Tensile properties of the inferior glenohumeral ligament

Abstract

Summary:The tensile properties of the inferior glenohumeral ligament have been determined in 16 freshly frozen cadaver shoulders. The inferior glenohumeral ligament was divided into three anatomical regions: a superior band, an anterior axillary pouch, and a posterior axillary pouch. This yielded 48 hone-ligament-bone specimens; which were tested to failure in uniaxial tension. The superior hand was consistently the thickest region, averaging 2.79 mm. The thickness of the inferior glenohumeral ligament decreased from antero-superiorly to postero-inferiorly. The resting length of all three anatomical regions was not statistically different. Total specimen strain to hilure for all bone-ligament-bone specimens averaged 27%. Variations occurred between the three regions, with the anterior pouch specimens failing at a higher strain (34%) thar, those from the superior band (24%) or the posterior pouch (23%). Strain to failure for the ligament midsubstance (11%) was found to be significantly less than that for the entire specimen (27%). Thus, larger strain must occur near the insertion sites of the inferior glenohumeral ligament. Stress at failure was found to be nearly identical for the three regions of the ligament, averaging 5.5 MPa. These values are lower than those reported for other soft tissues, such as the anterior cruciate ligament and patellar tendon. The anterior pouch was found to be less stiff than the other two regions, perhaps suggesting that it is composed of more highly crimped collagen fibers. Three failure sites were seen for the inferior glenohumeral ligament: the glenoid insertion (40%), the ligament substance (35%). and the humeral insertion (25%). In addition, significant capsular stretching occurred before failure, regardless of the failure mode. Key Words: Ligament-Biomechanics-Inferior glenohumeral ligament-Material testing-Instability-Shoulder.Recurrent anterior glenohumeral instability (dislocation or subluxation) is a common clinical problem that can often lead to significant disability. Maintaining glenohumeral stability is a complex phenomenon that depends on the interaction of dynamic muscular forces and static capsulo-ligamentous restraints. Many investigators have at-

The material properties of the bovine acetabular labrum

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“…The rate of change of the modulus is measured by the exponential parameter B. Typical of a tissue whose properties are heavily influenced by its fibrous structure, the modulus of the labrum increases rapidly with increasing strain, with the value of this parameter B greater on average than, for example, that reported for the fibrous glenohumeral ligament [3]. The modulus calculated for the near-linear portion of the stress-strain curve, 7,4.7&44.3 MPa on average, was similar to that reported for the bovine and human meniscus [ 10,2 1,30,32] and, as previously noted, much higher than that of the adjoining articular cartilage.…”

Sub-10-micrometer toughening and crack tip toughness of dental enamel

“…An up to 10µm long zone means that multiple crystallite nanofibers or even multiple enamel rods are included in the inelastic process and the bridging stress is not only caused by protein bridging alone. Experimental studies showed that the ultimate stress of proteins such as ligaments (mainly collagen), tendon (mainly collagen) and horn (mainly keratin) are 2.5-7MPa, 70MPa and 260MPa respectively (Sikoryn and Hukins, 1990;Bigliana et al, 1992, Meyers et al, 2008Druhala and Feughelman, 1974) and are generally lower than the calculated 163-770MPa Secondly, the stress intensity shielding contributed by the protein bridging can be estimated by using a Dugdale-zone model, K p =2*σ p *f p *(2*l p /π) 0.5 with K p the stress intensity due to protein bridging, σ p =2.5-260MPa the yield strength of protein, f p =0.1 the area fraction of protein bridging ligaments (estimated based on the volume fraction of protein in enamel), l p =1-10µm the protein bridging zone length (Evans and McMeeking, 1986). K p is calculated as 0-0.13MPa.m 0.5 and is much smaller than the crack tip toughness.…”

Multidirectional kinematics of the glenohumeral joint during simulated simple translation tests: Impact on clinical diagnoses

“…These studies have investigated the mechanical properties, [3,26,39] collagen fiber S M . Moore et al / Journal of Orthopardre Researth 22 (2004) 8891394 orientation, [6,9,27] composition, [32] in situ forces, [7] and strains [18,19] of the capsular regions, thus providing the baseline data required for experimental and analytical models of the intact and injured joint.…”