Friday, September 28, 2018 8:00 AM–9:00 AM interdisciplinary spine forum: abstract presentations: 143. Categorizing the Hip-Spine Syndrome: a step toward a collaborative multidisciplinary classification

Abstract

BACKGROUND CONTEXT Recently, there has been increased recognition of the interplay between degenerative conditions of the hip and spine (Hip-Spine Syndrome, HiSS). Loss of lumbar lordosis (LL) of more than 10° in proportion to the pelvic incidence (PI), PI-LL mismatch, has been emphasized as a marker of sagittal spinal malalignment. The impact of positive spinal sagittal malalignment on increased hip extension (pelvic posterior tilt in spinal literature) and subsequently the acetabular version is established. Communication between adult hip reconstruction and spinal deformity surgeons regarding HiSS is ineffective without common language, an established definition, or mutual radiographic imaging protocols. PURPOSE This study aimed to characterize various presentations of HiSS and suggest a simple method to distinguish between them. STUDY DESIGN/SETTING Retrospective review of a prospectively collected adult spinal deformity database. PATIENT SAMPLE A total of 1,389 patients who presented to a single center with orthopaedic complaints between 2013 and 2016. OUTCOME MEASURES Demographics, parameters related to spinopelvic alignment (PI, PT, LL, PI-LL), global spinal alignment (TPA, SVA, GSA), and lower extremities (SFA, KF, pelvic shift) from full-body sagittal radiographic imaging, and Kellgren–Lawrence grade. METHODS Demographic information was collected and full-body (FB) sagittal radiographs were analyzed using dedicated software to measure spinopelvic, global sagittal spinal alignment, lower extremity, and FB sagittal radiographic parameters. FB coronal radiographs were analyzed by two reviewers to assess hip osteoarthritis (HOA) via Kellgren–Lawrence grade. Patients were grouped based on their sagittal spinal alignment (PI-LL mismatch) and HOA into: HiSS None (PI LL 10°, HOA Grade 0; n=297), or HiSS Hip-Spine (PI-LL>10°, HOA Grades 3–4; n=30). All radiographic parameters were compared between the groups. P-values were Bonferroni method-adjusted. Significance level was set at p RESULTS A total of 1,389 patients were included with a mean age of 62.5±11.1 years and mean BMI of 27.6±5.7kg/m2. A total of 62% of the study population was female. HiSS Hip-Spine (n=30) had significantly greater pelvic posterior tilt (sagittal retroversion) in comparison to HiSS Hip (n=78) and HiSS None Types (n=444) (25.2° vs. 11.3° and 16.5°, respectively; p .05). CONCLUSIONS This study proposes a novel HiSS categorization system based on established spinal deformity and HOA classification methods. Radiographically, HiSS Hip-Spine Type patients can be distinguished by Adult Reconstructive Surgeons by measuring pelvic tilt angle. Increased PT>25° in HOA patients is a marker for sagittal spinal deformity that has the potential to impact acetabular version.