Association Between Insufficient Restoration of Meniscal Tension During Surgical Repair of Medial Meniscus Root Tear and Surgical Outcomes: Clinical Implication of Curtain-Cliff Sign

Background: Despite the clinical benefits over nonoperative treatment or meniscectomy, the clinical outcomes of surgical repair for medial meniscus posterior root tear (MMRT) remain suboptimal, which may be attributed to the insufficient restoration of meniscal hoop tension during surgery.

Purpose: To analyze the clinical outcomes of surgical repair of MMRT based on the appearance of the meniscal tension observed immediately after surgery.

Study design: Cohort study; Level of evidence, 3.

Methods: Electronic medical records of patients who underwent arthroscopic transtibial pull-out repair of MMRT between 2010 and 2021 were retrospectively reviewed. Patients with at least a 2-year follow-up and whose overall meniscal status after the surgical repair could be evaluated via arthroscopic images or videos were eligible to be included. Patients were classified based on the presence of the curtain-cliff sign, potentially implying insufficient postoperative meniscal hoop tension (group 1, patients without the curtain-cliff sign; group 2, patients with the curtain-cliff sign). Regression analysis was performed to evaluate whether the curtain-cliff sign reflects postoperative meniscal extrusion. Subsequently, comparative analyses were conducted between the 2 groups regarding baseline demographic data, clinical scores, intraoperative data, and radiologic parameters.

Results: A total of 79 patients were included (group 1, 59 patients; group 2, 20 patients). Regression analysis revealed a significant association between the curtain-cliff sign and postoperative meniscal extrusion, suggesting its potential to reflect the postoperative meniscal tension. In the between-group comparisons, there were no differences in baseline demographic data, preoperative clinical scores, and preoperative radiologic variables. However, at the final follow-up, group 2 showed a significantly lower International Knee Documentation Committee subjective score compared with group 1 (group 1, 61.7 ± 14.4; group 2, 52.9 ± 12.5; P = .017), while no significant differences were found in the visual analog scale for pain score and Lysholm score. Additionally, group 2 exhibited significantly higher postoperative meniscal extrusion compared with group 1, which was measured at both the midpoint of the medial femoral condyle (group 1, 4.0 ± 1.1 mm; group 2, 5.1 ± 1.5 mm, P = .004) and the posterior border of the medial collateral ligament (group 1, 4.4 ± 1.2 mm; group 2, 5.7 ± 1.5 mm; P = .004), with more pronounced progression compared with the preoperative status at these sites. Consistently, the progression of both the osteoarthritis grade and the hip-knee-ankle angle compared with preoperatively was significantly greater in group 2.

Conclusion: In patients in whom the restoration of meniscal tension appears insufficient immediately after surgical repair of MMRT, relatively poor clinical outcomes can be anticipated. The findings of this study suggest that efforts to reinforce meniscal tension may be required during surgical repair of MMRT in some cases, especially those showing the curtain-cliff sign.