Early clinical outcomes of Naton robotic-assisted medial unicompartmental knee arthroplasty

Purpose: Unicompartmental Knee Arthroplasty (UKA) has garnered increasing attention in recent years. Robotic-assisted systems have demonstrated enhanced precision, contributing to improved patient survival rates, satisfaction, soft-tissue balancing, alignment, and component sizing. The purpose of this study is to evaluate the early clinical outcomes of Naton robotic-assisted medial UKA by analyzing postoperative radiographic positioning of the unicompartmental prosthesis and comparing preoperative and postoperative functional outcomes in patients. Methods: A retrospective analysis was conducted on the clinical data of 32 patients (32 knees) who underwent Naton robotic-assisted medial UKA at Suining Central Hospital of Sichuan Province from November 2023 to January 2024. The cohort included ten males and 22 females, with a mean age of 70.53 ± 8.08 years, ranging from 53 to 88 years. All patients underwent surgery using the Naton robotic system and the Zhengtian Unique fixed-bearing UKA prosthesis. Radiographic (X-ray) findings, knee function, and complications were evaluated during follow-up. Radiographic assessments included prosthesis position, angle deviation, and posterior tibial slope (PTS). Knee function was assessed using a range of motion (ROM), Knee Society Score (KSS), Oxford Knee Score (OKS), and Forgotten Joint Score (FJS). Results: All patients in the study were followed for a period of eight to ten months, with a mean follow-up of (9.16 ± 0.68) months. No complications such as poor incision healing, periprosthetic infection, periprosthetic fracture, or prosthesis loosening were observed during the follow-up period. The medial unicondylar prostheses were found to be in place in all 32 cases, and no abnormal deviation of the prosthesis implantation angle was observed compared to immediate postoperative radiographs. The posterior tibial slope (PTS) was reduced from 13.00 ± 2.72° preoperatively to 5.08 ± 1.14° postoperatively, with a statistically significant difference (P ≤ 0.05). At the final follow-up, the knee range of motion (ROM) was improved from 107.03 ± 11.69° preoperatively to 128.25 ± 16.52° postoperatively. The KSS was improved from 46.28 ± 7.27 to 82.34 ± 14.72, and the OKS was improved from 36.13 ± 4.71 to 15.78 ± 3.52, all with statistically significant differences compared to preoperative values (P ≤ 0.05). The Forgotten Joint Score (FJS) was recorded as 89.2 ± 2.9. Conclusions: The short-term follow-up indicates a favorable prosthesis in situ rate for unicompartmental knee arthroplasty assisted by the Naton robot, with satisfactory knee function and patient-reported outcomes. The short-term clinical outcomes are satisfactory. © The Author(s) 2025.