Improved surgical accuracy in total knee arthroplasty using the ROSA® knee system: A randomised-controlled unblinded trial.

purposeRobotic-assisted total knee arthroplasty (RATKA) has been connected to improved surgical precision and implant alignment compared to conventional TKA (CTKA), with limited evidence from randomised-controlled trials (RCT) and a large range of different systems on the market. Consequently, this study aimed to compare RATKA using the ROSA® knee system and CTKA in a prospective RCT for surgical as well as patient-reported outcomes.

methodsSeventy-seven patients undergoing TKA were prospectively included in this monocentric, unblinded RCT. All patients had a minimum follow-up of 1 year. Primary endpoints were postoperative implant alignment accuracy and patient-reported outcomes using the Oxford knee score (OKS) and quality of life scoring (EQ-5D-5L). Secondary outcomes included range of motion, blood loss, length of stay, return to work and physiotherapy needs. Statistical analysis included multivariable regression with significance set at p < 0.05.

resultsRATKA lead to improved limb alignment with significant lower frequency of extreme malalignment (>3°; <-3° from the mechanical axis) compared to CTKA (38% vs. 18%, p = 0.047). Both groups had comparable postoperative improvement in patient-reported outcomes (OKS Δ prepost 18.0 vs. 17.7, p = 0.902; EQ-5D-5L Δ prepost 0.21 vs. 0.25, p = 0.089). Regression analysis identified preoperative OKS (b = 0.57, p < 0.001) and cruciate-retaining implant bearing (b = 5.42, p = 0.043) as significant predictors of improved postoperative outcome.

conclusionsRATKA using the ROSA® knee system improves implant positioning and radiological alignment compared to CTKA with similar short-term clinical outcomes. Future research should focus on long-term RCT data to determine whether the improved accuracy of RATKA results in superior implant survival and reduced revision rates. LEVEL OF EVIDENCE: Level II, prospective comparative study.