Quantitative Anatomic Analysis of the Native Ligamentum Teres

BACKGROUND While recent studies have addressed the biomechanical function of the ligamentum teres and provided descriptions of ligamentum teres reconstruction techniques, its detailed quantitative anatomy remains relatively undocumented. Moreover, there is a lack of consensus in the literature regarding the number and morphology of the acetabular attachments of the ligamentum teres. PURPOSE To provide a clinically relevant quantitative anatomic description of the native human ligamentum teres. STUDY DESIGN Descriptive laboratory study. METHODS Ten human cadaveric hemipelvises, complete with femurs (mean age, 59.6 years; range, 47-65 years), were dissected free of all extra-articular soft tissues to isolate the ligamentum teres and its attachments. A coordinate measuring device was used to quantify the attachment areas and their relationships to pertinent open and arthroscopic landmarks on both the acetabulum and the femur. The clock face reference system was utilized to describe acetabular anatomy, and all anatomic relationships were described using the mean and 95% confidence intervals. RESULTS There were 6 distinct attachments to the acetabulum and 1 to the femur. The areas of the acetabular and femoral attachment footprints of the ligamentum teres were 434 mm2 (95% CI, 320-549 mm2) and 84 mm2 (95% CI, 65-104 mm2), respectively. The 6 acetabular clock face locations were as follows: anterior attachment, 4:53 o'clock (95% CI, 4:45-5:02); posterior attachment, 6:33 o'clock (95% CI, 6:23-6:43); ischial attachment, 8:07 o'clock (95% CI, 7:47-8:26); iliac attachment, 1:49 o'clock (95% CI, 1:04-2:34); and a smaller pubic attachment that was located at 3:50 o'clock (95% CI, 3:41-4:00). The ischial attachment possessed the largest cross-sectional attachment area (127.3 mm2; 95% CI, 103.0-151.7 mm2) of all the acetabular attachments of the ligamentum teres. CONCLUSION The most important finding of this study was that the human ligamentum teres had 6 distinct points of attachment on the acetabulum (transverse, anterior, and posterior margins of the acetabular notch and cotyloid fossa attachments: ilium, ischium, and pubis) and 1 on the femur. On the acetabulum, the anterior attachment was substantially larger than the posterior attachment and was located at a mean clock face position of 4:53 o'clock. CLINICAL RELEVANCE These quantitative descriptions of the ligamentum teres can be used by clinicians to arthroscopically identify the attachments of the ligamentum teres, guiding arthroscopic surgical interventions designed to address ligamentum teres pathology.