Are implant designer series believable? Comparison of survivorship between designer series and national registries.

Performance of hip and knee implants reported by the designing surgeon(s) is often felt to be more optimistic than those observed in non-designer series. The purpose of this study is to compare the survivorship of hip and knee prostheses in series reported by designers with those in national joint registries. Fifteen different hip and knee implant results published by designers were identified and compared to four national registries. Thirty-two percent of comparisons performed demonstrated greater survivorship in the designer series compared to the registry, while 0% reported lower, and 68% demonstrated no difference. Two implants accounted for the majority (12/16) of the discordances. There was a lower (62%) concordance rate between the registries than between the designer series and registries (68%).