Introduction: A primary total knee arthroplasty (TKA) system was introduced with a modern universal femoral design with a wide range of size and constraint options to accommodate a variety of patient anatomy, while incorporating streamlined instrumentation for maximum operating room efficiency and economy. The purpose of this study is to review the early clinical outcomes and survivorship at minimum two-year follow up with this knee system.
Materials and methods: From September 2015 to December 2019, 797 patients (1004 knees) underwent primary total knee arthroplasty (TKA) at our center with the TJO Klassic® Complete Primary Knee System (Total Joint Orthopedics Inc., Salt Lake City, Utah) with ultracongruent bearings and were available for study with minimum two-year follow up. All office and hospital records were reviewed for patient demographics, preoperative and postoperative clinical assessments, including range of motion, Knee Society Scores (KSS), University of California at Los Angeles (UCLA) activity scales, complications, and reoperations.
Results: Mean follow up was 3.1 years (range, 2-6; standard deviation [SD] ±1.0). There were 471 female patients (59%) and 326 male patients (41%). Mean age at surgery was 69.3 years and mean body mass index was 32.9kg/m2. An all-polyethylene tibial component was used in 305 knees (30.4%) while a modular titanium tibial baseplate with polyethylene insert was used in 699 (69.6%). The patella was left unresurfaced in 381 knees (37.9%). KS scores, including pain component, clinical, and functional, as well as UCLA scores, all improved significantly (p<0.001). Two patients (3 knees) underwent revision. One patient required two-staged revision for treatment of infection in both knees, and one patient required patellar revision for aseptic loosening. Kaplan-Meier survival at 6.2 years was 98.4% (95% CI: ±0.97%) to endpoint of revision of any part for any cause and 99.6% (95% CI: ±0.36%) to endpoint of aseptic revision.
Conclusions: At early minimum two-year follow up, this modern universal complete knee system used with ultracongruent bearings demonstrates excellent clinical outcomes and survival.