Impact of navigation assistance on perioperative outcomes in UKA: A nationwide propensity score-matched cohort study.

Purpose: Unicompartmental knee arthroplasty (UKA) offers several clinical advantages compared to total knee arthroplasty, including faster recovery and reduced complication rates. Navigation-assisted UKA has been introduced to improve prosthesis alignment; however, comprehensive evaluations of perioperative complications, particularly in Asian populations, remain scarce. Methods: A nationwide, retrospective cohort study was conducted using the Japanese Diagnosis Procedure Combination database from 2016 to 2023. A total of 30,724 patients who underwent UKA were included, of whom 8096 (26.3%) received navigation-assisted surgery. After 1:1 propensity score matching for age, sex, body mass index (BMI), Charlson Comorbidity Index, anaesthesia type and bilateral procedures, 8056 patients were retained in each group. Perioperative complications, including deep vein thrombosis, pulmonary embolism, cerebrovascular events, surgical site infections and periprosthetic fractures, as well as length of hospital stay, were compared between groups. Given the large sample size in our analysis, the significance level was set at Results: The incidence of deep vein thrombosis was significantly higher in the navigation-assisted group compared to the conventional group (7.8% vs. 5.3%, Conclusion: Navigation-assisted UKA was associated with a higher overall incidence of perioperative complications, largely driven by an increased risk of deep vein thrombosis, while length of hospital stay was shorter compared with conventional UKA. These findings suggest that although navigation assistance may facilitate earlier discharge, careful perioperative management-particularly with respect to thromboembolic risk-is warranted. Level of Evidence: Level III.