Comparative analysis of clinical efficacy between OSR-2000 robotic-assisted total knee arthroplasty and conventional manual surgery for knee osteoarthritis: a retrospective cohort study.

Total knee arthroplasty (TKA) is the definitive therapy for end-stage knee osteoarthritis (KOA). Conventional manual TKA depends heavily on surgeon experience and carries risks of osteotomy inaccuracy, lower-limb mechanical axis malalignment, poor soft-tissue balance and unsatisfactory functional recovery. The domestically-developed OSR-2000 orthopedic surgical robot (MicroPort ChangHang Robot Co., Ltd., Suzhou, China) integrates 3-dimensional preoperative planning, real-time optical navigation and constrained robotic osteotomy. This study compared perioperative outcomes, radiographic alignment, pain relief, knee function and safety between OSR-2000-assisted and manual TKA to evaluate its clinical value for KOA. This single-center retrospective cohort study enrolled 86 patients with primary unilateral end-stage KOA who underwent primary TKA between March 2024 and March 2025, grouped according to the surgical technique actually received: the OSR-2000 robotic group (n = 43) and the conventional manual group (n = 43). All patients in both groups received the same posterior-stabilized (PS) prosthesis system. Primary outcomes included postoperative hip-knee-ankle (HKA) deviation and coronal/sagittal prosthetic angular deviations. Secondary outcomes included perioperative parameters, postoperative VAS pain scores, knee ROM and KSS at the 1-, 3- and 12-month follow-ups, plus 12-month postoperative complications. The independent-samples t-test, repeated-measures ANOVA and Fisher's exact test were applied; P < 0.05 indicated statistical significance. The OSR-2000 group achieved superior radiographic alignment, with smaller HKA deviation and prosthetic angular deviations (all P < 0.001). Despite longer operative and tourniquet time (both P < 0.001), it showed less intraoperative blood loss and 24-h postoperative drainage, and a smaller hemoglobin decrease (all P < 0.001). Lower postoperative VAS scores and better ROM and KSS were observed in the robotic group at the 1- and 3-month follow-ups (P < 0.05); at 12 months, KSS remained significantly higher (P = 0.004), whereas the ROM difference was no longer significant (P = 0.058). The length of hospital stay and the complication rates did not differ significantly between the two groups.No statistically significant inter‑group difference was found in the length of hospital stayAlthough the crude 12‑month complication rate was numerically lower in the robotic group (4.65%, 2/43) compared with the manual group (13.95%, 6/43), no statistically significant difference was identified by two‑sided Fisher's exact test (P = 0.265). No robot‑related adverse events occurred. OSR-2000-assisted TKA yielded more accurate prosthetic implantation and lower-limb alignment than conventional manual TKA, with less intraoperative blood loss and better early pain relief and knee function. The two groups did not differ significantly in the length of hospital stay, 12-month ROM or complication rates, and the operative time was significantly prolonged in the robotic group. These results suggest that the OSR-2000 robotic system is a safe and precise alternative for primary TKA; however, long-term, large-sample multicenter studies are required to confirm its clinical benefits.A numerically lower complication rate was observed in the robotic cohort, but statistical significance was not achieved in this single‑center retrospective study.