In situ compressive properties of the glenoid labrum

The purpose of this study was to measure the structural stiffness (load/dis placement response) and elastic modulus (stress-strain response) of the gle noid labrum at different locations throughout the tissue. It was intended t hat the results of this work would serve to define the properties of the la brum. This in turn may permit a better understanding of labral function and of the mechanics of injury or degeneration and may ultimately contribute t o improving the design of future labral reconstruction procedures. In addit ion, these data may allow incorporation of labral proper ties into a glenoi d arthroplasty component. The testing procedure consisted of rapid compress ion of the labrum using a flat indentor. Stiffness and modulus results demo nstrated differences between the superior and inferior portions of the labr um. The elastic moduli findings for the labrum were 0.18 +/- 0.17, 0.11 +/- 0.16, and 0.23 +/- 0.20 MPa for the inferior anterior, inferior, and infer ior posterior sections, respectively. The superior anterior, superior, and superior posterior sections were respectively 0.19 +/- 0.09, 0.32 +/- 0.22, and 0.41 +/- 0.32 MPa. These results are similar to those of knee menisci. The modulus findings for the substrate cartilage were 1.92 +/- 0.78, 1.99 +/- 0.70, and 2.00 +/- 1.33 MPa for the inferior anterior, inferior, and in ferior posterior sections, respectively. The superior anterior, superior, a nd superior posterior sections were respectively 1.60 +/- 0.79, 1.29 +/- 0. 75, and 1.42 +/- 0.54 MPa, which are comparable to previous cartilage findi ngs. (C) 2000 John Wiley & Sons, Inc.