# Benefits of Image-Free Robotic-Assisted Total Knee Arthroplasty in Early Postoperative Recovery and Tibial Alignment Accuracy

## TL;DR

This study shows that image-free robotic-assisted knee surgery leads to faster recovery, less pain medication, and better alignment compared to traditional methods.

## Contribution

The study provides new evidence on the short-term benefits of imageless robotic-assisted TKA using the Navio system.

## Key findings

- Quadriceps muscle strength recovered faster in the robotic-assisted group up to postoperative day 14.
- Robotic-assisted TKA resulted in 96.4% of tibial components aligned within 2° of the mechanical axis, compared to 72.2% in conventional TKA.
- Rescue analgesic use was significantly lower in the robotic-assisted group.

## Abstract

Background

Robotic-assisted total knee arthroplasty (RA-TKA) has been introduced to improve implant alignment and soft tissue balance, potentially enhancing early functional recovery and patient satisfaction. The Navio system (Smith & Nephew, Inc., Memphis, TN, USA) is an imageless, handheld, semi-active robotic platform, but evidence regarding its short-term outcomes remains limited. This study aimed to compare early postoperative recovery, pain, rescue analgesic use, and implant alignment between Navio RA-TKA and conventional TKA.

Methods

We retrospectively reviewed 113 knees in 100 patients undergoing primary bi-cruciate stabilized TKA for varus osteoarthritis between April 2019 and July 2022. Conventional TKA (55 knees) was performed using extramedullary guides, and Navio RA-TKA (58 knees) utilized haptic-guided burr resection. Postoperative quadriceps muscle strength (MS), knee range of motion (ROM), visual analogue scale (VAS) pain scores, femoral circumference, rescue analgesic doses, and coronal component alignment were assessed up to postoperative day (POD) 14.

Results

Quadriceps MS recovery was significantly faster in the RA-TKA group at POD three, seven, 10, and 14 (all p<0.05). ROM recovery was greater on POD 10 (p=0.0231). Rescue analgesic use was lower with RA-TKA (4.12±7.26 vs. 7.98±12.1 doses, p=0.0399). No significant differences were found in VAS scores or the femoral circumference. Tibial component alignment within 2° of the mechanical axis was achieved more frequently in the RA-TKA group (96.4% vs. 72.2%, p=0.0004).

Conclusion

Navio RA-TKA resulted in faster early functional recovery, reduced analgesic requirements, and improved tibial alignment accuracy compared with conventional TKA. These benefits may enhance early patient satisfaction and support the broader adoption of imageless, handheld robotic systems. Prospective randomized studies with long-term follow-up are warranted.