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

Abstract

Purpose: To evaluate cadaveric hip biomechanics in the intact, torn, and repaired labral states.

Methods: 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.

Results: 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.

Conclusions: 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.

Clinical relevance: Restoration of labral integrity may re-establish native biomechanics, supporting improved joint function after repair.