Effect of Total Knee Arthroplasty Design Evolution on Short-Term Patient Outcomes: A 3-Year Follow-Up Study

Background: Total knee arthroplasty (TKA) is an effective intervention for advanced osteoarthritis, although up to 20% of patients remain dissatisfied postoperatively. Newer implant designs aim to enhance outcomes by mimicking native knee kinematics and improving patellofemoral tracking. This study compares the clinical outcomes of two sequential TKA systems—first-generation (1G) and second-generation (2G)—over a 3-year period. Methods: A retrospective review of prospectively collected data was conducted on patients who underwent primary TKA using either 1G (n=121) or 2G (n=123) implants between June 2018 and March 2021. All procedures were performed by a single surgeon using a consistent technique and postoperative protocols. KOOS-JR and Knee Society Scores (KSS) were collected preoperatively and at 6, 12, 24, and 36 months. Complications were documented. Implant survival was determined at 3 years. Results: Both groups showed substantial functional improvement from baseline. In the 1G group, KOOS-JR scores rose from 30 ± 15.6 preoperatively to 80.9 ± 15.3 at 6 months, 84.0 ± 13.8 at 1 year, 85.0 ± 14.1 at 2 years, and 92.0 ± 15.2 at 3 years. In the 2G group, scores improved from 33.0 ± 11.9 to 88.0 ± 12.1 at 6 months, 88.0 ± 13.6 at 1 year, 91.0 ± 13.2 at 2 years, and 96.0 ± 9.6 at 3 years. The 2G group had significantly better KOOS-JR at 6 months (p < 0.05) as compared to the 1G group, but no significant differences were observed at 1, 2, or 3 years. The implant survival rate was 95% in both the 1G and 2G groups. Conclusion: Both TKA systems showed an acceptable safety profile and robust implant survival rate in the short term. The 2G implant showed an early advantage in patient-reported outcomes at 6 months relative to the 1G implants and greater convergence thereafter, suggesting that the new design may promote faster initial clinical recovery and improvement in clinical outcomes.