Imagine 50,000 parts. More than 500 unicompartmental knee implants. Twenty-three surgeons. Ten years. These numbers may not mean much to us, but they show 10 years effort and cooperation for the doctors of the HealthEast Hospital system in St. Paul, Minnesota.
In 1991 these doctors started a community-based registry to track the results of total joint implants. Type of implant, failure rate, cost, and patient data was collected on all patients getting a joint replacement.
Researchers recently looked at the results for unicompartmental knee replacements (UKRs). A unicompartmental implant replaces one side of the joint when arthritis has worn down the joint unevenly. The results show more than 90 percent of the UKRs were for the medial compartment (inside edge) of the knee. Most UKRs were cemented in place. Nine different designs were used. Hospital stay was about five days. Doctors were able to use this information to track which type of implants held up the best.
The most common cause of UKR failure was worsening of the arthritis. Loosening of the implant was the second reason for implant repair or removal. Overall results showed that 88.6 percent of the UKRs lasted at least 10 years. The authors say this isn’t as good as the 94.8 percent results for total knee replacements in the same study.
The authors suggest that every community start a local registry. Pooling the numbers gives the local doctors a snapshot of his or her results compared to other doctors in the same area. The goals are to improve implant success and reduce costs of implant failure.