title: Tensile properties of the human acetabular labrum and hip labral reconstruction grafts.
abstract: BACKGROUND
  In cases where the acetabular labrum is severely damaged and irreparable, labral reconstructions are becoming an increasingly preferred means of preserving the fluid seal effect of the labrum. However, the graft that most closely replicates the biomechanical properties of the native labrum remains undetermined.
  
  
  OBJECTIVE
  To characterize the tensile properties and geometry of the labrum, as well as iliotibial band, semitendinosus, gracilis, and anterior tibialis grafts.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Five graft groups--(1) acetabular labrum, (2) iliotibial band, (3) semitendinosus, (4) gracilis, and (5) anterior tibialis--with 8 specimens per group were tested. Grafts were tested using a materials testing system in response to a stepwise sinusoidal cyclic loading protocol. Uniaxial tensile loads were initially applied from 20 to 50 N for 100 cycles at 0.5 Hz, followed by incremental increases of 50 N in the upper force every 100 cycles until failure or successful completion of 100 cycles at 300 N. This protocol was designed to be representative of progressive loading experienced during rehabilitation. Cyclic displacement was recorded after 100 (50 N), 200 (100 N), 300 (150 N), 400 (200 N), 500 (250 N), and 600 (300 N) cycles.
  
  
  RESULTS
  The mean elongation (95% CI) after 100 cycles from 20 to 50 N was similar for all groups: acetabular labrum, 0.68 mm (0.57-0.78 mm); iliotibial band, 0.68 mm (0.47-0.89 mm); semitendinosus, 0.68 mm (0.51-0.84 mm); gracilis, 0.62 mm (0.46-0.79 mm); and anterior tibialis, 0.66 mm (0.58-0.73 mm). After 100 cycles from 20 to 300 N (600 cycles total), the mean elongation of the labrum was 4.53 mm (3.71-5.35 mm), and the mean elongations of the iliotibial band, semitendinosus, gracilis, and anterior tibialis were 4.65 mm (3.23-6.07 mm), 4.41 mm (3.45-5.36 mm), 5.12 mm (3.09-7.16 mm), and 5.33 mm (4.40-6.25 mm), respectively.
  
  
  CONCLUSIONS
  All tested grafts and the acetabular labrum exhibited similar cyclic elongation behavior in response to simulated physiologic forces. In addition, differences in variability in both elongation and geometry existed for all graft types.
  
  
  CONCLUSIONS
  All tested grafts can be considered viable acetabular labrum reconstruction graft options.
authors: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors: Fernando P
authors: FP
authors: Ferro
authors: Steadman Philippon Research Institute, Vail, Colorado, USA The Steadman Clinic, Vail, Colorado, USA mjp@sprivail.org.
authors: Marc J
authors: MJ
authors: Philippon
authors: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors: Matthew T
authors: MT
authors: Rasmussen
authors: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors: Sean D
authors: SD
authors: Smith
authors: Steadman Philippon Research Institute, Vail, Colorado, USA The Steadman Clinic, Vail, Colorado, USA.
authors: Robert F
authors: RF
authors: LaPrade
authors: Steadman Philippon Research Institute, Vail, Colorado, USA.
authors: Coen A
authors: CA
authors: Wijdicks
mesh_terms: D000077:Acetabulum / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D002102:Cadaver; D002358:Cartilage, Articular / Q000502:physiology* / Q000601:surgery; D006621:Hip Joint / Q000502:physiology* / Q000601:surgery; D006801:Humans; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000502:physiology / Q000601:surgery; D019651:Plastic Surgery Procedures / Q000379:methods*; D019737:Transplants; D055815:Young Adult
keywords: biomechanics of tendon; hip arthroscopy; hip labral reconstruction; hip labrum