Meniscus extrusion is a predisposing factor for determining arthroscopic treatments in partial medial meniscus posterior root tears

Abstract

Background Patients with partial medial meniscus posterior root tears (MMPRTs) sometimes require arthroscopic pullout repair because of their intolerable/repeated knee pains and continuous disturbance in gait during activities of daily living. However, the predisposing factors for future knee surgery in patients with partial MMPRTs remain unclear. We compared the findings of magnetic resonance imaging (MRI) between patients who underwent pullout repair and nonoperative management following partial MMPRTs. Methods Twenty-five patients who required arthroscopic repair for partial MMPRTs and 23 patients who were managed nonoperatively were evaluated during a mean follow-up period of 27.1 months. Sex, age, height, body weight, body mass index, duration from onset to initial MRI, MRI findings, and medial meniscus (MM) extrusion were compared between the two groups. Linear regression analysis was used to assess the correlation between MM extrusion and duration from onset to MRI examination. Results No significant differences were observed between the pullout repair and nonoperative management groups in terms of patient demographics and the positive ratio of MRI-based root tear signs. However, absolute MM extrusion in the pullout repair group (3.49 ± 0.82 mm) was larger than that in the nonoperative management group (2.48 ± 0.60 mm, P < 0.001). Extrusion of the MM (> 3 mm) was detected more frequently in the pullout repair group than in the nonoperative management group (P < 0.001). The odds ratio in the pullout repair and MM extrusion > 3 mm cases was 9.662. Linear regression analysis revealed a fair correlation between the duration from onset to MRI and MM extrusion only in the pullout repair group (0.462 mm/month increase in MM extrusion). Conclusions This study demonstrated that more severe MM extrusions were observed in the pullout repair group than in the nonoperative management group. Major extrusion (> 3 mm) was also observed more in the pullout repair group than in the nonoperative group. Assessing MM extrusion and its severity can help determine a valid treatment for patients with partial MMPRTs. Level of evidence IV, Retrospective comparative study.

Medial Meniscus Posterior Root Tear: How Far Have We Come and What Remains?

“…MMRTs show characteristic radiographic findings in each plane on MRI, which are as follows: (1) vertical high signal at the MMPR on the coronal image (truncation or cleft sign), (2) vertical high signal at the MMPR on the axial plane, and (3) absence of identifiable MMPR on the sagittal plane, but the meniscus reappears immediately in adjacent images (ghost sign) ( Figure 2 A–C) [ 42 , 43 , 44 ]. In addition, medial meniscus extrusion in the coronal plane, a medial displacement of the medial meniscus with respect to the outer border of the medial tibial plateau, can be used to predict MMRTs ( Figure 2 D) [ 45 , 46 , 47 ]. Choi et al reported that a medial meniscus extrusion >3 mm could be associated with the occurrence of an MMRT [ 47 ].…”