The role of registry data in the evaluation of mobile-bearing total knee arthroplasty.

The conventional wisdom that a mobile-bearing design may offer a benefit compared with a fixed-bearing design in total knee arthroplasty has not been supported by evidence. We reviewed the published literature and annual registry reports of all national and regional registries to determine the differences in clinical outcomes between mobile and fixed-bearing designs. We found only single-center reports and studies with small sample sizes in the published literature. These studies did not demonstrate any advantages of mobile bearings over fixed bearings. Moreover, major national joint registries reported higher failure rates associated with mobile-bearing total knee replacement compared with fixed-bearing total knee replacement. Similar findings from a U.S. national study in a community setting suggest that mobile-bearing knees have an increased risk of revision. After harmonization of methodologies, international collaborations of registries may provide the best insight into the performance of mobile-bearing total knee arthroplasty in real-world settings.