Research Square · Mar 25, 2026
Nutritional Status Influences Functional Outcomes After Robotic-Assisted Unicompartmental Knee Arthroplasty
By Xia C, Yang R, Ou S et al.
Background Robotic-assisted unicompartmental knee arthroplasty (RA-UKA) improves component alignment; however, improved radiographic precision does not consistently translate into superior clinical outcomes. Nutritional status may influence postoperative recovery and functional adaptation. We investigated whether preoperative nutritional status modifies the relationship between surgical technique and early functional outcomes after UKA. Methods Eighty-eight elderly patients (≥ 60 years) undergoing unilateral UKA were retrospectively analyzed. GNRI was calculated preoperatively. Restricted cubic spline modeling identified a GNRI threshold of 105. Patients were stratified into GNRI ≤ 105 and GNRI > 105 groups. Radiographic alignment parameters and postoperative Knee Society Scores (KSS) were compared between robotic-assisted and conventional UKA. Multivariable regression models adjusted for age, sex, BMI, and baseline KSS. Results RA-UKA demonstrated reduced alignment variability compared with conventional UKA. In the overall cohort, postoperative KSS did not differ significantly between techniques. Among patients with GNRI ≤ 105, RA-UKA was independently associated with higher postoperative KSS (adjusted P < 0.05). In contrast, among patients with GNRI > 105, improved alignment accuracy did not result in superior functional outcomes. Conclusion Preoperative nutritional status appears to influence the functional relevance of alignment precision in UKA. Elderly patients with lower GNRI may derive greater early functional benefit from robotic assistance. Nutritional assessment may assist in patient selection for RA-UKA.