Sagittal Tibial Tunnel Angle Is Associated with Meniscal Extrusion and Clinical Outcomes Following Transtibial Pull-Out Repair of Medial Meniscus Posterior Root Tears

Background and Objectives: This retrospective cohort study aimed to evaluate the association between sagittal tibial tunnel angle and radiological and clinical outcomes following transtibial pull-out repair of medial meniscus posterior root tears. Materials and Methods: A total of 81 patients who underwent arthroscopic transtibial pull-out repair between January 2022 and October 2025 and had a minimum follow-up of 6 months were retrospectively evaluated. Demographic, clinical, radiological, and functional data were analyzed. Meniscal extrusion, hip–knee–ankle angle, mechanical axis deviation, sagittal and coronal tunnel angles, International Knee Documentation Committee (IKDC) score, and Numeric Pain Rating Scale (NPRS) score were assessed preoperatively and at 6 months postoperatively. Receiver operating characteristic (ROC) analysis was performed to explore the ability of sagittal tibial tunnel angle to discriminate achievement of the patient acceptable symptom state (PASS) based on the postoperative IKDC score. The ROC-derived 51.5° value was considered an exploratory, cohort-specific threshold. For secondary between-group comparisons, patients were classified into two groups according to sagittal tibial tunnel angle: ≤51.5° and >51.5°. Results: The cohort included 56 female patients, and the mean age was 50.0 ± 9.97 years. Receiver operating characteristic analysis identified 51.5° as the exploratory cohort-specific threshold, with an area under the curve of 0.754, sensitivity of 77.8%, and specificity of 68.9%. Patients with a sagittal tunnel angle >51.5° had lower postoperative meniscal extrusion than those with an angle ≤51.5° (3.0 mm versus 4.0 mm, p < 0.001), greater reduction in meniscal extrusion (1.10 mm versus 0.3 mm, p < 0.001), higher postoperative IKDC (71.62 ± 10.69 versus 53.0 ± 15.44, p < 0.001), and lower postoperative NPRS scores (1 versus 4, p < 0.001). Achievement of the patient acceptable symptom state was also more frequent in the >51.5° group (66.7% vs. 17.9%, p < 0.001). Conclusions: A greater sagittal tibial tunnel angle measured on 6-month postoperative MRI was associated with lower concurrent meniscal extrusion, higher functional scores, and lower pain scores following transtibial pull-out repair. However, the retrospective design and short follow-up period limit causal and long-term interpretation. The cohort-derived 51.5° threshold should be considered exploratory and requires external validation before clinical application.