I had a hip replacement that's gone bad. The doctor says the "PE" is worn thin and cracked and must be replaced. I looked on the internet but all I found was pulmonary embolism for PE. I can't find anything about the hip. What is this?

It probably stands for polyethylene liner. This is a plastic insert that goes inside the cup or socket portion of the implant. It provides a cushion and surface against which the ball of the joint can glide over and move around.

Studies show the PE liner is the weak link in hip joint replacement. The other parts of the implant hold up and wear well for five, 10, even 15 years and beyond. But thinning, cracking, and breaking of the PE requires implant revision.

Some companies are making a thicker liner for surgeons to try. The next step is to see how long the liners last in various hip implants. Do they last longer in a ceramic or metal prosthetic? Do they last longer in younger patients? These questions are under study today.