Bony morphology of the knee and non-traumatic meniscal tears: is there a role for meniscal impingement?

Abstract

Meniscal tears are an important cause of morbidity. The aim of this study was to examine the relationship between non-traumatic meniscal tears and the intrinsic bony morphology of the knee. A retrospective analysis of 160 knee MRI scans in 150 patients was carried out who met the following criteria: (a) age between 20 and 45 years, (b) no history of knee trauma, surgery, infection, metabolic bone disease, and (c) no collateral or cruciate ligamentous injury. The medial tibial slope (MTS), lateral tibial slope (LTS), medial tibial plateau depth (MTPD), and medial and lateral femoral condylar offset ratios were calculated. The anterior horn, body, and posterior horn of the menisci were graded as 0 (no tear), 1 and 2 (degenerative changes), or 3 (definitive tear). One-way ANOVA and linear regression was used for statistical analysis. In patients with grade 3 tears of the posterior horn of the medial meniscus, there was a significant association with shallower MTS (p < 0.05), smaller medial femoral offset ratio (p < 0.05) and smaller lateral femoral offset ratio (p < 0.05). Patients with grade 3 tears of anterior horn of the lateral meniscus had a significant association with shallower LTS (p < 0.05). No significant association was seen between MTPD and meniscal tears. Our results suggest an association between bony morphology of the knee and non-traumatic meniscal tears. Shallower MTS and LTS may result in impingement of posterior horn of medial meniscus and anterior horn of lateral meniscus, respectively. Future kinematic studies will be needed to help confirm our findings.