Two-Peg Cementless Trabecular Metal Modular Tibial Components in Total Knee Arthroplasty: A Single-Center Comparative...

Background and Objectives: Cementless total knee arthroplasty (TKA) with two-pegged Trabecular Metal (TM) tibial components composed of porous tantalum was introduced to improve fixation and reduce aseptic implant failure, particularly in younger, more active patients. Despite these theoretical advantages, mid-term outcomes remain uncertain. This retrospective study compares the survival of consecutive cementless TKAs with TM posterior-stabilized (PS) and cruciate-retaining (CR) modular tibial components with cemented PS and CR components from the same implant system, using revision for aseptic causes as the primary endpoint. Materials and Methods: Institutional review board approval was obtained, and a minimum follow-up of two years was required. Between January 2017 and November 2021, a total of 1202 TKAs of a single implant design were performed at a high-volume academic center by five board-certified orthopedic surgeons, predominantly for primary osteoarthritis. Of these, 826 (68.7%) procedures were cemented, and 376 (31.3%) were cementless. Demographic data and revision outcomes were collected for all patients. Results: There was no statistically significant difference between cohorts in the 7-year survival rate for all causes of revision (97.4%, 95% CI 95.6-99.2 for cementless vs. 97.8%, 95% CI 96.6-99.0 for cemented; p = 0.63). However, the 7-year survival rate for aseptic causes was significantly lower (p < 0.05) in the cementless TKA group (97.9%, 95% CI 96.3-99.5) compared with the cemented group (99.4%, 95% CI 98.8-100). Revisions for aseptic causes occurred in 7 cementless (1.86%) and 4 cemented (0.84%) TKAs (p < 0.05), most commonly due to loosening of the tibial TM component (6 [1.59%] vs. 2 [0.24%], respectively; p < 0.05). During follow-up, 94 patients (8.7%) died of causes unrelated to TKA. Conclusions: Cementless TM PS and CR modular TKAs demonstrated inferior mid-term performance compared with their cemented counterparts for aseptic reasons. These findings raise concerns regarding the durability of this cementless design and underscore the need for cautious use and further investigation.