When I went to the surgical clinic to plan for a hip replacement, I couldn't believe all the choices for the type of implant that could be used. I hope I'm not going to have to be the one to choose which one I want. How does that all work?
The choice of implant type, size, and design is usually left up to the surgeon. Many surgeons do discuss their decisions and the various options to choose from. Implant selection depends on a number of different patient and surgeon factors. On the patient side of things, your age, activity level, and the size and condition of your bones will all make a difference.
The type of arthritis you have may also play a role. For example, osteoarthritis is different than rheumatoid arthritis -- the underlying causes, progression of disease, and medications used to treat these two conditions vary. And those differences can also have some influence on implant selection.
According to a study from Finland, over the years there have been 106 different stem designs recorded in use. Likewise, 110 different cup designs have found their way into use. Finland has the ability to count such things because they have a computer database called the Finnish Arthroplasty Registry. Almost every patient who has had a joint replacement from 1980 on have been included in this collection of information.
Information on the patient's age, sex (male or female), diagnosis, type of implant, and surgical approach is entered into a computer database. The information is confidential as to the individual patient names. Having this type of information makes it possible for researchers to examine trends in treatment over time. Changes in surgical techniques, implant designs, and technology have the potential to also change results or outcomes. Keeping track of those changes and trends helps guide continued improvements in patient care.
One major decision is whether to go with a cemented versus cementless implantation. This decision is usually driven by your bone density. More and more surgeons are opting for the cementless type for several reasons. One of the most significant is the fact that removing the implant later (if that becomes necessary) is easier and destroys less bone in the process.
With the new porous surface and tapered stem design, going without cement is possible in patients with weak, brittle (osteoporotic) bones that would otherwise have to be cemented in place to hold them. When it comes time for your next appointment with the surgeon, don't hesitate to ask what he or she is thinking in terms of an implant type for you.
Keijo T. Mäkelä, MD, PhD, et al. Cemented Versus Cementless Total Hip Replacements in Patients Fifty-Five Year of Age or Older with Rheumatoid Arthritis. In The Journal of Bone and Joint Surgery. January 19, 2011. Vol. 93-A. No. 2. Pp. 178-186.