Active robotics for TKA- is it safe and effective ?

Active robotics for total knee arthroplasty is safe and efficacious according to a new study published in  Journal of orthopedics.

Bernard N. Stulberg et al conducted a investigational device exemption (IDE) clinical trial  to evaluate the safety and effectiveness of the TS1 (TSolution one®) robot for TKA. This is the first multicenter trial of the TS1 active robotic device for TKA in USA.

An active robotic system (ARoS) for TKA automatically executes planned bone cuts without human guidance of the cutting tool during bone preparation. Active robotics for TKA has been available since 2000 with the introduction of the ROBODOC®, which has been used in more than 8000 interventions.

A total of 115 patients (58 males, 57 females) were enrolled at six US centers. Eight surgeons participated in the study, with varying levels of experience in computer-assisted surgery.

Inclusion criteria for this study included patients eligible for primary unilateral TKA due to osteoarthritis defined radiographically by a Kellgren-Lawrence Grade of 3 or higher.

Exclusion criteria for this study included previous open knee surgery in the operative knee; body mass index >40 kg/m2; coronal deformity greater than 20◦ or a sagittal flexion contracture greater than 15◦; any type of metallic implant in the operative leg.

All patients were enrolled from February 2017 through December 2018.

• Mean patient age at surgery was 65.9 years (range: 43.0–85.0) and mean body mass index was 30.7 kg/m2 (range: 20.6–39.8).

• The main finding of this study is that no patient (0 %) experienced any of the seven pre-defined complications commonly associated with manual TKA, confirming the safety of the device.

• The malalignment rate found in this study is 65 % less compared to manual TKA (11.2 % vs 32 %, respectively), which demonstrates a 40 % statistically significant reduction based on the confidence intervals, demonstrating the effectiveness of the device.

• The planned component sizes matched the implanted femoral and tibial component sizes in 100 % and 77 % of cases, respectively.

• No patient experienced revisions, reoperations, and bleeding complications, prosthetic joint infections.

• Significant improvements from baseline were observed in the KSS Functional, KSS Objective, KSS Patient Satisfaction, and SF-12 Physical Composite scores and maintained through the later follow-up visits at 6-weeks, 3-month, and 6-month.

• For this study significant operative time decreases occurred following 10–12 cases (36.51 ± 7.4 min) when compared to the first three (49.1 ± 17 min) cases (p < 0.028).

• No differences were found in patient reported outcomes, complications, and alignment accuracy between cases completed before and after the learning curve was overcome by the surgeons.

The authors concluded that this clinical trial demonstrated safety and effectiveness of an active robotic device and defined features of the process that ensure safety. It demonstrated the ability to achieve accurate alignment, a low level of complications, and good clinical outcomes.

Further reading :

Safe and effective use of active robotics for TKA: Early results of a multicenter study. Bernard N. Stulberg et al.

https://doi.org/10.1016/j.jor.2021.07.001