Comparison of the Insall-Burstein II and NexGen legacy total knee arthroplasty systems with respect to patella complications.

This study retrospectively contrasts 2 cohorts of consecutive patients ""(N = 202) after primary total knee arthroplasty with respect to the types and numbers of patella and extensor mechanism complications. Our results demonstrated an overall decrease of patellofemoral complications associated with the NexGen Legacy PS system (Zimmer Inc, Warsaw, Ind). Patella fractures decreased from 6 to 0 (P = .013), avascular necrosis from 9 to 0 (P = .0002), and lateral retinacular release trended down from 24 to 14. The Insall-Burstein II (Zimmer Inc, Warsaw, Ind) has a significantly higher incidence of patella fractures, avascular necrosis, and the lateral retinacular release. We feel that the alteration and adjustment of the patellofemoral dimension in the NexGen Legacy design to a more anatomical, extended design of the femoral component and patella modifications led to a decrease in the incidence of complications.