The Natural-Knee system: 25 years of successful results.

The Natural-Knee (NK) total knee arthroplasty (TKA) system has been in use for 25 years. The unique features of this system include a deep trochlear groove, an asymmetrical tibial baseplate, use of Cancellous-Structured Titanium coating for preferred bone ingrowth, and a bimetal cementless femoral component. So far, 3135 NK total knee replacements have been reviewed. Cementless femoral and tibial components were used in 22% of these cases, cementless femoral and cemented tibial components in 3%, and cemented femoral and tibial components in 75%. The revision rate was 1.6%. Only one revision was to correct uncomplicated aseptic loosening.