Do iterative implant innovations translate to better outcomes? A comparison of three implant designs after uncemented total knee arthroplasty.

Abstract

Despite advancements in total knee arthroplasty (TKA) implant design, 20 % of patients remain dissatisfied. Implants have been developed to improve biomechanics and patient-reported outcomes, yet evidence suggests comparable long-term results between modern anatomic and traditional implants. This study evaluated whether newer implant designs provide meaningful and measurable clinical value. Retrospective chart review for primary TKA patients at a single institution (01/2016 - 05/2023). Patients were stratified based on uncemented implant design. Exclusion criteria: missing data, incomplete Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS) questionnaires, or follow-up under 12 months. Preoperative and 12-month postoperative KOOS scores for activities of daily living (ADL), PAIN, and quality of life (QoL), as well as Mental (MCS) and Physical Component Scores (PCS), were analyzed. The Kruskal-Wallis test was used for continuous variables, and <i>Chi</i>-square/Fisher's exact tests for categorical data (P < 0.05). Baseline characteristics and preoperative outcome scores were comparable across groups. ADL, PAIN, QoL, and KOOS (P = 0.883) scores were comparable between groups at 12 months. MCS score change from baseline to 12 months was significantly different (P = 0.02), though its clinical relevance remains uncertain. Design modifications from the multi-radius trochlear groove for altered femoral geometry and 3D-printed porous surface for uncemented fixation were introduced to improve patellofemoral mechanics and implant integration, there was no significant translation to improved patient-reported outcomes in this study. These findings suggest that patient and procedure-specific factors may be influential in determining TKA outcomes more than implant design alone.