601 - The Impact of Pelvic Incidence on Hip Performance during Gait Phases:...

General Session: Pediatric Spine

Presented by: J. Varghese - View Audio/Video Presentation (Members Only)


A. Patel(1), J. Varghese(1,2), H. Bao(1), A. Assi(3), E. Godwin(2), L. Day(2), B. Diebo(1), V. Lafage(1), C. Paulino(1)

(1) Hospital for Special Surgery, Spine Service, New York, NY, United States
(2) SUNY Downstate Medical Center, Department of Orthopaedic Surgery, Brooklyn, NY, United States
(3) University of Saint-Joseph, Beirut, Lebanon


Introduction: Pelvic morphology, assessed by pelvic incidence (PI), is a cornerstone of sagittal alignment analysis. However, the extent to which pelvic morphology drives dynamic behavior of the hip during gait remains unclear.

Purpose: To investigate the impact of pelvic incidence on hip range of motion during gait in adolescent idiopathic scoliosis (AIS) patients.

Methods: Prior to surgical treatment, AIS patients underwent gait assessment and full spine radiographs. Gait analysis was performed in a 6-DOF motion analysis laboratory at a sampling frequency of 100 Hz. Thirty-four reflective markers were placed on each patient who then underwent straight-line walking trials. Patients were grouped based on pelvic incidence (Low PI: < 40th percentile of overall mean PI; High PI: > 60th percentile). Groups were matched by global coronal alignment (C7PL, distance between C7 plumbline and sacrum). Demographics, radiographic and gait parameters were compared between PI groups.

Results: 18 patients included (Low PI: mean 43.1°, High PI: mean 60.2°, 9 pts in each). Groups had similar age (13.8-16.5yo), gender (66% female) and BMI (22.1 vs. 25.8). High PI had a greater PT (11.6 vs. 1.7°) and PI-LL (-1.4 vs. -17.8°), all p< 0.05. Absolute coronal curve magnitude, pelvic obliquity, and leg lengths were similar between the groups. Overall, High PI had a greater range of pelvic motion in the sagittal plane (4.5 vs. 3.6°) and the frontal plane (9.4 vs. 5.6°), all p< 0.05. Analysis of the hip joint revealed that High PI had a greater flexion-extension range of motion (16.5 vs. 10.8°), less maximum hip extension during stance (-4 vs. -10.2°), greater flexion at initial contact (33 vs. 26.7°), greater hip abduction/adduction range of motion during overall gait cycle (14 vs. 10.1°), and greater hip abduction during swing (-7.8 vs. -2.1), all p< 0.05.

Conclusions: In addition to its substantial impact on the regulation of sagittal postural alignment, pelvic incidence seems to play a role in the hip range of motion during gait cycles. Though further work is needed, this may suggest the possibility of a more personalized analysis of gait patterns based on pelvic morphology.