title: Is There a Gender-Specific Full Body Sagittal Profile for Different Spinopelvic Relationships? A Study on Propensity-Matched Cohorts.
abstract: Retrospective review.
  
  
  
  To evaluate gender-related differences in compensatory recruitment to progressive sagittal malalignment.
  
  
  
  Recent research has elucidated compensatory mechanisms recruited in response to sagittal malalignment, but gender-specific differences in compensatory recruitment patterns is unknown.
  
  
  
  Single-center study of patients with full body x-rays. A female group was propensity matched by age, body mass index (BMI), and pelvic incidence (PI) to a male group. Patients were then stratified into five groups of progressive PI-lumbar lordosis (LL) mismatch (<0°, 0°-10°, 10°-20°, 20°-30°, >30°). Differences between PI-LL groups were assessed with analysis of variance, and between genders by unpaired t test. Knee flexion to pelvic tilt (PT) ratio was computed and compared between genders. Multivariate regression to develop predictive models for PT was performed for each gender, first with spinopelvic parameters and subsequently with inclusion of lower limb parameters.
  
  
  
  A total of 942 patient visits were included: 471 females (mean age 54 years, BMI 27, PI 51°) and 471 males (mean age 52 years, BMI 27, PI 51°). At the lowest level of malalignment, females had greater PT and less knee flexion. With progressive malalignment, females continued to exhibit a pattern of greater pelvic retroversion and less knee flexion compared to males. Hip extension was higher in females with progressive PI-LL mismatch groups. Both genders progressively recruited knee flexion and pelvic retroversion with increased PI-LL mismatch, except that at the higher PI-LL mismatch groups, only males continued to recruit knee flexion (all p < .05). Inclusion of lower limbs in the regression for PT markedly improved correlation coefficients for females but not for males.
  
  
  
  With progressive sagittal malalignment, men recruit more knee flexion and women recruit more pelvic tilt and hip extension. Knee flexion is a possible mechanism to gain pelvic tilt for females whereas for males, knee flexion is an independent compensatory mechanism.
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Shaleen
authors.initials: S
authors.lastname: Vira
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Bassel G
authors.initials: BG
authors.lastname: Diebo
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Matthew Adam
authors.initials: MA
authors.lastname: Spiegel
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Barthelemy
authors.initials: B
authors.lastname: Liabaud
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Jensen K
authors.initials: JK
authors.lastname: Henry
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Oren
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Renaud
authors.initials: R
authors.lastname: Lafage
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Elizabeth M
authors.initials: EM
authors.lastname: Tanzi
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Themistocles S
authors.initials: TS
authors.lastname: Protopsaltis
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Errico
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA.
authors.forename: Frank J
authors.initials: FJ
authors.lastname: Schwab
authors.affiliation: Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, 301 E 17th St., New York, NY 10003, USA. Electronic address: virginie.lafage@gmail.com.
authors.forename: Virginie
authors.initials: V
authors.lastname: Lafage
mesh_terms: D015331:Cohort Studies; D005260:Female; D006801:Humans; D008141:Lordosis / Q000000981:diagnostic imaging*; D035002:Lower Extremity; D008297:Male; D008875:Middle Aged; D010384:Pelvic Bones / Q000033:anatomy & histology*; D010388:Pelvis; D011859:Radiography; D012189:Retrospective Studies; D012737:Sex Factors; D013131:Spine / Q000033:anatomy & histology*
keywords: Adult spinal deformity; Compensatory recruitment; Full body x-ray; PI-LL mismatch; Sagittal malalignment