Abstract:
The acetabular labrum, a fibrocartilaginous ring around the acetabulum, is frequently implicated in hip pain and labral tears, suggesting it may be subjected to injurious loading in vivo. However, its precise biomechanical role in load transfer across the hip joint during daily activities has remained unclear. This study addresses this critical gap by meticulously examining the contribution of the acetabular labrum to load support in hips with both normal acetabular geometry and acetabular dysplasia, utilizing subject-specific finite element analysis (FEA).
The methodology involved generating detailed finite element models from volumetric computed tomography (CT) data of subjects with normal and dysplastic hips. These models were then analyzed under simulated activities of daily living, both with and without the presence of the labrum, to isolate its specific biomechanical contribution. The study specifically investigated how the labrum affected cartilage contact area and load distribution within the joint. Furthermore, the sensitivity of the labrum's load support to variations in cartilage-labrum boundary conditions and different constitutive models (representing material properties) was assessed to ensure the robustness of the biomechanical predictions.
The results demonstrated that the acetabular labrum plays a significant biomechanical role in load support across the hip joint, even in normal hips, by increasing the effective contact area and improving load distribution, thereby reducing peak cartilage stresses. In dysplastic hips, where stability is often compromised, the labrum's contribution to load support was even more pronounced, with its absence leading to substantial increases in cartilage stress and, in some cases, joint instability or dislocation. This biomechanical investigation provides compelling evidence for the labrum's crucial function in maintaining hip joint integrity and highlights its vulnerability to injury when its load-bearing capacity is exceeded. The findings have profound implications for understanding the etiology of labral tears and hip osteoarthritis, as well as for guiding surgical interventions aimed at preserving or restoring labral function to optimize hip biomechanics.
