The Effect of Rim Preparation, Labral Augmentation, and Labral Reconstruction on the Suction Seal of the Hip.

PURPOSE

To evaluate the biomechanical properties of the labral suction seal in the native labrum and after rim preparation, labral augmentation, and labral reconstruction.

METHODS

Eight hemi-pelvises were dissected to the level of labrum and mounted for biomechanical testing. Each specimen was tested in axial distraction starting with the native labrum and then sequentially following rim preparation from 12 to 3 o'clock, labral augmentation, and segmental labral reconstruction using the iliotibial band allograft. In each condition, the specimens were compressed to 250 N and then distracted at 10 mm/s with force and displacement continuously recorded. Each test was repeated 3 times, and the mean peak force, displacement at peak force, and work were calculated. Data were reported as a percentage of the intact values to account for sex and size differences. Statistical testing was performed via a repeated-measures analysis of variance with a post hoc Tukey analysis.

RESULTS

Peak loads occurred within 2.21 to 3.11 mm of displacement. The mean peak force, displacement at peak force, and work relative to the intact condition were the following: rim preparation (91.1% ± 8.5%, 94.4% ± 14.3%, 93.4% ± 23.5%, respectively), augmentation (66.1% ± 27.6%, 78.2% ± 16.3%, 55.7% ± 30.7%, respectively), and reconstruction (55.6% ± 25.7%, 64.7% ± 31.4%, 38.7% ± 27.2%, respectively). There was no significant difference in peak force following the rim preparation (P = .807), but peak force was significantly decreased after augmentation and reconstruction (P = .010 and P < .001, respectively). There was no significant difference in displacement at peak force following rim preparation or augmentation (P = .936 and P = .125, respectively), but displacement at peak force was significantly decreased after reconstruction (P = .005). The work from the suction seal was significantly less in both augmentation and reconstruction states compared to the intact labrum (P = .004 and P < .001, respectively) and rim preparation (P = .017 and P < .001, respectively).

CONCLUSIONS

The results show that the suction seal is not significantly changed following rim preparation. Relative to the rim preparation, labral augmentation may re-create the labral suction seal better than labral reconstruction.

CLINICAL RELEVANCE

This study provides a biomechanical basis for surgical decision making and clinical management of patients with labral tears of the hip.