[Comparison of early effectiveness and safety between domestic robot-assisted and conventional simultaneous unicompartmental knee arthroplasty for bilateral anteromedial compartment osteoarthritis].

OBJECTIVE

To compare the safety and early effectiveness between conventional manual technique and domestic robot-assisted simultaneous bilateral medial unicompartmental knee arthroplasty (UKA).

METHODS

Clinical data of 59 patients who underwent simultaneous bilateral UKA and met the selection criteria between January 2023 and June 2024 were retrospectively analyzed. Among them, 30 patients received bilateral UKA via conventional surgery with Oxford mobile-bearing unicompartmental knee prosthesis (conventional group); another 29 patients underwent bilateral UKA with LINK SLED fixed-bearing unicompartmental knee prosthesis assisted by the domestic NATON robotic surgical system (robotic group). Baseline data including gender, age, body mass index, disease duration, Kellgren-Lawrence grade, and preoperative American Knee Society Score (KSS) and Oxford Knee Score (OKS) showed no significant intergroup differences ( P>0.05). Intraoperative and perioperative indicators including operation time, length of hospital stay, perioperative hemoglobin (Hb) drop (preoperative vs immediate postoperative), and incidence of complications were recorded and compared. KSS and OKS scores were adopted to assess knee functional recovery preoperatively, at 3 months postoperatively, and at last follow-up. KSS satisfaction score was used to evaluate patient satisfaction at 3 months postoperatively and at last follow-up. Radiographic measurements of tibial prosthesis varus-valgus angle and the change in joint line height before and after surgery were performed to evaluate the accuracy of prosthesis implantation.

RESULTS

The conventional group had significantly shorter operation time than the robotic group ( P<0.05). There was no significant difference in length of hospital stay and perioperative Hb drop between the two groups ( P>0.05), and no patient required blood transfusion. All patients completed follow-up, the follow-up duration was (12.3±2.3) months for the conventional group and (12.1±2.4) months for the robotic group, with no significant difference ( t=0.324 , P=0.752). No severe complication including prosthesis loosening, periprosthetic infection, periprosthetic fracture, deep vein thrombosis of lower extremities, pulmonary embolism, knee stiffness, or knee instability occurred in either group. The tibial prosthesis varus-valgus angle and the change in joint line height in the robotic group were significantly smaller than those in the conventional group ( P<0.05). No significant intergroup difference was observed in patient satisfaction scores at 3 months postoperatively and at last follow-up ( P>0.05). Both KSS and OKS scores significantly improved at 3 months postoperatively and at last follow-up when compared with preoperative scores, with further improvement over time ( P<0.05); no significant intergroup difference in these scores was found at any postoperative time point ( P>0.05).

CONCLUSION

Although robot-assisted simultaneous bilateral UKA requires longer operation time, it achieves comparable early effectiveness and safety to conventional manual simultaneous bilateral UKA, with superior accuracy of prosthesis implantation. The domestic robot-assisted system demonstrates promising clinical application value in simultaneous bilateral UKA.