Cemented or Uncemented Artificial Joints

Topic Overview

A surgeon has a choice between using cemented or uncemented joints in a joint replacement surgery such as hip, knee, or shoulder replacement surgery.

This decision may be made before the surgery or during the surgery, when your surgeon can see your bones. One type of joint is not clearly better than the other. But your doctor will consider things like your:

• Age.
• Bone strength.
• Muscle strength and balance.
• Ability to follow instructions, such as how much weight you can put on the new knee.
• Normal activity level.

Cemented joints are attached to the existing bone with cement, which acts as a glue and attaches the artificial joint to the bone. They form an immediate, strong bond to the bone, but they often loosen after 10 to 20 years. A cemented bond is strongest immediately after surgery and gets weaker over time.

Uncemented joints are attached using a porous coating that is designed to allow the bone to adhere to the artificial joint. Over time, new bone grows and fills up the openings in the porous coating, attaching the joint to the bone. This forms a bond that is weaker at first but becomes a strong permanent bond as the bone fills in. After a strong bond has formed between the bone and the replacement components, uncemented joints are less likely to weaken or loosen over time. Most loosening that can be seen on an X-ray doesn't cause symptoms and isn't a problem.