Hip Implant Basics

General Information

The goal of hip replacement is to help you return to an active lifestyle with less pain. DePuy Orthopaedics, Inc., now offers many implant options to help restore your natural hip function—getting you back to moving more naturally and feeling like yourself again.

In a total hip replacement surgery, doctors replace the diseased or damaged hip with an implant consisting of a stem, ball, liner, and socket.

• The stem, made of metal, is inserted into the femur (thigh bone) and anchors the implant in place
• The ball is attached to the top of the stem
• The socket is anchored into the pelvis and the ball, which is attached to the top of the stem, fits into a liner within the socket

The "Bearing"

The area where the moving parts of the implant connect is known as the bearing. The bearing gives the ball of the hip implant a smooth surface on which to glide and rotate. The term "bearing" actually refers not just to a single part of the implant, but also to the area at which the ball and socket rub together (like in your actual hip). The bearing is especially important because it affects:

• Performance of the hip replacement
• Mobility, flexibility, and range-of-motion of the joint
• Durability of the hip replacement

Today's bearing materials offer excellent performance. Your surgeon can choose the materials best suited for you. Please read on to learn more about how implants work.

To understand how implants work, it helps to understand how your natural hip works.* The hip joint is like a ball that fits in a socket. The socket portion of the hip is called the acetabulum. The femoral head at the top of the thigh bone (femur) rotates within the curved surface of the acetabulum.

With hip replacement, an acetabular cup usually includes a metal shell and a plastic or metal liner to replace the acetabulum. The femoral stem is inserted inside the femur, and the femoral head (or ball) fits inside the acetabulum. Once the three components are aligned, more natural movement may be restored.

The bearing is where the weight and motion of the body are transferred from the pelvis to the femur. You often hear of ball bearings used in moving parts of machines-this is the same idea. The bearing is important because it affects how well your hip replacement will perform.

Today, due to innovations in orthopaedic technology, your surgeon can choose from a combination of polyethylene, metal or ceramic materials to create the appropriate bearing surface for you.

Next: About Bearing Surfaces

^{*Cartilage, synovial lining (lubrication), ligaments, muscles, and tendons also play an important role in how the hip works.}