Total hip replacements come in two parts. There's the cup to replace the acetabulum (socket) and the round head at the top of the femur (thigh bone) and femoral neck. These component parts can be made out of a variety of different materials.
Ceramic was first introduced about 30 years. It wears well but tends to fracture. Improvements in materials and design have increased its popularity again in the last few years. Ceramic-on-ceramic implants have the lowest wear rate but squeaking can be a problem.
Surgeons aren't quite sure yet what might be causing this to happen. Not all patients are affected. And sometimes it goes away on its own. Studies so far suggest there may be two main reasons for this squeaking.
The first is a lack of lubrication in the joint. This is called dry joint. But what causes the dryness is still unknown. There are many theories so far. It could be the liner inside the socket is mismatched in size. Or ceramic particles may chip off the implant and rub inside the joint.
Most likely there are either many possible causes or several factors that occur at the same time resulting in squeaking. A solution to the problem hasn't been discovered yet. Once researchers pinpoint the cause, then surgeons can find ways to avoid or eliminate the problem.