Lightning Podiums: Adult Spinal Deformity - Room 801A

Presented by: N. Frangella

Author(s):

L. Day(1), B. Beaubrun(2), P. Zhou(2), J. Moon(2), J. Tishelman(2), L. Steinmetz(2), C. Varlotta(2), N. Frangella(2), E. DelSole(2), D. Vasquez-Montes(2), J. Vigdorchik(2), R. Schwarzkopf(2), R. Lafage(3), V. Lafage(3), T. Protopsaltis(2), P. Passias(2), T. Errico(2), A. Buckland(2)

(1) SUNY Downstate Medical Center, Department of Orthopaedic Surgery, Brooklyn, NY, United States
(2) New York University Langone Orthopedic Hospital, Division of Spinal Surgery, New York, NY, United States
(3) Hospital for Special Surgery, New York, NY, United States

Abstract

Introduction: Diagnosis and treatment of patients with coexisting hip and spine pathologies can be challenging. Patients with sagittal spinopelvic deformity utilize pelvic tilt (PT) and their lower extremities in order to compensate for malalignment. In patients with lower extremity osteoarthritis (OA), these compensatory mechanisms can be compromised, leading to further disability. The aim of the study was to examine the effect of hip OA on compensatory mechanisms in the setting of sagittal spinal deformity (SSD).

Methods: Patients ≥18 years with SSD [SVA ≥ 50mm, PT ≥ 25°, or TK ≥ 60°] were included for analysis. Spinopelvic, lower extremity, and cervical alignment were assessed on standing full-body stereoradiographs. Hip OA severity was graded by Kellgren-Lawrence scale (0-4). Propensity score matching was used to control for age and T1 pelvic angle (TPA). Patients were categorized as limited OA (LOA: grade 0-2) and severe OA (SOA: grade 3-4). Spinopelvic parameters [SVA, TPA, TK, PT, LL, PI-LL, T1SPi], and lower extremity parameters [SFA, KA, AA, P. Shift, and GSA] were then compared between the LOA and SOA groups using an unpaired t-test.

Results: A total of 997 patients (LOA=929, SOA=68) were identified meeting inclusion criteria. After PSM, 136 patients (SOA: n=68, LOA n=68) were included in the study. SOA had less PT (17.8°±12.6°vs 22.6°±8.4°, p=0.011), TK (42.5°±21.2°vs 52.3°±20.2°, p=0.007), higher SVA (71.6 mm±47.1 vs 40.7 mm±43.9, p< 0.001) and T1Spi (+2.3°±6.4°vs -2.6°±5.5°, p< 0.001) than LOA. SOA also had a lower SFA (194.3°±12.4°vs 202.4°±9.5°, p< 0.001) and AA (5.9°±3.5°vs 7.2°±3.6°, p=0.043), increased P. Shift (49.7mm±39.5 vs 19.7mm±28.4; p< 0.001) and increased GSA (7.7°±4.5°vs 5.0°±4.0°, p< 0.001) compared to LOA. There was no difference in PI, PI-LL mismatch, LL, KA or cervical alignment (p>0.05).

Conclusions: Patients with coexisting spinal malalignment and severe hip OA compensate by pelvic shift and thoracic hypokyphosis rather than pelvic tilt, likely as a result of limited hip extension.