Anatomical And Digital Study Of Transverse Acetabular Ligament For Anterior Tilting Of Acetabular Prosthesis

Objective: To determine the value of transverse acetabular ligament in locating anterior obliquity of acetabular prosthesis in total hip arthroplasty.Methods: Anatomy descriptive study of transverse acetabular ligament was performed on fresh hip specimen to determine its walking line and its starting and ending point.The transverse acetabular ligament anterior anatomic inclination was measured in pelvic specimen and CT-based digital reconstructed pelvis.Results: The transverse acetabular ligament bridged the acetabular notch to form a complete circle.When the highest point of acetabular was defined as 12 points,take the left side as an example,the transverse ligament of acetabular was approximately between 6 and 9 points.The thickness of the upper part of the transverse acetabular ligament is slightly thicker than that of the anterior and lower part.The surface is covered by synovial membrane,the medial part is inclined downward,covering the femoral head cartilage and connecting with the acetabular pelvic lip.The medial portion of the transverse ligament of the acetabulum covers the fat in the acetabulum and is attached to the synovial tube that encloses the ligaments of the femoral head and the lateral to the hip capsule.The average anterior inclination of the transverse acetabular ligament was(12.8±3.5)°.The anterior inclination of the transverse acetabular ligament of three hips(7.1%)was outside the safety zone defined by Lewinnek(15±10)°;the average anterior inclination of the acetabulum was(17.8±4.0)°.There was a significant correlation between the anterior inclination of the transverse acetabular ligament and the anterior inclination of the acetabular(r=0.763,P<0.01).Conclusion:.In hip joints with normal acetabular morphology,the anterolateral ligament of the acetabulum is not exactly consistent with the anteroposterior walking of the acetabulum,but there is a significant correlation between the two,so the transverse ligament of the acetabulum can be used as an anatomical marker to locate the anterior dip of the acetabulum cup in total hip arthroplasty.It is worth noting that there is still a part of the transverse acetabular ligament tilted forward outside the safety zone,and the transverse acetabular ligament should be used with caution for the lack of a forward or acetabular dip.