Cumulative incidence rates (CIRs) of patellofemoral complications (PCCs) and patellofemoral symptomatic crepitus (SC) using a new knee system–total knee arthroplasty (NEW-TKA) were compared with those of a currently available product–total knee arthroplasty (CA-TKA).
Twenty-two investigators prospectively enrolled 704 patients into a study using CA-TKA; 364 received a posterior-stabilized configuration. Twenty-three investigators (19 from the CA-TKA study) enrolled 1138 patients with NEW-TKA; 584 received a posterior-stabilized configuration. CIRs were estimated with Kaplan-Meier methods.
CA-TKA had 32 PCCs (6.15% CIR at 1 year and 8.26% at 2 years). NEW-TKA had 19 PCCs (3.15% CIR at 1 year and 4.11% at 2 years). CA-TKA had 15 SCs, 12 before 2 years (CIR = 3.67%); NEW-TKA had 5 SCs before 2 years (CIR = 1.21%). NEW-TKA had a statistically lower CIR of overall PCC and SC (log-rank P values = .018 for PCC and .017 for SC).
Interim 1- and 2-year CIRs of PCC and SC in NEW-TKA were less than half of those for CA-TKA, which is a promising trend for this new implant.