AJSM - 2026-06-15 - Journal Article
Impact of the Posterior Tibial Slope on Medial Meniscus Posterior Root Tear Healing Based on Second-Look Arthroscopy.
Kim JS, Hwang UJ, Park SH, Choi CH, Chung KS
Topics
Key Takeaway
A posterior tibial slope ≥8.3° on lateral radiograph is associated with lax (failed) healing after medial meniscus posterior root repair at 1-year second-look arthroscopy, with mean PTS 9.3° in lax versus 6.6° in nonlax repairs (p=0.001).
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Summary
This study asked whether preoperative posterior tibial slope (PTS) predicts morphological healing after isolated medial meniscus posterior root repair using modified Mason-Allen sutures. Fifty patients underwent second-look arthroscopy at 1 year and were classified as nonlax (n=29) or lax (n=21) based on probing stability. Mean PTS was significantly higher in the lax group (9.3° vs 6.6°, p=0.001), and medial PTS on MRI similarly differed (8.6° vs 5.4°, p=0.001); cutoff values of ≥8.3° (radiographic) and ≥7.7° (MRI medial) identified patients at risk for lax healing.
Key Limitation
Single-surgeon, single-center case series without a control group or concurrent functional outcomes data, limiting generalizability and preventing determination of whether lax healing translates to clinically meaningful differences in extrusion or articular cartilage deterioration.
Original Abstract
BACKGROUND
Although a steep posterior tibial slope (PTS) has been reported to cause medial meniscus root tears, few studies have investigated whether the PTS affects healing outcomesPurpose/Hypothesis:This study aimed to investigate the influence of PTS on the healing status of repaired medial meniscus posterior roots via second-look arthroscopy. It was hypothesized that a steeper PTS is associated with an increased risk of compromised meniscal healing.
STUDY DESIGN
Case series; Level of evidence, 4.
METHODS
Patients who underwent isolated root repair using modified Mason-Allen sutures between 2019 and 2023 and consented to second-look arthroscopy at 1 year postoperatively were included. The primary endpoint was the morphological healing status characterized as lax versus nonlax tension. Patients were classified into group 1 (nonlax: stable during probing without separation; n = 29) and group 2 (lax: displacement during probing; n = 21). The anatomic PTS was primarily assessed using preoperative lateral radiographic views. Additionally, the medial PTS (MPTS) and lateral PTS (LPTS) were evaluated using preoperative magnetic resonance imaging of the central slices of the respective medial and lateral tibial plateaus. The PTS, MTPS, and LTPS were compared between the 2 groups. The cutoff value associated with lax healing was confirmed.
RESULTS
The PTS values (mean ± standard deviation) were 6.6°± 3.3° for group 1 and 9.3°± 2.5° for group 2, demonstrating a significantly elevated PTS in group 2 compared with group 1 (effect size, 0.484; 95% CI, 0.237 to 0.672; P = .001) The MPTS value was 5.4°± 3.2° in group 1 and 8.6°± 3.0° in group 2, with a significantly greater PTS in group 2 (effect size, 0.490; 95% CI, 0.245 to 0.676; P = .001). The LPTS value was 4.9°± 2.4° in group 1 and 5.8°± 2.7° in group 2; however, it did not differ significantly (effect size, 0.216; 95% CI, -0.066 to 0.467; P = .126). Based on the cutoff values, a PTS of ≥8.3° ( P = .004) and an MPTS of ≥7.7° were identified as a PTS associated with lax healing ( P = .001).
CONCLUSION
An increased PTS may contribute to lax healing, which in turn progresses to meniscal extrusion after root repair. Consequently, when performing root repair in patients with an increased PTS, it can be anticipated that the postoperative healing and clinical outcomes may not be as favorable as those in patients without an increased PTS.