Abstract
Abstract
Introduction
The UK National Joint Registry(NJR) has not reported total knee replacement (TKR)survivorship based on design philosophy alone, unlike its international counterparts. We report outcomes of implant survivorship based on design philosophy using data from NJR's 2020 annual report.
Methodology
All TKR implants with an identifiable design philosophy from NJR data were included. Cumulative revision data for cruciate-retaining(CR), posterior stabilised(PS), mobile-bearing(MB) design philosophies was derived from merged NJR data. Cumulative revision data for individual brands of implants with the medial pivot(MP) philosophy were used to calculate overall survivorship for this design philosophy. The all-cause revision was used as the endpoint and calculated to 15 years follow-up with Kaplan-Meier curves.
Results
1,144,384 TKRs were included. CR is the most popular design philosophy(67.4%), followed by PS(23.1%), MB(6.9%), and least commonly MP(2.6%). MP and CR implants showed the best survivorship(95.7% and 95.6% respectively) at 15 years which is statistically significant at, and beyond, 10 years. Observed survivorship was lower at all time points with the PS and MB implants(94.5% for both designs at 15 years).
Conclusions
While all design philosophies considered in this study survive well, CR and MP designs offer statistically superior survivorship at and beyond 10 years. MP design performs better than CR beyond 13 years yet, remains the least popular design philosophy used. Publishing data based on knee arthroplasty design philosophy would help surgeons when making decisions on implant choice.