title: A biomechanical basis for tears of the human acetabular labrum.
abstract: 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, hypolaxity 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.
  
  
  METHODS
  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. Semiconfined compressive testing and tensile testing were performed at a displacement rate of 10 mm/min in a controlled environment of 100% humidity at 37 (SD 1) degrees C.
  
  
  METHODS
  Cadaveric study.
  
  
  RESULTS
  The mean compressive stiffness was 31.75 (SD 16.7) MPa, and the mean tensile elastic modulus was 24.7 (SD 10.8) MPa. 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.
authors.affiliation: Department of Bioengineering, Imperial College London, Royal School of Mines, South Kensington Campus, London, UK. drcs1@doctors.net.uk
authors.forename: C D
authors.initials: CD
authors.lastname: Smith
authors.forename: S
authors.initials: S
authors.lastname: Masouros
authors.forename: A M
authors.initials: AM
authors.lastname: Hill
authors.forename: A A
authors.initials: AA
authors.lastname: Amis
authors.forename: A M J
authors.initials: AM
authors.lastname: Bull
mesh_terms: D000077:Acetabulum / Q000293:injuries*; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D002358:Cartilage, Articular / Q000293:injuries*; D055119:Elastic Modulus; D025981:Hip Injuries / Q000209:etiology*; D006801:Humans; D012421:Rupture; D013718:Tensile Strength / Q000502:physiology