Objective: Acetabular labral tears predominantly affect young patients and are a source of hip pain in the athlete. Four causes of the initiation of labral tears have been proposed; trauma, hypo-laxity of the anterior capsule, dysplasia and bony impingement. A further cause could be reduced biomechanical properties in the area most susceptible to tears. However, no work has defined these properties.
Design: 32 compressive and 32 tensile test samples were harvested from fresh frozen cadaveric acetabula. The labrum was divided into eight areas to allow comparison around its circumference. Semi-confined compressive testing and tensile testing was performed at a displacement rate of 10 mm/min in a controlled environment of 100% humidity at 37±1ºC.
Setting: Cadaveric study
Results: The mean compressive stiffness was 31.75 MPa (S.D. 16.7) and mean tensile elastic modulus was 24.7 MPa (S.D.±10.8). The anterosuperior region had a significantly lower compressive elastic modulus than either of the posterior quadrants (p<0.05) and a significantly lower tensile modulus to the anterioinferior area (p<0.05).
Conclusions: The biomechanical properties in the anterosuperior region may be a contributing factor to the initiation of labral tears.