Repair of Labral Tears in a Cadaveric Model Normalizes Acetabular Contact Pressure Distribution and Restores Dynamic Hip Motion.

Abstract

To evaluate cadaveric hip biomechanics in the intact, torn, and repaired labral states. Eight fresh-frozen cadaveric hips underwent 250 N of axial load on a material testing load frame. Contact pressures and areas were measured with a Tekscan sensor inserted into the acetabular wall. Measurements were divided into anterior (3 o'clock), superior (1 o'clock), and posterior (9 o'clock) acetabular regions. A motion capture system tracked the 3-dimensional hip motion. Peak contact stress, contact area, and dynamic motion were compared across conditions: (1) intact, (2) simulated labral tear from 11 to 2 o'clock, and (3) labral repair with 5 suture anchors, using repeated measures 2-factor analysis of variance. Labral condition significantly influenced joint mechanics. Tears increased superior peak contact stress by 27%, whereas repair reduced it by 45% compared with intact (P < .05). The total contact area decreased by 21% with tear and was restored within 10% of intact values after repair. Regional differences were also observed, with superior contact area increasing from 42% to 53% of the total contact area after tear (P = .03) and decreasing to 46% after repair. Dynamic analysis showed a 20% decrease in relative abduction with tear (0.96° vs 1.20°), which returned to 98% of intact (1.17°) after repair. Labral tears result in a proportional increase in contact pressure distribution and contact area in the superior acetabulum, correlating with a decreased femoral head abduction moment under a simulated axial load. Labral repair normalizes these biomechanics toward the intact state, which may more evenly distribute force across the acetabulum and restore dynamic hip motion. Restoration of labral integrity may re-establish native biomechanics, supporting improved joint function after repair.