Robot‐Assisted Medial Patellofemoral Ligament Reconstruction in the Treatment of Recurrent Patellar Dislocation Can Improve Tunnel Accuracy but Yields Similar Outcome Compared With Traditional Technique

Abstract

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 occurring 2 or more times; a Merchant view or computed tomography 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; and a minimum of 1-year postoperative follow-up. The operation duration, intraoperative number of fluoroscopies, hospitalization length, Kujala score, and Lysholm score were recorded. In addition, the Bisect offset index and the distance between the femoral tunnel and Schöttle point were measured based on preoperative and postoperative computed tomography data of each patient in the 2 groups. RESULTS: The mean follow-up times of the 2 groups were 27 ± 8 months and 31 ± 9 months, respectively (P = .05). Neither group of patients experienced patellar redislocation. The median number of fluoroscopies in the robot-assisted group was 4.5 times lower than in the freehand group (9 times, P < .001). The distance between the femoral tunnel and Schöttle point 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 < .001). The bisect offset index changed to 0.71 postoperatively compared with preoperatively 1.07 (P < .001) in the robot-assisted group; similar changes were observed in the freehand group (0.69 vs 1.00, P < .001). The Kujala and Lysholm scores were significantly improved postoperatively in the 2 groups. Specifically, the postoperative Kujala and Lysholm scores in the robot-assisted group (89 and 89) were higher than the freehand group (85 and 84, P = .03 and P = .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 analysis revealed no significant difference in the patient-reported outcomes (Kujala and Lysholm scores) between the 2 groups. CONCLUSIONS: Robot-assisted MPFL reconstruction for recurrent patellar dislocation achieved higher accuracy of femoral tunnel and lower radiation exposure compared to the freehand technique. Nonetheless, the patient-reported outcomes showed no difference in rates of achieving the minimal clinically important difference between the 2 groups. LEVELS OF EVIDENCE: Level Ⅲ, retrospective case-control study.