title: Labral reconstruction with iliotibial band autografts and semitendinosus allografts improves hip joint contact area and contact pressure: an in vitro analysis.
abstract: BACKGROUND
  Labral reconstruction using iliotibial band (ITB) autografts and semitendinosus (Semi-T) allografts has recently been described in cases of labral deficiency.
  
  
  OBJECTIVE
  To characterize the joint biomechanics with a labrum-intact, labrum-deficient, and labrum-reconstructed acetabulum in a hip cadaveric model. The hypothesis was that labral resection would decrease contact area, increase contact pressure, and increase peak force, while subsequent labral reconstruction with ITB autografts or Semi-T allografts would restore these values toward the native intact labral state.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  Ten fresh-frozen human cadaveric hips were analyzed utilizing thin-film piezoresistive load sensors to measure contact area, contact pressure, and peak force (1) with the native intact labrum, (2) after segmental labral resection, and (3) after graft labral reconstruction with either ITB autografts or Semi-T allografts. Each specimen was examined at 20° of extension and 60° of flexion. Statistical analysis was conducted through 1-way analysis of variance with post hoc Games-Howell tests.
  
  
  RESULTS
  For the ITB group, labral resection significantly decreased contact area (at 20°: 73.2%±5.38%, P=.0010; at 60°: 78.5%±6.93%, P=.0063) and increased contact pressure (at 20°: 106.7%±4.15%, P=.0387; at 60°: 103.9%±1.15%, P=.0428). In addition, ITB reconstruction improved contact area (at 20°: 87.2%±12.3%, P=.0130; at 60°: 90.5%±8.81%, P=.0079) and contact pressure (at 20°: 98.5%±5.71%, P=.0476; at 60°: 96.6%±1.13%, P=.0056) from the resected state. Contact pressure at 60° of flexion was significantly lower compared with the native labrum (P=.0420). For the Semi-T group, labral resection significantly decreased contact area (at 20°: 68.1%±12.57%, P=.0002; at 60°: 67.5%±6.70%, P=.0002) and increased contact pressure (at 20°: 105.3%±3.73%, P=.0304; at 60°: 106.8%±4.04%, P=.0231). Semi-T reconstruction improved contact area (at 20°: 87.9%±7.95%, P=.0087; at 60°: 92.9%±13.2%, P=.0014) and contact pressure (at 20°: 97.1%±3.18%, P=.0017; at 60°: 97.4%±4.39%, P=.0027) from the resected state. Comparative analysis demonstrated no statistically significant differences between either graft reconstruction in relation to contact area, contact pressure, or peak force.
  
  
  CONCLUSIONS
  Segmental anterosuperior labral resection results in significantly decreased contact areas and increased contact pressures, while labral reconstruction partially restores time-zero acetabular contact areas and pressures as compared with the resected state. Although labral reconstruction improved the measured biomechanical properties as compared with the resected state, some of these properties remained significantly different compared with the native intact labrum.
  
  
  CONCLUSIONS
  Labral reconstruction appears to improve femoroacetabular joint biomechanics as compared with the labrum-resected state; these improved biomechanics may translate into increased joint function clinically.
authors.affiliation: Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Lee
authors.affiliation: Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Thomas H
authors.initials: TH
authors.lastname: Wuerz
authors.affiliation: Rush University Medical Center, Chicago, Illinois, USA.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Shewman
authors.affiliation: Holy Cross Orthopedic Institute, Ft Lauderdale, Florida, USA.
authors.forename: Frank M
authors.initials: FM
authors.lastname: McCormick
authors.affiliation: Case Western University, Cleveland, Ohio, USA.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Salata
authors.affiliation: The Steadman Clinic and Steadman Philippon Research Institute, Vail, Colorado, USA.
authors.forename: Marc J
authors.initials: MJ
authors.lastname: Philippon
authors.affiliation: Rush University Medical Center, Chicago, Illinois, USA Shane.nho@rushortho.com.
authors.forename: Shane J
authors.initials: SJ
authors.lastname: Nho
mesh_terms: D065526:Acetabuloplasty / Q000379:methods*; D000077:Acetabulum / Q000601:surgery*; D000328:Adult; D064591:Allografts; D001182:Arthroscopy; D064592:Autografts; D001696:Biomechanical Phenomena; D002102:Cadaver; D005206:Fascia Lata / Q000637:transplantation*; D005260:Female; D006621:Hip Joint / Q000601:surgery*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D011312:Pressure; D016059:Range of Motion, Articular; D013710:Tendons / Q000637:transplantation*
keywords: biomechanics; femoroacetabular impingement; hip; hip arthroscopic surgery