Purpose: To review patients with recurrent patellar dislocation surgically treated with robot-assisted medial patellofemoral ligament (MPFL) reconstruction compared with patients who underwent surgery using the traditional freehand technique.
Methods: A retrospective cohort study was performed to identify patients who underwent MPFL reconstruction from January 2020 to December 2023 in our hospital. The inclusion criteria were: patients aged from 15 to 50 years; patellar dislocation occurred two or more times; a Merchant view or computed tomography (CT) scan indicating patellofemoral joint malalignment, external patellar inclination, or lateral patellar dislocation; underwent MPFL reconstruction via robot-assisted or traditional freehand technique; complete medical records and imaging data before and after surgery; a minimum of 1 year of postoperative follow-up. The operation duration, intraoperative fluoroscopy number, hospitalization length, Kujala score, and Lysholm score were recorded. In addition, the Bisect offset index (BOI) and the distance between the femoral tunnel and Schöttle point (DTS) were measured based on the preoperative and postoperative CT data of each patient in the two groups.
Results: The mean follow-up times of the two groups were 27 ± 8 months and 31 ± 9 months, respectively (p = 0.05). Neither group of patients experienced patellar re-dislocation. The median number of the fluoroscopy in the robot-assisted group was 4.5 times lower than in the freehand group (9 times, p < 0.001). The distance between the femoral tunnel and Schöttle point (DTS) in the robot-assisted group was 2.57 ± 0.97 mm, which was significantly shorter than the freehand group (5.58 ± 2.92 mm, p < 0.001). The bisect offset index (BOI) changed to 0.71 postoperatively compared with preoperative 1.07 (p < 0.001) in the robot-assisted group; similar changes were observed in the freehand group (0.69 vs. 1.00, p < 0.001). The Kujala score and Lysholm score were both significantly improved postoperatively in the two groups. Specifically, the postoperative Kujala score and Lysholm score in the robot-assisted group (89 and 89) were higher than the freehand group (85 and 84, p = 0.03 and p = 0.02). Moreover, the results also showed higher postoperative functional scores in the robot-assisted group when the cases were divided into 1-year and 2-year groups. However, the cohort-specific minimal clinically important difference (MCID) analysis revealed no significant difference in the patient-reported outcomes (PROs) (Kujala score and Lysholm score) between the two groups.
Conclusion: Robot-assisted MPFL reconstruction for recurrent patellar dislocation achieved higher accuracy of femoral tunnel and lower radiation exposure compared to freehand technique. Nonetheless, the PROs showed no difference in rates of achieving MCID between the two groups.
Levels of evidence: Level Ⅲ, retrospective case-control study.
Keywords: accuracy; medial patellofemoral ligament; reconstruction; robot-assisted.
Copyright © 2025. Published by Elsevier Inc.