gms | German Medical Science

Objectives: The evidence regarding the improved outcome and patient satisfaction following robot assisted surgery for TKA and UKA remains inconsistent, especially when compared to conventional techniques for these interventions.

This study aims to report and analyze the short-term outcomes after TKA and UKA, operated with MAKO robotic-assisted-technique.

Methods: Patients (n = 57; mean age = 68.9) were recorded prospectively and longitudinally. They were divided into a UKA-group (n= 17; n varus = 16; n valgus = 1) and a TKA-group (n = 40; n varus = 33; n valgus = 7). All were operated with the patient specific alignment (PSA) philosophy.

The clinical outcome and patient satisfaction 3 months after UKA or TKA surgery were recorded and analysed. Established scores for the measurement of clinical function and patient satisfaction were used (Patient Recorded Outcome Measurements: EQ-VAS, EQ-5D-5L, OKS, FJS). In addition, radiographic whole-leg preoperative and postoperative images were obtained to assess preoperative radiographic alignment and to evaluate the extent of alignment correction after surgery. The postoperative complications (AEs and SAEs) were also monitored in all cases.

Results and conclusion: The UKA-group showed statistical differences in 2 of 4 PROMs: FJS 9.3 (+-11.0 SD) vs. 28.3 (+- 25.1 SD); OKS 33.5 (+- 7.4 SD) vs. 33.0 (+- 7.4 SD). Patients undergoing UKA had a mean preoperative varus deformity in the tibiofemoral angle of 6.0 degrees and were corrected by an average of 4.8 degrees to a mean 1.2 degrees varus angle. No complications were recorded.

The TKA-group had statistically significant improvements in all 4 PROMs in the follow-up. EQ-VAS 63.0 (+-21.2 SD) vs. 69.2 (+-16.8 SD); EQ-5D-5L 0.8 (+- 0.2 SD) vs. 0.9 (+-0.2 SD); OKS 34.3 (+-8.1 SD) vs. 28.5 (+-9.3 SD); FJS 18.1 (+-18.3 SD) vs. 37.2 (+- 30.2 SD)

Patients with varus deformity in the TKA group were corrected by 5.4 degrees in the tibiofemoral angle on average, moving from a mean preoperative 6.3 degrees to a mean 0.9 degrees. Patients with valgus deformity had an average femorotibial angle of -4.9 degrees preoperatively and were corrected to an average angle of -1.8 degrees. In the TKA group, a total of 4 complications occurred.

The analysis shows that the robot-assisted technique is a procedure with the ability to precisely implement the planned PSA. Furthermore, it is a safe procedure with only a few complications. Contrary to the findings in the general literature, the results of this study suggest different levels of short-term improvements in patient satisfaction. Robotic surgery aiming for PSA seems to lead to better overall patient satisfaction in the short term for TKAs in comparison to UKAs.

An evaluation of the Comorbitity Index and the ASA Index would be interesting to better assess the patient population. Furthermore longterm results are necessary to get a more nuanced understanding of the use of robotics in arthroplasty and help defining a suitable patient collective for these interventions.