title: In vitro investigation of the influence of pelvic tilt on acetabular cup alignment.
abstract: This study investigates the influence of pelvic tilt on conventional alignment of acetabular cups. Cementless cups were aligned into a synthetic replica of the pelvis 300 times at different pelvic tilts. At +10 degrees pelvic tilt, average cup inclination was 46.2 degrees (32 degrees to 65 degrees ; +/-7.0 degrees ), and average cup anteversion was 19.8 degrees (4 degrees to 37 degrees ; +/-9.1 degrees ). At neutral pelvic tilt, inclination was 44.5 degrees (28 degrees to 59 degrees ; +/-7.2 degrees ), and anteversion was 15.6 degrees (-5 degrees to 33 degrees ; +/-8.1 degrees ). At -10 degrees pelvic tilt, inclination was 42.6 degrees (25 degrees to 61 degrees ; +/-7.2 degrees ), and anteversion was 10.5 degrees (-10 degrees to 37 degrees ; +/-12.2 degrees ). Overall, 50% of the cups were positioned outside the safe zone: 46% in pelvic inclination, 42% in neutral position, and 63% in pelvic reclination (P = .007). This study shows the considerable inaccuracies of conventional cup implantation by experienced and trainee surgeons and shows the influence of pelvic tilt on acetabular cup alignment.
authors.affiliation: Department of Orthopaedic Surgery, Regensburg University Medical Center, Regensburg, Germany.
authors.forename: Thomas Andreas
authors.initials: TA
authors.lastname: Kalteis
authors.forename: Martin
authors.initials: M
authors.lastname: Handel
authors.forename: Boris
authors.initials: B
authors.lastname: Herbst
authors.forename: Joachim
authors.initials: J
authors.lastname: Grifka
authors.forename: Tobias
authors.initials: T
authors.lastname: Renkawitz
mesh_terms: D000077:Acetabulum / Q000033:anatomy & histology*; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D006622:Hip Prosthesis; D006801:Humans; D066298:In Vitro Techniques; D008954:Models, Biological; D010384:Pelvic Bones / Q000033:anatomy & histology*; D017755:Prosthesis Fitting