Single-anchor centralization added to transtibial pullout repair for medial meniscus posterior root tears: early but not sustained extrusion reduction, no detectable clinical benefit at 12 months

To evaluate the 12-month clinical and radiographic outcomes of adding single-anchor meniscal centralization to double-loop suture transtibial pullout repair for medial meniscus posterior root tears (MMPRTs). This retrospective cohort study included 59 patients with MMPRT treated between March 2021 and June 2025. Patients were treated with either isolated double-loop transtibial pullout repair (group A, n = 27) or pullout repair combined with single-anchor meniscal centralization (group B, n = 32). Meniscal extrusion was measured on coronal MRI at baseline, immediately postoperatively, and at 3, 6, and 12 months. Posterior root healing was assessed on 12-month MRI. Clinical outcomes included Lysholm, IKDC, VAS scores, and knee range of motion. The primary outcome was the between-group difference in meniscal extrusion at 12 months. Secondary outcomes included posterior root healing on MRI and clinical functional scores. Preoperative meniscal extrusion was similar between groups. Extrusion decreased significantly in both groups immediately postoperatively. Group B showed greater early reduction than group A at 3 and 6 months, but this radiographic advantage was no longer detected at 12 months (the primary outcome; group A [repair alone] versus group B [centralization]: 4.24 ± 0.43 versus 4.18 ± 0.41 mm; between-group difference 0.05 mm, 95% CI − 0.16 to 0.27 mm, P = 0.63). Root healing and clinical functional outcomes were similar between groups at 12 months. Adding single-anchor meniscal centralization to transtibial pullout repair reduced meniscal extrusion during the early postoperative period, but this radiographic advantage was no longer detected at 12 months. No additional clinical benefit was observed in root healing or functional outcomes.