Comparison in radiographic outcomes between robotic-assisted cruciate- retaining and posterior-stabilized total knee arthroplasty: a prospective randomized controlled study

Abstract

Abstract Background Robotic-assisted total knee arthroplasty (RA-TKA) is currently increasingly used in the field of joint arthroplasty, with cruciate-retaining (CR) and posterior-stabilized (PS) prostheses currently being the most widely used prosthesis designs. The purpose of this study was to investigate the difference in radiographic outcomes and early clinical outcomes between CR and PS in RA-TKA. Methods This prospective randomized controlled study enrolled 120 patients who underwent primary CR or PS RA-TKA between July 2022 and March 2023. Knee radiographs were taken one-day postoperative, while range of motion (ROM) and clinical scores were recorded in the outpatient clinic six-month postoperative. Radiographic outcomes and early clinical outcomes between the two groups were compared, respectively. Results Patients implanted with PS achieved a lower postoperative PTS (P < 0.001), as well as a higher ΔFTA (P = 0.001), ΔHKA (P < 0.001) and absolute ΔPTS (P < 0.001) compared to patients with CR RA-TKA. All radiographic parameters in both groups were changed significantly after surgery (P < 0.001). No difference was found in Forgotten Joint Score-12 (FJS-12) or 5-point Likert Score. However, postoperative ROM (P = 0.034) and ΔROM (P = 0.012) was significantly higher in CR than in PS group. Conclusion Patients with PS can achieve a lower postoperative PTS, and a higher ΔFTA, ΔHKA and absolute ΔPTS compared to patients with CR RA-TKA. Postoperative ROM and ΔROM were higher in CR than in PS group. However, the significant difference in radiographic outcomes and ROM did not translate into any difference in clinical outcomes. No difference was found in FJS-12 or 5-point Likert Score.