Assessment of All-Inside Sutures to the Posteromedial Capsule in Medial Meniscus Posterior Root Repair: Findings From a Retrospective Three-Dimensional Magnetic Resonance Imaging Study

Purpose: Medial meniscus (MM) posterior root tears (PRT) cause pathological medial extrusion (MMME) and posterior extrusion (MMPE), particularly during knee flexion, leading to rapidly progressive knee osteoarthritis. We investigated pre- and postoperative MM extrusion using three-dimensional open magnetic resonance imaging (MRI) following two pullout repair techniques: two simple stitches (TSS) and TSS with an additional all-inside suture to the posteromedial capsule (TSS-PM). We hypothesized that TSS-PM would decrease MM extrusion more effectively than TSS.
Methods: Thirty patients who underwent MM posterior root repair were retrospectively evaluated. TSS and TSS-PM techniques were used for pullout repair. Open MRI was performed at 10/90° of knee flexion preoperatively and three months postoperatively. MMME, MMPE, and MM extrusion volume (MMEV) were measured and compared between groups.
Results: At 90° of knee flexion, postoperative MMPE and MMEV were significantly decreased compared to preoperative values in both the TSS and TSS-PM groups. Furthermore, a significantly decreased ΔMMPE was observed in the TSS group compared to the TSS-PM group, whereas no significant difference was observed in ΔMMEV.
Conclusion: TSS and TSS-PM repair techniques helped decrease MMEV at 90° of knee flexion, whereas a significantly decreased ΔMMPE was observed in the TSS group at 90° of knee flexion. An additional all-inside suture at the posteromedial capsule may be insufficient to decrease MMEV and may negatively affect the decrease in ΔMMPE at 90° of knee flexion.