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Since the modern total hip and total knee were created in the ‘60s and ‘70s, we've been improving upon these time tested traditional implants using biomechanical science. Hips and knees today are made out of metals – such as titanium - that are more biocompatible with a similar strength and mechanical property to bone. Plastic inserts today are better prepared than ever before; less plastic wear occurs thus improving the longevity of the implant.
I’m often asked, what's one of the biggest problems we face in joint replacement surgery? It's really the plastic. Traditionally, the plastic would wear creating a biological response, thus causing the implant to fail much sooner. A lot of science has gone into the plastic. Having a better understanding of how it's prepared, supplied and implanted, we're not seeing the significant failure rates we once saw 20 or 30 years ago.
We’re using bone cement less often although bone cement is still necessary for knee joints. Bone cement is not necessarily a glue but rather a grout, meaning it helps get the metal to stick to the bone for knees. It's considered the gold standard. For hips we've found that the implants have significant biomechanical advantages when they don't have the cement. Basically, the bone will grow into the metal implant improving longevity.
The risk of bone cement is something called third party wear. Those little cement particles can actually act like a pebble inside the joint causing catastrophic wear. So that's why we're trying to get away from bone cement. Unfortunately, cement-less knees just haven't had the track record that ones with cement have had. But the newer techniques and the newer designs are showing promising results. Plus, some of the newer designs are actually now allowing us to preserve the PCL and even now the ACL which is a new and exciting advancement in total joint replacement.
Another real exciting new advancement in total joint replacement is computer navigation and robotics, coinciding with our current culture of being very interested in computers and technology. This is under intense research but the literature is showing significant promising results. These new advancements in computer navigation and robotics can improve the accuracy of the implant position. In other words, I can dial in the perfect position for the implant based on the patient’s anatomy, ultimately improving the patient’s outcome. It’s decreasing the risk of dislocation and improving functional knee range of motion.
Another new exciting advancement here in the US is the creation of the American Joint Replacement Registry. This has been long talked about. The reason why the Joint Replacement Registry is so important is it allows us to identify good implants as well as bad implants. Take for example the metal on metal implants used for total hips which were showing early signs of failure. That’s why they've been pulled from the market - not all of them but a lot of them.
The US was not the first country to create joint replacement registries. Sweden was the first one followed by other Scandinavian countries, Australia, the United Kingdom, Canada, and finally the US in 2012. We can now track implants to make sure we've used the best that we can obtain. And if we do identify a problem, we can notify the patient right away.
Total knee and hip replacements in Colorado - Learn More About Dr. Nathan Cafferky