The function of the ligamentum teres in rotational movements of the hip

The function of the ligamentum teres, and its role in the hip joint more generally, is a controversial subject. Various opinions have been expressed about its role in the stability of the joint and about the effect of injury to it in pathological conditions of the hip joint. A recently published study in the journal “Arthroscopy” reports the results of a piece of work in which the function of the ligament in restraining rotation of the hip was studied in cadaveric specimens. Specifically, the aim of the study was to assess the function of the ligamentum teres in restraining rotation of the hip in 18 different positions of the joint while the ligaments of the joint capsule were preserved. Twelve hips from six cadaveric specimens were used, in which only the ligaments of the hip were preserved. These joints were arthroscoped through a portal located between the pubofemoral and the iliofemoral ligament, so as to confirm the integrity of the ligamentum teres. Three independent measurements were made of the hip, of the range of motion in internal and external rotation in 18 defined positions of the joint and with combinations of extension-flexion and abduction-adduction. The ligamentum teres was then divided and the same measurements were repeated in the same positions. Statistical analysis of the measurements followed. The results report a statistically significant influence of the ligamentum teres on internal and external rotation in eight of the 18 positions of the hip. The greatest increases in internal and external rotation occurred when the hip was in 90 or 120 degrees of flexion.
The authors of the study concluded that the principal function of the ligamentum teres in the hip is to control rotational movement. The ligamentum teres acts as a stabiliser at the end range of hip rotation, chiefly at 90 degrees of flexion or more. This study confirms the contribution of the ligamentum teres to the stability of the hip.