General Session: Adult Spinal Deformity-2

Presented by: S. Vira - View Audio/Video Presentation (Members Only)

Author(s):

S. Vira(1), B. Diebo(2), M. Spiegel(1), B. Liabaud(2), J. Henry(1), J. Oren(1), R. Lafage(2), E. Tanzi(1), T. Protopsaltis(1), T. Errico(1), F. Schwab(2), V. Lafage(2)

(1) NYU Hospital for Joint Diseases, Orthopedic Surgery, New York, NY, United States
(2) Hospital for Special Surgery, New York, NY, United States

Abstract

Background Context: There is growing interest and need for personalized care in the setting of deformity management and its evaluation. While extensive knowledge has been gained from recent research on sagittal alignment, little is known regarding gender-specific answers to sagittal plane deformity.

Purpose: This study evaluates gender related differences in compensatory recruitment to progressive sagittal malalignment.

Study Design/Setting: Single center retrospective review of adults spinal deformity (ASD) patients with full body radiographs.

Patient Sample: 1,758 patient visits were included: 879 females (54yo, BMI 26 kg/kg2) and 879 males (54yo, BMI 28 kg/kg2).

Outcome Measures: Sagittal radiographic parameters were measured using dedicated software. Differences between PI-LL groups were assessed with ANOVA, and between genders by unpaired t-test.

Methods: A group of female patients were age and pelvic incidence propensity matched to a group of males. Patients were stratified into five groups of progressive PI-LL mismatch (< 0°, 0°-10°, up to >30°).

Results: At lowest level of malalignment, females had less SVA (8.3 vs 1.0 mm), less knee flexion (-0.1 vs. 2.4°), and less ankle dorsiflexion (4.5 vs. 5.9°). For PI-LL 0-10, females had more PT (21.6 vs. 18.9°) and TK (47.1 vs. 43.9°). With progressive malalignment (PI-LL 10-20), females had significantly less knee flexion (4.5 vs. 6.3°) and more PT (group 4: 32.7 vs. 28.2°, this group had higher PI (62.3 vs 55.6°). Similarly, at highest level of malalignment, females had more PT (37.3 vs 34.2°, this group had higher PI (66.5 vs. 59.4°) and less knee flexion (11.5 vs. 15.9°). Hip extension (measured by sacro femoral angle SFA) was significantly higher in females in all PI-LL mismatch groups (196.7 vs. 194.7, 205.6 vs. 201.1, 208.2 vs. 205.8, 212.7 vs. 207.7, 214.3 vs. 207.0°). ANOVA analysis revealed that both genders progressively recruited knee flexion and pelvic tilt with increased PI-LL mismatch, except that at the highest PI-LL mismatch group, only males continue to recruit knee flexion (all p< 0.05).

Conclusion: This study demonstrated that, for a given lack of lumbar lordosis, men recruit more knee flexion and females recruit more pelvic tilt and hip extension. These findings can be put in perspective with purported gender differences in musculature. Future work is required to assess gender based morphologic differences in soft tissue distribution (for example, gluteal vs. quadriceps muscle recruitment and fat content).

Figure 1: Gender comparisons of compensatory mechanism by adjusted PI-LL mismatch.