A cadaveric model for ligamentum teres function: a pilot study

Despite the prevalence and clinical consequences of ligamentum teres pathology, its function is poorly understood. The purpose of this study was to help define the role the ligamentum teres may have in hip joint stabilization and determine whether a ball and string model could be used to describe the function of the ligamentum teres. Eight embalmed cadavers were dissected to remove all soft tissue from around the hip, leaving only the ligamentum teres intact. Available hip abduction, adduction, medial rotation, and lateral rotation range of motion were measured for three repeated trials. The position of the ligamentum teres in relation to the femoral head was recorded at the endpoint position of these movements. An endpoint position as limited by the ligamentum teres for abduction, medial rotation, and lateral rotation was identified at a mean of 73A degrees(SD 11A degrees), 64A degrees(SD 11A degrees), and 58A degrees(SD 10A degrees), respectively. Hip adduction was limited by bony contact and therefore was not measured. The ligamentum teres wrapped around the femoral head to prevent inferior, posterior, and anterior subluxation with abduction, medial rotation, and lateral rotation, respectively. Repeated measures ANOVA indicated no significant difference in endpoint position based on trial number for the three movements (n.s.). The ligamentum teres consistently tightened to limit hip abduction, medial rotation, and lateral rotation. These results support a ball and string model for the femoral head and ligamentum teres. This information could be important for those with hip instability and ligamentum teres pathology.