sits on top of the shin bone, the tibia. The tibial component has a part that extends into the hollow center of the bone to support the flat top tray of the tibial component.

Patellar Component

The patellar component is an artificial extension of the kneecap. While not every patient ends up with this component, those that do will have a plastic (polyethylene) patellar component. This part replaces the gliding surface of the kneecap. The kneecap itself is not replaced.

Polyethylene Spacer

A polyethylene spacer is a plastic appliance inserted between the metal femoral and tibial components. This allows for smooth movement of the knee joint back and forth. There are variations in the shape and thickness of the polyethylene components to match each particular patient and situation.

What Causes Knee Replacement Clicking?

Most noises are the result of the metal and plastic components rubbing against each other. Because the components are not connected but rather held in place by the body's own muscles and connective tissues, the noises will often settle as the tissues grow around them.

Unfortunately, there is no way to know how long it will take for tissues to grow around the implant and reduce noises. Knee-strengthening exercises can sometimes help, particularly weighted leg extensions.

If the problem is aggravating, consider seeing a physical therapist who can help you develop an action plan to build muscle and maintain flexibility in and around the joint.