Posterior tibial slope (>10°) is a risk factor for secondary medial meniscal tears in ACL-defcient knees,we suggest that tibial plateau slope is more likely to increase the incidence of concomitant medial meniscus tear in ACL-defcient knees.
To explore the effect of posterior tibial slope in chronic ACL-insufficient patients on concurrent medial meniscal tears.
Between July 2014 and February 2016, 163 patients were diagnosed with ACL tear who has been injured for more three months and underwent arthroscopic treatment. All patients were diagnosed with ACL-insufficient by preoperative examination, MRI and arthroscopy. The posterior tibial slope was measured via MRI. According to the presence of medial meniscus tear, 163 patients were divided into group A (with the medial meniscus tear) and group B (without the medial meniscus tear). Statistical analysis was employed to analyze two groups of patients' age, body mass index (BMI), injury time, tibial plateau slope, gender and side. Group A were divided into group A1 (tibial plateau slope> 10 °) and A2 (tibial plateau slope = 10 °). Statistical analysis was employed to analyze the incidence of concomitant medial meniscus tear with group A1 and A2 in injury time > 3 months, 6 months > and > 9 months. Values were considered statistically significant at probability values less than 0.05.
Result: All of the 163 patients, 91 patients(group A) were concomitant medial meniscus tear and 72 patients(group B) were not concomitant medial meniscus tear. There is no statistical difference between group A and B in age (t = 0.843, P=0.843), gender (X²=1.027 ,P=0.338), body mass index (t = 0.568, P = 0.568), side (X²=0.110 ,P=0.438) . Injured time of group A (8.63±3.74 months)is significantly longer than group B (6.68±2.13 months) (P = 0.000). Posterior tibial slope of group A (9.22°±2.40°) is significantly greater than group B (6.80°±4.49°) (P=0.000). All of the 91 patients with medial meniscus tear, the incidence of meniscal tears was 30.2%, 33.3%, 36.5% in group A1 with 63 patients and 10.7%, 25.0%, 64.3% in group A2 with 28 patients for the injury time>3 months, >6 months and >9 months (P=0.034).
Our data demonstrate that posterior tibial slope (>10°)is a risk factor for secondary medial meniscal tears in ACL-defcient knees.
Key words: Chronic ACL-insufficient; Posterior tibial slope; Medial meniscal tear