Ceramic component parts of total hip replacements (THRs) have been around long enough to find long-term reports of 20 years or more. In fact, there are reports of excellent results over the last 40 years.
At first, there were problems with fractures. But over time, these have been reduced considerably. The implant manufacturers have designed a better implant and improved ways of making them.
However, one new problem seems to be popping up. That’s a rise in the number of ceramic hip implants that squeak. It’s most noticeable when bending, walking, using the stairs, and during sexual activity. Surgeons are studying the problem and trying to identify the cause.
So far, they’ve noticed that the wear pattern on the implant often shows signs of impingement (pinching) of the femoral neck where it meets the rim of the acetabulum (socket). Further testing with an electron microscope showed metal debris along the area of wear.
Rim impingement is probably the number one cause of hip squeaking. But there isn’t just one cause of impingement. Besides socket malposition, there could be a loss of fluid film lubricating the joint. Some patients have lax (loose) ligaments that can lead to impingement.
There’s been some suggestion that an incomplete seal around the socket liner could cause squeaking. Some studies have shown that thicker sockets don’t squeak but thin ones do. It’s possible that the thinner sockets deform when they are put in place. Incomplete positioning of the liner may be the problem there.
Knowing all this, what can be done to stop the problem of squeaking in total hip replacements? First of all, the authors suggest a plan of prevention. Placement of the implant in the correct position and correct orientation is number one.
Patients with loose ligaments need some extra care and consideration during the procedure. The authors suggest using a polyethylene (plastic) liner for these patients. And for all patients, matching up the sockets with the right stem is a helpful strategy.