title: The Transverse Acetabular Ligament as an Intraoperative Guide to Cup Abduction.
abstract: The success of a total hip arthroplasty relies on optimal acetabular cup placement to ensure mating of the femoral head and acetabular cup throughout all positions of the hip joint. Poor cup placement is associated with dislocation, impingement, microseparation, component loosening, and accelerated wear due to rim loading. This study examined a novel method of using the transverse acetabular ligament (TAL) to guide cup inclination during primary total hip arthroplasty.
  
  
  
  A descriptive study using 16 hips from 9 cadavers. A computer navigation system measured inclination and version of the acetabular component in 3 positions with the lower edge of cup: (1) flush with, (2) 5 mm proximal to, and (3) 5 mm distal to free border of the TAL.
  
  
  
  The median inclination angles were 44° in position (1), 30° in position (2), and 64° in position (3). The median anteversion angle for all positions was 19°.
  
  
  
  Cup inclination was acceptable when the lower edge of the cup was flush or within 5 mm proximal to the TAL.
authors.affiliation: Department of Orthopedic Surgery, University of the Free State, Universitas Academic Hospital, Bloemfontein, South Africa.
authors.forename: Willem B
authors.initials: WB
authors.lastname: Hiddema
authors.affiliation: Department of Orthopedic Surgery, University of the Free State, Universitas Academic Hospital, Bloemfontein, South Africa.
authors.forename: Johan F
authors.initials: JF
authors.lastname: van der Merwe
authors.affiliation: Mediclinic Bloemfontein, Bloemfontein, South Africa.
authors.forename: Werner
authors.initials: W
authors.lastname: van der Merwe
mesh_terms: D000077:Acetabulum / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation* / Q000379:methods; D002102:Cadaver; D005260:Female; D005270:Femur Head / Q000601:surgery*; D006615:Hip / Q000601:surgery*; D006621:Hip Joint / Q000601:surgery; D006622:Hip Prosthesis; D006801:Humans; D004204:Joint Dislocations; D008023:Ligaments, Articular / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results
keywords: abduction angle; cup inclination; cup orientation; primary total hip arthroplasty; transverse acetabular ligament