Articles Posted in Depuy ASR

In the previous post we looked at artificial hips and what should happen before a new medical device product like the Depuy ASR Hip gets to the marketplace. Now, let’s look a little deeper into the Depuy ASR hip system, its metal-on-metal cup and ball design, and how it failed:

What is “ASR” anyway?

“ASR” stands for “Articular Surface Replacement.” ASR is a surgical procedure that is an alternative to a total hip replacement procedure. In an ASR procedure, only the articular surface of the hip (the cup and the ball) is replaced. On the other hand, a total hip replacement includes not only the cup and the ball, but also a large piece of metal (known as a femoral stem) that is implanted deep into the patient’s femur and on which the ball is attached.

First, a little history is in order to see how a medical device like a Depuy ASR artificial hip gets to the market (and ultimately, into your body).

What is a total hip replacement?

A “total hip replacement” replaces the body’s hip joint with an artificial one, and these artificial hips are usually made out of metal or plastics. A total hip replacement typically consists of four separate parts: (1) a stem, (2) a head, (3) a liner, and (4) a cup (called an “acetabular cup” or shell). After the surgeon hollows out the patient’s femur bone, the stem is implanted. The head is a metal ball that is fixed on top of the stem. The femoral head forms the hip joint when it is placed inside the liner and the cup (the “acetabular shell”).