ePoster #302 - ISHA Annual Scientific Meeting 2016

The Role Of The Ligamentum Teres In Stabilizing A Hip With An Intact Capsule: A Cadaveric Study

Suenghwan Jo, MD, PhD, Gwangju SOUTH KOREA
Alex Hooke, BA, Rochester, MN UNITED STATES
Kai-Nan An, phD, Rochester, MN UNITED STATES
Rafael J. Sierra, MD, Rochester, MN UNITED STATES
Robert Trousdale

Mayo Clinic, Rochester, MN, UNITED STATES

FDA Status Not Applicable

Summary: In the hip with intact capsule, LT injury can result in additional range of motion but its contribution on stability is questionable.

Background : The function of ligamentum teres (LT) remains controversial but literatures suggest that it may serve as a hip stabilizer. The purpose of this study is to determine the contribution of LT on hip biomechanics in the presence of capsule with special interest in change in range of motion (ROM) and in femoral head translation.
Hypothesis : The stability function of LT with an intact capsule will be negligible and may be a secondary stabilizer in limited hip positions.
Study design : Controlled laboratory study
Methods: Seven fresh-frozen cadaveric pelvises were utilized in the study with use of electromagnetic motion tracking sensor. The capsule was left intact for all test conditions. Following visual inspection of the LT at different hip positions, internal rotation angles were measured at 10° of extension and at 0° of flexion while external rotation was measured at 60°, 90° and 110° of flexion with different hip abduction angles. The tests were repeated after resection of LT. The results were compared between intact and LT resected conditions when torque of 2Nm and of 4Nm was applied.

Result: Compared to the intact hip, LT resected hip showed no significant difference when 2Nm torque was applied in all scenarios. With 4Nm torque application, significant increase in external rotation was found at 60° and at 90° of flexion (1.7±0.8° and 2.1±1.0° respectively). Significant difference was also noted at 60°, 90°, 110° of flexion when hip was in the adducted position while at 60° in abducted hip. However, LT resection did not show significant change in internal rotation. The mean translation distance ranged from 0.77 to 1.11 mm in the intact hip and 0.79 to 1.29 mm in the LT resected hip with 4Nm torque but the difference between the two groups were not significant.

Conclusion : Our results indicate that the LT can limit external rotation when the hip is in the flexed position but does not contribute to translation stability.