Importance of a balanced-gap technique in rotating-platform knees.

Rotating-platform knees are constructed of highly conforming polyethylene to reduce contact pressures that potentially cause wear. The mobile nature of the rotating platform can lead to bearing spin-out. The purpose of this study was to determine the prevalence of spin-out in a single series. A total of 426 knees in 393 patients were included in the study. All knees were implanted using a balanced-gap technique. The average follow up was 3.2 years. There were no cases of bearing spin-out. The author concludes that the balanced-gap technique reliably prevents spin-out in mobile-bearing total knee implantation. This implantation technique provides the potential wear benefits of the rotating platform design with a nominal bearing spin-out rate.