Robotic assistance improves success of cementless component fixation in one total knee arthroplasty system

Introduction: New cementless implant designs in total knee arthroplasty (TKA) have begun to shift the longstanding practice of cemented fixation. With aseptic loosening a leading cause for revision of cementless implants, initial osteointegration is critical for component survivorship. Robotic-assisted TKA (RA-TKA) has shown promising results in recent literature at improving component accuracy. The current study aims to evaluate if robotic assistance affects the success of cementless fixation in primary TKA.

Methods: 445 cementless primary TKA components from one manufacturer implanted by five surgeons between June 2018 and October 2022 were retrospectively reviewed. Those with minimum one-year follow-up were analyzed. Femoral and tibial components were reviewed separately and grouped based on whether manual or RA-TKA from the same manufacturer was performed. Fisher's exact test was used to analyze if aseptic loosening rates were different between the two techniques.

Results: 373 (82%) cementless components from a single knee system were included. 146 femoral and 103 tibial components were implanted using RA-TKA, while 63 femoral and 61 tibial components were implanted manually. At a mean follow-up of 18 months (range, 12 to 51 months), successful fixation was achieved in 96.2% of all components. No femoral components from either group were revised due to aseptic loosening. Four manually implanted vs. no robotically assisted tibial components were revised due to aseptic loosening (6.6% vs 0.0%; P = 0.038).

Conclusion: The performance of modern cementless femoral components was excellent with or without robotic assistance, however RA-TKA improved the survivorship of the same system's cementless tibial component.

Level of evidence: Level III.