Early Survivorship Analysis of a Modern Anatomic Cementless Tibial Baseplate: A Multicenter Retrospective Study.

BACKGROUND: Cementless total knee arthroplasty has seen increased adoption given the potential for durable biologic fixation. However, limited data exist on modern anatomic cementless tibial baseplate designs. This study evaluates early survivorship and functional outcomes of a novel cementless tibial baseplate compared to a cemented counterpart from the same manufacturer. METHODS: A multicenter retrospective review was conducted of 394 patients undergoing primary total knee arthroplasty at 2 academic-affiliated institutions from 2018 to 2023. Of these, 183 received a porous anatomic cementless tibial baseplate (Smith & Nephew, Memphis, TN) and 211 received a Genesis II cemented tibial baseplate. Mean follow-up was 1.4 years and 2.7 years, respectively. The primary outcome was all-cause revision-free survivorship; secondary outcomes included aseptic tibial loosening and Knee Injury and Osteoarthritis Outcome for Joint Replacement scores. RESULTS: One patient in each group required revision for aseptic tibial baseplate loosening. Two-year all-cause revision-free survivorship was 96.2% (95% confidence interval [CI]: 91.2-100) in the cementless group and 96.0% (95% CI: 92.6-99.6) in the cemented group (P = .92). Unadjusted Cox regression demonstrated no statistically significant difference in revision risk (hazard ratio 3.27, 95% CI 0.52-20.53; P = .207); however, estimates were imprecise and the hazard ratio consistently favored the cemented cohort. No significant between-group difference in Knee Injury and Osteoarthritis Outcome for Joint Replacement improvement was identified after multivariable adjustment (β = 3.46; 95% CI, -1.31 to 8.24; P = .154). CONCLUSIONS: This cementless tibial baseplate demonstrated low early revision and aseptic loosening rates; however, imprecise Cox regression estimates preclude conclusions regarding equivalent survivorship. Longer-term prospective studies with contemporary controls are warranted. LEVEL OF EVIDENCE: III, Retrospective comparative cohort study.