Summary

When controlling for gender, BMI and Elixhauser Comorbidity Index score, RAS TKA had shorter surgical time, shorter length of stay and decreased risk of all-cause revision compared to manual TKA while maintaining similar PROMs.

Abstract

Background

Recent advancements in total knee arthroplasty (TKA) have introduced robotic-assisted surgical (RAS) techniques which can be used as an alternative to the traditional manual approach. However, there remains a need for a comprehensive comparative analysis to determine whether these advancements translate into significant improvements in surgical and patient-reported outcomes measures (PROMs). The purpose of this study was to examine the utilization and impact of RAS versus manual TKA on a surgical outcomes and PROMs while controlling for critical variables to provide a clearer understanding of RAS effectiveness.

Methods

A retrospective study was performed using a large regional health system joint replacement database to identify patients who underwent RAS and manual TKA between 2017 and 2024 Medical records were reviewed to collect demographic variables, operative details, and clinical outcome data. Patients who underwent revision TKA were excluded from the study. Only surgeons who performed at least 100 TKA’s in their respective groups were included in the study. Patients were allocated to two groups based on the surgical modality used for their procedure: RAS TKA and manual TKA. Further subgroups analysis was performed to compare outcomes between the most commonly used implant for RAS TKA (Triathlon, Stryker, Mahwah, NJ) compared to manual TKA using the same implant. Statistical analysis was performed using Chi-square, student’s t-test, and multiple regression analysis with statistical significance defined as p<0.05. The multiple regression analysis was conducted for the clinical outcomes while controlling for gender, BMI, Implant Type (Triathlon vs non-Triathlon), and Elixhauser Comorbidity Index

Results

A total of 16,113 patients (1,642 RAS-TKA and 14,471 manual TKA) were included. Usage rate of RAS-TKA significantly increased from 2020-2024 (4%-587%, R2=0.9279) surpassing manual TKA. Mean BMI and Elixhauser were significantly lower in RAS-TKA (35±7 vs 36±7kg/m2; 1.8±1.4 vs 2.4±1.6, p<0.01) compared with manual TKA. RAS-TKA had lower total surgical time (76±20 vs 84 ± 25minutes, p<0.01) and shorter length of stay (0.90±1.1 vs 2.02±4.8days, p<0.01). Overall, all-cause revision per 1,000 procedures was significantly lower with RAS-TKA (8.5 vs 21.8, p=0.01). PROMS were similar with differences smaller than the minimal clinically important difference (MCID).

Conclusion

When controlling for gender, BMI and Elixhauser Comorbidity Index score, RAS TKA had shorter surgical time, shorter length of stay and decreased risk of all-cause revision compared to manual TKA while maintaining similar PROMs. While previous studies reported longer surgical times due to RAS setup and registration, the current study revealed a mean of 10-minute shorter surgical duration. While RAS TKA could be discharged the same day or within 1 day from surgery compared to a much longer hospital stay in manual TKA, recent changes in enhanced recovery pathways toward same day discharge must be considered.