Non-traumatic ligamentum teres tears: association with MRI morphometry of the hip

Background: The ligamentum teres has been recognized as an important stabilizer of the hip. Purpose: We aimed to examine the relationship between non-traumatic ligamentum teres (LT) tear and hip morphometry on magnetic resonance imaging (MRI). Material and Methods: Fifty patients who had undergone hip MRI were included (27 men, 23 women; average age = 54.0 years). The status of the LT and the morphometric hip parameters were assessed, including acetabular anteversion angle (AAA), acetabular depth (AD), acetabular index (AI), lateral center edge angle (LCEA), and extrusion index (EI). The morphometric hip parameters were compared between groups with one-way ANOVA, Student’s t-test, and Mann–Whitney U test. Results: A decreased acetabular coverage was noted in the severe tear group compared to the normal group, indicated by a significantly larger AD (P = 0.001) and smaller LCEA (P = 0.016). There was a statistically significant difference in the AAA, AD, and LCEA between the normal group and the complete tear group; the AAA was significantly larger (P = 0.031), the AD was significantly larger (P = 0.01), and the LCEA was significantly smaller (P = 0.043) in the complete tear group compared to the normal group. Conclusion: There is an association between LT tears and acetabular bony morphology; an insufficient acetabular coverage is associated with complete tear of the LT. As the insufficient acetabular coverage may predispose to ligamentum teres tear, the ligamentum teres should be thoroughly evaluated in those with insufficient acetabular coverage, as a potential cause of hip pain.