Cumulative Incidence of Revision for a Balanced KneeSystem at a Mean 8-Year Follow-Up: A Retrospective Review of500 Consecutive Total Knee Arthroplasties

The primary purpose of this study was to evaluate mid-term survival of a Balanced Knee System in the first 500 total kneearthroplasty (TKA) cases using a fully cemented, posterior stabilized TKA at a high-volume private practice.Patients and Methods.In this IRB approved retrospective cohort study, data were extracted from a surgical registry at a high-volume orthopaedic practicefor the first 500 total knee arthroplasty (TKA) cases performed using the Balanced KneeSystem (BKS, Ortho Development,Draper, Utah, USA). Procedures were performed between June 2000 and September 2003 by one of two orthopaedic surgeons.Follow-up was performed at 6 weeks, 6 months, 1 year, 5 years, and 10 years. 48 patients (9.6%) were considered lost to follow-up.A competing risk analysis was performed to evaluate the cumulative incidence of revision while accounting for the competing riskof death. In the model, failure was defined as revision of any BKS component. Those who failed prior to two years remained inthe analysis.Results.The mean age of the population was 69 years (range: 40–94) and 73% were female. The cumulative incidenceof revision of any component was approximately 1% at a mean 8-year follow-up (range: 0.11–14.1 years) when accounting for thecompeting risk of death. When considering all those lost to follow-up as failures, the cumulative incidence of failure at 8 years wasapproximately 10%.Conclusion.Based on the results of the current study, a posterior stabilized primary TKA, implanted using aflexion and extension gap balancing technique, had excellent survivorship and outcomes at a mean 8-year follow-up