Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers: 108. Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis

Abstract

BACKGROUND CONTEXT Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis. PURPOSE Hip osteoarthritis (OA) results in reduced hip range of motion, which affects sitting and standing posture. Spinal pathology (eg, fusion or deformity) may alter the ability to compensate for reduced joint mobility associated with hip OA in sitting and standing postures; however, the effect of hip OA on postural spinal alignment between sitting and standing remains unreported. In patients with severe hip OA, spinopelvic compensatory mechanisms can be compromised leading to greater pelvic tilt (PT) and lumbar lordosis (LL) change. STUDY DESIGN/SETTING Retrospective clinical and radiographic analysis at a single institution of patients with OA between 2012 and 2017. PATIENT SAMPLE A total of 548 patients with sit-stand radiographs. OUTCOME MEASURES Spinal and lower limb alignment Pelvic Incidence (PI), PT, LL, PI-LL, Thoracic Kyphosis (TK), Global alignment (SVA & T1-Pelvic Angle (TPA), T10-L2, proximal femoral shaft angle (PFSA: as measured from the vertical), sacrofemoral angle (SFA), Knee Flexion (KA) and hip ROM (difference between PT change and PFSA change). METHODS Hip OA severity was graded by Kellgren-Lawrence scale and divided into two groups: low-grade (LOA; grades 0-2) and severe (SOA; grades 3-4). Patients were excluded if they had transitional lumbosacral anatomy, prior spinal fusion or hip prosthesis. Changes in sit-stand alignment were compared between LOA and SOA by unpaired t-test RESULTS A total of 548 patients were identified with sit-stand radiographs, of which there were 311 patients with LOA and 237 with SOA. After propensity score matching for age, BMI, PI and standing SVA, 183 LOA & 183 SOA patients were analyzed. Standing alignment analysis demonstrated that SOA patients had lower PT (14.49 ± 9.2 vs. 16.78 ± 8.14, p CONCLUSIONS Spinopelvic compensatory mechanisms are adapted for reduced hip ROM in SOA between standing and sitting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.