The material properties of the bovine acetabular labrum

Abstract

The compressive and tensile material properties of the bovine acetabular labrum were measured. Confined compression testing was used to determine the aggregate compressive modulus and the permeability of the labrum. The compressive modulus of the labrum (0.157 & 0.057 MPa) is comparable to that of the morphologically similar meniscus, and approximately one-quarter to onehalf that of the adjoining acetabular cartilage. The permeability of the labrum (4.98 =k 3.43 x m'/N s) was lower than that of the meniscus and cartilage, with a significantly higher resistance to interstitial fluid flow across the acetabular rim than along the rim. Specimens from the posterior and superior regions of the labrum were tested to failure in uniaxial tension. The maximum stress at failure ( I I .9 i 6.1 MPa), maximuni strain at failure (26.5 i 7.6%) and tangent modulus (74.7 * 44.3 MPa) were similar to those reported for the bovine meniscus, and to other tissues composed of highly oriented collagen fiber bundles. In tension, the labrum is much stiffer (10-1 5x) than the adjoining articular cartilage, and the posterior region of the labrum is significantly stiffer (45'%) than the superior region. The labrum's low permeability may contribute to sealing of the hip joint. The high circumferential tensile stiffness of the labrum, together with its ring structure, reinforce the acetabular rim and may contribute to joint stability.

Labral Reconstruction Using the Ligamentum Teres Capitis: Report of a New Technique

“…Ferguson et al [10], in their studies on the material properties of the bovine acetabular labrum, demonstrated that the labrum's low permeability compared to the adjoining acetabular cartilage contributes to the sealing property attributed to the structure. They demonstrated that because of its high circumferential cell stiffness, the labrum also functions as a stabilizer of the joint.…”

“…There are new biomechanical data suggesting the effect of the labrum on hip stability [5,[7][8][9][10]23]. One clinical study [5] also suggests the importance of preserving and refixing the labrum on the outcomes of impingement surgery.…”

The effects of impingement and dysplasia on stress distributions in the hip joint during sitting and walking: A finite element analysis

“…15 The material properties of labral tissue were extracted from the toe region of tensile tests and set to be E ¼ 20 MPa, and u ¼ 0.4. 16 A surface-based, finite sliding contact was defined between the femoral cartilage, as master surface, and acetabular cartilage and labrum as slave surfaces, with an assumed frictionless interaction. The bony structures of the acetabulum and femur were modeled as rigid bodies, as pilot analyses showed no differences in predicted cartilage stresses for models with rigid and elastic bone structures.…”

Regenerative Injection Therapy (Prolotherapy) for Hip Labrum Lesions: Rationale and Retrospective Study

“…Since the labrum increases acetabular coverage by 28 percent [22] and has biomechanical properties comparable to the meniscus [23], it may serve to enhance joint stability. A stabilizing role is supported by cadaveric studies [24,25].…”