Increased Posterior Tibial Slope Is Associated With Increased Risk of Meniscal Root Tears: A Systematic Review

Background: While increased posterior tibial slope (PTS) is an established risk factor for anterior cruciate ligament tears, the association between tibial slope and meniscal posterior root tears is not well-defined. Purpose: To summarize the available literature evaluating the association between PTS and meniscus root injuries compared with patients without root tears. Study Design: Systematic review; Level of evidence, 4. Methods: A literature search was performed using the Scopus, PubMed, and Embase databases. Human clinical studies evaluating the associations between the medial tibial slope (MTS), lateral tibial slope (LTS), lateral-to-medial (L-to-M) slope asymmetry, and the risk of meniscus root tears were included. Patients with medial meniscus posterior root tears (MMPRTs) and lateral meniscus posterior root tears (LMPRTs) were compared with a control group without root injury. Study quality was assessed using the methodological index for non-randomized studies criteria. Results: Ten studies with 1313 patients were included (884 patients with root tears; 429 controls). The LMPRT subgroup (n = 284) had a significantly greater LTS (mean ± SD, 7.3°± 1.5° vs 5.7°± 3.91°; P < .001), MTS (5.26°± 1.2° vs 4.8°± 1.25°; P < .001), and increased L-to-M asymmetry (2.3°± 1.3° vs 0.65°± 0.5°; P < .001) compared with controls. The MMPRT group (n = 600) had significantly increased MTS relative to controls (8.1°± 2.5° vs 4.3°± 0.7°; P < .001). Furthermore, there was a higher incidence of noncontact injuries (79.3%) and concomitant ramp lesions (56%) reported in patients with LMPRT. Conclusion: Increased MTS, LTS, and L-to-M slope asymmetry are associated with an increased risk of LMPRTs, while increased MTS is associated with MMPRTs. Surgeons should consider how proximal tibial anatomy increases the risk of meniscus root injury.