Comparing Hip Contact Pressures Between Acetabulum Labral Repair vs. Total Labral Reconstruction

Abstract

To biomechanically compare the contact area, contact pressures, and peak forces of primary labral repair versus labral reconstruction. A cadaveric study was performed using 8 frozen hemi-pelvises with cam-type deformities (alpha angle >55°) with an intact labrum. Intraarticular pressure maps were produced for each specimen under the following conditions: 1) intact labrum, 2) labral repair, and 3) labral reconstruction using iliotibial band (ITB) allograft. Specimens were examined at neutral, 20° of extension and 60° of flexion to simulate the complete arc of the natural hip range of motion during normal gait on a level surface and during stair climbing. Each specimen was placed in a custom-designed jig in the MTS electromechanical test system to create pressure and area map measurements. In each condition, contact pressure, contact area, and peak force within a region-of-interest (ROI) were obtained. Repeated measures ANOVA was used to identify differences in biomechanical parameters among the three conditions with post-hoc analysis using pairwise comparison with Bonferroni correction to analyze the differences within each condition. Analysis of contact pressures between labral repair and labral reconstruction were normalized to the pressures measured in the intact labrum. Repeated measures ANOVA for contact area in neutral, extension, and flexion demonstrated statistically significant differences between study states (p<0.05). Post-hoc analysis for each consistently demonstrated significantly larger contact areas measured in labral repair specimens compared labral reconstruction specimens. In addition, paired-T test analysis demonstrated significantly higher contact areas (33.3+-7.9 vs 27.4+-6.9; p=0.009) and significantly lower contact pressures (2.5+-0.3 vs 2.7+-0.4; p=0.038) in labral repair specimens compared to labral reconstruction specimens. Finally, there was no statistically significant difference in peak forces measured between specimens (p<0.05 for all). Primary labral repair may result in lower intra-articular hip contact pressures and higher contact area compared to primary complete labral reconstruction.