This is a topic of much debate right now among surgeons. Probably the best answer is this: There is no perfect bearing surface. That is why there are so many options currently available.
I try to carefully select a bearing surface that best utilizes the potential benefits against the potential shortcomings. Here are some common hip bearing surfaces:
Ceramic-on-ceramic - This is the hardest, longest-wearing bearing available. It is been around in several iterations for at least 30 years. Major risks are that of ceramic fracture and the potential for an audible “squeaking” hip. Both of these issues have been identified, and the causes for them have largely been addressed. However, those possible problems still exist, which may warrant early bearing exchange surgery* (which is a smaller surgery in my hands). This is my bearing of choice for my young, active females. For larger men, where the potential for ceramic fracture risk may be increased, I prefer metal-on-metal.
Ceramic-on-metal – Not much is known clinically about this bearing surface yet. Lab studies show that this may be more wear resistant than metal-on-metal. However, the same potential risks of metal sensitivity exist. Additionally, since this bearing doesn’t have a long clinical track record, there may be other risks that have not yet been identified. I have used this bearing on occasion at my patients’ requests.
Metal-on-metal – extremely durable & long-lasting. This bearing has been around & researched for at least 30 years in different iterations.
Metal-on-metal surfaces have a risk of sensitivity to the metal ions which can lead to pain & catastrophic bone loss if ignored. This is what the unfavorable media coverage is currently focusing on. However, the risk of this “hypersensitivity reaction” is very small. Anyone receiving this type of bearing should be checked annually for maintenance of the joint.
This is my bearing of choice for young, active men (who do not have a history of nickel or metal allergy, and who have healthy kidneys)… accepting that there is a chance for bearing exchange surgery* if the hip presents with a metal hypersensitivity. I believe that the potential for a durable, long-lasting bearing outweighs the remote chance of metal sensitivity. And, even if a patient does present with metal sensitivity, the surgery to fix it is quick and easy.
Ceramic-on-plastic** – newer, very popular bearing surface. This is a wonderful bearing surface which has a great wear-resistance. It is less wear-resistant than ceramic-on-ceramic, ceramic-on-metal or metal-on-metal bearings. However, it has far fewer potential risks. Like any bearing that contains plastic, there is potential for bone loss from the plastic wear debris, which can manifest between 8-15yrs after the surgery.
Ceramic-like metal (oxidized zirconium)-on-plastic** – very similar to ceramic-on-plastic.
Metal-on-plastic** – this is the gold-standard for hip replacement. Excellent wear rates, low risk of side-effects. This bearing is not as wear-resistant as any of the above bearings, but appears better than the older metal-on-plastic bearings we were using 10-15 years ago. Like any bearing that contains plastic, there is potential for bone loss from the plastic wear debris, which can manifest between 8-15yrs after the surgery.
* bearing exchange surgery – In my practice, the surgery to exchange the bearings is done through the same SuperPATH approach, and recovery is quicker than the primary surgery since no bony work is done.
** “plastic” = highly cross-linked, ultra-high molecular weight polyethylene
