Relation of native acetabular anteversion to the orientation of transverse acetabular ligament.

Background: Precise positioning of the acetabular component during total hip replacement is the key to achieving optimal implant function and ensuring long-term patient comfort. However, different anatomical variations, degenerative changes, dysplasia, and other diseases make it difficult. In this study, we discuss a method based on the three-dimensional direction of the transverse ligament, predicting native acetabular anteversion with higher accuracy.

Methods: Angular positions of the acetabulum and direction of the transverse ligament were automatically calculated from routine computed tomography data of 270 patients using a registration algorithm. The relationship between acetabular angles and ligament direction and their relationship with sex, age, and pelvic tilt were sought. These relationships were then modelled using multilinear regression.

Results: Including the direction of the transverse ligament in the sagittal and transverse planes as a regressor in the multilinear model explained the variation in acetabular anteversion (R = 0.76 for men, R = 0.63 for women; standard deviation in prediction: men, 3.92° and women, 4.00°).

Conclusions: The results indicate that the ligament was suitable as a guidance structure almost insensitive to the ligament in the sagittal and transverse planes must be considered. Estimation based on the direction in only 1 plane was not sufficiently accurate. The operative acetabular inclination was not correlated with the direction of the ligament. The correlations were higher in men than in women.