High Rate of Failure with Wrist ReplacementPeople with severe wrist arthritis (usually from rheumatoid arthritis) find themselves in a bit of a bind -- literally. With pain, swelling, and loss of wrist motion it becomes increasingly difficult to perform even the simplest task.
Most often both wrists are affected -- not just one. Personal hygiene can become a huge problem. Whether in the bathroom, bedroom, or kitchen, even a few degrees of motion can make a big difference in function. What can be done to help these patients?
Conservative care with medications to control symptoms and even slow down the destructive effects of the disease comes first. But when the bones erode so much that the wrist becomes unstable, then surgery may be the next step.
For a long time, patients were offered two courses of action. First, removal of destroyed bones and replacement with bone graft. In some cases, a complete fusion called arthrodesis was necessary. Over time, other reconstructive procedures were developed. Eventually, an implant arrived on the market to replace the joint.
Total wrist replacement or arthroplasty is now more of a reality than a possibility. Manufacturers of implants have modified the shape and improved the design of their implants. Results are gradually improving, too.
If that last statement raises your eyebrows a bit, you're not alone. Surgeons are still reporting a pretty high complication and failure rate. In this study of 24 wrist arthroplasties, the failure rate was 50 per cent. And those were early failures -- not after the patient had the wrist implant for years and years.
What happened and what went wrong? A study like this can be very helpful in making changes that could result in improved outcomes. All the wrist implants were the Universal brand or design. Each one was put in place by one surgeon at the University of Iowa Department of Orthopaedic Surgery and Rehabilitation.
The biggest problem was loosening of the implant on the hand side (as opposed to the component part on the forearm side). The second most common problem was something called subsidence -- the implant literally sinks down into the bone. Most of those patients had to have another surgery to either remove and replace the implant or remove the implant and fuse the joint.
When the implant was removed, the surgeon could see how high pressure and uneven wear resulted in flecks of plastic from the liner of the implant being rubbed away. That type of debris entered the joint, rubbed against the bone, and loosened the implant away from the bone.
The other half who had good results gained enough motion to regain considerable function. And it didn't take that much increased motion to be considered a success. Even a few degrees of wrist motion can position the fingers in such a way to allow patients to complete many previously impossible tasks.
The results of this study (along with other similar studies) have shown the need for the next generation of Universal implants. In fact, that re-designed implant is now available (called the Universal 2).
A slight change in the shape of the implant surface that is acting as the joint surface has made a significant difference. Another surgeon who reported on patients receiving the Universal 2 indicated a much lower rate of loosening.
What's the next step? Of course, more studies would be helpful. Larger studies are needed, too. But with only a small number of people venturing into this treatment, it may be necessary to conduct multi-center studies where the same implant is used and results pooled.
A 50 per cent failure rate just isn't acceptable to most patients. Once an implant is developed with a much lower complication rate, then long-term survival will become another important variable. Studies over 10 to 20 years will show which implant has the best track record for the greatest number of patients.
Christina M. Ward, MD, et al. Five to Ten-Year Outcomes of the Universal Total Wrist Arthroplasty in Patients with Rheumatoid Arthritis. In The Journal of Bone and Joint Surgery. May 18, 2011. Vol. 93. No. 10. Pp. 914-919.
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